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Speaker wire receive only antenna?

Joined
Sep 23, 2013
Messages
5
Location
Toronto, Canada
#1
So I bought a 50ft 22AWG long spool of wire and would like to split the conductors on the far end and use it as a 1/4 wave antenna for 47MHz SDR reception.
I don't want to do a dipole as it'll need to be over 10ft high.
I'm looking at around 5ft vertical for 1/4 wave with one conductor, and then what should I do with the other conductor? Run it straight along the ground as a single radial at a 90 degree angle?
Ground it to earth at the end? Insulate it from Earth at the end?
Chop it off completely and use the feedline portion of the wire as the counterpoise instead?
Suggestions?
Yes I could play around with it and might still but I'd like to not have to do that while camping and not have the appropriate tools to undo mistakes.
 
Joined
Sep 23, 2013
Messages
5
Location
Toronto, Canada
#3
So the usual, cut my vertical to slightly longer than the lowest frequency I wish to receive?
And what about the radial? How long should it be relative to the vertical as it will be on the ground?
 
Joined
Sep 8, 2006
Messages
2,897
Location
Stockholm, Sweden
#4
Normal antenna elements have a delay factor on it's surface depending of the material that slows down the current that flows over the element. You usually make it 5% shorter than the 1/4 wavelenght of the frequency if it's made of steel to compensate for the delay. And to stop the coax from being part of the antenna you could use a balun to isolate the coax from the antenna. Easiest to use are a current balun with ferrite rings around the coax where it joins the antenna. The most effecient would be to have ferrite material covering the whole lenght of the coax that equals to 1/4 wavelenght but might be impractical at low-vhf frequencies. Curling up the coax 5-10 turns with a 10 inch diameter might also help.

/Ubbe
 

KE5MC

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
763
Location
Lewisville, TX
#5
andrewsfm,
All good information especially if used for transmitting. Receive only operations allow more compromise in antenna configuration without impacting reception. Basic tools, side cutters, wire strippers, wire nuts. Hang some wire, play around, change as needed... :)
Mike
 
Joined
Feb 28, 2019
Messages
133
#6
Mike pretty much summed it up. Most receivers are not as picky as transmitters. So, you have more than a little "lee-way" with antennas. Probably the simplest way to improve reception (especially at VHF and above) is to get that antenna higher (altitude, not attitude!).
 
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