Posted: 6/4/2026 1:43:01 PM EDT
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I know the formatting is not perfect, this is data I have for an average specific contact probability based on wattage / transmission type and distance. Call bullshit if you see it, but you can't say "it depends" without a probability estimate based on your experience. SOLAR MINIMUM SPECIFIC CONTACT PROBABILITY Distance & TargetTime of DayOptimal BandMode5 Watts (QRP)50 Watts100 Watts 100-Mile NVISDaytime40 meters (7 MHz)Digital (FT8 / JS8)95% – 98%99%99% 100-Mile NVISNighttime80 meters (3.5 MHz)Digital (FT8 / JS8)90% – 95%98% – 99%99% 100-Mile NVISNighttime160 meters (1.8 MHz)Digital (FT8)85% – 90%95% – 98%98% – 99% 100-Mile NVISDaytime40 meters (7 MHz)Voice (SSB)35% – 45%70% – 80%80% – 90% 100-Mile NVISNighttime80 meters (3.5 MHz)Voice (SSB)25% – 35%60% – 70%75% – 85% 100-Mile NVISNighttime40 meters [Wrong Band]Any Mode0%0%0% 2,000-Mile DXDaytime20 meters (14 MHz)Digital (FT8 / JS8)65% – 75%85% – 90%90% – 95% 2,000-Mile DXNighttime40 meters (7 MHz)Digital (FT8 / JS8)70% – 80%90% – 95%95% – 98% 2,000-Mile DXNighttime80 meters (3.5 MHz)Digital (FT8)35% – 50%65% – 75%75% – 85% 2,000-Mile DXDaytime20 meters (14 MHz)Voice (SSB)< 2%15% – 30%35% – 50% 2,000-Mile DXNighttime40 meters (7 MHz)Voice (SSB)2% – 10%25% – 40%40% – 55% 2,000-Mile DXRound-the-Clock80/160m [NVIS Bands]Any Mode< 5%10% – 20%20% – 30% |
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Realistically all those probabilities should be 50%. It either works or it doesn't. I seriously do not think you can put any reasonably accurate contact probabilities to any of that. There are way too many variables, including time of day, grayline position, solar activity at the time, noise levels at the time, local operator noise levels, to name a few and of course the antenna type, efficiency, height, and orientation to name a few. There are plenty of times you can make contact with someone and the ham 1/2 mile away from that contact you can't. You can't just make range rings for contact probability. Look up VOCAP which uses some base assumptions and VOCAP is extremely inaccurate and constantly changing. |
Mach
Nobody is coming to save us.
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Nobody is coming to save us.
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80 and 160 (an probably 40) at 100 miles is going to be ground wave and not NVIS, but the probabilities are in the right neighborhood for using digital modes and ground wave. Real NVIS lasts for periods of maybe an hour at most and usually happens in the 40M band as the day/night transitions happen, and when real NVIS happens it's very very obvious (doing QSOs through a dummy load works during real NVIS.) Digital + ground wave prop is shooting fish in a barrel level easy. Using WSPR I was picking up my home station's 5W beacon transmitting from my 43' antenna on a 2' CB antenna at 100 miles on 80M during the daytime on my mobile radio. I'm quite sure a couple stations using 5W 80M radios into short loaded verticals would do JS8CALL at 100 miles with the 99% reliability you're showing. But that highlights that you need to state what kind of antenna this data is for. |
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Originally Posted By seek2: 80 and 160 (an probably 40) at 100 miles is going to be ground wave and not NVIS, but the probabilities are in the right neighborhood for using digital modes and ground wave. Real NVIS lasts for periods of maybe an hour at most and usually happens in the 40M band as the day/night transitions happen, and when real NVIS happens it's very very obvious (doing QSOs through a dummy load works during real NVIS.) Digital + ground wave prop is shooting fish in a barrel level easy. Using WSPR I was picking up my home station's 5W beacon transmitting from my 43' antenna on a 2' CB antenna at 100 miles on 80M during the daytime on my mobile radio. I'm quite sure a couple stations using 5W 80M radios into short loaded verticals would do JS8CALL at 100 miles with the 99% reliability you're showing. But that highlights that you need to state what kind of antenna this data is for. Good point on the antenna. Let us assume a reasonable field deployable wire that could be carried in a backpack with the radio in use and hung on a tree or between trees type situation. |
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Originally Posted By Mach: Realistically all those probabilities should be 50%. It either works or it doesn't. I seriously do not think you can put any reasonably accurate contact probabilities to any of that. There are way too many variables, including time of day, grayline position, solar activity at the time, noise levels at the time, local operator noise levels, to name a few and of course the antenna type, efficiency, height, and orientation to name a few. There are plenty of times you can make contact with someone and the ham 1/2 mile away from that contact you can't. You can't just make range rings for contact probability. Look up VOCAP which uses some base assumptions and VOCAP is extremely inaccurate and constantly changing. I bet you know more about radio than I do, but I am not sure about your statistics pedigree. I know there are a ton of variables so let's boil it down to average case, average wire antenna, average radio, average everything except the details provided. If you tried this every second of every day I seriously doubt each description would result at 50% and if that was the case nobody would buy 100W radios or use digital modes when they prefer voice because both of those are intended to INCREASE the baseline probability. |
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Originally Posted By Greenspan: I bet you know more about radio than I do, but I am not sure about your statistics pedigree. I know there are a ton of variables so let's boil it down to average case, average wire antenna, average radio, average everything except the details provided. If you tried this every second of every day I seriously doubt each description would result at 50% and if that was the case nobody would buy 100W radios or use digital modes when they prefer voice because both of those are intended to INCREASE the baseline probability. Originally Posted By Greenspan: Originally Posted By Mach: Realistically all those probabilities should be 50%. It either works or it doesn't. I seriously do not think you can put any reasonably accurate contact probabilities to any of that. There are way too many variables, including time of day, grayline position, solar activity at the time, noise levels at the time, local operator noise levels, to name a few and of course the antenna type, efficiency, height, and orientation to name a few. There are plenty of times you can make contact with someone and the ham 1/2 mile away from that contact you can't. You can't just make range rings for contact probability. Look up VOCAP which uses some base assumptions and VOCAP is extremely inaccurate and constantly changing. I bet you know more about radio than I do, but I am not sure about your statistics pedigree. I know there are a ton of variables so let's boil it down to average case, average wire antenna, average radio, average everything except the details provided. If you tried this every second of every day I seriously doubt each description would result at 50% and if that was the case nobody would buy 100W radios or use digital modes when they prefer voice because both of those are intended to INCREASE the baseline probability.  