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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.

I'm waiting to get one of the Cobra 29 AM/FM ones as soon as they are available, the AM/FM 29 has the same PLL/VCO daughterboard as this new version of the LX. I have a couple of ideas that should work for channelizing both radios, but not an "A" kit. Or maybe. I won't know until I crack the...

Removing or cutting R249 merely disables the AMC. The diode goes somewhere else. I do not condone disabling the AMC or ALC circuits, because this is what causes 99% of the hash, trash, splash and bleedover in other people's receivers. The AMC responds to Negative going voltage swings. A...

I designed this a while ago, I have the Gerbers in queue to be made. This one has 40 pcs per sheet, 10mm x 15.5mm each sub-board on a sheet. I have a few other project boards in queue, too. Galaxy Spur Filter goes on top of the TX Mixer, either the SO42P or SM6130. The input buffering...

So, 12.205 and 42.205?

Where are the spurious spikes at? Frequencies? Or adjacent channel spikes?

It looks like the PLL and VCO are under that metal cover on the daughterboard. And, is Serial programmed. I wonder if it has 17 or 37 Meg VCO for the RX, and direct 27 Meg for the TX ?? And, looks like the same daughterboard that will be used in the new 29 AM/FM radios about to hit the market...

https://www.worldwidedx.com/threads/from-the-desk-of-jack-steel-cb-radio-newsletters-from-the-80s.263001/ Issues 1 through 10

Like most CB radios, the case ground is floating, so the radio can be mounted in either negative ground or positive ground vehicles. Case ground is capacitively coupled to board ground in various places, especially the audio and Transmit areas of the board. Always use board ground, or an IF...

Sue from LBComms in Sydney AUS?

You mean like this?? I need to get back on the ball and bring these out to market. Half (or less) the size of the Lou Franklin ones, 1 extra level of feed voltage stability. I have crystals for 7.8 MHz and 10.695 MHz.

You would want to install that before the AM-FM - SSB split, so it is for all modes. C118 (5pf) in green circle.

CB1 and CB2 are for AM and FM, and have no effect on SSB modes. The signal splits at D4 and recombines at D7. The AM/FM path also have the 2nd mixer injection to downmix the 10.695 signal (after CB1/CB2) down to 455KHz. After D7, the IF stages each have 2 coils, 1 for 10.695 (SSB) and 1 for...

I buy other components from them in bulk, too.

Magnum 257HP uses the 7530 with a 2030 driver. https://www.cbtricks.com/radios/rflimited/magnum_257hp/graphics/magnum_257hp_schematic.pdf

https://www.mouser.com/c/passive-components/frequency-control-timing-devices/crystals/?frequency=12.096%20MHz&instock=y

I have (in my storage unit) an AR3300-100w with the SP1A speech compressor. I got it on eBay 2008'ish.

No. Cobra 148GTL made by Uniden, The Grant XL etc... series have 3kc wide, 6 pole filters, hence the 1.5kc PLL and Carrier offsets. The exports use a 4kc wide, 4 pole filter (and 2.5kc offsets), where the AR3300 and AR3500 had either the 4kc wide filter (same as above), or the optional 2.6kc.