[Lowfer] Pixel Loop at LF ?

[Garry Hess]

Mark,

I have a Wellbrook LF 1 mtr loop 
(http://www.wellbrook.uk.com/Loop_Antennas/ALA1530LF-1) and a homebrew 1 
mtr shielded loop a la VE7SL 
(http://members.shaw.ca/ve7sl/burhans.html). They perform comparably in 
terms of SNR. Jack Smith of Clifton Laboratories has made extensive 
S+N/N comparisons between the Wellbrook and Pixel loop offerings 
(http://www.cliftonlaboratories.com/Documents/Loop%20vs%20Loop%20Final-Final.pdf). 
Table 1 shows the Pixel antenna is the winner below 100 kHz and the 
Wellbrook antenna does best at MF. No comparisons are presented between 
73.6 and 550 kHz. It seems reasonable to conclude that both antennas are 
quite comparable in performance and quality so price/availability is the 
decider. As Jay, W1VD points out LF antenna performance in practice is 
like real estate - "location, location, location". That's because the 
noise floor varies substantially with location. If you have the luxury 
of multiple sites you can benefit by trying them all to find out which 
is best.

So far the discussion has focused on which loop is best. Unfortunately, 
to my knowledge Jack hasn't yet included a comparison to his eprobe. I 
made some limited LF comparisons between my eprobes and a 10' shielded 
loop and initially found the loop usually a bit better. However, more 
recently I find the eprobe mounted away from the house in the back yard 
at only 10' performing a bit better on most LF signals than both the 10' 
loop and the eprobe mounted atop the house at 35'. That's telling 
because the 10' loop typically has about a 10 dB SNR advantage over the 
3' loop. Thus, both my e-probes substantially outperform my small loop 
antennas. Unless you need the nulling aspect of a loop antenna, or can 
build a small one with many more turns (like the "octalux" of W4DEX at 
http://www.w4dex.com/lf.htm), I think you'll find the eprobe hears 
better, at least at LF.

My 2 cents worth.

73, Garry, K3SIW, EN52ta, Elgin, IL


-- 
73, Garry, K3SIW, EN52ta, Elgin, IL
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