Wow that brings back a lot of good memories. When I was a young boy a friend gave me an old military shortwave radio and I figured out how to get it to let me listen to SSB on it. I used and old AM radio to add in the carrier and it worked great. Thanks for this video, it was very enjoyable! Tony
I have done this years ago with two radios - the one I'm listening on and another one sitting nearby to use as the "BFO". Very instructive video - thank you!
I had a domestic Marconi 5 valve radio once, and I used a transistor radio to get SSB on the Marconi, I got a 2 foot length of wire wrapped it around the RED oscillator can of the transistor radio and then to wrapped the other end to a IF can with careful fiddling I got SSB no problem, I done that for hours on end.
I remember doing this maybe 18 years ago using an LM-7 frequency meter and RCA K-80 console. I loosely coupled the LM-7 to the RCA by connecting a wire from the antenna jack of the LM-7 and making one turn around the K-80 antenna wire near the antenna screw. Worked real good. Most recently did this with a Stark LSG-10A and also an EICO 315 and the receiver was a BC-455A which had its BFO removed by a previous owner. I found those two RF generators were not stable enough to adequately work for SSB and also the tuning on those two generators was not geared down enough. That said basic service grade RF generators may not be good enough without modifications to make them more stable and further gear down the tuning. Stupidly disassembled my original LM-7 maybe 12 years ago for a tube socket, but I have another I got maybe three years ago still waiting on me to finish replacing the bathtub capacitors and once done I'll build a power supply then set it up again in such a way that it will work with multiple radios that have their antennas in the same room as the LM-7.
50 years ago I had this problem and by accident found a small two transistor radio placed on top of the receiver and tuned to 550kc allowed ssb to be understood clearly. If I remember correctly usb required the two trans to be tuned to 650 for usb and 550 for usb.
sounds like the BFO my dad homemade for his shortwave receiver. just put it along side and "wammo!' you now have side band radio with AM. direct injection is best to do but if you build it... they will be clear sounding. 73 ad0am
Just came across your channel and its awesome so much to learn. I wonder even though this is such an old video if you would mind if I were to ask a question. I recently built a pixie HF CW kit ...It comes stock with a 7.032 XTAL but I swtiched to 7.050 due to class restrictions . Regardless in order to verify it's operation I used a cheap SW radio and can get full quieting when I power the pixie up and have a 1/2 wave dipole connected on same freq.Of course as this SW radio similarly to what you show here is not SSB but only AM I cannot hear the CW properly . Now just for testing of something similar to this I used another SW radio tuned to almost same frequency to simulate a BFO and I was able to get center carrier quiet and either side a tone . The question is however If I transmit on the pixie all received is the inverse i.e. on the receiving radio I hear tone and the breaks vs nothing and tone if that makes sense. What am I doing wrong in ref. to this ? thank you if you see this .
Many happy memories listening to such signals as a child and wondering how to 'tune them Great to see, I used to get my students to build a BFO etc to allow a simple receiver to copy SSB etc when I used to instruct / examine for the intermediate 'Ham' licence in the UK. Heck! so inspired off to play 'radios' and stop watching this computer
Paul, after watching this video of using a sig-gen as a BFO to listen to SSB, it gave me an idea! With great difficulty I was able to use an old Grid Dip meter as a BFO for SSB! I was trying to couple it to the antenna but it was difficult to adjust and couldn't make the signal stable. It needed a more selective tuning adjustment, but with a steady hand it sort of worked! Anyway, maybe you can come up with a better way of coupling a receiver with an old Dip meter to listen to SSB. Let me know what you come up with! Hope to see a video of it too!
Hi Paul - love your vids and electronics course, youŕe such a bright guy. What is your background, military? Can you explain how this : !! extra carrier addition is working to get the circuit to decipher the sideband at relevant points in a circuit please?
You can also use another radio in close proximity. I used to use an old Panasonic multi-band to inject a leak into my Radio Shack desktop that lacked a variable BFO. I could tune the Panasonic to a sweet spot to generate a variable signal that decoded USB/LSB on the RS desktop.
I used to consumer grade shortwave radios to receive upper side and on the 20 meter band by tuning the SSB signal on the front facing receiver then using the vfo of the shortwave receiver behind it as the bfo and zero beat the usb signal.
