James Moritz wrote:
Dear Mal, LF group
A couple of suggestions to try with your loop:
Hello Jim and some observations on your comments.
This is not surprising in a quiet location, since the band noise will
define the SNR with any reasonable antenna - but the really interesting
experiment to try would be to compare efficiencies using the strength of
received signals, first with the loop, and second with the same antenna set
up as a vertical, ie. with one vertical leg and the bottom leg removed. The
vertical could be tuned with a small loading coil for receive only, wound
on a pot core for example. DCF39 could be used as a reference signal, and
your SPM12 would be ideal for comparing the sig levels.
I could try this, but this antenna is not too far away from the main vertical
and there could be interaction especially with the ground radial system near
by. It might not be a good assessment.
There is already some interaction between the loop and vertical.
.
-But you could try some QRP tests without going to all the trouble of the
full power version.
There would be just as much trouble on QRP building another atu for a one off
job, that would also be a backward step, knowing it would never perform
anything like the vertical. I should really be spending more time on improving
the vertical ground radial system.
Wonder Jim if you could put out a signal on 73 khz and work xband 136
sometime today so that I can try the loop for reception.
Tnx de Mal/G3KEV
Cheers, Jim Moritz
73 de M0BMU
| 