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Matching tranceiver with amp (2 replies and 1 comment)

M0LUX
6 months ago
M0LUX 6 months ago

Hello. I need an advice. How to match the transceiver output with the input of a linear power amplifier? The easiest way I know is to install an SWR meter between the transceiver and the amplifier. By supplying a small amount of power from the transceiver, adjust the input coils of the amplifier on each band to a minimum SWR. But I have a multi-band OCFD antenna and the SWR is not very good. Will this somehow affect the coordination between the transceiver and amp?? Or should I ignore this and only go for the lowest SWR between the transceiver and the amp? Thanks. 73!

M0LUX
6 months ago
M0LUX 6 months ago

Hello.

I need your advice and help. I am using a used Ameritron 811 linear power amplifier. On 10 and 15 meters there is a lot of excitation when transmitting. I'm guessing there isn't a good match between the transceiver and the PA. I'm guessing my PA needs to check the input coils on each band. I tried checking by SWR, but this method did not give me the desired result. Unfortunately, I do not have the appropriate testers to accurately adjust these input coils. I will be very grateful if someone can help me. Thank You. 73! Alex. M0LUX (UR5LUX)

G0UIB
5 months ago

You need to tune in and bias the valves for each frequency. The manual should walk you through this without the need for any extra test gear apart from the ammeter on the kit. It's best to do this at very low input power and into a dummy load (don't worry it will have high reverse isolation so won't change much when the antenna is attached, it just means any random output remains in the shack). Also, make a note of the settings for each band so you have a good place to start from next time.

Peter M0PWX (2E0PWX)
5 months ago

i found a manual for it, you have to change some settings for each band ?

AL-811 (qrzcq.com)

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