[Elecraft] Mag Loop from MFJ

[Fred Jensen]

Ciro Mazzoni loops run from $1,800-$2,500 at DX engineering.  They seem 
to use direct in place of inductive coupling.  The automated tuning is 
cool, but requires a control cable to the antenna as well as coax.  My 
experience with MFJ resembles Morgan's, I wouldn't call them junk but 
they don't stand up well outdoors.  SML's, if the loop plane is 
vertical, tend to be insensitive to ground [i.e. height AGL] and 
surrounding objects if their permeability is close to 1.0. My 
permeability must be close to 1.0 because I sit under it and can reach 
up and tune it, and my presence doesn't seem to affect it. The Alexloop 
Walkham has a reduction gear on the capacitor but it's not enough and 
below 20 m the adjustment gets very touchy.

My HOA antenna is a WOOF [Wire On Organic Fence], a 135' wire strung on 
plastic electric fence insulators on a wooden fence, about 6' AGL, and 
end fed through a 9:1 autotransformer.  Works all HF bands, good for a 
KW [I run a K3/100], and runs circles around the Alexloop. See 
myantennas.com

There is another disadvantage to portable mag loops ... in a public 
place, you may find yourself speaking with a law officer, it seems there 
a number of folks that will call the cops on on the guy with headphones 
sitting at the picnic table in the park.😉

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 1/18/2021 3:38 PM, Morgan Bailey 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
>
>