Well I can't get it to work like I see on videos lol. I have a 93 model and tried it. it tried to work but no sound like I've seen on Youtube.
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Trying To Do The VFO Wind Up Cobra 29 Chrome Help Please
- Thread starter blake25537
- Start date
Come ON! Guys what would you do if you wanted to make a 29 delta tune circuit do this silly frequency shift when you key the mic?
Think about it you are trying to add a timing circuit to the varactor circuit when the transmit voltage is switched from one setting to another during the REC/XMIT cycle. What is the capacitor added to the anode of D18 doing when you key the mic and remember D18 is only a switching diode and the cathodes of the delta tune circuit diode (D17 i think) and D18 are tied together. Also remember the offset has to be great enough to make an AM receiver notice the offset this could vary a little from one 29 to another as far as the value of the cap is concerned I never did this but it would seem you need about a 3kc shift or more to make this happen.
" It does not require another signal on the channel to hear this" the wisp sound is there because it's slowly coming on frequency so it's slowly drowning out the noise level and replacing it with an amplitude signal the only way you would not hear this affect is if there is no background or noise in the receiving radios receiver which could be what is happening to blake25537 if he is using a test radio that isn't hooked up to an outside antenna. Blake make sure you pay attention to the S-meter on the test radio and see if it slowly goes from 0 to s10 when you key the mic on the 29 you are modifying and make sure the volume is wide open on the test radios receiver. Just some thoughts please show me error of my ways!
Think about it you are trying to add a timing circuit to the varactor circuit when the transmit voltage is switched from one setting to another during the REC/XMIT cycle. What is the capacitor added to the anode of D18 doing when you key the mic and remember D18 is only a switching diode and the cathodes of the delta tune circuit diode (D17 i think) and D18 are tied together. Also remember the offset has to be great enough to make an AM receiver notice the offset this could vary a little from one 29 to another as far as the value of the cap is concerned I never did this but it would seem you need about a 3kc shift or more to make this happen.
" It does not require another signal on the channel to hear this" the wisp sound is there because it's slowly coming on frequency so it's slowly drowning out the noise level and replacing it with an amplitude signal the only way you would not hear this affect is if there is no background or noise in the receiving radios receiver which could be what is happening to blake25537 if he is using a test radio that isn't hooked up to an outside antenna. Blake make sure you pay attention to the S-meter on the test radio and see if it slowly goes from 0 to s10 when you key the mic on the 29 you are modifying and make sure the volume is wide open on the test radios receiver. Just some thoughts please show me error of my ways!
I remember seeing a video about this mod somewhere and they said that 2 radios in the same room may not be enough distance to notice it and suggested having someone on-the-air give you a report. Also, if (by chance) your receive radio is on SSB, to test on AM (because in SSB you can't hear your radio scream..
)You need to listen for it on usb on another radio in the same room then you can hear it.
This is how I did it on my 2007 29ltd and it works. Feel free to laugh lol.I wired it to the cb/pa switch. I like so many others, wanted to just see if it works. Apparently there are people out there charging $80 dollars to do this mod lol, this is not some magical life changing mod. If it’s something you want done to your radio, I would not even in my wildest dreams... think about paying for someone to do it. At the end of the day,you have to remember it’s a dumb thing to do lol.
This is how I did it on my 2007 29ltd and it works. Feel free to laugh lol.I wired it to the cb/pa switch. I like so many others, wanted to just see if it works. Apparently there are people out there charging $80 dollars to do this mod lol, this is not some magical life changing mod. If it’s something you want done to your radio, I would not even in my wildest dreams... think about paying for someone to do it. At the end of the day,you have to remember it’s a dumb thing to do lol.
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Not practical. Only works on a radio that already has a Delta Tune knob on the front. The circuit connected to that control is what's being modified for that trick. A radio that's missing that knob is also missing the circuit that would get modified.
73
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I suppose it was inevitable that someone would install a Cobra 29 Delta Tune circuit in a radio that wasn't built with it.
And you will need a varactor. Still not a terribly long list of parts.
Go for it!
73
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