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Re: Connectors for dish feeds

Another possibility would be high-quality TNC connectors.  Precision
BNC (and TNC) connectors with a solid outer ring, rather than spring
fingers, are not very common, but have the same dimensions as N
connectors and are suitable for higher frequencies, although the
coupling mechanism of TNC connectors is to be preferred.  I have used
TNC connectors successfully as high as 10GHz.

I definitely do NOT recommend using RG-8X for S-band signals, as the
shield coverage is insufficient.  RG-223, LMR-200 or 240 would be
better choices.  Many years ago I was working on a microwave test set
where someone had replaced several RG-214 cables (double-shielded) with
RG-213 (same dimensions, but single-shielded).  The leakage was

Bob N7XY

On Tue, May 28, 2002 at 10:36:35PM -0400, Woody wrote:
> Hi Bruce:
> BNC connectors are very poor above 70 cm.  If you need to use a smaller
> connector than an "N", try using an SMA connector.
> 73,
> Woody
> ----- Original Message -----
> From: "Bruce Nolte N3LSY" <brucenol@abs.net>
> To: <amsat-bb@AMSAT.Org>
> Sent: Tuesday, May 28, 2002 9:23 PM
> Subject: [amsat-bb] Connectors for dish feeds
> > I  have built a couple of feeds for my 3 foot offset fed dish, based on
> > the designs of K5OE and K3TZ  helical and patch feeds. One variation
> > from their design I made was to substitute BNC connectors in place of
> > the N connectors in their design, primarily because I had plenty of BNC
> > Chassis connectors, and no N connectors at hand.  From the connector at
> > the feed, I made a short jumper of RG8X Flex to the downconverter. On
> > the feed end, I use a BNC connector, and on the other end I use an N
> > connector designed for use with RG-8X.
> >
> > I wonder if it would be worth my while to redesign my feeds to use
> > N-connectors and a lower loss cable. Based on the information I could
> > glean off of Google, I can expect only 0.1 dB of improvement in loss by
> > upgrading the short (8 inch long) jumper between the feed and the
> > downconverter from 8X to something like LMR 400. Can I expect any
> > improvement in signal by upgrading the connectors?
> >
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