Cool....another way to copy SSB and CW is to cause the I.F. stage to go into oscillation by simply wrapping the insulated end of a piece of wire around the lead going to the plate of the converter/mixer stage...then, wrap the other insulated end of that wire around the lead going to the plate of the detector stage...wrap it right on around the insulation of those leads. ..just a few wraps on either end should be enough 'gimmick'-capacitor coupling to cause the IF stage to regenerate and mix with the incoming signal....experimentation will determine the optimum set-up..enjoy! :)
Basically the same thing, only on a much smaller scale ... locate the collector of the converter stage and locate the detector diode and wrap one end of the hook-up wire around the collector lead and wrap the other end around the diode's anode lead. The goal is to cause the IF stage to go into regeneration so it's self-oscillations will heterodyne with the incoming CW or SSB and make those signals understandable.
Could you set your signal generator to 455kHz, find a SSB signal then tune the signal generator to 454kHz for LSB or 456kHz for USB? I'm curious if that would also work so one could build a simple tunable IF frequency oscillator to use as a BFO rather that using a 2 to 30mHz wide band oscillator or signal generator.
An easier way is to inject a frequency close to the IF, about 455 khz. Best if you can do it in an IF stage but it would also leak in from almost anywhere. That way you don't need to retune it. Just rock the main dial until it's clear.
Mr. Carlson, I was just thinking. Since you know how to cleverly place modern components into radios originally designed with old-fashioned ones, I started thinking. You can create a 540 kHz (or 540,000 cps) solid-state oscillator and use it as a fixed carrier for pre- or post-filtered IF signals which happen to be SSB, and then the radio at least has a carrier which will work to decode SSB. An alternative is to use a "reversed IF" modulator, where you take the (f + 540kHz) carrier insert originally intended to add to the received signal to generate the 540kHz IF, and modulate the carrier through a 540kHz fixed carrier signal to generate a "reversed IF" carrier of f, which can then be inserted into the "front end" of the radio, and now it has a carrier which can help to decode SSB.
Would this work with modern shortwave receivers? I have a C Crane-SW. I enjoy this radio but it obviously doesn't have a BFO for SSB/CW. It seems to be difficult to find a TG37 module and I was hoping that a cheap RF signal generator could do the same thing.
Hi Stephen. That would be a fixed frequency BFO, being only single knob tuning. That procedure would be a little more complex for most antique radio owners. With this mode of operation, the radio can drift off frequency and no change in pitch will be heard on sideband. This requires the signal generator to be stable though. For a more advanced application, your idea would be great. Thanks for stopping by!
really cool, thanks! can you go into a bit about why this works? you say in the video that the radio "thinks" there is a carrier there, but obviously we are not tricking the radio (it doesn't "know" anything).... why doesn't just tuning the center frequency correctly to where the carrier would be, allow the envelope detector to work like this too? why do we need a carrier (a fake one or not)? the "information"/baseband is all in the sideband already and we don't add anything "special" with the fake carrier injection right?
Mr. Carlson: This method works with small digital shortwave radios like the SWED 100 A1, a portable model by TARGA ? No BFO for SSB/CW in this "World Receiver", of course. And it doesn't had antenna input soi made one with a female RCA. So, if this solution really works with small radios like the TARGA SWED 100 A1, i will buy a signal generator and go ahead. But before, please confirm it if possible. Thanks in advance for your comment. Macedo Pinto Portugal
Pretty sure I’d have to be very careful trying to attempt this on a 1940s ac/dc set I’ve got, actually from listening to what you’ve said at the end. I think I’ll need to study this a bit more, as well as the receiver it’s self! I’m not sure how much noise that receiver produces, haven’t bought it back to life yet, I fed it a bit over 70 volts and it wasn’t happy pulling too much current.
So, if I build a VFO working (for example) in the 80mtr band, feed a little bit of that signal into the antenna input of my old radio, then I am able to receive SSB signals? It makes sense, because I'm adding a "carrier" to the signal! And the radio can demodulate it! Thanks Carlson! That was an eye opening moment. I Always thought that SSB receiving was a very complicated thing to do. Uhm... Generating SSB signals is just a little bit more complicated I guess? I Like your channel, thank you for all the videos!
You can actually generate both AM and DSB signals using the same 4-quadrant multiplier circuit, if you are interested. The AD835 allows you to do both AM and SSB signal generation with just a small change to the circuit. If you then use a band pass filter to suppress the unwanted sideband when on DSB mode, you can emit in either LSB or USB. However, that extra step might not be needed.
Cool. Can you hook up an aerial in addition to the signal generator? Those signal must have been fairly strong if no exteranl antenna was connected yes?
