[HCDX] An easy MW loop

["Sean \(G4UCJ\)" <g4ucj@xxxxxxxxxxxx>]

Hello all, just thought I would share with you how I made my MW loop
antenna. For a circular loop, it is quite large-the diameter is 1.3 metres
and consists of 5 turns of hook up wire, close wound, with a single pick up
turn overwound. I had looked at various methods of constructing loops, all
of which seemed a bit cumbersome and heavy when they approached the 1m
square/diameter mark. I was looking for something that would give me
adequate signal pick up and be easily turned. My solution was to use 2
children's hula hoops (made of plastic, with an in line joint). Using two of
these hoops gave me a maximum diameter of about 1.6 meters, but that was
just a little too big for the location the loop was to be used in. I trimmed
them down and made a "T" type cross support from bamboo canes. The "down"
part of the T would be used to support the loop for rotation. The bamboo
cane was just the right diameter to fit into a 6.4mm (quarter inch) jack
plug-the plastic barrel providing the support. A plastic box that houses the
tuning capacitor array (a switched  3 gang air spaced variable plus
switchable fixed capacitors) and an FET preamplifier also serves as the base
support for the loop. The whole thing is surprisingly sturdy and very
lightweight. The loop tunes from 360kHz up to 2MHz, with extremely sharp
nulls (aided by the increased "Q" that the preamp introduces). I heard
Boston, MA on 1510 a few nights ago, so it must be working OK! I did make a
small version which was 30cm in diameter and that performed very nicely too.
It is a lot easier (and cheaper) than having to saw up a forests' worth of
timber to make a frame (that is so heavy you can't turn it!). If anyone
needs any info, please drop me an email to g4ucj@xxxxxxxxxxxx .

Good Dx-ing!

Sean Gilbert

---[Start Commercial]---------------------
World Radio TV Handbook 2002 is out!
You can get yours for $17.47 + shipping + possible tax in some states.
Please visit: http://www.amazon.com/exec/obidos/ASIN/0823059332/hardcoredxcom
And while you buy it, you'll also support Hard-Core-DX. Thank you.
---[End Commercial]-----------------------
________________________________________
Hard-Core-DX mailing list
Hard-Core-DX@xxxxxxxxxxxxxxxx
http://www2.hard-core-dx.com/mailman/listinfo/hard-core-dx
http://www.hard-core-dx.com/
_______________________________________________

THE INFORMATION IN THIS ARTICLE IS FREE. It may be copied, distributed
and/or modified under the conditions set down in the Design Science License
published by Michael Stutz at http://dsl.org/copyleft/dsl.txt