Here is some real questions though. What is the average noise level of the average ham station? Are we talking city, rural farm, is there a solar farm nearby, does the close neighbor have a solar installation or plasma TV. How many dirty switching power supplies are nearby? What is the average antenna? Is it a 1/4 vertical, a short vertical, a random wire or a resonant dipole at 5 feet or a resonant dipole at 40 feet? . How much lose in the transmission line? is it 10 watts or 50 watts? I think the best you could come up with is specifying base parameters like VOCAP does. Power, antenna and height. The problem is, that the ionispere is in constant flux, even VOCAP that takes current measured conditions and averages those condition, they only come up with a probability by band and by time of day based on right now, and they get is very wrong a lot. So trying to come up with a probability without using specific band conditions in real time will not have a lot of use. NVIS is especially in constant flux because it relies on conditions directly or almost directly overhead using a radiation pattern that must be near vertical in angles and those band conditions change like the wind. For further away, say outside 500 miles or so, not only does it depend on the attenuation through the D layer, it also depends on the height of the F layer(s) and the power lobe pattern of each antenna. It is always said, you have a good chance of contacting somebody, contacting a specific person ( read a specific range ) not so much. Obviously small bandwidth digital modes helps tremendously in improving those odds, but trying to quantify that by range doesn't seem accurate enough to be worth while. The best you could do is pull up JT8 ( because it has a lot more reporting stations than JS8Call) and go to PSK Reporter map and see who and where your signal is being decoded and that will give you a real idea of where you can make JS8Call contacts right now. You will notice individual stations will decode your signal on and off. Only some stations will decoded every transmission of yours, most will decode one, skip a few and decode another. Trying to get a probability estimated for between 1000 and 2000 miles to any specific station isn't really going to work. If you want a chart that says what the probability of decoding something that has come from between 1000 and 2000 miles away, sure you can probably come up with something, but then you are going to have to specify which direction in a vector format because you can get on 40 meters in the winter if you are in the NorthEast US and hit the EU pretty reliably, but you will not get into CA which is the same distance because the propagation on 40m is good in the middle of the atlantic ocean but not so good over Oklahoma at the same time, but you will also notice you are killing it going into south America +- 10 degrees of the grayline and that grayline moves by the minute so you could hit somebody on the east side of the grayline in Brazil and 10 minutes later he is gone but now you are picking up signals from Chile. All due to grayline. If your antenna radiation patter is oriented more for N / S then you will have more power going north south and you could be hitting South America better and getting into Oceana because you have a stronger signal going over the north pole compared to an antenna pattern going East / West or do you have a vertical that is omni directional because you have 64 radials in a good circle. i am just saying there are too many variables to make a prediction chart worth while. having a chart for which band is best for what time of day sure while also counting in direction based on your antenna and time of year. people will tell you 20 meters dies at night, except if you are in the northern hemisphere with an antenna that radiates best north / south you can get into asia at midnight because the north pole is always lit by the sun and you are getting the bounce off the ionisphere over the north pole down into asia, but getting into south american probably will not happen. If you make a chart with all those variables that would be a good chart to have to remind you which band is best for time of day, and season, and type of antenna and which way it radiates best so you know which band to try first, but even the over the pole winter scenario at midnight on 20 meters will not work if there is too much attenuation in then D layer over the pole. It would have to be a complicated chart to be useful. Just my opinion, don't let me discourage you from doing it, I could be completely wrong and you could have some good ideas to make it work, good enough to be useful. And weak signal modes certainly opens up the probabilities just like a better antenna will or more power will or all 3 at the same time. |
Mach
Nobody is coming to save us.
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Nobody is coming to save us.
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Propagation charts are worthless IMHO, but like Mach said it a toss up 50/50 if they are correct. It's almost as bad a long range weather forecasting. Get on the air and listening or calling CQ is the only way to know for sure. |
“Every man has two deaths, when he is buried in the ground and the last time someone says his name. In some ways, men can be immortal. “ - Ernest Hemingway
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Originally Posted By Greenspan: Do people genuinely not know what probability is? A chart with what band might be best for short range vs long range would be useful and that information is generally known. But you did ask But like I said, just my opinion, doesn't mean I am right. Ham radio is magic and we are all just trying to make the magic work when we have the time to play radio. |
Mach
Nobody is coming to save us.
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Nobody is coming to save us.
