Re: Preliminary results -- W8TEE/AC8GY Mag Loop Testing
Robert D. Bowers
A friend of mine reported very good results with one of the loop
antennas sold by MFJ (40-6 coverage as I remember). He liked it
because of the noise problem - here it can be a huge issue (not
unusual to have S9 noise at least a couple hours out of the day,
and some days 20-40db over the whole day). He got out fine - but
the big difference is that he could hear others. (I've been
thinking about building a loop - because of the noise, but even
more so because they're small and work without being high up - and
this area IS bad for lightning (a couple of direct hits on the
tower over the years and many strikes within a couple of hundred
feet at most, only a few repairs needed in the shack due to very
good grounding, a disconnect 'patch board', and careful layout).
This thread reminds me of what I was told about a person wanting
to run 40m (I think it was for a contest, but for something
'special'). He made up a quicky dipole and just threw it across
the tops of some bushes, a few feet off the ground. He said it
worked GREAT, so much so that a couple of other hams were going to
try it. You wouldn't think it would work so good, but he said he
did really well with it.
Another story - there was a huge sinkhole that suddenly formed
here in Florida. A ham lived just outside of the danger zone, and
reported differences in how his antennas operated as the water
level (immediate water table) rose in the sinkhole. (I don't
remember if his setup worked better or worse - just that it
The thing is, every ham lives in a different situation...
different factors that will strongly affect the performance of
their antennas. Good ground and conductive soil (moisture) vs dry
desert and poor ground, you name it. If one has an idea for an
antenna, try it. It might be just what is needed in that person's
situation - and it's great fun trying. That's part of learning
the electronics/radio portion of Amateur Radio... so you can have
ideas of how to work around issues you may encounter (like poor
grounding). That's just part of being a good op.
On 6/9/19 10:14 AM, EI4GNB wrote:
I knocked up a 3-turn loop, with an old soviet era vac-cap, total length was 10m of copper tube, and it covered 160m thru' 30m and did work very well, although the bandwidth was so skinny on topband, it did not allow for use of the internal tuner in my rig, tuning slightly off the SSB frequency as auto-tuners do when using a carrier. It just weighed so much that it was impractical. Did manage trans-atlantic on FT8 on Topband using it, so not all bad.