[time-nuts] Choke Ring Antenna - Patch Placement? (Bob Stewart)

[johncroos at aol.com]

 Howdy Bob -


Hi John,

I don't have LH here.? I've never looked into it.? Will it work with an NMEA GPS 
receiver?


Bob - AE6RV



 My error. The T-bolt and LH combination is so common I just assumed you were using a T-bolt. As to your receiver, I do not know. Perhaps someone else on the list knows.

If you can come up with a T-bolt, even to borrow, LH is a free download. In the survey mode it gives a nice map of levels vs elevations and azimuth.

Hopefully you are having a lot of fun with this project. However my experience as a RF/Microwave guy argues that without a real antenna range and some standard gain antennas most of your data will be inconclusive if not down right maddening. The ground bounce is significant. This is why the amateur microwave guys often put one end of an outdoor range right on the ground.

I did some gain measurements on an axial mode (i.e. end fire) helix for 2.4 GHz a couple of years ago. With both antennas at 4 ft above the grass moving one of them up or down a few inches changed the received level several dB. So I ended up with the Tx end on the grass. Much better.

Most receivers have an "elevation mask" parameter that you can set. It throws out any data when a sat gets below the mask setting.
This gets you most of the benefits of the choke ring, though I am sure for the super serious time nut there is some advantage to the choke ring. 

GPS is a fairly robust system design and will provide very good performance with some pretty shabby setups. However it is all a matter of your requirements as to when enuf is enuf!

-73 john k6iql