Nevada Scanmaster Airmaster antenna
I am after a good V/UHF airband antenna and found this on a Google search.
Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html -- Regards Troy Rowland |
Troy R. wrote:
|| I am after a good V/UHF airband antenna and found this on a Google || search. Anybody actually own one and can tell me how they perform? || || http://www.nevadaradio.co.uk/acatalo...airmaster.html || || -- || Regards || Troy Rowland I dont personally, but know someone who does, and loves it, uses it to listen to the shipping etc clear pickup, mind you, he does live V close to the port lol -- http://www.stb-clan.com Simply the best |
Looks like the wind blew the fabric off some old ladies umbrella!
Bill Crocker "Troy R." wrote in message u... I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html -- Regards Troy Rowland |
Troy
Try a decent ham dual band antenna, cheaper and a lot better. Marco "Troy R." wrote in message u... I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html -- Regards Troy Rowland --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.786 / Virus Database: 532 - Release Date: 29/10/2004 |
On Fri, 29 Oct 2004 22:45:21 +1000, "Troy R."
said in alt.radio.scanner: I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html They don't seem to know much about it. Discones aren't resonant antennas, but they do pick up signals from the design frequency to daylight.. |
I've gone down the dual band amateur path before and been disappointed,
hence the interest in something like this. "Marco" wrote in message ... Troy Try a decent ham dual band antenna, cheaper and a lot better. Marco "Troy R." wrote in message u... I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html -- Regards Troy Rowland --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.786 / Virus Database: 532 - Release Date: 29/10/2004 |
Al Klein schrieb: On Fri, 29 Oct 2004 22:45:21 +1000, "Troy R." said in alt.radio.scanner: I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html They don't seem to know much about it. Discones aren't resonant antennas, but they do pick up signals from the design frequency to daylight.. Not having read the linked page.... Discones ARE resonant on an extremly wide range. Therefore they have nearly no gain above the (theortical) isotropic antenna. This means they have a loss of around 1/2 S-unit against a dipole or a half-wave vertikal antenna on a specified frequency. Not too bad for a compromise. The resonant range of a well designed and built discone is spread 1:10 on wich you can transmit. This is 50 to 500 Mhz or 100 to 1000Mhz for example, covering the most wanted frequencies for scannists and is also usable on ham-bands or FRS to transmit. The receiving range -allowing an impedance mismatch- is much wider when (usually) allowing a loss of 1 S-unit (-6dB). The difference you only will notice on faint signals. There are some other antennas too -directional and omnidirectional-, providing a relatively wide resonant range but not nearly as wide as a discone. |
On Sat, 30 Oct 2004 11:55:50 +0200, Volker Tonn
said in alt.radio.scanner: Al Klein schrieb: On Fri, 29 Oct 2004 22:45:21 +1000, "Troy R." said in alt.radio.scanner: They don't seem to know much about it. Discones aren't resonant antennas, but they do pick up signals from the design frequency to daylight.. Not having read the linked page.... Discones ARE resonant on an extremly wide range. Therefore they have nearly no gain above the (theortical) isotropic antenna. This means they have a loss of around 1/2 S-unit against a dipole or a half-wave vertikal antenna on a specified frequency. Not too bad for a compromise. The resonant range of a well designed and built discone is spread 1:10 on wich you can transmit. This is 50 to 500 Mhz or 100 to 1000Mhz for example, covering the most wanted frequencies for scannists and is also usable on ham-bands or FRS to transmit. We're using different definitions of "resonant". The definition I use says that an antenna can only resonate on a frequency. (Pretty much, the frequency a dip meter will indicate when coupled to the antenna.) It can have a bandwidth over which it can be used, but the resonant point is (usually) one single frequency. Discones look like dipoles with the 2 legs being different lengths, so the best one could say - using my definition - is that they "resonate" on the frequency at which the disc is 1/2 wavelength in diameter and the frequency at which the cone element length is 1/4 wavelength. But they probably are the best tradeoff for multi-band scanning. |
Snip...
