Hi Frank

I bought a Radio Shack Loop antenna a while back
; works pretty well!
- But I need a smaller, lighter A.M antenna for travel;
the smaller & lighter the better;

- hence the ferrite experiment.
Already have a Sony AN-LP-1 works great for SWR

Dan


Have you made a box loop? I never bothered with ferrite rod antennas,
because I figured a good sized loop would be a better performer. But
I'd be curious about a side to side comparision.


In article ,
"Frank Dresser" writes:


"Diverd4777" wrote in message
...
Frank, thanks:

- took a 2-3 inch peice of paper wrapped it rond the ferrite,
then wound ~50 turns ( tight spaced) round the paper.
( About ten feet of 26 gague wire.)

Taped it in place, the whole thing slides tightly up & down the
ferrite.

Will go to Goodwill & pick up a radio tomorrow; - found the price goes
up if
you say it fer parts; - maybe if I say I've fallen & found JESUS
Price'll go
down
- In any case..
This being NYC, I'll bring bus spray & a plastic bag; spray the radio
whilst in
the bag. Tye it up, put it in the trunk & drive on home.

Once home, will take the bag ouot to the lawn,
unwrap it,

Kill whatever staggers out

( - New York! New York! It's a wonderful town !!)

Then clean the radio with Paper towels & bring it inside.
Plan on disassembling it in the Apt house Basement.

then bringing the cleaned up parts ( Capacitor, radio's ferrite.)
upstairs..

& THEN I'll try the procedure someone from the ferrite group sent to
Elfa..
& modify as needed..
with a few tricks..
SHOULD work.. !

Dan

It'll work, but it's hard to give specific instructions on how to make
it work the first time. It's something to experiment with. By the way,
the variable capacitors from Ocean State Electronics are pretty good. I
have three of them, and they're date coded from 1999. They may still be
in production. The plastic dielectric caps are harder to tune and work
with. Nearly all of them are designed for AM/FM radios and have a bunch
of unmarked tabs sticking out. More to experiment with. You can also
use the original antenna winding to tune the AM band. There's likely at
least one smaller winding on the ferrite rod you can use to connect to
the antenna terminals of a radio.

Have you made a box loop? I never bothered with ferrite rod antennas,
because I figured a good sized loop would be a better performer. But
I'd be curious about a side to side comparision.

Frank Dresser

Yodar & CW,

Multi-Stranded "LITZ" Wire will generally require fewer turns and
produce a higher "Q" for a given Ferrite Rod and frequency range.

Solid (single-Stranded) "Magnet" Wire will generally require more
turns and produce a some what lower "Q" for a given Ferrite Rod and
frequency range; than Litz Wire.

Both Litz Wire and Magnet Wire are preferred over everyday Insulated
Hook-Up Wire to wrap a coil on a Ferrite Rod for an Antenna.
Generally, Insulated Hook-Up Wire would produce the lowest "Q" of the
three types of wire.


iane ~ RHF
..
..
= = = "CW"
= = = wrote in message news:hhYmb.25685$mZ5.115003@attbi_s54...
Unless you don't have it then use magnet wire. You'll never know the
difference.


"Joe Strain" wrote in message
m...
Litz wire, a specially woven fabric insulated wire is required for
Loopsticks SKYCRAFT electronics in Orlando has it at iirc $0.08/ft
.
Yodar


On 26 Oct 2003 14:08:45 GMT, (Diverd4777) wrote:


- anyone have any idea which type / gauge wire is best for a ferrite
antenna ?

That's not a bad price.................I have been using Litz wire, with
good results.

Pete

Joe Strain wrote in message
m...
Litz wire, a specially woven fabric insulated wire is required for
Loopsticks SKYCRAFT electronics in Orlando has it at iirc $0.08/ft
.
Yodar


On 26 Oct 2003 14:08:45 GMT, (Diverd4777) wrote:


- anyone have any idea which type / gauge wire is best for a ferrite
antenna ?

FD,

If you are going to try the 'fully covered evenly spaced' wire wrapped
Ferrite Rod Antenna (FRA). Try using nylon/poly Fishing Line as the
non-electrical/non-magnetic spacing material. Start at one end with
both the wire and the FishLine and tightly wind them as a 'pair' flat
and evenly over the FRA. Usually, 100 LB FishLine works well. For
some 'types' of FRA Material and FRA "Sizes" using one wire and two(2)
FishLines (twice the space) will work better.

