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Goof Proof Patch Antenna for 900-1200MHz

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Goof Proof Patch Antenna for 900-1200MHz

Old 02-10-2003, 07:53 PM
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bobc1
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Default Goof Proof Patch Antenna for 900-1200MHz

I have reviewed the RC-Cam.com site and printed the plans for the GGP antenna for 2.4 GHz. What needs to be changed for 900-1200 MHz?

Any help would be appreciated.
Old 02-11-2003, 06:53 PM
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Default Goof Proof Patch Antenna for 900-1200MHz

You need to rescale all dimensions then tweak for max performance, as needed.

900Mhz: Increase all dimensions by 2.667
1.2Ghz: Increase all dimensions by 2.00

Yes, ALL dimensions are affected. Material should be stout enough to support the extra mass. By the way, accuracy counts. A tiny insignificant error will reduce performance (and you may not even recognize that it is a bit crippled).

So, build it with precision in mind. The presentation of the project on the RC-CAM web site was such that it helped minimize the possibility of errors.
Old 02-11-2003, 08:17 PM
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Default Goof Proof Patch Antenna for 900-1200MHz

Thanks. I'll give it a try.
Old 02-12-2003, 06:59 AM
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Default 1.2 ghz GPP

I built a 2x GPP for my 1.2ghz HK system and it did improve reception dramatically. In fact, the 1x GPP helped a lot on my 2.4ghz system. It's well worth the time and effort.
-Tom
Old 02-12-2003, 09:25 PM
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bobc1
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Default Goof Proof Patch Antenna for 900-1200MHz

To clarify 2x "all dimensions." Does this include the air gap spacers, also.

I realize this is probably a dumb question but my knowledge of antenna theory is zero.

Thanks.
Old 02-13-2003, 05:23 AM
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mr.rc-cam
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Default Goof Proof Patch Antenna for 900-1200MHz

The air dielectric spacing must be 2.00X for the 1.2Ghz antenna.
Old 02-23-2003, 04:40 PM
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bobc1
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Default Goof Proof Patch Antenna for 900-1200MHz

I completed & tested the GPP antenna. I sized it up for 1050 MHz, halfway between 900 & 1200 MHz. The receiver that I have uses an F connector instead of an SMA connector so I used a PCB mounted F connector.

Unbelievable results! Almost no glitches while flying. The only area that has poor reception is almost directly behind the antenna.

Thanks for the plans.
Old 02-23-2003, 04:52 PM
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Default Goof Proof Patch Antenna for 900-1200MHz

That is great news. Congrats!

Performance will be even better if you build it for the exact frequency you are using (down to the hundredths of an inch). The losses expected when it is not a accurate match are a bit high, due to resonance issues.

When you have the time your should build it as such. You will get more gain (or more precisely put, you will eliminate the match losses). I would expect another 2 or 3 dB's, which is certainly worth the effort.
Old 03-02-2003, 05:03 PM
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Default Goof Proof Patch Antenna for 900-1200MHz

I gained access to a frequency counter & discovered that the transmitter is broadcasting on 1150 MHz. I scaled another GGP Antenna to that exact frequency, smaller than the previous one tuned for 1050 MHz.

No real noticeable change from the first one. Still very good line of sight reception as long as the airplane is in front of the antenna.

Thanks again.
Old 03-02-2003, 05:15 PM
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Default Goof Proof Patch Antenna for 900-1200MHz

The improved gain will show up if you have a way to accurately measure it. At resonance, the antenna will perform a few dB's better.

BTW, that is not a valid RF band for our use. 960-1215Mhz is the Aviation Services (NAVAIDS DME) band. It is illegal to use in the USA (even with your ham license). You need to retune to 1215-1300Mhz.

Another fellow was in your situation. He manipulated the VCO's coil on the Tx board to get into a legal area.

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