RadioBanter

RadioBanter (https://www.radiobanter.com/)
-   Shortwave (https://www.radiobanter.com/shortwave/)
-   -   Homemade AM ferrite antenna question (https://www.radiobanter.com/shortwave/38691-homemade-am-ferrite-antenna-question.html)

CW October 19th 03 10:14 AM

They are a tuned resonant circuit the same as a box loop. Half of that
resonant circuit is in the radio. Due to differences in the circuitry, there
is hardly a way to just say "take a ferrite rod and wind X number of turns
on it". I could tell you how to do it, including the math necessary, if you
really want to get that deep. If not, and you just want performance, build a
box loop. Lots easier and plans are readily available.


"
You're too far ahead of me RHF. I haven't a clue as to how they work.

All I
wanted to do was just make one 2 times as big as on in a junk radio to see

if I
can get stations better based on size of antenna. At this point, I can't

find a
website that even explains windings etc.





donutbandit October 19th 03 10:26 AM

elfa wrote in :

You're too far ahead of me RHF. I haven't a clue as to how they work.
All I wanted to do was just make one 2 times as big as on in a junk
radio to see if I can get stations better based on size of antenna.
At this point, I can't find a website that even explains windings etc.



My God, can't anybody do anything any more without having to consort with
the Internet and get permission from the Netizens?

You wind some wire on a ferrite bar. You put a variable capacitor across it
and see how it tunes. You adjust the windings until you get what you are
looking for.

Do you need toilet training instructions, as well?


elfa October 20th 03 12:58 AM

In article , donutbandit says...

elfa wrote in :

You're too far ahead of me RHF. I haven't a clue as to how they work.
All I wanted to do was just make one 2 times as big as on in a junk
radio to see if I can get stations better based on size of antenna.
At this point, I can't find a website that even explains windings etc.



My God, can't anybody do anything any more without having to consort with
the Internet and get permission from the Netizens?

You wind some wire on a ferrite bar. You put a variable capacitor across it
and see how it tunes. You adjust the windings until you get what you are
looking for.

Do you need toilet training instructions, as well?


No...no need for the toilet training instructions. I can **** in your face
without consulting a manual.

elfa



CW October 20th 03 02:36 AM

Elfa, I hope you plonked this guy, you didn't deserve that.


"elfa" wrote in message
...
In article , donutbandit

says...
No...no need for the toilet training instructions. I can **** in your

face
without consulting a manual.

elfa





elfa October 20th 03 03:08 AM

In article E_Gkb.598055$cF.262444@rwcrnsc53, CW says...

Elfa, I hope you plonked this guy, you didn't deserve that.


It's the main reason I rarely visit this group. Too many blowhards and not
enough of those with genuine expertise.

I appreciate your offer of instructions re the ferrite bar antenna but I think
I'll just skip it for now. This was the wrong group for this kind of request.
It should have been in an electronics group.

elfa




"elfa" wrote in message
...
In article , donutbandit

says...
No...no need for the toilet training instructions. I can **** in your

face
without consulting a manual.

elfa






Brenda Ann October 20th 03 03:41 AM


"elfa" wrote in message
...
I appreciate your offer of instructions re the ferrite bar antenna but I

think
I'll just skip it for now. This was the wrong group for this kind of

request.
It should have been in an electronics group.

elfa


The number of turns necessary for a loopstick antenna depends on several
factors.

1) the frequency range required
2) the permeability of the ferrite core
3) the spacing of the turns

For experimentation purposes, you might start with about 80 turns of AWG 30
enameled or cloth covered wire, contiguously spaced, near one end of the
core. With this, use a ~360 pF variable capacitor.

If you have a grid dip meter, you can easily find where this is resonant. If
you don't, then you have to poke about on the AM dial of a cheap radio, and
see where you can tune it.




Timo Nieminen October 20th 03 12:50 PM

Good strategy is to make a guess and wind some extra turns. Then find out
whre you are. It is easier to to remove the extra turns than wind some more.
Adding the windings expects you to make solder joints, maybe several ones.

timo


"Brenda Ann" wrote in message
...

"elfa" wrote in message
...
I appreciate your offer of instructions re the ferrite bar antenna but I

think
I'll just skip it for now. This was the wrong group for this kind of

request.
It should have been in an electronics group.

elfa


The number of turns necessary for a loopstick antenna depends on several
factors.

1) the frequency range required
2) the permeability of the ferrite core
3) the spacing of the turns

For experimentation purposes, you might start with about 80 turns of AWG

30
enameled or cloth covered wire, contiguously spaced, near one end of the
core. With this, use a ~360 pF variable capacitor.

If you have a grid dip meter, you can easily find where this is resonant.

If
you don't, then you have to poke about on the AM dial of a cheap radio,

and
see where you can tune it.






Diverd4777 October 20th 03 01:40 PM

Brenda,

thanks for the info... May try it myself !

Dan

In article , "Brenda Ann"
writes:


"elfa" wrote in message
...
I appreciate your offer of instructions re the ferrite bar antenna but I

think
I'll just skip it for now. This was the wrong group for this kind of

request.
It should have been in an electronics group.

elfa


The number of turns necessary for a loopstick antenna depends on several
factors.

1) the frequency range required
2) the permeability of the ferrite core
3) the spacing of the turns

For experimentation purposes, you might start with about 80 turns of AWG 30
enameled or cloth covered wire, contiguously spaced, near one end of the
core. With this, use a ~360 pF variable capacitor.

If you have a grid dip meter, you can easily find where this is resonant. If
you don't, then you have to poke about on the AM dial of a cheap radio, and
see where you can tune it.





GrtPmpkin32 October 20th 03 04:36 PM

This was the wrong group for this kind of request.
It should have been in an electronics group.


Actually, this group has fielded ferrite, air core, active and passive loop
designs hundreds of times over the years. Do an archive search under loops, or
loop construction. Or, do the same kind of search on an engine somewhere. But
this group is a VERY good place for such info, the usual idiots
notwithstanding. In fact you'll get a better answer here than a lot of places,
even if you do have to put up with a few things in the meantime, if only
because the serious and helpful replies you DO get are coming from people with
real-world experience over many years in antenna experimentation.
I've been in this group off and on for many years, and while I've also had my
share of flame wars and idiot posts, a GREAT deal of the antenna experience I
have gained has come directly (and in some cases *exclusively*) from this
group.
Linus

radiok3pi October 21st 03 03:27 AM

don't quit the group elfa.

that question was very appropriate for rec.radio.sw

I have found this to be the best place to ask MW/AM radio and antenna
questions. Just ignore the reptiles that come out from under their
rocks. You have to sift and sort thru the replies, but there are some
very knowledgeable,helpful and friendly posters here. I have learned
a lot from them in the past several years.

73 Russ K3Pi


All times are GMT +1. The time now is 09:35 AM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com