Posted: 10/22/2011 4:51:32 PM EDT
| I am thinking about a receiver so I can listen to all the diff bands and have a small budget of around $400. The Ham bands are what I am most interested in hearing. Any advice is helpful at this point. |
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I am thinking about a receiver so I can listen to all the diff bands and have a small budget of around $400. The Ham bands are what I am most interested in hearing. Any advice is helpful at this point. In that price range you can find a transceiver capable of general coverage for SWL, and if/when you decide to get your ticket you won't have to make another purchase. |
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I am thinking about a receiver so I can listen to all the diff bands and have a small budget of around $400. The Ham bands are what I am most interested in hearing. Any advice is helpful at this point. In that price range you can find a transceiver capable of general coverage for SWL, and if/when you decide to get your ticket you won't have to make another purchase. Agreed. For $400.00 you can find a rig like an Icom IC-735 or Kenwood 430 or 440S and a power supply to run them. If you want more portability, the Sony ICW 7800? (model#) can be had for $200'ish. |
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I often see slightly used Icom R75's for sale on their yahoo group for around $350.
(edited to add this link) http://groups.yahoo.com/group/icomr75/ and check Message #17515. It covers from way below the AM broadcast band (aka Medium Wave or MW) up to 60 mhz (above the 6 meter ham band). It does AM, FM, RTTY, and SSB modes. Some have asked rhetorically and wrongly, why buy an R75 when for a few bucks more you can get (fill in the blank with popular ham transceivers) and have a transmitter, too? Well, the R75 has a triple conversion receiver, not dual conversion like all of those suggestions. It is a superior receiver. I know, I have one. Besides, if you aren't licensed you don't need a transmitter and are just likely to get in trouble with it. The filters that come with the R75 will do for all but the most serious CW (morse code) users, and are well suited to AM and SSB. |
Well, I don't want to beat up on AFM, but the IC-735 has a triple conversion reciever. AFM is right on the R-75 being a superior reciever to many ham transcievers, but it is a dedicated reciever. We were just being frugal in our suggestions as hams are known to be.
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Yeah, the R75 is close in price to the Icom IC-718, with very similar appearance. REALLY similar appearance. Here's a picture of the two slaved together, with a relay, so that the tx portion of the 718 is used to transmit, and the R75 for receive.
The 735 is a nice older radio, but on those older radios you would really have to know which are the jewels and which are not. One thing to do is look through the reviews at eHam. There are a few posters there that are fulla crap, that apparently have personally tested and done A/B comparisons of every radio ever made, but it is easy to separate those guys out of the reviews by reading enough to get a consensus on any particular one. |
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The Ham bands are what I am most interested in hearing. ...which means that eventually, you'll probably be talking on the ham bands... ...which means that having a radio that's capable of transmitting on the ham bands would be nice... I vote for an IC-718 - The performance of the general-coverage receiver section is very respectable, and you get a nice ham transceiver thrown in for free. 
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The Ham bands are what I am most interested in hearing. ...which means that eventually, you'll probably be talking on the ham bands... ...which means that having a radio that's capable of transmitting on the ham bands would be nice... I vote for an IC-718 - The performance of the general-coverage receiver section is very respectable, and you get a nice ham transceiver thrown in for free. What he said...but I'd be remiss if I didn't mention my own rig The Kenwood TS-50s . you can't buy 'em new anymore, and can prolly find a 718 for the same $ or less...YMMV |
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The first question to ask yourself is where you are going to be next year.
