Using a 900MHz yagi for 1090MHz plane tracking?

Analoguesat

Analoguesat

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My Satellite Setup
TM 5402HD
Sky+ UK.
My Location
Scottish Borders
Has anyone tried one of the small 900MHz cell phone booster yagis for ADS-B? I know there would be frequency mismatch but seeing as they are fairly cheap Ive been thinking of buying one to see if I can push my northern coverage out further.
 
Analoguesat said:
Has anyone tried one of the small 900MHz cell phone booster yagis for ADS-B? I know there would be frequency mismatch but seeing as they are fairly cheap Ive been thinking of buying one to see if I can push my northern coverage out further.
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Have you got a pre amp?
 
If your not going to be transmitting on it then it may work, some yagis can cover a bit further out of their designed band on the receive side.

You could do a little cutting as the 1090 MHz 1/2 wave is 13.75 centimeters, versa the 900 MHz at 16.65 centimeters.

This 2.9 cm difference you would cut off on all elements, (1.45 cm on each end of the front directors and driven element) but leave the back reflector alone, it should work just fine then.
 
I think mky old tv antenna is still over at the old place - I sghall have to go and pick it up and see if I can get anything useful out of that - Cant perform much worse than it did for the telly after DSO!
 
I have one like that sitting unloved in a drawer. Yours for nowt.
 
Like Terryl said, shortening the directors (but better still, all elements) of a 900 MHz yagi by the given amount should make a fine 1090 MHz yagi.
Without shortening, the 900 MHz yagi will be lousy, because at 1090 MHz all directors turn into reflectors so to speak.
I wouldn't bother trying the same with UHF TV yagis, if you don't want to shorten the spacing between elements as well.
 
What HVDH said, don't bother with the TV aerial unless you scale it up for 1090. A better bet might be a log periodic as they do work above their design frequency or a UHF bowtie that would be easier to scale. The inline preamps do work on ADS-B but remember it will need line powering (probably 12V) and it will have DC pass through which will need blocking if you're using something with a folded dipole. Dedicated filtered preamps for 1090MHz are cheap enough but all benefit from being fitted under the aerial.
 
Lot of info on various ADB antennas (including the bow-tie) & kit on many forums, but notably FighterControl on the Worldwide Milair Monitoring part of the forum, but you have to register before you have access to that.
 
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