is there ane tune and peak mods for this radio im looking into an rfx75 but want to know modulation pots or power pots to tune thnxs
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uniden bearcat 880
- Thread starter pimphand442
- Start date
One of the shortcomings of the Uniden 880 is the lack of tuning points within the radio, the only one's that I recall are for the squelch control, weather alert and meter functions.
They can be tuned a peaked but the labor involved is not worth it.
If you wanted to do it to your own radio for your own satisfaction and have some older junk CB radios around for parts swapping it can be done. Basically you remove the fixed coils in the transmit chain and replace them with the adjustable "screwdriver" ones out of the junker radio. Do it one coil at a time and check results. After done with that use some low value caps ~~10 to 50 pf to jumper (parallel) the caps between the driver and final. Once you find the cap and coil combo for most power out move on the the next connection cap and do the same. Don't mess with the last coil between the final and coax socket, that's to filter out the second harmonic which falls into the channel 2 of TV sets and right on the edge of the Ham's 6 meter band.
Don't ask me how I know this but I have a screaming swing monster Viet Nam Pro 510xl.
Monk
If you wanted to do it to your own radio for your own satisfaction and have some older junk CB radios around for parts swapping it can be done. Basically you remove the fixed coils in the transmit chain and replace them with the adjustable "screwdriver" ones out of the junker radio. Do it one coil at a time and check results. After done with that use some low value caps ~~10 to 50 pf to jumper (parallel) the caps between the driver and final. Once you find the cap and coil combo for most power out move on the the next connection cap and do the same. Don't mess with the last coil between the final and coax socket, that's to filter out the second harmonic which falls into the channel 2 of TV sets and right on the edge of the Ham's 6 meter band.
Don't ask me how I know this but I have a screaming swing monster Viet Nam Pro 510xl.
Monk
Back when the 880 and new line of Uniden surface mount radios came out. I bought a few to test. Maxing the RF section out is a no go on these things. As Monk pointed out using coils from donor radios is optional but I can tell you that it wont gain much. I tried using 25/29 back end to see if that was the bottle neck and it just wouldn't gain more. I did every audio modification I knew to include Mauldulators/NPC/Direct Inject and they all resulted in the same. Lowering the deadkey/carrier is a way to increase your modulation, the other is more audio drive and/or lower AMC action. Since the 880 is transformer modulated like a 29, you could do the "JP36" mod to lower the deadkey and increase your modulation that way. Adjusted with an Oscope , you could get a very nice signal and sound. For power , go amplifier.
I don't know if anyone cares about this one way or the other but I had a customer the other day that asked while I was repairing his 880 if I could eliminate the damn beep so after I brought it back to life I did some circuit tracking and came up with this in about 20 minutes or so.