Scott MacKenzie wrote:
>I have a 6M beam that is showing high SWR (10:1). I checked each
>connector to the antenna by disconnecting and placing a dummy load.
>Finally up at the antenna, I disconnected the antenna, and placed the
>dummy load as the antenna. Readings were 1:1 SWR. I then clean up the
>connector at the antenna, and retest. SWR is still high.
>
>I then pull down the antenna (K1FO or similar - not M2) and check it
>out.
>
>With the coax disconnected, I check the connector - good continuity
>from the center pin to the otherside of the connector (where the gamma
>match is attached.
>
>I check from center pin to ground on the conductor to see if shorted -
>Circuit is open.
>
>I check to make sure I have continuity between outside of gamma and
>rest of antenna. Circuit is fine - and shows continuity.
>
>The only thing I can think of left is to replace the coax less shield
>inside the gamma.
>
>What else can it be?
1. Check the SWR with an antenna analyser connected directly to the
antenna. The DC measurements were a good place to start, but they don't
tell you everything.
2. If there are N connectors involved, it's possible that a centre pin
may have pulled back inside the cable. N connectors don't have a lot of
tolerance for axial movement, and very occasionally you find a pair of
connectors where each one works fine with the test equipment, but they
still don't connect to each other.
--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
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