I have been reading, and reading, and reading trying to figure out how to make certain comms situations work.  First priority is for day to day emergency use out of cell range 100mile radiuse, second is for simplex comms during power outage/storm/etc. 20 mile radius.

It looks like NVIS could be viable, but seems to be limited to 40/80m bands in practice.

The biggest issue is that I am trying to have mobile comms, ideally with a handset on one end, and at HF that seems to be a no go. Am I missing something? Any way to use an HT to at least recieve? Might be able to use SDR to recieve, but then use a portable to xmit if you had to?

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My proposed workaround is to use quick deploy beam antennas on tall masts on VHF/UHF. I am told that people lose the repeater about 23 miles out in their vehicle, assuming with mobile antenna. Hoping to use a HT with a 22' antenna(yagi or improved super J) to extend that a few more miles. Does that sound potentially workable? Anything that could help make it work (amp?)? Not 100 mile radius, but hoping for 70ish using repeater.

VHF / UHF needs line of sight.

Height of the antennas is everything. If you don't have the height, power will do very little for you.

How high AGL is the repeater antenna?

Once you know that, assuming level ground you can figure out line of sight using your 22 foot mast for your antenna.

You will not get 70 miles to the repeater unless the repeater antenna is very high, as in one is on top of a mountain several thousand feet up.

Assuming a mobile antenna is 10 feet above ground

and the ground is flat

you need a repeater at about 250 feet to get about a 26 mile line of sight.

So that repeater you are trying to hit that mobiles are getting at 27 miles is about 250 feet, assuming a uniform level ground.

This page has some calculators you could use.

http://www.hamuniverse.com/lineofsightcalculator.html

There are no HF HTs. NVIS will be on 40 or 80 meters.

There are portable sets ups for HF 40/80, but you are not going to walk around with it. It will be stationary due to size of antenna.
Since NVIS is less than 1/4 wavelength above the ground, the ground loses will be significant, so you need a low loss antenna or more power than QRP, in todays conditions or both.  Everything NVIS is dependent on overhead propagation. If the D layer sucks, NVIS with 40 may be ok during the day time. But if the D layer is strong, your signal will go through the D layer, lose 12 db on the way up through the D layer, reflect off the F2 ( I think ) layer, come back down and then lose another 12 db going through the D layer again.  Without the D layer at night NVIS mostly works better on 40 or 80.

That is how I understand it.

If you find a good mobile NVIS antenna, I sure would be interested in that.

Don't forget the 60M band, which is prime real estate for NVIS (which is why it's a bit goofy for hams to use, due to being a secondary allocation.)

There aren't many handset-type HF transceivers, but there are several smaller HF units out there (most being QRP, though.) It's not impossible to do mobile NVIS but in most practical cases, portable (e.g. get out put down an antenna) is going to be the NVIS solution.

As far as VHF, range largely comes down to antenna height as you've noticed, which is why repeaters are popular. Without repeaters, gain antennas will help but height and terrain will really dictate the propagation without getting into more exotic modes like troposcatter. It'll be virtually impossible to get 100 miles in all but perfect circumstances. 20 miles will be doable in most instances with mobile antennas, terrain permitting.

More power won't fix the problem of not hearing the repeater. The earth does curve so height is the only real solution.

The "100 mile problem" is a well-known one, and repeaters and satellite (using commercial units like an inreach) are the main answers to that, but depend on infrastructure working. NVIS is the only real solution that doesn't, but you're going to need the right equipment.

On the bright side, NVIS antennas can pretty much just be a wire thrown on the ground, and need not be too complicated.

First of all, for all that is holy, STOP with the NVIS nonsense. Unless you are in a deep canyon, you don't need it, and 90% of the time you don't have it anyway. It's easy to put up an antenna that is horizontal and less than 1/4 wavelength above the ground. But if your operating frequency is not within 1MHz of FoF2 aka Max. Usable Freq. (MUF) you are not going to get NVIS propagation. This condition exists only for short periods of the time during the day and night and the 1MHz window is often between ham bands, meaning no NVIS.

