RadioBanter - View Single Post - Collins 30L-1 Output drops at higher bands

Ralph Mowery · November 19th 20, 10:48 PM posted to rec.radio.amateur.boatanchors

In article ,
says...

I just bought a 30L-1 at a local auction.

It puts out 500 watts on 3.5 MHz and 7.2 MHz

On 14.5 MHz it's 350 Watts.

On 21.2 and 28.25 MHz its 200 Watts.

Any thoughts on where to start trouble-shooting?

I'm thinking of checking the bias voltage and working from there.

I'm driving it with a Ten-Tec Omni -D with 100 watts output. The reflected power in the exciter is low, less than 1 watt.

I've ordered the power supply HV upgrade kit since the caps are old and this amp has sat for many years.

Thank you for your suggestions.

The tubes are probably soft. The power supply voltage could be low due
the bad capacitors, but that would not account for the drop off in power
as you went higher in frequency.

You did mention the swr was very low so hope you checked that on all the
bands.