We're using different definitions of "resonant". The definition I use says that an antenna can only resonate on a frequency. (Pretty much, the frequency a dip meter will indicate when coupled to the antenna.) It can have a bandwidth over which it can be used, but the resonant point is (usually) one single frequency. Discones look like dipoles with the 2 legs being different lengths, so the best one could say - using my definition - is that they "resonate" on the frequency at which the disc is 1/2 wavelength in diameter and the frequency at which the cone element length is 1/4 wavelength. But they probably are the best tradeoff for multi-band scanning. Let's use an accepted engineering definition- resonance is defined when the input Z has zero reactance- a properly designed discone (disc and cone- not a skeletal version) is virtually reactance free over a very wide band. Discones may look like dipoles- although you really have to be imaginitive, is a derivative of the bicone antenna (replace the disk with another cone). With proper included cone angle and proper machining of the junction (this limits hi end performance) it is a wonderfully broadbanded antenna. Dale W4OP |
Al Klein schrieb: On Sat, 30 Oct 2004 11:55:50 +0200, Volker Tonn said in alt.radio.scanner: Al Klein schrieb: On Fri, 29 Oct 2004 22:45:21 +1000, "Troy R." said in alt.radio.scanner: They don't seem to know much about it. Discones aren't resonant antennas, but they do pick up signals from the design frequency to daylight.. Not having read the linked page.... Discones ARE resonant on an extremly wide range. Therefore they have nearly no gain above the (theortical) isotropic antenna. This means they have a loss of around 1/2 S-unit against a dipole or a half-wave vertikal antenna on a specified frequency. Not too bad for a compromise. The resonant range of a well designed and built discone is spread 1:10 on wich you can transmit. This is 50 to 500 Mhz or 100 to 1000Mhz for example, covering the most wanted frequencies for scannists and is also usable on ham-bands or FRS to transmit. We're using different definitions of "resonant". The definition I use says that an antenna can only resonate on a frequency. (Pretty much, the frequency a dip meter will indicate when coupled to the antenna.) It can have a bandwidth over which it can be used, but the resonant point is (usually) one single frequency. Discones look like dipoles with the 2 legs being different lengths, so the best one could say - using my definition - is that they "resonate" on the frequency at which the disc is 1/2 wavelength in diameter and the frequency at which the cone element length is 1/4 wavelength. To say so, a discone has it's "middle frequency". But impedance curve stays constantly over a very wide range around. So in theoretics you can get a frequency modulated signal with center frequency of let's say 500Mhz and a bandwidth of 800Mhz through a discone with a straight power curve wich has no loss by mismatching of the antennea. I don't know of any TRX providing such a signal :-) As I understand the principle of a discone the disc is a load plate wich spreads the bandwidth in conjunction wich the conical "antenna wire". So the "resonant" wavelength is more related to the length of the cone measured from the the top plate in 90 degree angle to the bottom. You may correct me if I'm wrong :-) Have a nice weekend. |
So what you are saying Dale is that a bicone antenna is a good wideband
antenna? Do they exhibit any gain? "Dale Parfitt" wrote in message news:uSQgd.874$cA4.853@trnddc01... Snip... We're using different definitions of "resonant". The definition I use says that an antenna can only resonate on a frequency. (Pretty much, the frequency a dip meter will indicate when coupled to the antenna.) It can have a bandwidth over which it can be used, but the resonant point is (usually) one single frequency. Discones look like dipoles with the 2 legs being different lengths, so the best one could say - using my definition - is that they "resonate" on the frequency at which the disc is 1/2 wavelength in diameter and the frequency at which the cone element length is 1/4 wavelength. But they probably are the best tradeoff for multi-band scanning. Let's use an accepted engineering definition- resonance is defined when the input Z has zero reactance- a properly designed discone (disc and cone- not a skeletal version) is virtually reactance free over a very wide band. Discones may look like dipoles- although you really have to be imaginitive, is a derivative of the bicone antenna (replace the disk with another cone). With proper included cone angle and proper machining of the junction (this limits hi end performance) it is a wonderfully broadbanded antenna. Dale W4OP |
Troy R. schrieb: So what you are saying Dale is that a bicone antenna is a good wideband antenna? Do they exhibit any gain? Gain? ...compared to what? Yes, the bicone antenna has gain! It's gain is comparable to a dipole. But a bicone is far away to be as broadband as a discone. |
"Volker Tonn" wrote in message ... Troy R. schrieb: So what you are saying Dale is that a bicone antenna is a good wideband antenna? Do they exhibit any gain? Gain? ...compared to what? Yes, the bicone antenna has gain! It's gain is comparable to a dipole. But a bicone is far away to be as broadband as a discone. Can you show me a text indicating that a bicone has a bandwidth different from a discone? Dale W4OP |
So after all that is someone out there going to answer the original question
