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Post by station8 on Sept 21, 2019 13:52:25 GMT
Howdy y'all:
Give me your opinion on this idea and has someone tried or
Thought of this idea?.
Let's here from other radio sites about this as well pass it along!.
1) What if you made a fm antenna like a am ferrite bar antenna?.
2) What kind of receiving range would you get?.
3 ) What kind of signal to noise ratio would you see?.
4) Would it work or be a big flop?.
What a topic.
Have fun with this topic and idea.
Station 8
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Post by thelegacy on Sept 21, 2019 19:36:46 GMT
There was an FM loop antenna with a tuning capacitor in which was demoed and it brought a station in that without the loop could not even be heard. I've thought of that too since the FCC told me that a Decade MS-100 would go 1,000 Ft to a good Radio. So that being said you may get your range up to 3,000 Ft in which you could tell your listeners about the FM antenna and Boom you have listeners and nothing could be done to stop you.
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Post by Boomer on Sept 25, 2019 0:44:52 GMT
I don't know that a small loop antenna like an AM radio's ferrite bar job would improve reception over a standard whip.
The whip has a big advantage on FM, it can be at or near a quarter wavelength at 100 mhz, and that naturally resonant antenna would pick up the most signal.
Now I think a large sized loop might do some good, several feet in diameter, maybe for some broadband or directional characteristic when receiving.
The good thing is, FM antennas are small, so you could experiment with coat hangers and make loops out of them, no winding huge coils.
Boomer
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Post by station8 on Sept 25, 2019 14:04:20 GMT
Hi Boomer & Others:
You understand as frequency gets higher antenna gets shorter.
Am I right, yes I am
So explain why won't using a am ferrite antenna same design would
NOT work for fm or tv reception antenna!.
It should it's how you build and construct the antenna.
( So how is a short antenna receiving am broadcast when you guys
Think I need a large antenna to get the signal because
The only way it will work is by a large antenna the
Ferrite bar antenna just show you wrong you can have
A small compact antenna ).
Another example dummy load antennas ( rubberduck antennas )
Do I need to say more!, NOPE!.
You need to do more homework in this field this is why:
1) The build short emergency antennas for am broadcast on portable trailers!.
2) Read up on building miniature antennas!.
3) They make short antennas for ham operation as well!.
Just some things to look at guys
Have fun
Station8
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Post by station8 on Oct 1, 2019 22:31:27 GMT
Howdy Y'all: I made a fm wire antenna and wrapped around a ferrite for And it worked pretty good I was surprised what pulled in my area.
I even tried a am radio antenna on fm and it worked too.
More testing and adjustment to try.
Have fun with the hobby
Station 8 |
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Post by mark on Oct 1, 2019 23:55:45 GMT
Theoretically it could work as the size/inductance of the coil could be adjusted for the FM frequencies but there must be a reason why a length of wire or telescoping "whip" is used. But notice with cars a whip outside on the fender or wire imprinted in the window is used for AM and FM and car radios are the best of all. So if the same antenna can be used for each band in a car the ferrite rod and coil antenna could probably be used for AM and FM in home or portable radios. Now you've got me wondering.....I will try to research this. Good question, why is a telescoping whip used for FM and the loop or ferrite stick used for AM and why can't, with all radios, the whip be used for both like a car? or visa/versa?
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Post by mark on Oct 2, 2019 0:04:13 GMT
Just read that to have a whip for AM with a home or portable would be impractical because of the long length needed(100s of feet) so the coil over the ferrite rod with the ferrite rod greatly magnifying the signal strength of the coil is used but that still doesn't explain how a 25" length of wire works so good with cars for both. I will research later why a ferrite rod/coil can't be used for FM/TV.
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Post by mark on Oct 2, 2019 4:14:47 GMT
OK here's the reason ferrite loopsticks are not used for FM.....because the ferrite would act as a choke for the FM frequencies so it wouldn't work.
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Post by station8 on Oct 2, 2019 5:30:29 GMT
Howdy y'all:
First of all I can tell you from actually experience that,
The car window antenna pressed in between glass work like trash for Am & fm!.
If you notice small car rubber duck antennas also did not work good
At all do to they where not built right!.
You guys should know from so called experience if you don't
Build the antenna right what happens to your signal!.
When using a small whip antenna on a car fender wall is short do to the
Amount of metal that is used on the vehicle which helps!.( Counter balance ).
You need to read books on short and miniaturized antenna to get the grasp
The understanding!.
Just don't do book research do some actually testing you might be surprised!.
I notice some down some people shoot ideas down first without trying it first
At all before speaking!.
This is why I don't speak much on these sites anymore!.
When I made my fm ferrite antenna I pick up station through the whole fm
Band without tuning!.
I also had a adjustable fm ferrite antenna as well and it worked!.
Hope this helps
Station 8
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Post by mark on Oct 2, 2019 16:05:35 GMT
I think we all know that car radios are the best that radios can be, and they use the wire whip for both AM and FM, whether mounted on the fender, in the window or on newer cars on the roof so it must work. The circuit design in the receiver is designed for this type of antenna and is different than home/portable receivers.
This type of antenna is omnidirectional so no matter what direction the car is going reception is the same.
I have driven all kinds of cars with the antenna on the fender, in the window or a short one on the roof and found reception in a car is superior to any home/portable. Just see with our part 15 stations the difference with a car vs another receiver.
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Post by station8 on Oct 2, 2019 17:13:02 GMT
Howdy y'all:
Window car wire antenna are just pure junk!.
I seen boom boxes that receive just as good as car radios
But are few and far between.
Now the antennas they put on the roof of back fenders they are
The worse due to the length in the cable line.,
If you don't believe me take the car radio cable apart and you
Will see what I mean very cheap thin center conductor!.
As long you keep cable short within 4 foot max you will be ok!.
Station 8
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Post by station8 on Oct 18, 2019 16:03:32 GMT
Howdy y'all:
I did get a pre check on the ferrite coil antenna on fm receiver,
Here is what I saw on the tecsun pl880 radio
1) station I used 88.5 fm antenna collapsed no signal
When placing coil antenna Port on radio my signal was 07db!.
2) station I used 102.3 fm antenna collapsed 07db,
When placing coil on antenna Port my signal went up
To 14db now!.
I did not tune the coil up or down on the ferrite time of the test!.
Pretty good results if you ask me
Station8
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Post by mark on Oct 19, 2019 5:37:41 GMT
The same would have happened if you touched the antenna with your finger. Maybe more!
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Post by station8 on Oct 19, 2019 13:07:00 GMT
Hi Everyone:
Correction it was 89.5 , i had to turn off the auto correct again to googles!.
First off it's common knowledge if you touch your antenna you will see your signal go up,
Mine showed approximately about 5db more in signal!.
Test was done when antenna would be in collapsed position
To make the test fair!.
When i built my ferrite fm antenna:
Ferrite antenna was about 2 inches long.
Ferrite flat bar was about 4 inches long.
Wire was 30awg enamel wire.
I checked low, middle and end of the fm frequency band and the
Antenna worked very good.
I did the test on the station dead to weak areas,
I also touch the antenna to see if there was any improvements
NO there wasn't it stayed stable through the fm band.
Keep in mind if you build it right you will be surprised!
Built it wrong it will still work,But not so good!.
I hope this clear up more information
Station8
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