But that's OK, because you don't need it. 100W of ground or sky wave will work just as well for regional comm's <300 miles, and certainly less than 100 miles. I talk to mobile units on 40 and 60M all of the time, and let's just say "portable" units (not mobile, because mobile antennas really start sucking wind) on 80M, depending on the time of day, no NVIS required.

As for man-portable HF, the KX3 is very popular. However, for routine, reliable comm's, that's a very small signal. Most people playing with the KX3 are doing the QRP "even a blind squirrel finds a nut" thing, not looking for reliable, repeatable commo. You would be much better off making up your own man-portable 100W station out of something like an IC7000, 857D, or similar small form factor HF radio, combined with a LiFePo battery and a portable wire antenna of some sort, like this one. Again, this is not handheld, but it is highly portable. With a good sked and only occasional check-in's that battery should last you for a while. It's not like you need to spend hours chasing DX or SOTA contacts or something.

When you make contacts on 80 meters regionally it is because your antenna is NVIS.

Unless you have an 80m antenna much more than 20 meters high, it is an NVIS antenna, meaning it has a significant vertical pattern component.

My 80m antenna is at 40 feet high, that equates to about 12 meters, which is about 1/7 of a wavelength high.

Can I talk to the EU with it? Sure, because it does have some horizontal component to it, but it also has a large vertical component, which is why it works regionally. I talked to the EU last night on 75M and this orning I talked to a regional net with many people in my own state. It does that because it is only 12 meters high and is an NVIS antenna. I talked to Ct from MA today because my 40m antenna is 40 feet high which is about 12 meters and 12 meters is slightly more than 1/4 wavelength, so even though most of the radiation pattern has a horizontal take-off, there is a vertical component, and propogation today on 40m was good at times overhead.

NVIS is nothing magical, it is just having an antenna with a strong vertical radiation component.

A good DX antenna has a very low takeoff angle getting very long skips, like a high yagi.
A good NVIS antenna has a large straight up component in the radiation, like a low dipole.

It really is that simple. The reason for the distinction is to maximize the direction you want and that takes a difference in type of antenna and difference in height vs. the wavelength.

So talking NVIS has a purpose.

ETA: I do not believe frequency is as critical as you say it is.

You just need to be below the MUF, ( and most of the time the 80m and 40m band is ). You may get a bunch of attenuation going through the D layer, but the signal isnt going that far anyway, so 100 watts and mostly straight up and straight down works. It is my understanding that ground wave doesn’t go much past about 30 miles, even with a very low takeoff angle. Off course power and takeoff angle does matter.

I am going to pick one nit with your otherwise excellent post:

YouKits TJ2B 40/20/17M HT. (Currently sold out, tho.)

How close you are to the critical frequency makes a huge impact on on the amount of signal that comes back.

So while it's true it's not absolutely critical it does make a very big difference.

When you're right on top of the critical frequency you can probably get a solid signal station to station with power measured in the 100s of milliwatts.

I know when KB7DX was a regular on the net (we're about 40 miles apart, with two mountain ranges between us) I could watch as the critical frequency
fell through the 40M net frequency -- his signal would go from uncopyable to blowing out my front end before going back to uncopyable. When it was
right at the critical frequency we even managed to work each other via a dummy load by accident.

I discovered just today reading up about this that there's a bunch of milliwatt-power pirate beacons spread around SW Arizona and SE California deserts
that are pretty much dependent on the NVIS mode to be copied.

Wow! Thanks for the input.

It is my fault, but those distances should be halved; I meant 100 mile DIAMETER... So trying to get 50 each way.

The handset could just be for recieving, then perhaps set up a good antenna on a car. I have been reading antenna books for a couple days, so feel like I can do anything... Thninking a horizontal loop could be the ticket.

One side of the comms can be mobile, since they would be set-up for hours or days. The other side would be moving, so pretty much requires a HT, though that could be for an alert, at which point you could move to a vehicle station or similar. The other option might be a data link to a base HF station for the roving side, if there was a way to do it inexpensively.

