You can build your own but it's actually not worth it.
--
Ron Hardin



I beg to differ about loops that you build are not worth it.
I designed and built many MW loops that are as good or better in some ways
that the Kiwa loop. The problems with homemade loops is poor construction.
This link has pictures of loops that I built.
http://www.frontiernet.net/~jadale/M...20Antennas.htm

Jim

"Jim" wrote in message ...
You can build your own but it's actually not worth it.
--
Ron Hardin



I beg to differ about loops that you build are not worth it.
I designed and built many MW loops that are as good or better in some ways
that the Kiwa loop. The problems with homemade loops is poor construction.
This link has pictures of loops that I built.
http://www.frontiernet.net/~jadale/M...20Antennas.htm

Jim

I agree....My homemade loops are better for my uses than what you can
buy. I can design any feature I want, and generally they are bigger
and deliver more voltage than most storebought. I built two more loops
yesterday just farting around. "Both for longwave". Maintaining
balance is the secret to success. Also, I did an experiment on mine a
couple of days ago. I've been using a simple coupling loop on mine
lately, but do have a shielded coax coupling loop also. "IE: the coax
shield is cut in the middle at the top". One had mentioned an
advantage to using a shielded loop vs a non shielded. Well, I tried
both feeding my 12 turn 16 inch round loop. No difference whatsoever
in noise, or null depth. I had never noticed much difference with
single loops of each type either if you were careful to detail.
So far, I have not been able to see much of an advantage to a shielded
loop vs unshielded as long as you are careful with balance. They seem
to work about the same here.
I'll never buy any antenna. For the prices they charge for a loop, I
could build a house full of them, and do. I noticed the guy that makes
the little wooden ones, and sells on e-bay got like about $85 for the
one he listed recently. Good grief...Most of the money is for the
fancy woodwork I assume..But electrically, his loops are inferior to
my mine. Mine was free, except for the price of the wire. I know of
no storebought loop that provides the exact performance of my usual
"general use" 16 inch loop. IE: provides coverage from 500-2000 hz to
include 160m. The freq coverage of the one on e-bay was less as an
example.
But I do agree on one thing. Properly built, a loop is a loop is a
loop. If you have one that is working well on a certain freq, and has
good nulls and enough voltage, there is little to gain by trying
another one. My next project??? I wanna design a *small* terminated
loop if it's possible. Kind of a rotatable *baby* K9AY loop. I'm not
sure if it will work or not though. I'm wondering if it's feasable to
terminate a normal multi-turn loop, and make it unidirectional by
inserting a terminating resister on one side. I really need a ground
point to tie the terminating resister to...Maybe not, as so far I have
trouble making it work. If not, I'll try building a normal smaller
K9AY outside I guess...
Oh yea...A last comment...Long wires on MW are just great if you like
4 stations at one time...:/ A loop is much better if you want
directivity and the ability to null out unwanted stations or noise.
MK

In article ,
(Mark Keith) wrote:

Jim" wrote in message
...
You can build your own but it's actually not worth it.
--
Ron Hardin



I beg to differ about loops that you build are not worth it.
I designed and built many MW loops that are as good or better in some ways
that the Kiwa loop. The problems with homemade loops is poor construction.
This link has pictures of loops that I built.
http://www.frontiernet.net/~jadale/M...20Antennas.htm

Jim

I agree....My homemade loops are better for my uses than what you can
buy. I can design any feature I want, and generally they are bigger
and deliver more voltage than most storebought. I built two more loops
yesterday just farting around. "Both for longwave". Maintaining
balance is the secret to success. Also, I did an experiment on mine a
couple of days ago. I've been using a simple coupling loop on mine
lately, but do have a shielded coax coupling loop also. "IE: the coax
shield is cut in the middle at the top". One had mentioned an
advantage to using a shielded loop vs a non shielded. Well, I tried
both feeding my 12 turn 16 inch round loop. No difference whatsoever
in noise, or null depth. I had never noticed much difference with
single loops of each type either if you were careful to detail.
So far, I have not been able to see much of an advantage to a shielded
loop vs unshielded as long as you are careful with balance. They seem
to work about the same here.

The shield is electrostatic and would only help against local noise
(example - in the room computer) being the pickup loop.

If you had an un-tuned broadband amplified single turn shielded loop
compared to one that was not shielded then you would expect to see a
difference.

Loop antenna is a broad term.
Here are some features:
1. Small or large compared to the received wavelength.
2. Shielded or not.
3. Single or multi turn and shape type example - pancake or solinoid.
4. Tuned or un-tuned.
5. Several ways to couple them to the receiver.

Now you can mix and match the 5 above into many possibilities all with
different tradeoffs.