Just a simple 'trick' to keep the Wire Coil Tight and Evenly Spaced.

iane ~ RHF
..
..
= = = "Frank Dresser"
= = = wrote in message ...
"CW" wrote in message
news:hhYmb.25685$mZ5.115003@attbi_s54...
Unless you don't have it then use magnet wire. You'll never know the
difference.


That's true. I have several radios with standard wire wrapped around
the ferrite rods. Usually when they use standard wire, the turns are
spaced widely enough to take up nearly the length of the rod. A wide
wire spacing, about twice the thickness of the wire should reduce losses
and increase the tuning frequency range, compared to close spaced wire.
In practice, the tuning range problem will probably be more noticable.
Just wrap a bunch of wire, spaced maybe 1/16 to 1/8 inch or so, over the
length of the rod. This probably won't tune to the top of the AM band.
Then remove turns until it tunes to the top when the cap is fully open.

Frank Dresser

Pete / Joe ; thanks for the advice !

Here's the URL for Skycroaft in Orlando...Litz wire source ( & probably more !)


http://www.skycraftsurplus.com/

- Since I've got the loop wrapped in magnet wire already I'll try that first..
- really not critical for what i'm doing;
I guess I could take some monofilament, spiral it around hte magnet wire in 1/2
/ 1/4 inch spirals, rewrap it & maybe get the same effect as when using Litz
wire..

- Wonder what they use for the Justice antenna . . ?

Dan



In article ,
"Pete KE9OA" writes:


That's not a bad price.................I have been using Litz wire, with
good results.

Pete

Joe Strain wrote in message
om...
Litz wire, a specially woven fabric insulated wire is required for
Loopsticks SKYCRAFT electronics in Orlando has it at iirc $0.08/ft
.
Yodar


On 26 Oct 2003 14:08:45 GMT, (Diverd4777) wrote:


- anyone have any idea which type / gauge wire is best for a ferrite
antenna ?

Magnet wire is made of copper. But if you make a loop (coil) and run a
voltage through it it becomes a electro magnet. Lower gauge wire will give
you more turns per inch. So you can pick up lower frequencys.

Bill, N5NOB

Bill Hennessy wrote:

Magnet wire is made of copper. But if you make a loop (coil) and run a
voltage through it it becomes a electro magnet. Lower gauge wire will give
you more turns per inch. So you can pick up lower frequencys.

Bill, N5NOB

Wouldn't that be higher guage wire giving more turns per inch? Higher the
gauge, smaller the wire size.

Steve
Holland, MI

Drake R7, R8 and R8B

"Diverd4777" wrote in message
...
Hi Frank

I bought a Radio Shack Loop antenna a while back
; works pretty well!
- But I need a smaller, lighter A.M antenna for travel;
the smaller & lighter the better;

- hence the ferrite experiment.
Already have a Sony AN-LP-1 works great for SWR

Dan


I see. A box loop still might be workable. They can be made
collapsable or foldable. I saw an antique box loop in which the upper
center support of the X telescoped into the lower center support and the
side supports folded down. Pretty cool, but not so easy to fabricate
with whatever is around the house.

Still, a cardboard form maybe 4 inches wide and 1 foot or so on each
side could be folded into a reasonably compact package. It should
perform about the same as the RS loop. Or a piece of cardboard could be
cut for a spiderweb winding. Just cut an odd number of notches about
1 -2 inches deep, spaced about 2-4 inches apart around the perimiter of
a piece of cardboard. Maybe 8 or 10 turns, depending on your cap - but
add a few more turns, so you can tune it in.

A plastic dielectric cap is smaller and less fragile than a air
dielectric cap and will be better for portable use. You don't need to
spend alot of time trying to figure out which are the AM oscillator or
AM antenna or the FM parts of the capacitor. Just figure out which are
the common lugs and the cap lugs. You can wire up the all AM and FM
lugs together for more total capacity. The higher total capacity will
mean you need fewer turns for your antenna. Be sure to open all the
half moon trimmers so you get the widest capacity range.

Frank Dresser