Thanks for the link on the kit and the handset.

The repeater that is typically available is 200' up on a 250' hill. The area around is mostly 50-150' above sea level, so line of sight is decent. Would like to hit this from 35 miles out, for a 70 mile DIAMETER...

From the charts I see for NVIS, it looks like 40m during the day until it quits working, then 80 is a pretty reliable rule of thumb. Just using 80 alone would be iffy for 1/2 of the day, but between 2 bands it *should* be pretty workable.

The NVIS looks like it could be 'best', but making VHF/UHF work would be easier in that everything *could* cost less, though at the expense of likely directional antennas and shorter range.

Agreed!

Wrong!

Thank you, @seek2, for addressing this issue.

As I specifically wrote in my first post, and as seek2 points out, an antenna with a strong vertical lobe is NOT sufficient. One must also be operating within but not above approx. 1MHz of FoF2 for there to be an NVIS propagation path.

What confuses the crap out of people is that they seem to be able to communicate regionally on 40, 60 and 80M with or without NVIS. But because they have a low antenna they think it's always NVIS. But it's not, indeed most of the time it's plain old ground or sky wave.

If you want some idea of where FoF2 is, this website is your best bet:

http://www.sws.bom.gov.au/HF_Systems/6/5

No, a thousand times no! You did not read my post (or you thought I was a crackpot ) NVIS conditions do not exist like that, nor are they even the least little bit necessary unless you are in a canyon to canyon situation. Located in central New England, I can communicate from Maine to southern New Jersey and out to Ohio reliably using 40, 60 and 80M, depending on the time of day, and it's just plain old ground wave or skywave, no NVIS.

Look at this web site to get an idea if you have a prayer of actual NVIS propagation conditions at any given time, and on which band:

http://www.sws.bom.gov.au/HF_Systems/6/5

Field day 2 years ago @TNC and I had an NVIS QSO on 60M. I was at 5W.

If you can use 2m SSB and directional antennas, 50 miles should be the proverbial chip shot. 

I am seeing what you are saying, but when I look at the map it says 75 or 60meters for almost the entire US at the moment. It appears that in the US you will never go below 3mhz or above 6 or 7mhz most of the time. What makes it so difficult to use? (honest question)

Also interested in how much ground wave you might get, as it could be simpler than NVIS. Assuming skywave is out at 50miles.

-Edit- But I guess incorporating Seek2's answer, it could be very difficult to monitor each other if you are hopping around much attempting to get the 'right' frequency. One end would end up scanning constantly if you knew it was going to be changing hourly or some such.

hot damn

I had no idea. What does it use for an antenna? 817 antenna.

I bet that will be fun to have when the cycle is a the peak

And that would be nearly ideal. Waiting on a cheap radio to ship, and building a portable antenna and mast while waiting. The only drawback is the directionality. Good for gain, bad for multiple concurrent users traveling, though area is fairly good for it.

I guess that explains why I talked to a guy in Maine on 80 with my 7300 power set to zero and he said I was 40 db over.

What is the difference between plain old skywave and Near Virtual Incidence Skywave when the stations are 200 miles apart?

I dont think there is any. NVIS is nothing more than skywave with a much higher angle of reflection. Dont they both use the same ionization level? A higher angle 'skip' just needs the ionization level with the proper critical frequency sbove you.

For long distance skip, that ionization level just needs to be someplace over the atlantic to get to the EU and the critical frequency location determining where the strongest signal will come down for a given  antenna.

OP, look at the elecraft kx2 and 3. They are probably the closest thing to what you are looking for in a portable HF radio. I had pretty good luck with my KX3 and a packtenna mast and base loaded wire antenna, if you have trees around you don't even need that, just throw a wire in a tree.

here is an arrl chart that shows ground wave at 80 meters does not get out past 70miles

http://www.arrl.org/files/file/Technology/tis/info/pdf/8501031.pdf

anything past that, say new england regional, 71-300 miles
must therefore be skywave.