If you think you will never get licensed to transmit, go with a receiver, but if you even think for a minute you will get a ticket, than plan ahead. As far as the fear of getting in trouble transmitting without a license goes, simply leave the mike in the box and don't plug it in. In fact, don't buy an antenna tuner until you get licensed. |
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Im also just a SWL'er but I picked up one of these:
http://www.gigaparts.com/store.php?action=profile&sku=ZAL-DX-SR8T And I love it! I have owned many many receivers and transceivers from the Yaesu FT817ND, FT-897D, two FT-101EE's, an Icom 7000, several Grundigs, Realistic PRO's, and a bunch I cannot remember at the moment. But this rig is one of the cheaper ones out there but is a pleasure to listen to! It may not have the DSP and filters etc.. the other ones have but it does a good job. There is also a receiver only version. Of course none beat the IC 7000 of the ones I have had but I had to let her go, to expensive of a toy to just listen to, and it went to a good HAM home. |
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Yeah, the R75 is close in price to the Icom IC-718, with very similar appearance. REALLY similar appearance. Here's a picture of the two slaved together, with a relay, so that the tx portion of the 718 is used to transmit, and the R75 for receive. http://i6.photobucket.com/albums/y209/AFreeMan/7IC718-R75.jpg The 735 is a nice older radio, but on those older radios you would really have to know which are the jewels and which are not. One thing to do is look through the reviews at eHam. There are a few posters there that are fulla crap, that apparently have personally tested and done A/B comparisons of every radio ever made, but it is easy to separate those guys out of the reviews by reading enough to get a consensus on any particular one. OT, but when you have it set up like that can you use the R75 to monitor your transmitted signal? Does it use the same antenna? |
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Congrats! If you are interested in decoding CW or digital modes, there are plenty of choices for software. All you need to decode is the software, mic input on your sound card and a cheap mic. Place the mic next to the speaker and decode away! I have been reading about the radio control software. Do any of these decode the digital stuff? |
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Congrats! If you are interested in decoding CW or digital modes, there are plenty of choices for software. All you need to decode is the software, mic input on your sound card and a cheap mic. Place the mic next to the speaker and decode away! I have been reading about the radio control software. Do any of these decode the digital stuff? HRD (ham radio deluxe) has combination remote control and decoding.. it's actually a bunch of pieces of software that talk to each other. It comes with DM780 which is hands down the best digi comm program there is. It will decode PSK, CW, RTTY, SSTV, Olivia, Feldhell, and dozens of other modes nobody uses 
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Picked up a copy of HRD and it works for about an hour and blue screens my system. I sent an e-mail to the HRD guys and hope to here back soon. My mother board dose not have an RS232 port so I picked up a USB-RS232 cable and think it my be my problem. I do have an RS232 header on the mobo put do not have a bracket to plug into it.
I'll get this figured out sooner or later. I also need a cable to go from the radios tape out to my sound card. E bay should have this. |
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Yeah, the R75 is close in price to the Icom IC-718, with very similar appearance. REALLY similar appearance. Here's a picture of the two slaved together, with a relay, so that the tx portion of the 718 is used to transmit, and the R75 for receive. http://i6.photobucket.com/albums/y209/AFreeMan/7IC718-R75.jpg The 735 is a nice older radio, but on those older radios you would really have to know which are the jewels and which are not. One thing to do is look through the reviews at eHam. There are a few posters there that are fulla crap, that apparently have personally tested and done A/B comparisons of every radio ever made, but it is easy to separate those guys out of the reviews by reading enough to get a consensus on any particular one. OT, but when you have it set up like that can you use the R75 to monitor your transmitted signal? Does it use the same antenna? You don't want to do that!!! Your transmitted signal will just overpower the R75 and possibly even damage it. It would feedback if you try to transmit. To do this, slave the two, is very easy. You use a cord with 1/8" mono, or 1/8" stereo plugs, it really doesn't matter, to connect the two radios. How to do this is in the manual. They will, in a second or two, sync