[amsat-bb] Antenna Opinions?
ko6th_greg at hotmail.com
Tue Sep 21 22:03:31 PDT 2010
So, we had a swap meet a couple of weekends ago, and I found a bargain I couldn't refuse. Of course, now I need to decide what to do with it...
The Find was a 35 element 1296mHz antenna, well built and in excellent condition. Linearly polarized, horizontal; supposed to be 23dBi gain. Manufacturer, of course, is unknown. No markings, but it does not look home-built. By the mounting hardware, it looks like it was part of some sort of stacked array.
The problem is that I already have a 1296mHz antenna. Home-made, circularly polarized, 18 turns Helix. Should be something like 17dBic, if the calculations are correct.
In the shack, which is at the wrong end of 60' of 1/2" hardline and a total of about 15' of RG-213 or something like it, I have my Yaesu 736R and its 10 watts of screaming RF power. No preamps.
Which antenna should I keep up on the rotor assembly?
Last weekend I put up the new antenna. I've made one AO-51 LU pass with the new antenna, and I was not impressed. Several times I couldn't get into the bird, presumably because of the crossed polarization. But when I did get in, it was full quieting, even at low elevations. I don't recall having this much trouble with the Helix. I think AO-51 is the only current satellite on L-band, right?
For other uses, there's nothing terrestrial to aim at, repeaters-wise; they're all hiding behind one or more hills, or went off the air years ago. That leaves Weak Signal work (hence the horizontal mounting). I do have one shot into the valley, to the North West, but probably slim pickings for contacts. I haven't tried EME.
I'm leaning towards putting the Helix back up, and passing the new one on to someone more able to use it. What are your thoughts?
More information about the AMSAT-BB