Which is the very definition of NVIS. Near Vertical Insidence Skywave. Or in plain english almost straight up skywave. Like  any skip, where it gets reflected determines where it comes back down which is why it is difficult to contact a particular area at a particular time .

With NVIS the place you want to contact is a couple hundred miles away so the reflection to get there has to be over the top of you.

Maybe it is, maybe it isn't but unlike a skip to Australia, the signal is not traveling very far so it does not need a very efficient reflection,  It just needs a poor reflection to work.

If your signal is 1 mhz below the critical freq hen the reflection will be efficient. If it is 5 mhz below it will be less efficient but there will still be reflection and it will still work power dependent. If the critical freq is below your signal it will not work at all.

That is the way I understand it. If it is wrong please explain why

While they are the same -- they're both skywave! --  there's a subtle difference, namely that because of the angle of incidence you don't get a good refraction until you're close to the critical frequency, and then you get really good refraction. The D-layer absorption is also lowest at higher frequencies, so basically the point of maximum efficiency happens right at the critical frequency. That's not to say it doesn't work at lower than critical frequencies, just that it's noticably better near the critical frequency.

Essentially when NVIS happens as a propagation mode it's a lot 10M during a solar maximum -- really, really efficient reflection. And it happens with a very short path (a few hundred miles up and down) and between the two, that's why you get crazy high SNRs with no power. If you can find a near-ish station that's transmitting regularly (say with WSPR) below 10MHz you can usually watch the process happen in real time, and it's very very obvious when the NVIS kicks in v. conventional propagation.

As I comment on over and over... it's really easy to throw out the magic letters "NVIS" as if it was the solution to all survival forum communications needs.

Yes, it functions. And you can debate the specifics of critical frequencies if you want, but that's one tree in the forest.

The problem is the operating environment. 80 and 40 meters, as well as all HF bands, have the challenges of operating in a heavily used, non-channelized environment along with all the vagueness of HF operation, as well as the limitations of SSB voice. OP is looking for something with a handset so he can talk on the telephone. Amateur operation on 80 meters is not and will never be a telephone.

Yes you can put an NVIS antenna on a vehicle. Very few are going to be willing to do so on something that they actually drive every day. I think it's important to deal with reality.

If you have never operated SSB voice on the HF bands, especially the lower frequency bands that work for NVIS, you need to get some experience first. You are looking for a hardware solution without even knowing what software you need. It would be easy to just give you a list of equipment that would enable you to make contacts over 100 mile distance. The problem is, that the result might be something that you are unable to operate, or just doesn't fulfill your needs.

Try http://websdr.org/ and find a US receiver and take a listen to the 80m band at night and the 40m band during the day (LSB mode).

I know the OP has started a couple threads and I don't remember if you have mentioned what part of the country  you are in and what the terrain is on your desired 20 mile and 100 mile paths. Depending on your situation there might be other alternatives.

There should be copies of the ARRL Antenna Book out there somewhere.  It provides various recommendations for antennas that don't require a NVIS lobe to get you range.

Awesome idea. Never knew all that existed. I am looking for a solution, as a newb, to 1 real problem, and one potential survival forum type problem. I realize most of this seems like stupid questions, but really starting from 0 knowledge, and trying to move forward.

So far have read the "Novice antenna notebook" and a decent part of the "AARL Antenna Book". Like I say, working at solutions, but not efficiently due to lack of knowledge.

My area has light hills 100-200' until you get 35+ miles away, and you start getting into the mountains and out of cell range. Those start being fairly high relief, so what I though the NVIS might work best for. Trying to have comms with someone out there who will be logging alone, mostly for emergency use. They can set up a mobile or portable station, but I need to monitor it, and then be able to get to a xmitter.

Within the same range in the other direction is just light hills, and UHF/VHF could very well be preferable. That is what I am hoping to make a portable mast/antenna setup for. That end has a decent shot at hitting a repeater, though from 35-70 miles away, depending on direction they are shooting for.

Been over a bunch of that. Love it! Can't wait to try a couple.

