[NLRS] Give away + Need advice on DirecTV dishes

[David Palm]

Jerry wrote:

The Vivaldi that Kent sells is 10-25 GHz, not very useful on 3.4 GHz. His
PCboard log periodic that does cover 2.1 to 11 GHz has less gain and I
think the spill over the sides of the dish will be great, hurting the
transmit gain and the receive signal to noise ratio.

The Vivaldi that I got from Kent is 5 - 18 GHz, but he says it works down
to 3.5 GHz.  It's quite a bit bigger than the 10 - 25 GHZ model.

So Jerry, I wonder if you can clarify: are you saying that the Vivaldi will
do a better job at limiting overspill than the log periodic?  Or are they
both equally bad in that regard?

Donn wrote:

I look forward to seeing the multi-band dish on the antenna range.
 (Assuming the WX is such that we can do another antenna range.  We got
skunked at Aurora last month and next week's make up is iffy with the WX
pattern we seem to be in.  Maybe later in the summer....

Thanks for your encouragement, Donn.  Yes, if the antenna range is offered
later in the summer I'm going to try hard to get up there for that.  The
earlier dates have not worked for me, but I'd love to have another crack at
it.

73,

David  W9HQ



On Fri, Jun 7, 2013 at 12:23 AM, Dr. Gerald N. Johnson
<geraldj at netins.net>wrote:

> The Vivaldi that Kent sells is 10-25 GHz, not very useful on 3.4 GHz. His
> PCboard log periodic that does cover 2.1 to 11 GHz has less gain and I
> think the spill over the sides of the dish will be great, hurting the
> transmit gain and the receive signal to noise ratio. The dish will
> concentrate the received signal on the feed, but the feed will see noise
> sources like hot earth from the spillage.
>
> You could make a Vivaldi for a lower frequency range, just make it 3 times
> the size of his 10-25 GHz and it has better gain than the LP, but still may
> spray RF past the edges of the dish and pick up some noise sidelobes. It is
> possible to array Vivaldi's but it gets messy.
>
> 73, Jerry, K0CQ
>