cobra 29 lx dead key potentiometer

replaced coax, took most of the afternoon taking apart the interior and routing the cable thru. had to cut off the pl259 connectors to pull it thru the mirror brackets. (Pete 386) Going to get 2 Astatic connectors tomorrow and solder them on. Then I should be ready to go I hope. The hard part is over at least.

 

finished today and took SWR reading. Nothing has changed as far as SWR goes, I seem to still have an abnormally high swr with the meter hooked in-line as compared to just using the radios meter w/ the radio plugged straight into the antenna. tried a new jumper cable, nope. Reading are inconsistent but seem to come out slightly higher on ch40 than on ch 1. Still can't always cal. the analog meter and all channels are over 3.0:1. Radios digital meter is pegged w/ analog meter plugged in but good (1.3/1.5:1 across the spectrum when just plugged into the antenna. Was picking up some good skip but keyed up once for radio check but got no response. Very low noise levels this afternoon it seemed. have to see if that continues after replacing coax. What are the chances the problem is in the meter? I cant see what else in the antenna system could be wrong. have two new firestick antenna, that didnt help. Im going to take it to a shop and have someone look at it. Im out of my league here. I wish these things were just plug and play More like pay and play.

 

I am running a 2013 386 myself and this is what I did. Routed a single coax to the drivers mirror. I pulled the antenna bracket out of the mirror, drilled a hole in a flat spot of the bracket and attached a ground cable to it. Routed the ground cable to the pivot bolt on the mirror bracket arm. I also went and got a stainless dome mount for the antenna. I had to modify it slightly with a bench grinder so that it would fit flat on the bracket. Remember that when using a single antenna you must get the coax that is designed for single antenna. You can't just use the coaphased coax. It is a different resistance load to it then the single phased stuff.

I also made up a short ground jumper and grounded the radio chassis to a piece of metal in the over head.

My SWR is almost a perfect 1:1 using my connex 4600 turbo and it does not change with my power settings. I checked it with two different meters. A radio shack SWR/power meter and a cheap bajaran meter that I had in my bag.

I still have two antennas on the truck but one is just there for looks and does nothing. I pull a fairly tall mostly steel trailer and I have not noticed any loss of performance when going to a single phased antenna setup. I talk all over the country with my setup. Was hitting Oregon, New York, Florida and Cali all day on sunday and yesterday on channel 28 with my setup.

I like the single phased because it is a lot less to deal with as far as cleaning connections etc in the winter months.

 

What lenth coax and wbat mind of meter? You need to use a analyzer to start off the use a bird meter with the slug turned backwards. Tbe advice these your getting on here is a joke

 

Carrier pot L10 .
The only problem with adjusting that potentiometer is that you just destroyed the tune of the radio by tampering with that adjustment. Once you change that adjustment there are other adjustments that need to be made to compensate to keep everything in proportion. And assuming that is a Class C amplifier that complicates the matter further and it really needs to be done on a tuned bench as a complete unit to see what the output waveform looks like coming out of the amplifier. If it was a class A/B amplifier technically you could guess and make your adjustments with an educated guess but it's always best to hook everything up on a bench and look at the output waveform on an oscilloscope as you are making adjustments.