[Microwave] just starting out

[Dr. Gerald N. Johnson]

On Sun, 2008-06-29 at 12:19 -0500, tom scott wrote:
> hello and greetings from south texas
> 
> brand new to the list and to microwaving per se.
> 
> i have a kenwood ts-2000x with the 1.2 GHz module with no antenna.  i have
> no idea where to get started on what type to get, and what coax to interface
> with it.

One good resource is the CSVHF Conference web page that has a collection
of antenna test, I think over several years. There you can see what
antennas performed as claimed. Generally the loop yagis are the most
likely to work well for SSB/CW. They have been commercially available
(in kit form) from Directive Systems or C3I. I think the kits are worth
their money, with all the pieces cut and drilled, assembly is only
tedious, doesn't take machine tools to make a good performing antenna. 

Coax should be as large as you can connect to the antenna and run past
the rotor.

> first off, there are 2 1.2g repeaters near here that i would like to try and
> reach.  any good omnidirectional i can use? 

There might be, but omnidirectional antennas test poorly at CSVHF
ranges. Omnidirectional antennas are hard to test in any environment
because of the lack of directivity. The trouble is that its almost sure
the FM repeaters are vertically polarized and SSB/CW is horizontally
polarized. I've adopted a scheme on general purpose yagis set up for FM
modes is to tilt them 20 or 30 degrees from vertical. That reduces the
vertical signal strength very little (13.6% for 30 degrees) put gives me
a backup horizontally usable signal effectively with half the power that
would be radiated from that antenna set purely horizontal. If you tilted
a 1296 yagi 20 or 30 degrees from horizontal you could work those
repeaters and anyone from Houston to Dallas and beyond on CW/SSB. Unless
you know there are users on those repeaters you may have to call someone
with the capability of using them on the phone to get activity there,
and then you may find the owners tend to want them to be private.

The nearest 1.2 GHz repeater to here (Ames, Iowa) is still coordinated
but hasn't been on the air for a couple years and the owner hasn't plans
for putting it back on that he will admit. I think it had virtually no
users. It would have been handy for testing rigs at least i it was
working.

> if i stuck with a beam only,
> can lmr0400 coax be good?  i have plenty of that ready with type n
> connectors.

Its a start, LM600 would be nicer though I've used 3/4" cable TV line
for many years effectively too.
> 
> and is anyone on the list in the san antonio area that can Elmer me in this
> area?
> 
> tom ad5fd