Indoor Telescoping antenna
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Don_Burke
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GTO_04
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It should be set to 1/2 or 5/8 of a wavelength if possible.
Edit: Forgot about the matching network required. It is correct that for a telescoping antenna you would be better off with odd multiples of 1/4 wave.
GTO_04
Edit: Forgot about the matching network required. It is correct that for a telescoping antenna you would be better off with odd multiples of 1/4 wave.
GTO_04
Last edited:
nd5y
Member
Which telescoping antenna do you have?
If you have the Radio Shack BNC antenna with the coil in the middle http://www.radioshack.com/product/index.jsp?productId=2103159 you don't want to extend it all the way unless you are listening to low band (29-54 MHz)
It won't cover all bands at the same time.
The instructions http://rsk.imageg.net/graphics/uc/rsk/Support/ProductManuals/2000006_PM_EN.pdf tell you what to do but doesn't really explain it that well.
The loading coil acts like a RF choke at higher frequencies (over 100 MHz or so) and effectively cuts off the top section above the coil giving you an 8 3/4 inch long antenna. That will work well at 40 MHz and 320 MHz but might not be much good any place else.
You want to make it close to 1/4 wave or odd multiples of 1/4 wave, NOT 1/2 or 5/8 wave like somebody else posted above.
(1/4 wave in inches = 2808/frequency in MHz)
1/2 and 5/8 wave antennas have high impedance and require a matching network.
What I normally do with mine is extend 1 section below the coil and 4 sections above the coil, with the first section above the coil collapsed down into the coil which shorts it out. That gives you a 19 inch long antenna with no coil that works good from 118-174 MHz and reasonably well from 406-470 MHz.
If you have the Radio Shack BNC antenna with the coil in the middle http://www.radioshack.com/product/index.jsp?productId=2103159 you don't want to extend it all the way unless you are listening to low band (29-54 MHz)
It won't cover all bands at the same time.
The instructions http://rsk.imageg.net/graphics/uc/rsk/Support/ProductManuals/2000006_PM_EN.pdf tell you what to do but doesn't really explain it that well.
The loading coil acts like a RF choke at higher frequencies (over 100 MHz or so) and effectively cuts off the top section above the coil giving you an 8 3/4 inch long antenna. That will work well at 40 MHz and 320 MHz but might not be much good any place else.
You want to make it close to 1/4 wave or odd multiples of 1/4 wave, NOT 1/2 or 5/8 wave like somebody else posted above.
(1/4 wave in inches = 2808/frequency in MHz)
1/2 and 5/8 wave antennas have high impedance and require a matching network.
What I normally do with mine is extend 1 section below the coil and 4 sections above the coil, with the first section above the coil collapsed down into the coil which shorts it out. That gives you a 19 inch long antenna with no coil that works good from 118-174 MHz and reasonably well from 406-470 MHz.
Last edited:
mmclem1112
Member
Wow thanks for all the great info i sure have a lot to learn about antennas
yes your correct. i figured that out myself yrs ago. many people declare that RS antenna junk before reading the instructions and learning how to use it. quite a good antenna. i just got tired of the ugly looks of it. the Diamond RH77CA style antennas look more proffesional.
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