On air oscillation?
Howdie gord, The way you descibe having to turn your mic. gain almost completely down, sounds as if some one has already gotten to one of the VR's.. This would also require the standard nylon tuning tools. You can google up the specs for the radio, just google the type & model, being sure to specify "mods" on the end. Like: Cobra 148 gtl mods... There are several hundreds of hits you will get. It sounds to me as if someone went in and turned 1 or more of your Variable Resistors in order to get more audio out of your rig! With a Watt and modulation Meter in line I would concentrate on the AM section of mods. Audio in particular. You should also be able to download the schematics for your rig. It will at least show you in relation to your antenna output symbol, where to find your VR's.. The audio is what I would work on 1st. It will say some thing like adjust VR14 or VR12 ect, to adjust your output audio. There are a Great Number of modifications for that rig. It should be checked by an FCC Certified Technician. But alot of Folk's just dive right in! These models, depending on the PLL Chip, may also be capable of talking "Out of Band", and Uncle Charlie is still very active, along with other HAMS in finding the Offenders. I have to say, that I can not stop you from trying to save a few bucks by making adjustments on your own. Dependable Radio Shops are getting pretty far apart now though.. But really gord, all the answers are on youtube, or google. On youtube, you at least get an idea of what you are looking for to cut the audio back down, and make the rig a little less responsive as far as your mic. gain knob goes! I have several Cobras, all SSB,AM, and a couple with FM. I stick with my Kenwoods and Collins gear though. I do like the 148gtl's alot, but they are not type excepted for HAM use!
Good Luck gord, and I Hope I have helped in some small way. I live outside of Atlanta, GA. There are alot of truck stops near by. Truckers will most times tell you who is got a Golden Screwdriver and who to stay away from. I wish you a lot of luck and SEASONS GREETINGS from W4Land! 73 P.S. Since no one has to know Morse Code any more, You could study online for Free at www.qrz.com to prepare for a HAM Ticket! It is Very Easy and Quick to get your Technicians Class now. I have a freind that is a Maritime HAM I need to get ready and try and reach him. He is out of Hong Kong by now, so ya'll have a Great Season. Collin...
Cobra 148 GTL...
on Dec 05, 2011