[UK-CONTEST] Attn: any ZX-yagi owners out there.

[Clive GM3POI]

I found that ZX boom to mast plates did not have enough U bolts holding the
stub mast side. My 30m Mono yagi plate was 10mm thick and had 4 U bolts
fixing the boom but only 2 on the stub mast. The fix is to introduce a
second plate with 4 U bolts to fix the stub mast Back to Back with the
existing boom plate, the two plates being bolted together with 10mm bolts.
The resulting 4 U bolts on both boom and stub does the job so far, but I
have not seen over 87mph this winter so we are just in the breeze stage at
present. 73 Clive GM3POI
----- Original Message -----
From: <pat058 at abdn.ac.uk>
To: <uk-contest at contesting.com>
Sent: Wednesday, January 28, 2004 7:25 PM
Subject: [UK-CONTEST] Attn: any ZX-yagi owners out there.


Hi folks,
Truely evil night up here in the frozen north. Got home through the drifts
(eventually) with a little daylight to spare to see my 3el 20m ZX yagi
lashing about at 70ft in this force 11, doing untold damage to itself and
the 15m yagi underneath it, held up only by what is left of the bracing
rope. A sight for sore eyes for sure!
Lowering and tilting over this tangled mess of aluminium was a pantomime
that even I thought was extreme.

Diagnosis: The boom to mast clamp has completely sheared forward and aft
of the U-bolts fixed to the mast. Clear metal fatigue job and a most
spectacular failure. This yagi....the source of more intra-contest grief
than I care to think of.....was put up in almost identical weather in I
think it was 2001, just prior to ARRL. Some may recall my report!
This is not a big yagi but clearly the boom to mast clamp is unable to
cope with the rotational and flexing forces when it gets windy. I am NOT
impressed.

Just thought I should warn any other owners. Looks like I am out of any
All Band activity for a while and maybe any band activity if this keeps
up. 80, 40 and 10m still standing when last I looked!
Good luck,
Keith GM4YXI (GM7V)


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