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Originally Posted By Mach: Sure. To forecast an accurate probability all the variables need to be taken into account, and that simply is not possible because there are so many variables and many of them are in constant flux. That is the problem with doing this. this is why weather forecasting a week out is almost complete garbage because of chaos theory. IMO due to all the variables in constant flux in ham radio propagation, just like long term weather forecasting, forecasting probabilities of contact in ham radio in a static chart that does not take into account current conditions ( like VOCAP does ) is going to be pretty hard to do and IMO not going to be useful. A chart with what band might be best for short range vs long range would be useful and that information is generally known. But you did ask But like I said, just my opinion, doesn't mean I am right. Ham radio is magic and we are all just trying to make the magic work when we have the time to play radio. Originally Posted By Mach: Originally Posted By Greenspan: Do people genuinely not know what probability is? A chart with what band might be best for short range vs long range would be useful and that information is generally known. But you did ask But like I said, just my opinion, doesn't mean I am right. Ham radio is magic and we are all just trying to make the magic work when we have the time to play radio. I'm not trying to determine if it will work in any given moment, I'm trying to quantify the probability it will work in relative and actual terms to the extent possible knowing there are multiple variables that any given time could result in a no contact. We know some things are more likely than others even if we can't observe the space weather on some website. You are misunderstanding probability and forecast. I'm not trying to determine of Phoenix AZ will be 110 degrees on August 18th. I'm trying to quantify on average what does the probability look like that Phoenix is above 100 on that date and for that relates to other cities being that temperature on that day. |
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Originally Posted By Mach: IMO due to all the variables in constant flux in ham radio propagation, just like long term weather forecasting, forecasting probabilities of contact in ham radio in a static chart that does not take into account current conditions ( like VOCAP does ) is going to be pretty hard to do and IMO not going to be useful. Attached File |
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Originally Posted By Greenspan: I'm not trying to determine if it will work in any given moment, I'm trying to quantify the probability it will work in relative and actual terms to the extent possible knowing there are multiple variables that any given time could result in a no contact. We know some things are more likely than others even if we can't observe the space weather on some website. You are misunderstanding probability and forecast. I'm not trying to determine of Phoenix AZ will be 110 degrees on August 18th. I'm trying to quantify on average what does the probability look like that Phoenix is above 100 on that date and for that relates to other cities being that temperature on that day. |
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Originally Posted By TVille: This you can do with the available tools. There are a slew of variables that you do control, mode, power, antenna system, etc. The antenna system is probably the most important. A properly installed antenna system doesn't need to be expensive to work. I piece of wire is about all you need, just assembled as a system, knowing the weak points. In the ham world every antenna has its haters that will promise you it worn't work...And then some joker on YouTube goes and gets cornstalks to work as an antenna. I think Kevin is awesome! "Let's see if we can make a contact with a tube full of creek water." |
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Originally Posted By seek2: 80 and 160 (an probably 40) at 100 miles is going to be ground wave and not NVIS, but the probabilities are in the right neighborhood for using digital modes and ground wave. Real NVIS lasts for periods of maybe an hour at most and usually happens in the 40M band as the day/night transitions happen, and when real NVIS happens it's very very obvious (doing QSOs through a dummy load works during real NVIS.) Digital + ground wave prop is shooting fish in a barrel level easy. Using WSPR I was picking up my home station's 5W beacon transmitting from my 43' antenna on a 2' CB antenna at 100 miles on 80M during the daytime on my mobile radio. I'm quite sure a couple stations using 5W 80M radios into short loaded verticals would do JS8CALL at 100 miles with the 99% reliability you're showing. But that highlights that you need to state what kind of antenna this data is for. thank you, this was very helpful in my analysis. |
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The reason many experienced operators dismiss charts as "worthless" is that a static chart cannot predict local, real-time chaos. Chaos theory and hyper-local variables can instantly tank an 80% probability down to 0%: 1. The Space Weather Wildcards A solar flare, a sudden Coronal Mass Ejection (CME), or a geomagnetic storm can completely alter the ionosphere in a matter of minutes. If the K index spikes to 6, a path that has a "95% historical probability" on a static chart can instantly go dead. 2. Local Noise Floors (The QRM Problem)Standard prediction engines use average models for rural or urban noise. They have no idea if the guy on the other end just turned on a cheap, unshielded solar inverter, a dirty switching power supply, or a grow light next door. If his local noise floor jumps by 20 dB, your signal is buried, regardless of what the chart says. 3. The Takeoff Angle Reality Charts make basic assumptions about your antenna. If you are using a 40-meter dipole hung only 15 feet off the ground, your antenna is a "cloud-burner"—it fires most of its energy straight up (perfect for short-range NVIS). If a chart tells you there is a 60% chance of hitting a DX station 2,000 miles away on 40m, that estimate assumes a low-angle radiator. Your low wire might drop your actual real-world probability down to 5%. Think of an HF contact probability chart exactly like a climatology report. If a climate chart says Phoenix, Arizona has a 99% probability of being above 100°F on July 15th, that is an incredibly safe, statistically sound prediction to use for long-term planning. It doesn't guarantee a freak storm won't roll in and drop the temperature to 75°F for two hours on that specific afternoon, but it means designing a system based on those odds is smart money. Charts work beautifully for establishing a baseline operating strategy (knowing which bands to try first, what modes yield the highest reliability, and when to save your battery power). To find out if the path is open right now, you look at live tools like PSK Reporter or Reverse Beacon Network—but you use the charts to understand the macro-odds of the game you're playing. So as always, the rule thumb when it comes to HF propagation..."It depends".  |
“Every man has two deaths, when he is buried in the ground and the last time someone says his name. In some ways, men can be immortal. “ - Ernest Hemingway
