开云体育

It is very possible the problem is on his end, not yours.

One interesting way to "listen to yourself" is to use WebSDR (). Find an open SDR with an appropriate freq range and antenna, tune it to where you'll transmit and listen (or record) while you send. Of course, you can always call a friend to listen as well ... but that is less techy :)

--
-Mat Breton, N8TW

I'd take the comments of that particular station with a grain of salt.

What was the VE7 using for a receiver? Was the noise blanker, DNR or other noise-fighting features enabled - and possibly mis-configured?

Our 980s have a relatively good noise blanker - few other rigs can extract a signal from man-made QRN as well, at least in my experiences. It's entirely possible to mis-adjust the NB Level control and make an otherwise clean-sounding station sound like garbage but this is relatively easy to verify from a glance at the controls. A late-model menu-driven rig might not be so intuitive; I know of one recent occurrence with a friend and his 7300 which resulted in this exact scenario.

The old OO program was also replete with people who IMNSHO had absolutely no business commenting on a signal's characteristics, as they had limited understanding of how their receivers worked. Fewer still had lab-quality receive measurement equipment at their disposal to properly qualify a suspected "problem".

If you have a doubt regarding your station's spectral purity and linearity, trap-display monitor scopes and HF spectrum analyzers are getting to be commodity items these days. Pretty much anyone can afford them.

73 - Fred, N8YX?

Just for what it is worth. I am today involved with ( series 040XXX) PA. All capacitors and in (fan) control unit attached to it are tantalum. As I said in a former post the TX13.5V from RF unit to PA unit went to 3V. The source is OK, so I will start changing tantalum capacitors 9 in total. Very clear overload, some capacitor went nuts (as expected). They dont go open, they short, and may damage circuit upwards.

Mine went too far because 25 years of no use. But the first symptom of malfuntion is distorsion because the capacitors pull down the PA bias voltage. When you notice it may be too late. Anyway the 13,5V PS overload control made its job in my case. Probably cut the whole and left 3V. Q01 in 13.5V PS acts as a constant intensity source.

Dry tantalum (and Niobium-Oxide) are typically more stable than wet electrolytics when left uncharged. Field failures can often be traced as secondary failures caused by a primary failure elsewhere (large AC ripple due to an upstream dried electrolyte, or an overvoltage caused by a downstream shorted semiconductor). And of course ... poor design. If you replace a tanty , I would recommend double-checking the circuit in operation for excessive ripple, voltage margins to avoid a repeat down the road.

--
-Mat Breton, N8TW

Thanks Mat Breton N8TW. Sorry for the noise in this topic on overdrive.

I think I will continue on a new topic on this

73 EA1FC (not familiar at all with transistors)