which was basically (Is the scanmaster airband discone that nevada sell worth it's price tag) rgds all from M3PAC.... PAUL..... "Troy R." wrote in message u... I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html -- Regards Troy Rowland |
Perhaps
a) Nobody on this NG uses it, or b) Any that do use do not think it worth commenting on. Possibly the "silence speaks volumes". Marco (Who uses a Diamond D707) "paul churchill" wrote in message ... So after all that is someone out there going to answer the original question which was basically (Is the scanmaster airband discone that nevada sell worth it's price tag) rgds all from M3PAC.... PAUL..... "Troy R." wrote in message u... I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html -- Regards Troy Rowland --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.788 / Virus Database: 533 - Release Date: 01/11/2004 |
"paul churchill" wrote: So after all that is someone out there going to answer the original question which was basically (Is the scanmaster airband discone that nevada sell worth it's price tag) rgds all from M3PAC.... Being an antenna nut and regular listener to aircraft communications, I, too, would like to know. I presume you mean this antenna: http://www.nevadaradio.co.uk/acatalo...airmaster.html It is sort of a bi-cone antenna and sort of a "dipole cluster" antenna. The same basic idea (dipole cluster) is used in the Antennacraft Scantenna ST-2: http://www.grove-ent.com/ANT7.html but this one is not optimized for the aircraft bands. The discontinued Channel Master 5094A Monitenna is much the same and has proved to be a good monitor antenna for me for the "public service" bands. It, too, is not optimized for the aircraft bands The Scanmaster Airmaster should work pretty well just by looking at it but one never knows until they are in place and operating. I created and moderate and aircraft listener's group http://groups.yahoo.com/group/AirCommSouthwest/ of nearly 600 members and I posted an inquiry about the Scanmaster Airmaster but apparently no one has had experience with one, though the inquiry did start and aircraft monitoring antenna thread. One problem in the U.S. is that no one seems to sell the Airmaster, at least, I can't find a retailer. One may be able to buy them from the U.K. though. I did buy a so called "Double Discone" (bi-cone) on eBay and have yet to try it but it looks like one could make and Airmaster out of it by cutting the elements. It would be nice to have the element dimensions from the Airmaster. Here is a description of the "Double Discone:" http://www.radio-ware.com/products/ant426.htm Here is another option: http://www.ssejim.co.uk/vhfairbandant.htm http://www.ssejim.co.uk/uhfairbandant.htm http://www.ssejim.co.uk/dip2002abeu.htm I did buy the last item from the U.K. and it seems to work well. I have separate antennas for VHF and UHF aircraft and then combine them into a single coax feed. Another option to combine VHF and UHF aircraft antennas would be the CF-142: http://www.cometantenna.com/products...=23&childID=44 Iden - Northern California |
"Troy R." wrote in
u: Hi Troy, I used to have one, it worked fine for about 1 year then it got broke. Dunno what was wrong with it though. I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html |
"Henk" wrote in message . 2.2... "Troy R." wrote in u: Hi Troy, I used to have one, it worked fine for about 1 year then it got broke. Dunno what was wrong with it though. I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html Troy Why not try a !good! amateur dual band 2m/70cm antenna, a lot cheaper, less obtrusive, and IMHO a lot better. Marco --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.802 / Virus Database: 545 - Release Date: 26/11/2004 |
Yes! Or just buy a regular discone OR open dipole. That'll work just as
well but cheaper ;-) "Marco" wrote in : Troy Why not try a !good! amateur dual band 2m/70cm antenna, a lot cheaper, less obtrusive, and IMHO a lot better. Marco |
Marco wrote:
Why not try a !good! amateur dual band 2m/70cm antenna, a lot cheaper, less obtrusive, and IMHO a lot better. This may not really be a good idea. The aircraft band is a long way from the 2m bands and you will be using the antenna well outside its designed frequency band. Depending on the precise construction of the antenna, it may receive no better than a damp piece of string. My own 2m/70cms co-linear (well sited, outside) actually receives less than a discone in the loft on airband. No contest on 2m or 70cms though, the co-linear is far better. -- Laurie |
YES THE SCANMASTER AIRBAND DOUBLE DISCONE WORKS WELL.
But you could make one for a few pounds. Dual or Tri-band band amateur antennas have internal matching networks which can give poor results when used outside their intendend frequency ranges. They can work reasonably well upto approx. +/- 20% outside their design frequencies (plus a few odd harmonic resonses), which may be OK for PMR monitoring. But it will not provide good coverage of the whole of the UHF MIL air band. I use a Double discone and can monitor re-broadcast satcom traffic in the UHF Mil band, so I think it is good enough..... UKM "paul churchill" wrote in message ... So after all that is someone out there going to answer the original question which was basically (Is the scanmaster airband discone that nevada sell worth it's price tag) rgds all from M3PAC.... PAUL..... "Troy R." wrote in message u... I am after a good V/UHF airband antenna and found this on a Google search. Anybody actually own one and can tell me how they perform? http://www.nevadaradio.co.uk/acatalo...airmaster.html -- Regards Troy Rowland |
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