up. The only time they won't is if you have the R75 on a frequency or mode the 718 can't do, such as FM, or frequencies higher than 30 mhz. Then the 718 won't follow along, it can't. The other thing to do, you will need an MFJ-1708 Antenna Relay. This will switch your antenna between units, triggered by the PTT signal from the back of the 718. An RCA cord is plugged from the 718's Send Control Jack (which grounds when you press PTT), the same jack you would use to operate an amplifier, to the MFJ1708's Control Jack. But!!! An RCA Y-cable should be used, plugging into the 1708's Control jack AND the R75's Mute Jack. In addition, turn the volume control of the 718 all the way off, fully to the left. Now the one antenna will switch via the MFJ1708 from RX to TX when you push PTT. When the relay switches, it grounds the antenna jack of the R75, and the PTT circuit also mutes the audio of the R75 so there is no feedback from the R75's speaker to the microphone. If the 1708 fails, power to it is lost, it defaults to the transmit position. This is good... because that means you have an antenna load on the transmitter, the receiver antenna input is grounded and disconnected from the antenna, and therefore also protected. If you want to do an A/B test of the 718's rx vs the R75, simply turn up the volume on the 718's audio, and unplug the power jack to the MFJ-1708. It will default to the TX side, and you will then be hearing with the 718. You will find a better signal via the R75, I assure you. Quieter, more sensitivity, just better copy. AFM |
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Yeah, the R75 is close in price to the Icom IC-718, with very similar appearance. REALLY similar appearance. Here's a picture of the two slaved together, with a relay, so that the tx portion of the 718 is used to transmit, and the R75 for receive. http://i6.photobucket.com/albums/y209/AFreeMan/7IC718-R75.jpg The 735 is a nice older radio, but on those older radios you would really have to know which are the jewels and which are not. One thing to do is look through the reviews at eHam. There are a few posters there that are fulla crap, that apparently have personally tested and done A/B comparisons of every radio ever made, but it is easy to separate those guys out of the reviews by reading enough to get a consensus on any particular one. OT, but when you have it set up like that can you use the R75 to monitor your transmitted signal? Does it use the same antenna? You don't want to do that!!! Your transmitted signal will just overpower the R75 and possibly even damage it. It would feedback if you try to transmit. To do this, slave the two, is very easy. You use a cord with 1/8" mono, or 1/8" stereo plugs, it really doesn't matter, to connect the two radios. How to do this is in the manual. They will, in a second or two, sync up. The only time they won't is if you have the R75 on a frequency or mode the 718 can't do, such as FM, or frequencies higher than 30 mhz. Then the 718 won't follow along, it can't. The other thing to do, you will need an MFJ-1708 Antenna Relay. This will switch your antenna between units, triggered by the PTT signal from the back of the 718. An RCA cord is plugged from the 718's Send Control Jack (which grounds when you press PTT), the same jack you would use to operate an amplifier, to the MFJ1708's Control Jack. But!!! An RCA Y-cable should be used, plugging into the 1708's Control jack AND the R75's Mute Jack. In addition, turn the volume control of the 718 all the way off, fully to the left. Now the one antenna will switch via the MFJ1708 from RX to TX when you push PTT. When the relay switches, it grounds the antenna jack of the R75, and the PTT circuit also mutes the audio of the R75 so there is no feedback from the R75's speaker to the microphone. If the 1708 fails, power to it is lost, it defaults to the transmit position. This is good... because that means you have an antenna load on the transmitter, the receiver antenna input is grounded and disconnected from the antenna, and therefore also protected. If you want to do an A/B test of the 718's rx vs the R75, simply turn up the volume on the 718's audio, and unplug the power jack to the MFJ-1708. It will default to the TX side, and you will then be hearing with the 718. You will find a better signal via the R75, I assure you. Quieter, more sensitivity, just better copy. AFM Oh I know it's not straightforward; when I was doing a lot of AM I used my receiving rig connected to a dummy load with the antenna a few hundred feet away. There was probably more radiated power from the tap I used for the oscilloscope to monitor the waveform