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Originally Posted By K9-Bob: The reason many experienced operators dismiss charts as "worthless" is that a static chart cannot predict local, real-time chaos. Chaos theory and hyper-local variables can instantly tank an 80% probability down to 0%: 1. The Space Weather Wildcards A solar flare, a sudden Coronal Mass Ejection (CME), or a geomagnetic storm can completely alter the ionosphere in a matter of minutes. If the K index spikes to 6, a path that has a "95% historical probability" on a static chart can instantly go dead. 2. Local Noise Floors (The QRM Problem)Standard prediction engines use average models for rural or urban noise. They have no idea if the guy on the other end just turned on a cheap, unshielded solar inverter, a dirty switching power supply, or a grow light next door. If his local noise floor jumps by 20 dB, your signal is buried, regardless of what the chart says. 3. The Takeoff Angle Reality Charts make basic assumptions about your antenna. If you are using a 40-meter dipole hung only 15 feet off the ground, your antenna is a "cloud-burner"—it fires most of its energy straight up (perfect for short-range NVIS). If a chart tells you there is a 60% chance of hitting a DX station 2,000 miles away on 40m, that estimate assumes a low-angle radiator. Your low wire might drop your actual real-world probability down to 5%. Think of an HF contact probability chart exactly like a climatology report. If a climate chart says Phoenix, Arizona has a 99% probability of being above 100°F on July 15th, that is an incredibly safe, statistically sound prediction to use for long-term planning. It doesn't guarantee a freak storm won't roll in and drop the temperature to 75°F for two hours on that specific afternoon, but it means designing a system based on those odds is smart money. Charts work beautifully for establishing a baseline operating strategy (knowing which bands to try first, what modes yield the highest reliability, and when to save your battery power). To find out if the path is open right now, you look at live tools like PSK Reporter or Reverse Beacon Network—but you use the charts to understand the macro-odds of the game you're playing. So as always, the rule thumb when it comes to HF propagation..."It depends". Yep, I get there are all those outliers, but conversations need to be more productive than, "it depends" with some reasonable long term average condition. For guys just trying to get into HF it just does not help to have the fine print as the main print. We read the theory and see the youtube videos of guys on 5 watts doing everything they want to do, and we want to understand what can we expect % of the time to be able to enjoy this. I do come at it from a prepper standpoint, but I enjoy radio also, I don't want to spend money and find out I totally wasted it and realistically it's 1% probability in reasonably normal conditions anything I want to do will work. I also don't want to get into things with the cheapest crap possible and then fail because the equipment. |
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It is incredibly easy to get paralyzed by "analysis paralysis" when you are looking at charts, propagation models, and YouTube videos of guys making effortless QRP contacts. The reality of HF—especially when you are trying to build a reliable setup for portable use, POTA, or emergency preparedness—is that nothing beats dirt-time and actual RF in the air. While baseline probability models (like the climatology analogy used in the thread) are great for a macro-level strategy, they can't tell you how a specific piece of wire hung between two trees in your local terrain is going to perform right now. Here is why getting on the air beats watching the screen every single time: 1. You Learn Your Specific Local Noise Floor (QRM) A YouTube video or a static chart won't show you the localized RFI (Radio Frequency Interference) you have to deal with. Experimenting with different antennas—like comparing a random wire with a 9:1 UNUN to a resonant center-fed dipole—teaches you how your specific deployment handles local noise. 2. You Build Muscle Memory for Deployment If you are coming at this from a preparedness or portable operation standpoint, knowing the theory of an NVIS (Near Vertical Incidence Skywave) antenna is completely different from actually tossing a weighted line over a tree branch, tensioning the wire, and getting a low-profile dipole up at the optimal 15-to-20-foot height. Real-world experimentation forces you to solve practical problems: How do I quickly tune this wire if the ground conditions change? Is my portable mast stable in a 15 mph gust? Can I reliably deploy this setup in the rain or under stress? 3. You Discover the "Invisible" Variables As the thread notes, the ionosphere is dynamic, but your immediate surroundings matter just as much. Getting on the air lets you see firsthand how factors like soil conductivity, nearby structures, or the takeoff angle of your specific wire affect your signal. 4. Real-Time Tools Give Better Feedback Than Videos Instead of trusting a highly edited YouTube video where someone makes a 2,000-mile contact on 5 watts (often skipping the 45 minutes of calling CQ that failed), you can throw your own signal out on a mode like JS8Call or FT8 and check PSK Reporter. That gives you honest, objective data on exactly where your signal is landing with your exact equipment at that exact minute. The best way to know what a 5W, 50W, or 100W radio can actually do for you is to pack it up, head outside, string up some wire, and start transmitting. |
“Every man has two deaths, when he is buried in the ground and the last time someone says his name. In some ways, men can be immortal. “ - Ernest Hemingway
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Originally Posted By K9-Bob: It is incredibly easy to get paralyzed by "analysis paralysis" when you are looking at charts, propagation models, and YouTube videos of guys making effortless QRP contacts. The reality of HF—especially when you are trying to build a reliable setup for portable use, POTA, or emergency preparedness—is that nothing beats dirt-time and actual RF in the air. While baseline probability models (like the climatology analogy used in the thread) are great for a macro-level strategy, they can't tell you how a specific piece of wire hung between two trees in your local terrain is going to perform right now. Here is why getting on the air beats watching the screen every single time: 1. You Learn Your Specific Local Noise Floor (QRM) A YouTube video or a static chart won't show you the localized RFI (Radio Frequency Interference) you have to deal with. Experimenting with different antennas—like comparing a random wire with a 9:1 UNUN to a resonant center-fed dipole—teaches you how your specific deployment handles local noise. 2. You Build Muscle Memory for Deployment If you are coming at this from a preparedness or portable operation standpoint, knowing the theory of an NVIS (Near Vertical Incidence Skywave) antenna is completely different from actually tossing a weighted line over a tree branch, tensioning the wire, and getting a low-profile dipole up at the optimal 15-to-20-foot height. Real-world experimentation forces you to solve practical problems: How do I quickly tune this wire if the ground conditions change? Is my portable mast stable in a 15 mph gust? Can I reliably deploy this setup in the rain or under stress? 3. You Discover the "Invisible" Variables As the thread notes, the ionosphere is dynamic, but your immediate surroundings matter just as much. Getting on the air lets you see firsthand how factors like soil conductivity, nearby structures, or the takeoff angle of your specific wire affect your signal. 4. Real-Time Tools Give Better Feedback Than Videos Instead of trusting a highly edited YouTube video where someone makes a 2,000-mile contact on 5 watts (often skipping the 45 minutes of calling CQ that failed), you can throw your own signal out on a mode like JS8Call or FT8 and check PSK Reporter. That gives you honest, objective data on exactly where your signal is landing with your exact equipment at that exact minute. The best way to know what a 5W, 50W, or 100W radio can actually do for you is to pack it up, head outside, string up some wire, and start transmitting. No disagreement, but listening to those with experience and evaluating data before jumping into an expensive interest seems prudent. I don't want to end up with 10 HF radios. I just want a one and done. Learn it, know it, but I want to start at the right entry point. |
