[TenTec] Not TT - Wire antenna question.

Paul gw7lhi at hotmail.com
Thu Jan 8 22:44:35 EST 2004


Hi all.

Many thanks for all of your comments, much appreciated and now digested a
little!

The loop is playing well for me in some respects.
To my surprise, I'm getting good reports on top band using 25 watts PEP.
A few days ago, the QRO segment of 160 was alive with North American
stations.
Some of these guys were a few dB over S9 with me here, the radio is a
Ten-Tec Omni V.
I didn't attempt to call any of them, as they all wanted to work an IZ7 who
was 40dB over S9 here.
I used to have a 50m long random wire at a location not far from here, and
the RX signals from that were not as strong as they are on this loop.. nor
are signals from my 20m long random wire.
On 80m, the loop doesn't seem to work well at all. Groundwave TX reports are
down to S3 compared to S9 on a ground mounted vertical. I haven't tried any
DX or EU on 80m yet. RX on 80m is good, so I assume that TX is lousy because
the loop is just over a half wave on 80m.. it's very reactive for sure, and
much easier to tune on 160m or 40m.
On 40m, reports from UK ops are excellent, 10-20dB over the vertical.
Further afield, reports are mixed, for some the loop is better and others
find the vertical better.
I haven't tested any higher bands on TX, the loop loads on them all.

I changed the feed arrangement to some balanced twin feeder to see whether
the tuning on 80m improved.
it did, but several other bands became very touchy and there was more RF in
the shack than there was with the short length of RG58 with it's feedpoint
RF choke. The ATU's internal balun started complaining too.
The RG58 and shield RF choke is back in place now.
Somewhere, I have a commercial 6:1 balun.. I may try this with the open wire
feeder..
I'm not sure what impedance the twin feeder is, it's grey with stranded
copper conductors approx 1/2 inch spacing. Not the stuff that comes with
G5RV's.

The loop is still up in the air on the fibreglass poles, despite 70mph winds
and torrential rain last night & today. I note that the tuning doesn't seem
to be seriously affected by the wire movements in the wind.

All in all, an interesting wire antenna to play with.
I'm particularly taken by it's low noise characteristics compared to the
ground mounted vertical and a 20m long dog legged random wire.

All the best..

Paul MW0CDO.


More information about the TenTec mailing list