[Tech-Assist] Moseley SL9003Q

[radioranger]

>>Now, why didn't the Moseley TX LCD display indicate high VSWR?  Called
>>Moseley tech services.  The young punkin who answered (note: wear your hip
>>waders when talking to this person) told me that they have a circulator in
>>the transmitter output circuit and that the VSWR circuitry monitors TX
>>power
>>BEFORE the circulator.  

I second the thought about measuring the output of the transmitter with a
Bird thru-line meter.  Because the signal isn't a continuous wave carrier
the Bird will read a lower figure than you'd expect--- more like 3/4 watt
forward on the Bird for a displayed figure of maybe 1.25 watts on the
internal Moseley meter.

Of course you can also turn the slug in the Bird around to get some idea of
reflected power, but with a 5 watt Bird slug you won't see very much, even
if there is a problem with the line or antenna.

The other gotcha I ran into is a low received signal level on the receiver
that may have nothing to do with the line or antenna.  In my case something
was going south in the first stage of the receiver, before the signal level
meter, that dropped the level from a normal -58 dBm to about -78dBm.
Replacing only the first module (the one with the N connector) took care of
that problem. 

A spectrum analyzer, directional coupler and tracking generator are still
the best way to troubleshoot these problems.

Steve Brown
Radio Rangers
Minneapolis