Portable Scanner UHF Antenna?
- Thread starter Videokid
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jred184
Member
The RS 800MHz antenna seems to do good on UHF.
N
N_Jay
Guest
Videokid said:
Almost all portable antennas are BELOW 0dB gain.
You will be best with a good antenna designed for UHF.
b7spectra
EMS Dispatcher
I've got some UHF stubby antenna's that are new in the package if interested - $5.50 each and that is INCLUDING the shipping (plain white envelope).
MacombMonitor
Member
- Joined
- May 18, 2005
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- 3,551
Try this, the Diamond SRH77CA. They claim 2.15 dBi at 440MHz.
http://www.universal-radio.com/catalog/hamantht/2368.html
http://www.universal-radio.com/catalog/hamantht/2368.html
Hi all,
I agree with Bill, the Diamond is best overall, it's a ham favorite.
As for gain, let me get just a bit but not too technical. Gain is very hard to achieve in portable operation because there is no counterpoise ground for the radiator to work against but all is not lost. The biggest deficit is cross polarization loss, gain of any sort, unity or otherwise can only be realized if the unit is held vertically to match the polarization of the signal. At any other angle loss cancels gain, you end up with less than zero particularly at horizontal.
That's what the joke on another forum was all about, Wal Mart employees not knowing which way is up. (;->)
The bottom line is hold it vertically and away from your body (which absorbs signal) and you'll get all that any antenna has to offer. Since this is often impractical you'll nearly always get somewhat less but still gain is better than nothing.
BTW, body absorption can be used for direction finding under certain circumstances if the signal isn't so strong as to overcome it. Holding the portable straight up to avoid causing additional and confusing directional effects and a few inches in front of you turn in a circle. With your back to the source the signal nulls and be strongest when facing it. It's sloppy and crude, fairly inaccurate but it works.
I agree with Bill, the Diamond is best overall, it's a ham favorite.
As for gain, let me get just a bit but not too technical. Gain is very hard to achieve in portable operation because there is no counterpoise ground for the radiator to work against but all is not lost. The biggest deficit is cross polarization loss, gain of any sort, unity or otherwise can only be realized if the unit is held vertically to match the polarization of the signal. At any other angle loss cancels gain, you end up with less than zero particularly at horizontal.
That's what the joke on another forum was all about, Wal Mart employees not knowing which way is up. (;->)
The bottom line is hold it vertically and away from your body (which absorbs signal) and you'll get all that any antenna has to offer. Since this is often impractical you'll nearly always get somewhat less but still gain is better than nothing.
BTW, body absorption can be used for direction finding under certain circumstances if the signal isn't so strong as to overcome it. Holding the portable straight up to avoid causing additional and confusing directional effects and a few inches in front of you turn in a circle. With your back to the source the signal nulls and be strongest when facing it. It's sloppy and crude, fairly inaccurate but it works.
xusmarine1979
Active Member
I didn't want to start a new topic for this, but I would like to ask if anybody recomends a cheap somewhat portable antenna for my Pro-95. My wife just has it on our end table in the living room, and the bands we listen to are VHF, UHF and 800(analog of course). Anybody recomend something like a homemade wire antenna or something that isn't huge or doesn't take up a lot of room. Our town is on VHF and doesn't even have a repeater, I am also using the stock rubber duckie. She really doesn't want to spend a lot of money on it. Right now, the only spare item I have is an old Radio Shack mobile antenna that I don't use, any ideas? Thanks ya'll...
Al42
Member
A mag mount? Stick it on a pie plate or cookie sheet.xusmarine1979 said:
Or:
SO-239 connector - upside down
4 wires, one in each hole, about 18" long each, at about a 45 degree angle to the horizontal
3 wires soldered into the center pin, spread out just enough so they're not touching - 3", 6", 18"
If you have to buy the wire, it should cost under $10. (If you can solder quickly with a torch, you can use a couple of wire hangers - cost, about nothing.)
It'll look like some kind of weird modern art spider.
xusmarine1979
Active Member
Yes Sir, I kinda know what you're talking about. Yep, it's their magnetic mount antenna that I've had for a long time and I don't even use anymore. I just might cut off the end and try what you suggested. Just hope the coax is still in descent shape.
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