Yes, it tends to stay between 3 and 7MHz most of the time.

It's not difficult to use, per se, but you do have to wait around for the right conditions. When it's at 7MHz it's too low for 40 and too high for 60. When it's at 3 it's too low for 80 and too high for 160. And of course that map is somewhat approximate. But as @seek2 says, you know it when you see it either kick in or kick out. It's like somebody flipped the switch on everyone's amplifiers. However, to my point, it's only the "switch on the amp", not the "switch on the radio", i.e. the band continues to work, or maybe you need to change gears down or up a band, but you can still make comm's without it.

Again, many thanks to @seek2 for his well thought out explanations of my crude exhortations NVIS is merely a special case of skywave with unique properties. You generally don't need it for most regional commo, but you certainly enjoy it when conditions do permit. The only time you need it is when extreme terrain features, e.g canyons, prevent more general forms of sky and ground wave communications. Unfortunately, when you need it you may be waiting for the right ionospheric conditions to occur. Government and military users don't have to wait because they have access to frequencies that are between amateur radio bands and therefore do not suffer gaps in coverage (and they tend to enjoy things like ALE to pick their freq's for them).

And we were at about 600 mi distance, from the Washington Cascades to somewhere in Montana. I could barely copy you on SSB; we would've had a much better QSO using Olivia but my laptop chose that day to go TU

I built an antenna from these plans: DX Engineering and found that it needed significant tuning to resonate.

Yeah there are bunch of HF handhelds, some old some new. Its a weird form factor, but way back in the day they were great for high band DX ing (10-12m). These days a few watts on 40 or 80m isn't really gonna work too well, even if you can rig up some sort of antenna.

It uses whatever antenna you can build for it that gives it 50ohm impedence just like anything else, its just a BNC connector. Given the low power and  bands it provides I'd build a dipole, but I imagine a buddistick would work too. There were some 80's 90's era Mizhuo (sp) handhelds that IIRC worked from like 10-40m that were similar to this, on 10m you could actually get a decent collapsible whip antenna to use with it.

Look up the 4 dollar satcom antenna if you want to build a cheap 440/2M antenna out of a 1x2 and some coat hangers. Otherwise arrow antennas have commercial versions of that, they just cost like 100 bucks or so.

And actually at the ranges you are talking about brute force low band HF should work fine too. One thing I'd say that most posters here are unaware of historically speaking is that many military HF manpacks back in the 60's and 70's were specifically designed to provide an intermediate range capability for long range patrols, i.e. beyond what was possible with VHF setups, but still not really "skywave". A great many of those packs were designed to work between 1-7, 1-12 mhz. The original PRC-74 used during the vietnam war was a 1-12mhz setup with a center loaded whip, and it put out 15W power, and generally ranges were up to ~40miles IIRC on the direct/ground wave circuit. Same deal for the PRC-320 which was more advanced and had a bit more oomph, this capability was used significantly during the falklands campaign.  Of course all of these radios could do NVIS/Skywave as well, but the main reason they had the whip was for short range comms, not "DX". So I'm pretty sure 100W on 80-40m with a vertical whip mounted on a car would go 50ish miles in many cases. Worst case drive to a hilltop if its not working.

The TJ2B has a BNC antenna connector, so whatever you want to connect.

The Elecraft KX2 is also about the size of an HT.

I'd like to refocus this conversation back on your original need for all this, which some may have missed in your last post. I would almost consider editing your first post to include this new info.

Assuming this individual will be out in the woods cutting down trees by themselves, and that civilization still exists, I would focus on two priorities first:

1) Some professional, cold-hard wilderness first aid training that expressly deals with how not to bleed out and die if you put a chainsaw into your leg.

2) Look into a Personal Locator Beacon for the remote party, and make sure they register the thing properly.


Anything after that is a nice fallback/non-emergency communications link and we can go roundy-round on VHF/UHF vs. HF Skywave vs. NVIS vs. HFLINK/ALE vs. Spot messenger vs. Garmin inReach vs. Cell Boosters vs. some combination of the above.