Hi Mel. There is an antenna hooked up. You use the signal generator to inject a very small signal at the antenna jack on the rear of the radio. So basically your mixing the two at that jack.
+Mr Carlson's Lab When you mix the two signals you don't need any diodes or anything? You literally have the siggen output in parallel with the antenna? Great video. Thanks.
I used to recieve south african radio on my guitar amp when I had some effects pedals into it in a certain sequence, Would have been quite anoying if I was trying to record.
Yeah It was something in the chrus and flanger pedals that combined with the strings and the foil isolation on the scratchplate. I guess that could act as groundplane.
Really cool idea for a BFO. You can also listen to CW that way. Love your channel Paul!
Thanks Ed!
Wow that brings back a lot of good memories. When I was a young boy a friend gave me an old military shortwave radio and I figured out how to get it to let me listen to SSB on it. I used and old AM radio to add in the carrier and it worked great. Thanks for this video, it was very enjoyable!
Tony
Glad you enjoyed the video Tony.
I have done this years ago with two radios - the one I'm listening on and another one sitting nearby to use as the "BFO". Very instructive video - thank you!
always interesting stuff !!!!! love your channel
That is the most beautiful radio I think I've ever seen
I had a domestic Marconi 5 valve radio once, and I used a transistor radio to get SSB on the Marconi, I got a 2 foot length of wire wrapped it around the RED oscillator can of the transistor radio and then to wrapped the other end to a IF can with careful fiddling I got SSB no problem, I done that for hours on end.
used to do that years ago. so awesome.
That is a beautiful cabinet on that radio.
I remember doing this maybe 18 years ago using an LM-7 frequency meter and RCA K-80 console. I loosely coupled the LM-7 to the RCA by connecting a wire from the antenna jack of the LM-7 and making one turn around the K-80 antenna wire near the antenna screw. Worked real good.
Most recently did this with a Stark LSG-10A and also an EICO 315 and the receiver was a BC-455A which had its BFO removed by a previous owner.
I found those two RF generators were not stable enough to adequately work for SSB and also the tuning on those two generators was not geared down enough.
That said basic service grade RF generators may not be good enough without modifications to make them more stable and further gear down the tuning.
Stupidly disassembled my original LM-7 maybe 12 years ago for a tube socket, but I have another I got maybe three years ago still waiting on me to finish replacing the bathtub capacitors and once done I'll build a power supply then set it up again in such a way that it will work with multiple radios that have their antennas in the same room as the LM-7.
Very good tip! Thank you
50 years ago I had this problem and by accident found a small two transistor radio placed on top of the receiver and tuned to 550kc allowed ssb to be understood clearly. If I remember correctly usb required the two trans to be tuned to 650 for usb and 550 for usb.
sounds like the BFO my dad homemade for his shortwave receiver. just put it along side and "wammo!' you now have side band radio with AM. direct injection is best to do but if you build it... they will be clear sounding. 73 ad0am
Just came across your channel and its awesome so much to learn. I wonder even though this is such an old video if you would mind if I were to ask a question. I recently built a pixie HF CW kit ...It comes stock with a 7.032 XTAL but I swtiched to 7.050 due to class restrictions . Regardless in order to verify it's operation I used a cheap SW radio and can get full quieting when I power the pixie up and have a 1/2 wave dipole connected on same freq.Of course as this SW radio similarly to what you show here is not SSB but only AM I cannot hear the CW properly . Now just for testing of something similar to this I used another SW radio tuned to almost same frequency to simulate a BFO and I was able to get center carrier quiet and either side a tone . The question is however If I transmit on the pixie all received is the inverse i.e. on the receiving radio I hear tone and the breaks vs nothing and tone if that makes sense. What am I doing wrong in ref. to this ? thank you if you see this .
Many happy memories listening to such signals as a child and wondering how to 'tune them Great to see, I used to get my students to build a BFO etc to allow a simple receiver to copy SSB etc when I used to instruct / examine for the intermediate 'Ham' licence in the UK. Heck! so inspired off to play 'radios' and stop watching this computer
kool video paul'''''i really enjoyed it''''''thank you.
Glad you enjoyed it!
Beautiful radio
Paul, after watching this video of using a sig-gen as a BFO to listen to SSB, it gave me an idea! With great difficulty I was able to use an old Grid Dip meter as a BFO for SSB! I was trying to couple it to the antenna but it was difficult to adjust and couldn't make the signal stable. It needed a more selective tuning adjustment, but with a steady hand it sort of worked! Anyway, maybe you can come up with a better way of coupling a receiver with an old Dip meter to listen to SSB. Let me know what you come up with! Hope to see a video of it too!
