[Elecraft] Fw: HIgh swr on 6m

[Edward R Cole]

I have seen higher SWR with amplifiers connected in-line but not 
energized.  It seems I saw this in recent tests I made with my Mirage 
A1015G (10w/150w), so I did a quick check.

I ran 5w with the K3/10 so I could use the 5A element (25-60 MHz) in 
my Bird power meter and tested into a dummy load to start with.

had 1.0 SWR indicated by the K3 and zero reflected showing on the 
Bird with power adjusted exactly to 5w forward.  Then I inserted the 
6m PA and got exactly the same readings.  I did see forward power 
shift about 0.2w so its not a perfect match.

I repeated the test with my 3-element 6m yagi as load.  Straight 
connection shows 0.25w reflected and SWR=1.5.  I got exactly the same 
measurements when the amp was inserted.

I would not have been surprised to see a change in readings with the 
antenna load since it is not a perfect match.  Getting a good match 
is often not realized with the open frame relays that are commonly 
used in ham amplifiers
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While I had everything set up I decided to measure the amp output 
with my 100H and 500H elements.   With 6w drive I found I get 100w 
output showing with the 100H and 110w showing with the 500H.  With 
power set to full output of 8w 130w is displayed with the 500H 
element.  I typically claim it will do 125w.
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Subject: Re: [Elecraft] Fw: HIgh swr on 6m
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Stewart, do you have an amplifier attached? ?I have found that having 
my Clipperton L in the circuit causes high SWR on 6 meters, but if I 
connect direct to the antenna switch the SWR on my SteppIR is low as 
it should be. ?
?
Willis 'Cookie' Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart

73, Ed - KL7UW
http://www.kl7uw.com
dubususa at gmail.com
"Kits made by KL7UW"