--
Telamon
Ventura, California

Telamon wrote in message

The shield is electrostatic and would only help against local noise
(example - in the room computer) being the pickup loop.

Yes, And I could tell no real difference from it to a unshielded loop.
This assumes the unshielded loop is fairly well balanced though.

If you had an un-tuned broadband amplified single turn shielded loop
compared to one that was not shielded then you would expect to see a
difference.

I would think so. But so far I don't really see a drastic difference.

Loop antenna is a broad term.
Here are some features:
1. Small or large compared to the received wavelength.

A small loop is directional inline with the windings. A large loop,
broadside to the windings.

2. Shielded or not.

Again, this is debatable as to the effectiveness...I consider it an
option.

3. Single or multi turn and shape type example - pancake or solinoid.

A pancake coil is directional broadside to the loop. A solenoid,
inline with the loop. Or so I've read...So far, almost all of my small
loops are solenoid type. I have thought about planting a big pancake
coil on a door though...

4. Tuned or un-tuned.

All small passive loops should be tuned. At the least, using the self
resonant freq. With the cap, lower in freq...

5. Several ways to couple them to the receiver.

I use normal coupling loops, both shielded, and unshielded as a test.
I see no difference in results..I don't use preamps. Don't need em...

Now you can mix and match the 5 above into many possibilities all with
different tradeoffs.

Thats what I'm doing here, but with not always the results I want...
IE: I made a 45 turn LW loop that I hang up against my usual 16 turn
MW loop. I used the same cap for each loop, by using a switch. It
worked great on both "bands". Didn't mess up the MW loop. So then, I
decided to wind a LW loop on the same frame hoping for the same
results. The LW worked fine, but the MW was detuned. So I just now
ripped all the LW turns back off and will go back to the previous
method with a bit more separation between the windings. I'm rigging
mine up to cover from about 150hz to 2000 hz in two steps. "coils".
This lets me use the same cap for both, and I don't have to tack on
extra fixed caps for LW. But I still want to build some type of
unidirectional rotatable small loop. In messing with the LW loops, I
have discovered something about my radio I hadn't noticed.
"IC-706mk2g". Although it tunes down to 30 cycles, the radio goes
pretty dead below about 150 cycles. Not the greatest LW radio in the
world for real low freq's... It's ok from about 175 hz, up.. MK

I agree....My homemade loops are better for my uses than what you can
buy. I can design any feature I want, and generally they are bigger
and deliver more voltage than most storebought.

MK,
would you mind emailing me? I have a question.

(Dxluver) wrote in message ...
I agree....My homemade loops are better for my uses than what you can
buy. I can design any feature I want, and generally they are bigger
and deliver more voltage than most storebought.

MK,
would you mind emailing me? I have a question.

Actually, I prefer to keep it on the NG, but you can e-mail me if you
want.
The main reason I like to keep it on the group is if I lay a clam,
someone will usually correct me... MK

The main reason I like to keep it on the group is if I lay a clam,
someone will usually correct me.

huh, OK.

(Dxluver) wrote in message ...
The main reason I like to keep it on the group is if I lay a clam,
someone will usually correct me.

huh, OK.

Yea... As an example, the other day I said a pancake loop's nulls
were at right angles compared to a solenoid loop. The reason I said
this, was I saw it mentioned on a web page somewhere. But after
thinking about it more, I'm not so sure that is correct. Seems to me,
they should act the same as a solenoid loop as far as null direction,
being they are both "small loops". But I'm not sure...All my current
loops are solenoid. Any comments from any pancake loop owners? Are the
nulls broadside to the loop, as in a solenoid loop? Or opposite?
I do know a ferrite bar antenna is opposite from a solenoid loop. BTW,
I just built a new bigger loop yesterday. It's a diamond loop appx 43
inches per side.
It's 5 ft across at the spreaders. Built it from PVC and is a simple
cross frame. I have it in the room with me, and it's rotatable on a
stand like my 16 inch loop. It's working real good so far. It does
give a lot more voltage than the small loop. About 2 s units worth on
average. Will be good for weak signals in quiet cdx. Good for LW too,
being it's pretty big. Started out with 7 turns, but ended up with 5.
I couldn't tune 160m at first. I'm using two variable caps, one appx
850 pf?, and one that is maybe 50 pf or less full mesh, and two sets
of fixed capacitance to tune from 250 cycles to about 2.5 mhz. On the
high end, I'm using very small capacitance values. In fact, I had to
take a 3 150 pf?? "guessing" piece variable, and only use one section
for those upper freqs. The balance came out as good as my other one,
and about equal or better nulls. Using a one turn coupling loop inside
the tank coil. The nulls seem even and the same either side. Thats
what you really want to see. If they slew off from actual direction,
or are unequal , you know you have a balance problem.
MK