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Originally Posted By Greenspan: Good point on the antenna. Let us assume a reasonable field deployable wire that could be carried in a backpack with the radio in use and hung on a tree or between trees type situation. Note that IME, ground wave is poor on the low bands with horizontally polarized antennas and much better with vertical antennas. Both antennas must be vertically polarized. NVIS is near non-existent with vertical antennas. You can get a little bit of both with an inverted L deployment. |
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Originally Posted By tyrex13: Note that IME, ground wave is poor on the low bands with horizontally polarized antennas and much better with vertical antennas. Both antennas must be vertically polarized. NVIS is near non-existent with vertical antennas. You can get a little bit of both with an inverted L deployment. You're very right. It has to do with how the E-field v. H-fields interact with the ground, vertically polarized signals loses significantly less energy to ground losses than horizontal polarized signals do, and this relationship was well-understood since the early days of radio which is why AM stations all had vertical antennas. The alignment of verticals leaves a lot to be desired for actual NVIS propagation, but when that propagation mode is in effect the signal behavior is very similar to line of sight and the massive loss of gain due to poor alignment is made up by how efficient the propagation is. Probably anything would be better than a vertical for NVIS but it usually still works. |
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Originally Posted By Greenspan: No disagreement, but listening to those with experience and evaluating data before jumping into an expensive interest seems prudent. I don't want to end up with 10 HF radios. I just want a one and done. Learn it, know it, but I want to start at the right entry point. Originally Posted By Greenspan: Originally Posted By K9-Bob: It is incredibly easy to get paralyzed by "analysis paralysis" when you are looking at charts, propagation models, and YouTube videos of guys making effortless QRP contacts. The reality of HF especially when you are trying to build a reliable setup for portable use, POTA, or emergency preparedness is that nothing beats dirt-time and actual RF in the air. While baseline probability models (like the climatology analogy used in the thread) are great for a macro-level strategy, they can't tell you how a specific piece of wire hung between two trees in your local terrain is going to perform right now. Here is why getting on the air beats watching the screen every single time: 1. You Learn Your Specific Local Noise Floor (QRM) A YouTube video or a static chart won't show you the localized RFI (Radio Frequency Interference) you have to deal with. Experimenting with different antennas like comparing a random wire with a 9:1 UNUN to a resonant center-fed dipole teaches you how your specific deployment handles local noise. 2. You Build Muscle Memory for Deployment If you are coming at this from a preparedness or portable operation standpoint, knowing the theory of an NVIS (Near Vertical Incidence Skywave) antenna is completely different from actually tossing a weighted line over a tree branch, tensioning the wire, and getting a low-profile dipole up at the optimal 15-to-20-foot height. Real-world experimentation forces you to solve practical problems: How do I quickly tune this wire if the ground conditions change? Is my portable mast stable in a 15 mph gust? Can I reliably deploy this setup in the rain or under stress? 3. You Discover the "Invisible" Variables As the thread notes, the ionosphere is dynamic, but your immediate surroundings matter just as much. Getting on the air lets you see firsthand how factors like soil conductivity, nearby structures, or the takeoff angle of your specific wire affect your signal. 4. Real-Time Tools Give Better Feedback Than Videos Instead of trusting a highly edited YouTube video where someone makes a 2,000-mile contact on 5 watts (often skipping the 45 minutes of calling CQ that failed), you can throw your own signal out on a mode like JS8Call or FT8 and check PSK Reporter. That gives you honest, objective data on exactly where your signal is landing with your exact equipment at that exact minute. The best way to know what a 5W, 50W, or 100W radio can actually do for you is to pack it up, head outside, string up some wire, and start transmitting. No disagreement, but listening to those with experience and evaluating data before jumping into an expensive interest seems prudent. I don't want to end up with 10 HF radios. I just want a one and done. Learn it, know it, but I want to start at the right entry point. Then save money and make your own antenna wires to get started until you figure out what you like in antennas and either improve your wires, like add bands because it is cheap or buy a pre-made antenna. many people here use endfeds and off center dipoles for a single antenna that runs 80-10 meters with a tuner. Those 2 things like the IC-7300 and an 80-10m endfed or 80-10 off center fed dipole and a tuner depending on if the antenna you put up need more than the internal 3:1 tuner that some radios come with are stations that several here use. Like saws, radios all have their strong points. easy to carry for out of the way places but low power or 100 watts and bigger, or 100 watts and smaller but not good for digital modes. You would not usually use a circular saw to make kitchen cabinets, you would use a table saw, but you don't need a table saw to cut 2x4s for framing you would use a more agile circular saw. It's kinda like that. So based on what you have said so far, maximum probability of most contacts and digital modes I would suggest: A good easy to use 100 watt radio and easy to use in digital modes ( digital sound interface built in ) with an internal tuner (ie. IC-7300) and any horizontal wire multiband antenna up as high as you can get it will give you the best possible probability of doing what you want to do. then you turn off all the power in your house and turn on each breaker one at a time to hunt down all the stuff that generates RFI and increases your noise floor and noise spikes in your house and make a list of all the stuff you will want to unplug or turn off when you want to play radio. That is the best you can do. everything else is dynamically up to chance and is out of your control except learning which bands are expected to be active during what time of day, ie where the sun is in the sky since that is the real constant variable not the actual time since it is not uniform through out the year. I remember when I first started out, talking to someone on 20 meters on the other side of the country and looking at all the signals on the IC-7300 waterfall and instantly it was like someone turned off a switch, no signals, no more contact with the guy i was talking to and the waterfall completely clean. i thought my IC-7300 burned something up inside. i was pissed and disappointed as I had only had it for a month or so. It tried changing things, but only had a 20m antenna so I could not change bands. I was sure my radio was fried. It turned out a small CME had just hit the atmosphere and turned off the 20 meter band like a light switch. nothing was wrong with my radio but it took a couple of days to figure that out. |
Mach
Nobody is coming to save us.
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Nobody is coming to save us.