If I was setting somebody up for some solo backcountry logging, I would go in the order of medical training/equipment, the Garmin inReach, at least attempting a cell booster with an external antenna up on a mast (assuming it's not a total no-hope'er after some research), and then experimenting with various amateur radio options at my leisure.


I hope that helps refocus all this somewhat.

Which is an excellent point. When my SO and I started venturing into the deeper recesses of my state, I started carrying a Delorme Inreach,
even though we have excellent repeater coverage I can't guarantee someone is listening. Inreach has a 2/47 monitoring center, and can
handle not-quite-emergencies (in my case, 4WD towing, if needed) a PLB isn't meant to. It also lets you send free-form text messages to
pre-selected parties.

One thing I've noticed in a lot of survival communications planning is an inbuilt assumption that we go from grid up to TEOTWAWKI.
That's almost never the case.

a 40 meter dipole is about 65 feet long,  an 80m is about 120ft long.

the old ARFCOM Tuesday night net was a good indicator that guys with dipoles and 100watt stations are often hard to hear.

Guys like K9bob and Gyprat with big amps and good antennas had the most success.



An HT on 40 & 80 would be pretty much useless for reliable voice.




80m voice is probably my least favorite band,  old farts acting like they "own" a frequency, it's as bad ( and crowded ) as CB when it was popular.  .  .  .   especially the General section of the band.


expecting ham HT's to operate as well as a cellular network is folly.

It's takes a huge amount of telcom infrastructure to make your iphone work.

.

The other thing that is nice about PLBs and SMS SATCOM like inReach and Spot: one button SOS, and no setup except a view of the sky. That way, when you are too sick/injured/shocky/trapped or whatever to setup or operate a ham radio, much less figure out and transmit coordinates, you just push a button and they come a runnin'! You can do that and pass out and it will happily keep calling for help with your position until somebody turns it off or it runs out of batteries. And any member of your party can be trained to do that in 30 seconds or less.

Excellent responses!

I had considered a sat phone, but expected it to be too much expense for the expected use. The PLB seems like a really nice compromise between having satellite access and cost. Thank you!

I also appreciate the input on the HF bands. I spent some time listening on websdr.org, and much of the comments make sense. I can see the HTs having not much chance, and the idea of being unable to utilize the frequencies needed as propogation changed would definitely put a kink in the plan!

It sounds like my best bet is just to spend some time playing with a radio or two and some DIY antennas, and find out what capabilities I DO have, and then work with that for now. Thanks for heading me that way! Also going to look into the PLB a bit. Haven't used them for years, imagine they are better now.

Don't necessarily write off repeater coverage in the mountains either. In many places there are some large area coverage mountaintop repeaters. Doesn't mean 100% coverage, but not zero either.

BTW, FYI, newer HT radios with GPS, like an Icom ID-51 have a database of repeaters loaded on a memory card. You can basically see all the nearby repeaters based on your GPS coordinates. This feature can be very helpful when traveling. You just choose the repeater you want to use and all the data (frequency, offset, PL-tone etc) is automatically loaded into the active channel. This includes both analog and D-Star digital repeaters.

You're shitting me. I need a link.

Link

I have the 51a plus (not plus2) and really like it. This site will let you put in a zip code and download the file. The programming is all done on the SD card so you dont need a cable. After my 7100 and 51a I am really starting to be impressed by Icom. However being limited to 750 repeaters when I have a multi gigabyte card is absurd.

So that will do not only D star, but regular analog 2m & 70cm fm, correct?  I have no use for D star in MT.

Yup

Same here. No dstar but that radio has a voice recorder, fm broadcast rx, airband AM rx, and a GPS receiver

Shit.

I got excited too until I saw the price tag

It's on its way.

HRO was trying to clear there 51a plus inventory back in June, they had walk in specials of $250 on them.

The only downfall is finding a RepeaterBook with gps coord.  
I put a bunch in via the editing icom software.  

The id-5100 and the 51 are real nice radios.  Even if you don’t use d-star.