[Elecraft] K3 - G5RV vs ZS6BKW antenna
Rich - K1HTV
k1htv at comcast.net
Sat Mar 10 09:01:10 EST 2012
Dick,
Instead of the G5RV antenna, consider using a modified version of it, the
ZS6BKW, with your K3. The ZS6BKW antenna has better impedance characteristics on
more bands than the G5RV. The K3's ATU matches the antenna on all of the bands
that it is designed to work on, 80, 40, 20, 17, 12 and 10 meters. It will also
work on 6 Meters, but its lowest SWR is at 51 MHz, not very helpful. The ZS6BKW
antenna has a slightly shorter flat top and slightly longer section of ladder
line than the G5RV. I've installed two ZS6BKW antennas with a 45 degree
difference in orientation and can switch between either of them. On 20 Meters,
the results is that the 4 major nulls of one antenna can be covered by switching
to the 4 major lobes of the other antenna.
So, how do they work? Well, in the past 3 years since retiring from VOA and
moving to a new VA QTH, I have worked 275 countries with 100 Watts. I recently
added a borrowed 3 element tribander for most of the last 15 countries worked.
Over 260 countries were worked using ZS6BKW antennas. With the K3 and its ATU
the ZS6BKW will work well on 80, 40, 20, 17, 12 and 10 Meters. On 160, 30 and
15M, the ZS6BKW does not work well at all, even though the ATU can produce a
match for the K3 on some of those bands.
A ZS6BKW construction note, for one of the antennas I used a common mode RF
choke made up of the 20 turns of the 50 Ohm RG58U coax feed line wound around a
6 inch diameter plastic COSTCO nut container. The second ZS6BKW antenna uses a
choke made of the same type coax but wound on a pair of toroids, as described by
Jim, K9YC on his website. In each case, the choke is installed where the ladder
lead meets the coax and NOT at the shack end of the coax. If you are interested
in the ZS6BKW antenna, check out the articles below.
http://www.ab4oj.com/dl/sprat_zs6bkw.pdf
http://www.w5ddl.org/files/Zs6bkw_vs_G5rv_20100221b.pdf
73,
Rich - K1HTV
www.k1htv.us
= = =
-----Original Message-----
From: raroth7 at comcast.net [mailto:raroth7 at comcast.net]
Sent: Friday, March 09, 2012 2:38 AM
To: Elecraft Reflector
Subject: [Elecraft] G5RV antenna experience on K3
Hi there--
Am considering putting up a g5rv antenna and was wondering what experiences K3
users have with this antenna. Is an external tuner necessary? Is internal KAT3
up to the task of taming this wire?
Any hints will be helpful
--
73 de Dick, ka1oz
Elecraft K3/100
GAP Titan-DX Antenna
PS...Tried sending via my gmail account, but haven't seen it posted. I
appologize for any wasted bandwidth.
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