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Picked up a copy of HRD and it works for about an hour and blue screens my system. I sent an e-mail to the HRD guys and hope to here back soon. My mother board dose not have an RS232 port so I picked up a USB-RS232 cable and think it my be my problem. I do have an RS232 header on the mobo put do not have a bracket to plug into it. I'll get this figured out sooner or later. I also need a cable to go from the radios tape out to my sound card. E bay should have this. You can make a simple interface for receive only, by using a small computer mike and just taping it by the R75's speaker. You will have electrical isolation. In the past with direct cable connection I have had ground loop problems particularly with HP laptops. |
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Picked up a copy of HRD and it works for about an hour and blue screens my system. I sent an e-mail to the HRD guys and hope to here back soon. My mother board dose not have an RS232 port so I picked up a USB-RS232 cable and think it my be my problem. I do have an RS232 header on the mobo put do not have a bracket to plug into it. I'll get this figured out sooner or later. I also need a cable to go from the radios tape out to my sound card. E bay should have this. You can make a simple interface for receive only, by using a small computer mike and just taping it by the R75's speaker. You will have electrical isolation. In the past with direct cable connection I have had ground loop problems particularly with HP laptops. Just get a 1:1 isolation transformer at Radio Shack or rob one off an old modem and wire it inline with a 1/8" jack patch cable. I did this with several older radios and worked great at removing the ground loop interference. |
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This is a description of Professor Arnie Coro's (CO2KK) digital interface. Arnie is host of Radio Havana's "DX'ers Unlimited" radio show. He has several very interesting articles on the web about indoor SWL antennas and other SWL related subjects. More recently, Arnie coordinated relief into Haiti following their devastating earthquake.
I asked Arnie to do a write up of his very simple digital interface described to me during a PSK31 contact. The following is edited from two emails. OH Yes amigo ! It is very easy to assemble, and several Cuban radio amateurs use it with excellent results. Here is the full description: For receiving.... the signal from the transceiver's audio output is connected to a small loudspeaker that fits inside a length of PVC pipe of about 5 inches, that is filled with sound absorbing material... at the other end there is a small microphone that picks up that acoustic wave and is connected to the microphone input of the computer's sound card. You have two places where to regulate the input to the sound card... at the transceiver volume control , and at the computer audio control program sound level setting. That is the RECEIVING path. FULLY AND TOTALLY ISOLATES THE TRANSCEIVER AND THE COMPUTER !!!! For transmitting.... what we have been doing lately is to fit a small microphone inside one of the computer's loudspeaker.... and that microphone output is connected to the transceiver's microphone input JACK. We have also taken the sound card output signal directly to the microphone input by means of a 600 to 600 ohms transformer... but I prefer to use the ¨acoustic coupling method ¨ because the acoustic coupler avoids the possibility of having ground loops and the certainly dangerous RF feedback that can be damaging to the computer, as some people have found out the hard way!!! Here is the reply to your question about how the HF transceiver is turned on to transmit with my SIMPLE DIGITAL MODES INTERFACE ... I simply do a careful setup of the rig's VOX, so that it will turn ON and OFF the transceiver. For my FM rig , when I want to transmit the satellite photos during the hurricane season, my only choice is to turn on the transmit by pressing the PTT button using a footswitch. The reason why I do it this way is to keep the TOTAL ISOLATION, between the computer and the transceivers. In other words, if you add a circuit that receives the signal from a serial port to activate the transmission, this will require a physical connection with a cable (and of course a single transistor or better yet an optocoupler ) that links the computer with the radio. A local friend uses what he describes as a much more perfect protection by employing an optocoupler device (supposedly 5000 volts isolation ) that feeds a mechanical relay.... and then the wires that go to the rig's PTT are only connected to the contacts of the relay. I had to agree with him that it was a very clever approach... and that it indeed provides an almost perfect isolation... BUT, it your HF transceiver has VOX, then IMHO, that is the way to go!!! I use FLDIGI as my digital modes software, running on a LINUX box that runs PUPPY LINUX 5.2.8 , a very rugged and small operating system that is easy to install and runs very well in old machines with little RAM available !!! 73 and DX Your friend in Havana Arnie CO2KK |