(meteorobs) US Air Force Space Surveillance Radar - tuning in?

[stange]

Thomas, Pat, & group...

Others may want to look at this more closely. I have been away from active 
Ham Radio about 10 years or so. But it appears to me (on the surface) that 
Thomas's TV antenna at a frequency of 216 Mhz is resonating the FM music 
band driven element at a second harmonic of 108 Mhz making the driven dipole 
a full wavelength as opposed to a normal 1/2 wave.

Unfortunately, FM antennas have a VERY severe roll-off at 108 Mhz and are 
designed for the low to mid FM band even (IF) the Radar was operating on 108 
Mhz instead of 216..

This also means that ONLY the dipole is resonant, and the reflectors, and 
ALL the directors are just hanging pieces of metal because each of the 
directors & reflectors MUST have specific spacing(logarithmic) to act as a 
high gain Yagi in any specific band.

Right now I think you have just a dipole in the air Thomas. Others may want 
to chip in on this observation of a QRT person.  -KR6FG  YCSentinel


----- Original Message ----- 
From: "Thomas Ashcraft" <ashcraft at heliotown.com>
To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
Sent: 2009/01/23 07:59
Subject: Re: (meteorobs) US Air Force Space Surveillance Radar - tuning in?


> Pat Branch wrote:
>> Using the Radar power equation you should be able to calculate the
>> size of objects you could detect based on your antenna gain, the
>> radiated power (768 KW), the distance between you, the meteor, and
>> the station, etc etc....ok so it is not real easy!
>>
>> I would expect you would hear a few per hour at best (depending on
>> your minimum size resolution - which I would expect to be in the
>> fraction of an inch area)...but I'm not an expert on that. You might
>> try and coordinate your observation using a known satellite pass over
>> the Space Radar (or Amarillo). I happen to be pretty close to the
>> radar site (I'm in NW Fort Worth).
>>
>
>
> Thanks Pat.
>
> I am still trying various combinations of filtering and tuning off
> frequency.  I think I heard a couple of meteors though they were not
> prominent. Although I get the radar tone strong I am wondering if I need
> better antenna gain to get actual meteor reflections? I am using an old
> tv antenna but I think other folks might be using multi element yagis
> that are made for 220 MHz.  Not sure about this.
>
> In my research I found a very fine radio meteor page that gives info on
> the Space Surveillance Radar at :
> http://www.k5kj.net/meteor.htm
>
> I will update further if I come across more information.
>
> Thomas in New Mexico
>
>
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