Directional antenna for an FM TX ?

[Forrest]

I just sent away for a "Ramsey FM30" FM transmitter, build it yourself kit.
It's only 25 mW and I want to maximize the power in one direction. Can
anybody direct me to an antenna for sale or give me a link to a page to
build my own. I would also appreciate any comments on this unit or tips on
its construction. Should be here early next week. Thanks in advance.

 

[Dave Plowman (News)]

I just sent away for a "Ramsey FM30" FM transmitter, build it yourself
kit. It's only 25 mW and I want to maximize the power in one direction.
Can anybody direct me to an antenna for sale or give me a link to a
page to build my own. I would also appreciate any comments on this unit
or tips on its construction. Should be here early next week. Thanks in
advance.

I dunno your local regs but often these sort of unlicensed FM transmitters
are restricted to an ERP which won't cause problems to others. Upping the
ERP by use of other than a simple aerial breaks this concession. If you
need a greater range other frequencies are available for this.

 

[maple]

Maybe these guys have something that will work for you:

http://www.fmdxantenna.com/

 

[DaveM]

I dunno your local regs but often these sort of unlicensed FM transmitters
are restricted to an ERP which won't cause problems to others. Upping the
ERP by use of other than a simple aerial breaks this concession. If you
need a greater range other frequencies are available for this.

--
*A fool and his money are soon partying *

Dave Plowman [email protected] London SW
To e-mail, change noise into sound.

An FM band Yagi antenna will provide you with the best directional
characteristics. As noted above, the FCC (if you're in the US) might frown on
you putting one of these on an unlicensed transmitter, but the legalities and
consequences are for you to investigate. Directional FM antennae that you can
buy:
http://www.starkelectronic.com/ac.htm has the FM-6 FRINGE 6 ELEMENT 70"LONG
$26.97
https://www.tselectronic.com/winegard/pr6000.html?tse_Session=25049555ecefc76616879a90d135799d


Plans to build an FM Yagi are here:
http://www.geocities.com/zbtaz/
http://radio.meteor.free.fr/us/antenna.html
http://www.skyscan.ca/Antennas.htm

If none of those suit you, then you can do your own research on Google. Search
for Yagi FM Antenna

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

"In theory, there isn't any difference between theory and practice. In
practice, there is." - Yogi Berra

 

[Peter Kolbe]

Hi Forrest.

You might be able to use a normal VHF Tv Antenna.
The VHF TV band is just above the normal FM range (88-108 MHz), The TV
antenna might have enough leighway in it's bandwidth range.

Just remember to remove any caps and coils that are in the TV antennas
junction box, or you might mess up the tuning of the transmitter.

Reciprocity with antennas means that an Antenna will have the same gain
whether it is transmitting or receiving a signal.

Peter

 

[GregS]

Hi Forrest.

You might be able to use a normal VHF Tv Antenna.
The VHF TV band is just above the normal FM range (88-108 MHz), The TV
antenna might have enough leighway in it's bandwidth range.

Just remember to remove any caps and coils that are in the TV antennas
junction box, or you might mess up the tuning of the transmitter.

Reciprocity with antennas means that an Antenna will have the same gain
whether it is transmitting or receiving a signal.

Peter

In the US its illegal to use an antenna other than the requied length of wire
of a few inches.

greg

 

[msg]

GregS wrote:

In the US its illegal to use an antenna other than the requied length of wire
of a few inches.

The O.P. should be aware of regulations in his country but mostly these specify
EIRP for this class of device, and if it is a kit, then the builder may be as
responsible for compliance as well as the maker. Using supplied parts is likely
to maintain compliance but the builder is often able to make substitutions if
he can verify compliance if challenged. Test and measurement is your friend.

Regards,

Michael