Search results

https://www.ebay.com/itm/283737307487?mkcid=1&mkrid=711-53200-19255-0&siteid=0&customid=link&campid=5336136228&toolid=20001&mkevt=1 This is an FM conversion board. They have 4 left at the moment.

That is actually a Noise Activated Squelch board, not an FM detector. This is tied directly to the Discriminator output of an FM detector, before filtering. I used to make FM detector boards on perf-board based on the FM detector section in an Export radio (uPC1028H is ECG1234) (like in a...

I have had a good number of 1st gen 2950's and 2970's (have one in my storage now). I noticed when operating in split frequency, and the Roger Beep was on, it would beep on the RX frequency. I rerouted the PTT line from the Mic plug, to the dual op amp like in a Galaxy (etc...) then run the TX...

The previous pic was of the smallest "A" kit you will ever see. This is for the older gen 29's, with either a uPD2816 or the Cobra29 Chinese clone that fits the 29's. This does the 15.36 over-ride. The new AM/FM radios, along with the latest gen of the 29LX, has the new CPU serial data driven...

You mean, an Expo100 "A" kit? This is the smallest "A" kit you will ever find. It has 4 bands, 1 up, 2 down, plus regular. So, A= -80, B= -40, C= regular CB and D= +40. And has auto-switching. C87 is removed and is now on the board. I used to "roll my own" FM boards on perf board, back...

It will have a slight delay before releasing to RX if left in SSB mode, but no other affect.

I'm working on it.

VR7 is FM Deviation.

I have a couple of ideas. Stay tuned....

There is no mixer frequency. No offset like older 29's. These use a direct PLL signal of 37/38 MHz to the RX mixer, and direct 27 MHz to the TX buffer stage.

When comparing the new AM/FM radio to earlier model schematics, other than the PLL daughterboard section, and FM daughterboard section, the rest match up (mostly) to the same on the schematics as, say, the 29 LTD Classic. C65 (.01uF or 103) feeding the TX buffer TR16 and most of the rest of the...

Another thing I noticed, Case Ground is no longer capacitively coupled to Board Ground, it is now direct. So, Negative Ground Only. This is from the C29 Classic AM/FM I got last weekend.

The PLL in this latest generation of Cobra 29LX and the new 29 AM/FM models are serial programmed, this particular PLL outputs the VCO frequencies direct. Here are FCC submittal pictures for the new AM/FM Cobra 29 radios out now. This also uses the same PLL/VCO daughterboard as what the 2nd...

CBC quit advertising the Channel Guard filters in 2011. I contacted him in 2019, he said he quit selling them because of slow sales. Lou had a few left unfinished, and some guy bought the whole lot, thought he had a "corner on the market, jacked up the price. I have an updated model, in both...

I received a C29 Classic AM/FM through Amazon Sat. I have opened the case to evaluate, thus far, I have deduced these: - VR7 is indeed the Deviation control, as the wiper terminal goes to JP34, which goes to the FM-Mod connection of the PLL/VCO daughterboard. The "high side" of VR7 goes over...

What does VR7 do? It looks like it might possibly be the FM Deviation control, seeing as it is near the PLL/VCO daughterboard. Have you tried to adjust it, listen on another radio, see if that is it? Then put it back if it isn't.

Most CBs use AGC level squelch, where a signal has to get over S5 or whatever the Squelch is set to, before it opens the audio. FM in a VHF or UHF Ham Radio uses FM Noise Activated Squelch. This takes the random high frequency noise that an FM detector puts out in between signals, then when a...

https://cbradiomagazine.com/wp-content/uploads/2010/01/CB_SECRETS_VOLUME_23_Page_4220Custom.jpg

1 and 4 are fed by the VCO and 10.240 all the time, pin9 is only "live" when TX voltage (+8v TX) is fed to it through R33 and R95. IC3 is your TX Mixer chip. IC2 is your VCO chip. TR21 is indeed the TX switch. A PNP transistor, the center pin is Collector. So that part is correct.

IC3 is only active in TX mode.