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10M DF Loop

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10 M DF Loop

This is a design that I found some years ago and it certainly provided a very usful DF tool for 10M.  Recently I have been looking at this design again and thought I should pop it on the net.  The article is written by a well known foxhunter from the 60's and 70's in Gil Sones VK3AUI (SK). Click on the link to download the article. This is scanned and OCR'd so is not in the original format.

If you want to add the sense antenna here is what I found.  The inductor is 20 turns of .5mm wire on an 8mm former with slug.  Sense antenna is 370mm long 1.6mm diam wire. Rather that use the 100K pot in the article I used a 1K pot his gave much better results and made tuning easier. Tune for a null and there should be a peak 180 degrees away. The null is much more pronounced that the peak.

I fed the power up the co-ax to the amplifier using 1mH chokes and .02uf coupling capacitors.  I have had some problems burning out the choke at the DC injection point but have built a current limit circuit for this now that solved this problem.


Last Updated on Sunday, 20 May 2012 00:54