[NLRS] [BC'ers] Fwd: Re: Anybody have experience with multi-band feeds?

[David Palm]

Thanks for all the great feedback so far.

>> Its a trade off situation, where having individual band antennas can
speed band changing, but makes on site erection slower. Where the gang
of loopers make give better performance at the cost of greater antenna space
volume and more difficult aiming. <<

Exactly.  To me the potential advantage with the multi-band dish is that it
gets peaked up on a station and then you run some bands with them without
having to horse around with aiming another antenna.  So if the different
between a looper on 2304 and the less-than-optimum dish really was only 4-5
dB, then it might be worth it just to stick with the dish.  On the other
hand, if I already have a mast with yagis for 902, 1296, etc. peaked on the
station then having another looper on there for 2304 would be optimal.

>> I think there's been something written recently about feeding a dish with
the Vivaldi, I'll look for it after while, likely a recent magazine or MUD
proceedings. I have the feeling that the Vivaldi as supplied by Kent is more
appropriate for a short focal length prime focus dish than the Direct TV
style offset dish. Because the pattern of the Vivaldi is more like a dipole
than a multiple wavelength horn. <<

I would be interested in seeing this, if you can find it.  It seems that
basically this is something that just needs to be tried.  Hopefully we can
give it a go at Aurora '11.  I have both the Vivaldi and the log periodic
PCB antennas.  It might be interesting to try both, if there's enough range
time available.

Does anybody have some ideas about the best way to mount a PCB feed?  I have
some ideas, but I'm not very mechanically creative--it seems that as soon as
I put something together I'll see an idea that's way more clever than what I
came up with myself.

Finally, I'm probably going to do this with the DirecTV dishes, since that's
what I have.  But if anybody knows of a place to get a dish that may be more
optimal for this experiment, I'm certainly open to that.

Thanks and 73,

David  W9HQ