Hmmm. A 25 year-old mobile CB. They say it's not just the miles, it's the years, too.
Gotta wonder how many miles AND mods it has acquired since 1979 or 1980. Might need to consider the "Ten-Volt Blues" if it spent a lot of time on the shelf before you got it. The ten Volt-rated electrolytic caps in any Uniden-made radio that old often wait until you have run the radio for a few days or a week before they go bad. One of them will kill all transmit. Another just kills the mike audio. Another will kill the receiver audio only, without affecting transmit. Another will roach the loudspeaker and/or audio chip when it fails. Someday I gotta put up a "scorched earth" procedure for replacing the whole list at once on those old models. Don't see how I could cover expenses selling a three-dollar bag of electrolytic caps, even if I marked them up to ten. Not rich enough to outsource it to China. Dang.
If it's really the legal 40-channel version, and NOT the 3-band EXPORT version, it has the 8719 chip and a 11.1125 MHz crystal. Same circuit board as the Cobra 142GTL or Uniden Washington. Only mobile.
The three top choices on the hit parade for added frequencies are:
1) An Expo kit. Type "B", if memory serves. Not the best choice for SSB, but relatively simple. If you can live without stretching the clarifier one whole channel, the Expo kit doesn't drift that much when used as a base. Put it in a vehicle, and the temperature extremes will reveal enough drift to be annoying. Covers 40 below and 40 above. If it's a newer kit, will show the same digits on the channel selector as an "export"-type multi-band radio does for one band up and one band down. An older Expo-100 type "B" would be off by one or two channels from what a Galaxy radio shows for the same upper or lower frequency.
2) Change the 11.1125 crystal to an 11.325 and use the fairly-simple toggle-switch mods used for Cobra 148, Grant XL/LT-type radios. Again, skipping the "one channel slide" routine on the clarifier helps make this setup more stable, even in a mobile environment. Using a center-off toggle to select the skipped "RC" channels is usually a better choice for SSB than the 'stretch-down-one-channel' routine on the clarifier. This is the most stable choice for mobile SSB use, but puts the sequence of your new frequencies in an odd order. Requires a "map" to find a particular frequency, and you can't just "scan" all the uppers in sequence looking for DX. Bottom line: More effort to use, but more stable, especially in mobile use.
3) "Try" the so-called "Six-position rotary-switch" channel mod with the stock 11.1125 crystal. This one covers from 64 channels below channel 1 up to 28.045. Doesn't mean the radio will perform over more than 60 or 80 out of all those, but it can be optimized for lowers at the expense of upper-channel performance, or for uppers with reduced performance below 1. This setup is notorious for behaving oddly when temperatures rise or fall a lot, like in mobile use. I recommend it as a base-station use only mod. Even so, one or two out of every ten radios will be 'twitchy' with this mod, losing and regaining whole sets of channels when the radio feels like it. The other eight or so out of ten will run for years before internal adjustments drift, and it starts to twitch. Requires a "map" of the new frequencies, and may get squirrelly if the clarifier is stretched too far. Should be accompanied by the center-off toggle-switch for the skipped "RC" positions on the channel selector. The reason I started #3 with the word "Try" is that you'll want it taken back off if your radio wants to "twitch" and jump up or down 64 channels after the radio's been running for an hour or so.
Pretty sure Defpom stopped making his EPROM kits. They kept the channels in a nice, sequential order, but there are a LOT of wires to hook up with that method.
Too bad nobody ever got around to making a plug-it-in "Viagra" kit for these radios.
One last thought. The Galaxy "FC-347,FC-390,FC-148" external frequency displays will wire up to this radio, but will read off by 1 kHz on USB and LSB. AM will read okay. These external displays are directly compatible with a 148, Grant Xl/LT, Cobra 2000GTL, and President Madison, but only PARTLY compatible with the Stalker 9/142/UWashington.
73
TR-32).