Date: Fri, 05 Feb 2010 13:45:56 -0600
From: donroden@hiwaay.net
Subject: [Amps] QRO Questions
To: amps@contesting.com
I've never run anything stronger than a SB-220 or a 30S-1, and I was wondering
after seeing some of the European QRO+++ stations ....... what do they
use for a rotor loop ? Seems that RG-8 and PL-259s or type "N"s would
be a limiting factor to any QRO project ... not to mention burning up
TA-33 CL traps ( or other trapped beams ) ??
Don WA4NPL
## simple. Use RG-393 Teflon coax. It's aprx .391" OD on the Teflon
outer jacket...... vs .405" fro RG-213. RG-393 has a 13 ga stranded
center
conductor.. and all strands are silver plated. It has TWO braids, and BOTH
are silver plated strands. Dielectric is solid TEFLON. Connectors used are
7-16 DINS . [ That's 7 mm + 16mm.. and NOT 7/16"]
## baluns are large type 43 beads, 1" OD x 1/2" ID x 1" long... 17 of em
slid over the 393 [40-6m] 24 x beads used on 80m. 30 x beads used on
160m.
## There is no RF on the pins on any of these coax connectors. The RF is
flowing on the OUTSIDE of the mating female. OUTSIDE of a 7-16
is 7mm [ .284"] INNER collet is 16 mm. Loss on 393 is only a tiny
bit better than 213. Type N's and QRO are a bad mix. Teflon 259's
will also work....just.
## For real hi power QRO.... they use LMR-1200 for the rotor loop.
2-3 x wraps, abt 3' in diam.. wrapped around the mast, with yagi
mounted part way up the mast. Enough flex in the 3 x turn coil,
to allow 360 deg rotation. Type 43 ferrites slid over the LMR-1200
for the balun.
## Traps are out... and that includes the KT-36XA .
## apparently, they also make a bigger DIN, called a 13-30
Later.... Jim VE7RF
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