Wow. Cool man. Btw, that first persons voice you cleaned up, that was Barry from IV8888. RIP.
Fascinating! Neat stuff! Now I just need to get my radio and signal-generator fixed... XD
Hi Paul - love your vids and electronics course, youŕe such a bright guy. What is your background, military? Can you explain how this : !! extra carrier addition is working to get the circuit to decipher the sideband at relevant points in a circuit please?
Holy cow... you've got yourself some nice test gear, I think I've got bench envy - hi, hi. 73 for a nice video OM.
+pcomp
Thanks for the kind comment!
I enjoyed that!
lol you learn something new everyday.
Glad you enjoyed.
U can also do that with a transistor radio with the volume turned down & turn the variable capacitor bring in your ssb
Great video thanks for sharing. I must admit though, that cyclops radio with the big green eye is intimidating. It keeps staring at me. :-)
also you can do the same with a second Shortwave reciever if you don,t have a signal generator
You can also use another radio in close proximity. I used to use an old Panasonic multi-band to inject a leak into my Radio Shack desktop that lacked a variable BFO. I could tune the Panasonic to a sweet spot to generate a variable signal that decoded USB/LSB on the RS desktop.
I used to consumer grade shortwave radios to receive upper side and on the 20 meter band by tuning the SSB signal on the front facing receiver then using the vfo of the shortwave receiver behind it as the bfo and zero beat the usb signal.
Good job.
Cool....another way to copy SSB and CW is to cause the I.F. stage to go into oscillation by simply wrapping the insulated end of a piece of wire around the lead going to the plate of the converter/mixer stage...then, wrap the other insulated end of that wire around the lead going to the plate of the detector stage...wrap it right on around the insulation of those leads. ..just a few wraps on either end should be enough 'gimmick'-capacitor coupling to cause the IF stage to regenerate and mix with the incoming signal....experimentation will determine the optimum set-up..enjoy! :)
+Terry McKean
Thanks for your comment Terry!
+Mr Carlson's Lab You're welcome :)
How do you do this with a transistor radio...that has shortwave, but no bfo control.???
Basically the same thing, only on a much smaller scale ... locate the collector of the converter stage and locate the detector diode and wrap one end of the hook-up wire around the collector lead and wrap the other end around the diode's anode lead.
The goal is to cause the IF stage to go into regeneration so it's self-oscillations will heterodyne with the incoming CW or SSB and make those signals understandable.
Could you set your signal generator to 455kHz, find a SSB signal then tune the signal generator to 454kHz for LSB or 456kHz for USB? I'm curious if that would also work so one could build a simple tunable IF frequency oscillator to use as a BFO rather that using a 2 to 30mHz wide band oscillator or signal generator.
That's a much easier way to demodulate SSB
An easier way is to inject a frequency close to the IF, about 455 khz. Best if you can do it in an IF stage but it would also leak in from almost anywhere. That way you don't need to retune it. Just rock the main dial until it's clear.
Mr. Carlson,
I was just thinking. Since you know how to cleverly place modern components into radios originally designed with old-fashioned ones, I started thinking. You can create a 540 kHz (or 540,000 cps) solid-state oscillator and use it as a fixed carrier for pre- or post-filtered IF signals which happen to be SSB, and then the radio at least has a carrier which will work to decode SSB. An alternative is to use a "reversed IF" modulator, where you take the (f + 540kHz) carrier insert originally intended to add to the received signal to generate the 540kHz IF, and modulate the carrier through a 540kHz fixed carrier signal to generate a "reversed IF" carrier of f, which can then be inserted into the "front end" of the radio, and now it has a carrier which can help to decode SSB.
That's pretty cool using a freq generator as a beat frequency oscillator.
how much power are you feeding to the ant jack ?
+digitalmediafan
Low microvolt signal.
Is it essentially like this inside a radio made for receiving side-band?
Would this work with modern shortwave receivers? I have a C Crane-SW. I enjoy this radio but it obviously doesn't have a BFO for SSB/CW. It seems to be difficult to find a TG37 module and I was hoping that a cheap RF signal generator could do the same thing.
+Trever Minton
If your signal generator is stable and not a harmonic type, it should work.
Nice little video. Have you tried coupling the signal generator to the IF which would allow you single knob tuning of the band?
