High SWR with amplifier in line

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oe3ide
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High SWR with amplifier in line

Postby oe3ide » Fri Jun 25, 2021 8:33 am

Hi all,

I have a strange behavior regarding high SWR:
1) Gemini HF1K switched off
2) Carrier on 40m (2-tone)
=> 1w to 100w ... SWR constant 1 : 1,24 ALL OK

1) Gemini HF1K switched on (bypass mode)
2) Carrier on 40m (2-tone)
=> 1w to ~42w ... SWR constant 1 : 1,24
=> >43w ... SWR starts with 1: 2,5 and goes down to 1 : 1,24
=> >65w ... SWR starts with 1 : 3  and goes down to 1 : 1,24
=> >80w ... SWR starts with 1 : 3, but goes down to 1 : 2,2

This happens with my 4sqare (SWR direction west 1:1,24) and the endfed-wire antenna. 40m-band SWR on endfed-wire is 1:1,3.
If I switch off the Gemini... everything is normal.
Same happens on 80m band (endfed-wire SWR 1:1,55)
The same problem also if I use ANT B on the Gemini, which is connected to a dummyload.

Normaly I use only max 25w, enough to drive the Gemini. Yesterday I wanted to transmit with 100w on the 40m band, and then this things happened.

Any ideas?

I also contacted Roger from TheDXShop.... So I am not sure if its the Amps fault or maybe something wrong on my Anan / Settings.

73 de Ernst
OE3IDE
User avatar
oe3ide
Posts: 389
Joined: Tue May 05, 2020 8:36 am
Location: JN78XK
Contact:

Re: High SWR with amplifier in line

Postby oe3ide » Fri Jun 25, 2021 8:59 am

Helmut, 100% correct. I have the confirmation from Roger.
In standby pass-thru (diode matrix) is max 50w....

73 de Ernst
OE3IDE

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