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There is a good example of
Mini-whip V 40 ft end fed vertical , db
levels are the average over 32 mins , so
that would tend to give a
realistic evaluation , as opposed to peak ,
which would reflect one major incident
during the time lime
Stations about 25 miles apart
west<>east
G..
23:02 136 G3XDV de G4WGT Op32 160 mi -12 dB in Chorley, IO83qo with
0.3w + Inv-L
23:02 136 G3XDV de G0NBD Op32 163 mi -23 dB in Nr Liverpool with 0.3w
+ Inv-L
Sent: Friday, July 05, 2013 5:26 PM
Subject: Re: LF: Wellbrook RX loops
Hi Roger
I use a Wellbrook Loop type ALA1530 (MW/HF) mounted 1m off the ground and a PA0RDT mini-whip
mounted about 7m above ground. Sometimes the loop wins other
times the miniwhip. The miniwhip is omnidirectional and uses the e
field, whereas the loop is directional and uses the magnetic field.
The miniwhip is more open to BC breakthough than the loop but more
sensitive. I tend to monitor with the miniwhip, and switch to the
loop after homing in on the signal if this helps. BC breakthough is
overcome using a simple series LC circuit tuned to the required band at the RX
end of the coax. The QRM at my QRT can be horrendous, as I am only
100 yards from the OH lines on the East Coast main railway line, surrounded by
houses and a block of flats with associated busy roads. My 'T'
transmitting aerial 8m high is useless for RX. I can fully
recommend both miniwhip and Wellbrook Loop, both of which cover from LF to
10m. For best results, I suppose a tuned loop about 1m
square has the edge, but not as convenient.
73 Dennis M0JXM
Can anyone advise, from actual use, how
well a Wellbrook loop works on 136 and 472kHz RX ? The excellent OIP2 and OIP3
figures and directivity suggest one could be very useful.
73s
Roger
G3XBM
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