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Originally Posted By seek2: You're very right. It has to do with how the E-field v. H-fields interact with the ground, vertically polarized signals loses significantly less energy to ground losses than horizontal polarized signals do, and this relationship was well-understood since the early days of radio which is why AM stations all had vertical antennas. The alignment of verticals leaves a lot to be desired for actual NVIS propagation, but when that propagation mode is in effect the signal behavior is very similar to line of sight and the massive loss of gain due to poor alignment is made up by how efficient the propagation is. Probably anything would be better than a vertical for NVIS but it usually still works. Originally Posted By seek2: Originally Posted By tyrex13: Note that IME, ground wave is poor on the low bands with horizontally polarized antennas and much better with vertical antennas. Both antennas must be vertically polarized. NVIS is near non-existent with vertical antennas. You can get a little bit of both with an inverted L deployment. You're very right. It has to do with how the E-field v. H-fields interact with the ground, vertically polarized signals loses significantly less energy to ground losses than horizontal polarized signals do, and this relationship was well-understood since the early days of radio which is why AM stations all had vertical antennas. The alignment of verticals leaves a lot to be desired for actual NVIS propagation, but when that propagation mode is in effect the signal behavior is very similar to line of sight and the massive loss of gain due to poor alignment is made up by how efficient the propagation is. Probably anything would be better than a vertical for NVIS but it usually still works. |
Mach
Nobody is coming to save us.
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Nobody is coming to save us.
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Originally Posted By Mach: Which is why you want a 100 watts radio that is easy to use in changing modes, changing filters, changing power, etc. The IC-7300 is a solid radio and can do digital modes at 100 watts all day long and has great out of the box audio, and very intuitive touch screen menus and an internal tuner. Nobody needs to even look at the manual to figure it out, until it's time to setup digital modes. But has some limitations like audio bandwidth that much more expensive radios can increase past 2900 hz.. The FT-891 just can not do digital modes at 100 watts, that and the menus are a nightmare to use. But is is a great form factor size. It depends on you your priorities. If you don't need to put it in a back pack, the IC-7300 is a solid choice. So are some of the bigger FT radios, I think but I don't have any of those. And you need a power supply. A good ham radio switching supply will work fine and are RF quiet and relatively inexpensive compared to non-switching supplies. I think everybody that has bought an IC-7300 is still using it, I have 2, or have upgraded to the version 2 which has some improvements. 100 watts all day long digital modes and an easy to use and configure touch screen display is hard to be in a self contained radio. Then save money and make your own antenna wires to get started until you figure out what you like in antennas and either improve your wires, like add bands because it is cheap or buy a pre-made antenna. many people here use endfeds and off center dipoles for a single antenna that runs 80-10 meters with a tuner. Those 2 things like the IC-7300 and an 80-10m endfed or 80-10 off center fed dipole and a tuner depending on if the antenna you put up need more than the internal 3:1 tuner that some radios come with are stations that several here use. Like saws, radios all have their strong points. easy to carry for out of the way places but low power or 100 watts and bigger, or 100 watts and smaller but not good for digital modes. You would not usually use a circular saw to make kitchen cabinets, you would use a table saw, but you don't need a table saw to cut 2x4s for framing you would use a more agile circular saw. It's kinda like that. So based on what you have said so far, maximum probability of most contacts and digital modes I would suggest: A good easy to use 100 watt radio and easy to use in digital modes ( digital sound interface built in ) with an internal tuner (ie. IC-7300) and any horizontal wire multiband antenna up as high as you can get it will give you the best possible probability of doing what you want to do. then you turn off all the power in your house and turn on each breaker one at a time to hunt down all the stuff that generates RFI and increases your noise floor and noise spikes in your house and make a list of all the stuff you will want to unplug or turn off when you want to play radio. That is the best you can do. everything else is dynamically up to chance and is out of your control except learning which bands are expected to be active during what time of day, ie where the sun is in the sky since that is the real constant variable not the actual time since it is not uniform through out the year. I remember when I first started out, talking to someone on 20 meters on the other side of the country and looking at all the signals on the IC-7300 waterfall and instantly it was like someone turned off a switch, no signals, no more contact with the guy i was talking to and the waterfall completely clean. i thought my IC-7300 burned something up inside. i was pissed and disappointed as I had only had it for a month or so. It tried changing things, but only had a 20m antenna so I could not change bands. I was sure my radio was fried. It turned out a small CME had just hit the atmosphere and turned off the 20 meter band like a light switch. nothing was wrong with my radio but it took a couple of days to figure that out. Hi mach, This happened to me back in the 80s, I was still in college, and had rented an up stairs apartment for the summer. I brought over my HW16 and loaded the shield on the cable tv coax with my trusty Dentron random wire tuner. I had not signed up for anyhing so I'm sure the cable was disconnected at the far end. Anyhow, I came home one evening and there was NOTHING on any band. I actually took the rig into work and went through the alignmet procedure. A day or two later I found out about the solar flare. 73, Rob 
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Sic semper tyrannis!
