[aprssig] MFJ Data Radio

Frank Knobbe k4fhk at knobbe.us
Wed Mar 16 16:51:51 EDT 2016

On Wed, 2016-03-16 at 12:59 -0500, Al Wolfe via aprssig wrote:
> Richard et al,
>     This one is on 144.39 so had hoped to use it for APRS. Service monitor 
> says transmit power is nearly 5 watts, but on receive it takes a couple of 
> microvolts to see anything out of the noise. Maybe I'm expecting too much.

I have a 8621A. When I first received it, it was near deaf. Or totally
deaf, don't remember. I had sent it back to MFJ (lazy, no time, was
brand new and I expected more) and it arrived back on my door step in
the same deaf condition. So I took a look at it myself.

Basically, the solder job was crap. I resoldered everything. What fixed
the problem was the solder joints on the crystal itself. Since the
ground is on large area of copper, that solder joint just needed some
extra TLC. Once it was soldered properly, the radio worked like a charm.

Take a look at your solder joint, especially in areas where cold joints
can happen easily. Check the joints of the crystal. (I still recommend
spending a bit extra time to resolder every joint).

Hope that helps,

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