Monday, September 10, 2007

Murphy's Law as applied to antennas

Have you ever noticed that when you really, really want to be able to use an antenna, then it suddenly and mysteriously develops a hitherto unknown fault!

3B7C hit the bands dead on schedule at 2000z on Friday. 10MHz looked like the place to try and work them first off. I dropped down the band and though the antenna was receiving ok, on transmit, the SWR started off at about 1.5 and gradually crept higher. I could tell something, somewhere wasn't right and was heating up.

I reterminated the PL259 at the shack (not aided by the fact that my soldering iron wasn't where I expected it to be! I hasten to add, that it was me that had misfiled it, not any other hands..). No difference.

Went up the garden in the dark and checked the feed. Seemed fine. No difference.

Gave up in disgust and went to bed, to look at the problem fresh in the morning.

Tried all the usual stuff - no difference. Thought it had to be something to do with the feeder and sure enough, picking up the SO239 barrel connector where the coax feed is attached to the aerial - it was warm! Thank goodness I don't run a KW!

I took the connector apart - cleaned it out and the problem vanished. Phew!

Now, of course, the pileup for 3B7C is huge! But given a few days, I'm sure I'll be able to work them. Have heard the guys on 80, 40, 30, 20 and 17m so far. Best signals from them on 40 and 30m for me.

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