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Scanner antenna ???
Yes, I have the tower and have a bracket that extends to the side about 4 ft
and this antenna will be at the end of that extension. Realistic 2037. I see those links for those scanner antennas and think that one from 25 mhz to 1000 ish is suitable. I see a lot of them have ground planes or are all those elements part of the center wire in the bnc? I have an old 2m 70cm diamond antenna with gnd planes, Suppose that would work also? But someone gave it to me because it didn't work so might take a closer look at it. thx 73s "Jeff Liebermann" wrote in message ... On Sat, 4 May 2013 08:26:09 -0400, "Tom" wrote: I have the Realistic Programmable scanner with 200 programable channels. A lot of range there like 6 m, 2 m, 70 cm, marine, etc etc etc, wide range. Realistic scanners have model numbers. Could I trouble you to disclose the exact model number? Do you have a tower? I want to put up an external antenna that I can hook it up to its own BNC connection for external antenna. I believe the higher the better. Forget about using long wire antennas as a scanner antenna. At VHF/UHF, long wires look more like big RF chokes. It's unlikely to hear much connected to an HF antenna. There are numerous scanner antennas on the market. If you have a tower for your HF antenna, you also should have room for a discone, "spider", trapped vertical, or something similar. I don't know exactly what to recommend as broadband antennas are always a compromise between gain, bandwidth, vertical radiation takeoff angle, size, etc. Something on this list should work (except for the handheld and mobile scanner antennas). http://www.universal-radio.com/catalog/scanants.html RG-58a/u or RG-58c/u to between the scanner and antenna will probably need to purchases seperately. Attach your own BNC or UFH connectors. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#2
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Scanner antenna ???
Tom wrote:
I have an old 2m 70cm diamond antenna with gnd planes, Suppose that would work also? But someone gave it to me because it didn't work so might take a closer look at it. A dualband transmit antenna may work less well as a wideband receive antenna than a plain dipole, as it is constructed to match well and even provide gain at two distinct bands, and the methods used to achieve this may result in nulls at other frequencies. But you can always try it and find out how it works at the bands you are interested in. |
#3
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Scanner antenna ???
On Sat, 4 May 2013 15:48:22 -0400, "Tom" wrote:
Yes, I have the tower and have a bracket that extends to the side about 4 ft and this antenna will be at the end of that extension. Perfect, but not for the obvious reason. Retail discone antennas cost $25 to $150, which seems a bit high. Mostly, it's because of the large number of parts involved. If you have a tower and yard-arm, you can hang a center fed vertical biconical antenna off the end, which in my never humble opinion will work better than a discone (due to the reduced up tilt of the vertical radiation pattern) than a discone. Discones are good for broadband, and listening to airplanes, but if you want distance, the radiation pattern should point to the horizon, not the sky. Something like one of these: https://www.google.com/search?q=biconical+antenna&tbm=isch Realistic 2037. http://www.rigpix.com/rs-realistic/realistic_pro2037.htm Made by GRE starting in about 1996. It has a marginal front end design that is easily overloaded by strong signals and will produce intermod mixes with little effort. The "ATT" for attenuation switch is an obvious clue. If you hear obvious intermod, you may want to insert a 1/4 wave stub notch filter between the antenna and receiver to get rid of strong paging junk and such. http://dl4xav.sysve.de/coax.filter/coax-filter.html The more strange looking and ugly the antenna, the better it works. I see a lot of them have ground planes or are all those elements part of the center wire in the bnc? The bottom angled elements are at ground potential. The flat top "hat' is connected to the center wire of the UHF connector. If you replace the flat top hat, with a mirror image of the ground elements, you have an instant biconical antenna. I have an old 2m 70cm diamond antenna with gnd planes, Suppose that would work also? But someone gave it to me because it didn't work so might take a closer look at it. A dual band antenna will work on 2m and 70cm, and little else. You can probably hear something on the adjacent frequencies, but at more than a few MHz away, such an antenna is going to be comatose. If you use your scanner mostly for these ham bands, put a ground plane under it, as if it were mounted on a vehicle, and attach it to your yard-arm. If that's too messy, several 1/4 wave at 2m horizontal ground radials will probably suffice. Incidentally, don't toss the antenna. Diamond make good antennas and it's probably worth your time to determining why it didn't work. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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