Hi Stephen. That would be a fixed frequency BFO, being only single knob tuning. That procedure would be a little more complex for most antique radio owners. With this mode of operation, the radio can drift off frequency and no change in pitch will be heard on sideband. This requires the signal generator to be stable though. For a more advanced application, your idea would be great.
Thanks for stopping by!
really cool, thanks! can you go into a bit about why this works? you say in the video that the radio "thinks" there is a carrier there, but obviously we are not tricking the radio (it doesn't "know" anything).... why doesn't just tuning the center frequency correctly to where the carrier would be, allow the envelope detector to work like this too? why do we need a carrier (a fake one or not)? the "information"/baseband is all in the sideband already and we don't add anything "special" with the fake carrier injection right?
The carrier needs to be added. Thats what injecting the signal does
I'm wondering if this would work if you tuned the signal generator to the IF frequency?
It would, the signal would have to be stronger though, as the IF section is shielded, and it would have to travel through the tuned antenna section.
Mr. Carlson:
This method works with small digital shortwave radios like the SWED 100 A1, a portable model by TARGA ? No BFO for SSB/CW in this "World Receiver", of course.
And it doesn't had antenna input soi made one with a female RCA.
So, if this solution really works with small radios like the TARGA SWED 100 A1, i will buy a signal generator and go ahead. But before, please confirm it if possible.
Thanks in advance for your comment.
Macedo Pinto
Portugal
Pretty sure I’d have to be very careful trying to attempt this on a 1940s ac/dc set I’ve got, actually from listening to what you’ve said at the end. I think I’ll need to study this a bit more, as well as the receiver it’s self!
I’m not sure how much noise that receiver produces, haven’t bought it back to life yet, I fed it a bit over 70 volts and it wasn’t happy pulling too much current.
I suppose you could tune a signal generator just off the IF (in this case ~465kHz) and inject it into an IF stage?
If you inject the 455kHz into the antenna input you will get enough through the mixer
HUH. That's all I can say. Huh! Very nifty!
So, if I build a VFO working (for example) in the 80mtr band, feed a little bit of that signal into the antenna input of my old radio, then I am able to receive SSB signals? It makes sense, because I'm adding a "carrier" to the signal! And the radio can demodulate it! Thanks Carlson! That was an eye opening moment. I Always thought that SSB receiving was a very complicated thing to do. Uhm... Generating SSB signals is just a little bit more complicated I guess? I Like your channel, thank you for all the videos!
Glad you're enjoying!
You can actually generate both AM and DSB signals using the same 4-quadrant multiplier circuit, if you are interested. The AD835 allows you to do both AM and SSB signal generation with just a small change to the circuit. If you then use a band pass filter to suppress the unwanted sideband when on DSB mode, you can emit in either LSB or USB. However, that extra step might not be needed.
I have 3 Stoner Sideband items listed on eBay and am wondering if anyone knows how to test the OSC-40. I am not familiar with Ham radio anything.
amazing equipment yes but, I notice mr.carlson is just as an amazing tech
Thanks for the kind words Doug!
Doug G double that!
That one sound sounded like a broken robot! Ha! XD
Very impressive bench. Just curious how long it took to accumulate that much equipment.
+Gary J
Thanks Gary! Well, it took a while. Stuff just follows me home :^)
oh tghe only things thatg follow me home are dogs, not test equipment LOL thanks 73
Your basically replicating a BFO (Beat Frequency Oscillator).
A trick I did was to place another valve receiver at the side and tune that until ssb became clear.
Cool. Can you hook up an aerial in addition to the signal generator? Those signal must have been fairly strong if no exteranl antenna was connected yes?
Hi Mel. There is an antenna hooked up. You use the signal generator to inject a very small signal at the antenna jack on the rear of the radio. So basically your mixing the two at that jack.
+Mr Carlson's Lab When you mix the two signals you don't need any diodes or anything? You literally have the siggen output in parallel with the antenna? Great video. Thanks.
You got it.
But where do the antenna connects
I used to recieve south african radio on my guitar amp when I had some effects pedals into it in a certain sequence, Would have been quite anoying if I was trying to record.
+rimmersbryggeri
Wow, something was in tune in that circuit.
Yeah It was something in the chrus and flanger pedals that combined with the strings and the foil isolation on the scratchplate. I guess that could act as groundplane.
I used to get cb chatter on my corded land line phone and also the old pay phone across the street. Don’t know how that happened.
That radio looks EVIL
2 minutes in and still talking!