Quesstion for Communications Specialists users

I'm wondering how those who use the Communications Specialists tracker units deal with the 20" transmitter antenna length. I'm considering using one in a nose cone mount but I'm not sure how to route the antenna. It seems to me that any configuration other than straight will decrease the range. Any suggestions welcome. Thanks.




Bob
(First post)

milehighrkts said:

I'm wondering how those who use the Communications Specialists tracker units deal with the 20" transmitter antenna length. I'm considering using one in a nose cone mount but I'm not sure how to route the antenna. It seems to me that any configuration other than straight will decrease the range. Any suggestions welcome. Thanks.




Bob
(First post)

Click to expand...

Welcome to the TRF Bob !

In my use of the tracker i have just taped to the shock cord with electrical tape.

Two of our greats have shared what they have done in the past .. CJ would drill small hole in nosecone bulkhead and feed the antenna through it ...then seal hole with a bit of putty.

John Coker has 'arced' or softly bent the antenna around the interior wall of the nc..or loop around the antenna into a self holding circle I believe..YMMV he was not using that technique on a small nc

Kenny

I've wound the antenna on an older CSI tracker (which I replaced with more flexible wire) in a spiral form and put it inside a 38mm nose cone. I'm sure I degraded the range substantially but it's still more than adequate for most recoveries.

I've also looped the antenna once when I couldn't use the hole in bulkhead technique that Kenny mentions.

You've got a fair amount of margin with these units -- at least the older higher-power AT2B (I haven't tried the newer one yet.)

I have found that over time & use, my antenna has curled up quite a bit. Still find my rocket. & like KenRico, I just tape it to shock cord with electrical tape.

timbucktoo said:

I have found that over time & use, my antenna has curled up quite a bit. Still find my rocket. & like KenRico, I just tape it to shock cord with electrical tape.

Click to expand...

Me too.

Not sure what altitude you are tracking to and what the frequency/power/data rate/many other factors are. As others have said, keep it straight for the most effective transmission.

How much bend you can get away with depends on who much spare signal you have in your link budget. As long as you are above the minimum signal at the Rx for the decoding you will likely not notice any difference. You generally only see a difference on the edge of detection. Many factors reduce the signal and the ability of the system to maintain the link. Some ground testing might give you an inkling of what to expect if you curl/shorten/whatever to the Tx system. Probably won't give you an absolute limit on the distance but you could get a feel for the amount of degradation you can induce by curling etc.

The best indication would probably be what others' flights have achieved and maintained the link.

Thanks for all the replies and suggestions. For the foreseeable future, my altitude will remain under 20K. I like the ideas of running the antenna thru the bulkhead and also taping the button to the shock cord. I will also do some range testing with winding the antenna versus straight. The forum is THE place to go to learn how things are done. Thanks again.


Bob