[Elecraft] Mag Loop from MFJ

[Paul GACEK]

I can’t speak to the MFJ but I do have a 3 ft diameter AlexLoop that I imagine is similar at a very high level and in addition as M0SNA I have the Ciro Mazzoni Baby Loop which can handle a wicked amount of power and is built like an Italian sports car. One thing that surprises me about magnetic loops is there high price.

Anecdotally, my AlexLoop did an amazing job on 10-20m and was a really crap shoot on 40m. I think the numbers quoted might be very optimistic as I think on 40m (and 30m) a 3 ft magnetic loop is horribly inefficient.

One thing I learnt from talking to Ciro Mazzoni is that the lobes created by these smaller magnetic loops are pretty high of the ground possibly with a concentration of power at 50-60 degrees off the horizon. That aside, my AlexLoop surprised me in early 2016 during NPOTA as I managed phone WAS using 10w portable from the San Francisco area. My Ciro Baby Loop seems to have no issue with stations out 2-3K miles but beyond that its a really luck of the draw and clearly tied to bands and propagation. From the UK on 20m and 40m I struggle to get East Coast stations.

I’m happy to have the Magnetic Loops in my arsenal but would pick another antenna if circumstances dictated.

Here is a short write up on my AlexLoop which I do like…..https://nomadic.blog/2018/09/20/oh-ye-of-little-faith-my-journey-with-an-alexloop/ <https://nomadic.blog/2018/09/20/oh-ye-of-little-faith-my-journey-with-an-alexloop/>

Paul
W6PNG/M0SNA
www.nomadic.blog <http://www.nomadic.blog/>
 

> On Jan 18, 2021, at 4:40 PM, Mooneer Salem <mooneer at gmail.com> wrote:
> 
> FWIW, mine has worked fairly well (on the roof of my second floor condo)
> since last year, moreso on 20 than 40 meters. At the time I was honestly
> not sure how else I'd have been able to have something permanently set up
> outdoors (unfortunately needed due to stucco construction) and HOA approved
> otherwise*, so there's definitely a market for them. In my experience, the
> "band change" buttons stop tuning when the SWR gets close--even when
> retuning within the same band--and the slow tune buttons seem to have
> enough granularity to allow someone to stop when the dip in reflected power
> happens. If one's loop doesn't do that, there's a pot that one can adjust
> inside the control box to fix that particular issue.
> 
> Anyway, this thread does remind me that I should go back up and confirm the
> conductor diameter for sure; I had been assuming something close to 1"
> before but it's likely smaller than that.
> 
> -Mooneer K6AQ
> 
> * I only found out about the Isotrons after setting up the loop.
> Considering the supposed bandwidth of the 40m and up ones, it's possible
> I'd have gone with those instead (since less effort is always nice).
> 
> 
> On Mon, Jan 18, 2021 at 3:43 PM Morgan Bailey <mbaileycrna at gmail.com> wrote:
> 
>> They are unreliable pieces of junk. The housing does not protect the
>> capacitors that are in house made and bugs can crawl into the housing and
>> short them out. Secondly, the plastic housing in Kansas will be destroyed
>> by the sun. The best thing about the loop is the loop itself. It is built
>> well. The caps are cheap. Tuning the bastard is not consistent, not fast,
>> and highly touchy. The only loop worth purchasing is the Ciro Mazzoni loop
>> from Italy sold by DX engineering. It will take abuse and has an excellent
>> tuning feature that will follow your radio. Each time you change freq with
>> the MFJ it is a task to get it to tune again. A friend of mine bought one
>> and it was soon offered to me for $100. Then he became so frustrated with
>> it that he wanted me to take it for free if I would dig the post out of the
>> ground he mounted it on. I Passed knowing that any dipole would blow it
>> away. Even an end fed random wire will beat it in performance if put up
>> right. In the end there are many cheaper options that work far better than
>> the MFJ mag loop.
>> 
>> 73,
>> Morgan NJ8M
>> 
>> BS + MS + $2.98 = COFFEE
>> Real Life Experience = Priceless, says the man who set his back yard on
>> fire with a breadboard tuner loading a 160 meter inverted L with 1000
>> watts. LOL
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