I have used the MFJ model (1786 ?) which covers 10 to 30 MHZ. I have also used various horizontal "wire" loops in bedrooms & currently have a 40M full size version (more-or-less) following the edges of my loft - about 33 ft AGL. This one is a good general-purpose qwiet receive antenna for 80 upwards, a reasonable NVIS in the day, all-round EU by night on 40M and "OK" generally on higher bands.
I feed it at a corner with 100 Ohm coax into a T type tuner - not purist but OK. So I guess this is similar in polarization & effect to Wayne's indoor loop. The MFJ is mounted high in the same loft in its' vertical orientation. Results over a no. of years have generally been better than the expectation for a "small" antenna - eg 1st contact on 10MHZ when newly-installed was a cross-town CW chat - but - followed immediately by Reunion Isle and then a ZS before the EU pile-up wiped-out my QRP ! Understand some of the MFJ quality comments - but this loop is manufactured like a tank - including the butterfly C. The weak part of the system is the tuner - the cross-needle bit was hard to interpret & has now failed - however, I have added an-inline VSWR/Power meter & it seems as good, with the bonus that I need << 15 W MFJ recommend when tuning... There is a big long-running debate between Jack Belrose & Mike Underhill re the efficiency/performance of small loops - well worth trying to follow (I'm at work, call-signs not to hand - I can supply some refs if wanted) The other bonus is - it acts as useful pre-selection, although not required for the K2 ! I am trying to figure out how to couple a low-loss inductor effect into my loop to get it down onto 40M - I suspect MFJ use a different, bigger butterfly capacitor in their 40M version. Any comment on my problem would be appreciated 72 George G4TPV This e-mail is intended only for the above addressee. It may contain privileged information. If you are not the addressee you must not copy, distribute, disclose or use any of the information in it. If you have received it in error please delete it and immediately notify the sender. Security Notice: all e-mail, sent to or from this address, may be accessed by someone other than the recipient, for system management and security reasons. This access is controlled under Regulation of Investigatory Powers Act 2000, Lawful Business Practises. _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
