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Discone for 88-108 MHz?

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#1
Can I use my discone antenna for broadcast FM reception (88-108 MHz)? If so, can I use a splitter at the antenna to feed my FM tuner and my scanner? I do not transmit with the antenna.

Thanks!
 
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#3
Discone question

I will assume it is one covering aircraft through UHF+..
(The one I use also has 6-meter (50MHz) coverage and I DO use it for transmitting satisfactorily on 6 Meters as well as 2 and 440 ham bands as well as scanning and FM reception on my R7000)

For FM Radio reception, the omnidirectional characteristic of a discone won't give you any gain or directivity for specific station locations. Nearby/local stations should work fine if the splitter is not TOO lossy. ;-)

However, the scanner LO (Local Oscillator) and spurious harmonics/spurs from the scanner searching or scanning may create a "putt-putt" interference to the FM station reception as it scans across whatever ranges you use it on..

A lot depends on the port-to-port isolation as to how severe that will be, but testing won't hurt anything. :)

Give it a try!

Tom, W4NOV

DiscConeHead said:
Can I use my discone antenna for broadcast FM reception (88-108 MHz)? If so, can I use a splitter at the antenna to feed my FM tuner and my scanner? I do not transmit with the antenna.

Thanks!
 
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#4
Thanks

zz0468 said:
You haven't given us enough information to answer. Discones have a specified upper and lower frequency range. Without knowing that range, your question is impossible to answer.
Thanks for pointing me to my answer. (Wide 25-1300MHz coverage) I should have looked up the specs. It's from Radio Shack. I am now picking up the target station that an indoor amplified or 300 ohm dipole wouldn't but I think I need still more gain since it is noisy on stereo and mostly clean on mono. What do you recommend? I think a directional will solve the problem and still pick up the locals (all very strong). The mast is mounted on top of a two story house.

THANKS
 
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#7
The discone also does not exhibit any gain and was designed mainly to pick up vertical polarization signals, which explain the marginal performance. There is beam antennas for FM 88-108Mhz, most Radio Shack beam antennas are a combo of VHF/UHF/FM( offering 75-100 miles reception on FM), or if you don't want beams, there is the cross monopole version that looks like an "X". I use a log periodic( Create) that is mounted to receive horizontal polarization FM signals. Back in NY , I could pick up +120 miles.
 
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#8
nycrich said:
The discone also does not exhibit any gain and was designed mainly to pick up vertical polarization signals, which explain the marginal performance. There is beam antennas for FM 88-108Mhz, most Radio Shack beam antennas are a combo of VHF/UHF/FM( offering 75-100 miles reception on FM), or if you don't want beams, there is the cross monopole version that looks like an "X". I use a log periodic( Create) that is mounted to receive horizontal polarization FM signals. Back in NY , I could pick up +120 miles.
A couple of points...:

1. "no gain" does no imply it's not effective. It just means signal levels delivered to the receiver are comparable to a dipole, which is the usual reference antenna for gain measurements.

2. FM broadcast signals are USUALLY circularly polarized, so it matters not whether a vertical or horizontal receiving antenna is used.
 
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#9
Many, if not most, FM stations use circular or cross polarization to have good coverage for car antennas which are obviously vertical. The Radio Shack discone should work fine but, as stated, does not really show gain or directivity.
 
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