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Originally Posted By tyrex13: Note that IME, ground wave is poor on the low bands with horizontally polarized antennas and much better with vertical antennas. Both antennas must be vertically polarized. NVIS is near non-existent with vertical antennas. You can get a little bit of both with an inverted L deployment. Originally Posted By tyrex13: Originally Posted By Greenspan: Good point on the antenna. Let us assume a reasonable field deployable wire that could be carried in a backpack with the radio in use and hung on a tree or between trees type situation. Note that IME, ground wave is poor on the low bands with horizontally polarized antennas and much better with vertical antennas. Both antennas must be vertically polarized. NVIS is near non-existent with vertical antennas. You can get a little bit of both with an inverted L deployment. Thanks! |
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Originally Posted By Mach: Which is why you want a 100 watts radio that is easy to use in changing modes, changing filters, changing power, etc. The IC-7300 is a solid radio and can do digital modes at 100 watts all day long and has great out of the box audio, and very intuitive touch screen menus and an internal tuner. Nobody needs to even look at the manual to figure it out, until it's time to setup digital modes. But has some limitations like audio bandwidth that much more expensive radios can increase past 2900 hz.. The FT-891 just can not do digital modes at 100 watts, that and the menus are a nightmare to use. But is is a great form factor size. It depends on you your priorities. If you don't need to put it in a back pack, the IC-7300 is a solid choice. So are some of the bigger FT radios, I think but I don't have any of those. And you need a power supply. A good ham radio switching supply will work fine and are RF quiet and relatively inexpensive compared to non-switching supplies. I think everybody that has bought an IC-7300 is still using it, I have 2, or have upgraded to the version 2 which has some improvements. 100 watts all day long digital modes and an easy to use and configure touch screen display is hard to be in a self contained radio. Then save money and make your own antenna wires to get started until you figure out what you like in antennas and either improve your wires, like add bands because it is cheap or buy a pre-made antenna. many people here use endfeds and off center dipoles for a single antenna that runs 80-10 meters with a tuner. Those 2 things like the IC-7300 and an 80-10m endfed or 80-10 off center fed dipole and a tuner depending on if the antenna you put up need more than the internal 3:1 tuner that some radios come with are stations that several here use. Like saws, radios all have their strong points. easy to carry for out of the way places but low power or 100 watts and bigger, or 100 watts and smaller but not good for digital modes. You would not usually use a circular saw to make kitchen cabinets, you would use a table saw, but you don't need a table saw to cut 2x4s for framing you would use a more agile circular saw. It's kinda like that. So based on what you have said so far, maximum probability of most contacts and digital modes I would suggest: A good easy to use 100 watt radio and easy to use in digital modes ( digital sound interface built in ) with an internal tuner (ie. IC-7300) and any horizontal wire multiband antenna up as high as you can get it will give you the best possible probability of doing what you want to do. then you turn off all the power in your house and turn on each breaker one at a time to hunt down all the stuff that generates RFI and increases your noise floor and noise spikes in your house and make a list of all the stuff you will want to unplug or turn off when you want to play radio. That is the best you can do. everything else is dynamically up to chance and is out of your control except learning which bands are expected to be active during what time of day, ie where the sun is in the sky since that is the real constant variable not the actual time since it is not uniform through out the year. I remember when I first started out, talking to someone on 20 meters on the other side of the country and looking at all the signals on the IC-7300 waterfall and instantly it was like someone turned off a switch, no signals, no more contact with the guy i was talking to and the waterfall completely clean. i thought my IC-7300 burned something up inside. i was pissed and disappointed as I had only had it for a month or so. It tried changing things, but only had a 20m antenna so I could not change bands. I was sure my radio was fried. It turned out a small CME had just hit the atmosphere and turned off the 20 meter band like a light switch. nothing was wrong with my radio but it took a couple of days to figure that out. Originally Posted By Mach: Originally Posted By Greenspan: Originally Posted By K9-Bob: It is incredibly easy to get paralyzed by "analysis paralysis" when you are looking at charts, propagation models, and YouTube videos of guys making effortless QRP contacts. The reality of HF especially when you are trying to build a reliable setup for portable use, POTA, or emergency preparedness is that nothing beats dirt-time and actual RF in the air. While baseline probability models (like the climatology analogy used in the thread) are great for a macro-level strategy, they can't tell you how a specific piece of wire hung between two trees in your local terrain is going to perform right now. Here is why getting on the air beats watching the screen every single time: 1. You Learn Your Specific Local Noise Floor (QRM) A YouTube video or a static chart won't show you the localized RFI (Radio Frequency Interference) you have to deal with. Experimenting with different antennas like comparing a random wire with a 9:1 UNUN to a resonant center-fed dipole teaches you how your specific deployment handles local noise. 2. You Build Muscle Memory for Deployment If you are coming at this from a preparedness or portable operation standpoint, knowing the theory of an NVIS (Near Vertical Incidence Skywave) antenna is completely different from actually tossing a weighted line over a tree branch, tensioning the wire, and getting a low-profile dipole up at the optimal 15-to-20-foot height. Real-world experimentation forces you to solve practical problems: How do I quickly tune this wire if the ground conditions change? Is my portable mast stable in a 15 mph gust? Can I reliably deploy this setup in the rain or under stress? 3. You Discover the "Invisible" Variables As the thread notes, the ionosphere is dynamic, but your immediate surroundings matter just as much. Getting on the air lets you see firsthand how factors like soil conductivity, nearby structures, or the takeoff angle of your specific wire affect your signal. 4. Real-Time Tools Give Better Feedback Than Videos Instead of trusting a highly edited YouTube video where someone makes a 2,000-mile contact on 5 watts (often skipping the 45 minutes of calling CQ that failed), you can throw your own signal out on a mode like JS8Call or FT8 and check PSK Reporter. That gives you honest, objective data on exactly where your signal is landing with your exact equipment at that exact minute. The best way to know what a 5W, 50W, or 100W radio can actually do for you is to pack it up, head outside, string up some wire, and start transmitting. No disagreement, but listening to those with experience and evaluating data before jumping into an expensive interest seems prudent. I don't want to end up with 10 HF radios. I just want a one and done. Learn it, know it, but I want to start at the right entry point. Then save money and make your own antenna wires to get started until you figure out what you like in antennas and either improve your wires, like add bands because it is cheap or buy a pre-made antenna. many people here use endfeds and off center dipoles for a single antenna that runs 80-10 meters with a tuner. Those 2 things like the IC-7300 and an 80-10m endfed or 80-10 off center fed dipole and a tuner depending on if the antenna you put up need more than the internal 3:1 tuner that some radios come with are stations that several here use. Like saws, radios all have their strong points. easy to carry for out of the way places but low power or 100 watts and bigger, or 100 watts and smaller but not good for digital modes. You would not usually use a circular saw to make kitchen cabinets, you would use a table saw, but you don't need a table saw to cut 2x4s for framing you would use a more agile circular saw. It's