Re: automatic magnetic loop adjustment


Murray Wills (ZL2IQ)
 

This looks fantastic Jack. Can’t wait to see the article. Murray ZL2IQ


From: BITX20@groups.io <BITX20@groups.io> on behalf of Jack, W8TEE via Groups.Io <jjpurdum@...>
Sent: Friday, March 6, 2020 9:58:36 AM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] automatic magnetic loop adjustment
 
Al Peter (AC8GY) and I have an article in the Feb. 2020 issue of Rad Com that describes our Double-Double Mag Loop:

Inline image

It is a 3' diameter loop, but the double configuration raises its efficient from about 10% to 50% on 40M and over 90% on 20M. We tested the remote control unoit at Field Day last year using 100' of cable and it worked fine. Tuning is done by Fast Tune (i.e., previously-stored values in EEPROM) and then fine tuned if necessary. All bands can get the SWR to 1.2 or less. The control unit uses the STM32F103 ("Blue Pill"). The cap can be air or vacuum (high power).

It's probably not a good choice for pedestrian mobile use, but those who face HOA restrictions might find it useful.


Jack, W8TEE






On Thursday, March 5, 2020, 1:48:26 PM EST, Mark Muller <markvmuller@...> wrote:


Excellent Project!

For some reason, the link above did not work in my browser, and perhaps others might have the same problem. Hopefully this link is operational: https://www.qsl.net/py2ohh/trx/loopauto/loopauto.html

There seems to be some improvement to the original work here: https://www.qsl.net/py2ohh/trx/loopauto2/loopauto2.html 

Parabéns Miguel! 73 de N5KNG (Mark Muller)

--
Jack, W8TEE

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