kinda like that. So based on what you have said so far, maximum probability of most contacts and digital modes I would suggest: A good easy to use 100 watt radio and easy to use in digital modes ( digital sound interface built in ) with an internal tuner (ie. IC-7300) and any horizontal wire multiband antenna up as high as you can get it will give you the best possible probability of doing what you want to do. then you turn off all the power in your house and turn on each breaker one at a time to hunt down all the stuff that generates RFI and increases your noise floor and noise spikes in your house and make a list of all the stuff you will want to unplug or turn off when you want to play radio. That is the best you can do. everything else is dynamically up to chance and is out of your control except learning which bands are expected to be active during what time of day, ie where the sun is in the sky since that is the real constant variable not the actual time since it is not uniform through out the year. I remember when I first started out, talking to someone on 20 meters on the other side of the country and looking at all the signals on the IC-7300 waterfall and instantly it was like someone turned off a switch, no signals, no more contact with the guy i was talking to and the waterfall completely clean. i thought my IC-7300 burned something up inside. i was pissed and disappointed as I had only had it for a month or so. It tried changing things, but only had a 20m antenna so I could not change bands. I was sure my radio was fried. It turned out a small CME had just hit the atmosphere and turned off the 20 meter band like a light switch. nothing was wrong with my radio but it took a couple of days to figure that out. Thanks, and great story too, but it's there any radio that meets those requirements you mention that is a field radio? |
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Originally Posted By Greenspan: Thanks, and great story too, but it's there any radio that meets those requirements you mention that is a field radio? Originally Posted By Greenspan: Originally Posted By Mach: Originally Posted By Greenspan: Originally Posted By K9-Bob: It is incredibly easy to get paralyzed by "analysis paralysis" when you are looking at charts, propagation models, and YouTube videos of guys making effortless QRP contacts. The reality of HF especially when you are trying to build a reliable setup for portable use, POTA, or emergency preparedness is that nothing beats dirt-time and actual RF in the air. While baseline probability models (like the climatology analogy used in the thread) are great for a macro-level strategy, they can't tell you how a specific piece of wire hung between two trees in your local terrain is going to perform right now. Here is why getting on the air beats watching the screen every single time: 1. You Learn Your Specific Local Noise Floor (QRM) A YouTube video or a static chart won't show you the localized RFI (Radio Frequency Interference) you have to deal with. Experimenting with different antennas like comparing a random wire with a 9:1 UNUN to a resonant center-fed dipole teaches you how your specific deployment handles local noise. 2. You Build Muscle Memory for Deployment If you are coming at this from a preparedness or portable operation standpoint, knowing the theory of an NVIS (Near Vertical Incidence Skywave) antenna is completely different from actually tossing a weighted line over a tree branch, tensioning the wire, and getting a low-profile dipole up at the optimal 15-to-20-foot height. Real-world experimentation forces you to solve practical problems: How do I quickly tune this wire if the ground conditions change? Is my portable mast stable in a 15 mph gust? Can I reliably deploy this setup in the rain or under stress? 3. You Discover the "Invisible" Variables As the thread notes, the ionosphere is dynamic, but your immediate surroundings matter just as much. Getting on the air lets you see firsthand how factors like soil conductivity, nearby structures, or the takeoff angle of your specific wire affect your signal. 4. Real-Time Tools Give Better Feedback Than Videos Instead of trusting a highly edited YouTube video where someone makes a 2,000-mile contact on 5 watts (often skipping the 45 minutes of calling CQ that failed), you can throw your own signal out on a mode like JS8Call or FT8 and check PSK Reporter. That gives you honest, objective data on exactly where your signal is landing with your exact equipment at that exact minute. The best way to know what a 5W, 50W, or 100W radio can actually do for you is to pack it up, head outside, string up some wire, and start transmitting. No disagreement, but listening to those with experience and evaluating data before jumping into an expensive interest seems prudent. I don't want to end up with 10 HF radios. I just want a one and done. Learn it, know it, but I want to start at the right entry point. Then save money and make your own antenna wires to get started until you figure out what you like in antennas and either improve your wires, like add bands because it is cheap or buy a pre-made antenna. many people here use endfeds and off center dipoles for a single antenna that runs 80-10 meters with a tuner. Those 2 things like the IC-7300 and an 80-10m endfed or 80-10 off center fed dipole and a tuner depending on if the antenna you put up need more than the internal 3:1 tuner that some radios come with are stations that several here use. Like saws, radios all have their strong points. easy to carry for out of the way places but low power or 100 watts and bigger, or 100 watts and smaller but not good for digital modes. You would not usually use a circular saw to make kitchen cabinets, you would use a table saw, but you don't need a table saw to cut 2x4s for framing you would use a more agile circular saw. It's kinda like that. So based on what you have said so far, maximum probability of most contacts and digital modes I would suggest: A good easy to use 100 watt radio and easy to use in digital modes ( digital sound interface built in ) with an internal tuner (ie. IC-7300) and any horizontal wire multiband antenna up as high as you can get it will give you the best possible probability of doing what you want to do. then you turn off all the power in your house and turn on each breaker one at a time to hunt down all the stuff that generates RFI and increases your noise floor and noise spikes in your house and make a list of all the stuff you will want to unplug or turn off when you want to play radio. That is the best you can do. everything else is dynamically up to chance and is out of your control except learning which bands are expected to be active during what time of day, ie where the sun is in the sky since that is the real constant variable not the actual time since it is not uniform through out the year. I remember when I first started out, talking to someone on 20 meters on the other side of the country and looking at all the signals on the IC-7300 waterfall and instantly it was like someone turned off a switch, no signals, no more contact with the guy i was talking to and the waterfall completely clean. i thought my IC-7300 burned something up inside. i was pissed and disappointed as I had only had it for a month or so. It tried changing things, but only had a 20m antenna so I could not change bands. I was sure my radio was fried. It turned out a small CME had just hit the atmosphere and turned off the 20 meter band like a light switch. nothing was wrong with my radio but it took a couple of days to figure that out. Thanks, and great story too, but it's there any radio that meets those requirements you mention that is a field radio? I use my IC-7300 car camping, but it is too big to carry around. The IC-705 is basically a small 10 watt version of the IC-7300 and I use that kayak camping. I don't know of any 100 watt radio that is small enough to hike with that can cool 100 watts of digital modes but there are 5, 10 and 20 watt small radios. Sticking to digital and a decent antenna 10 watts can go a long way. Even with a very compromised antenna 10 watts digital can be done, but it will be more limiting. Usually QRP ( low power ) requires patience and some knowledge to overcome the limitations. It is harder to start that way, but some people do it, @Lorazepam makes it work, he has a lot of experience QRP and I think he started out QRP. maybe he can offer some advice starting out QRP and the reliability of contacts with digital modes. he is already bin this thread but maybe he will come back. |
Mach
Nobody is coming to save us.
.
Nobody is coming to save us.
.