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Re: Antennas for sale

Thanks, Lem, for making the surplus antennae available.

For anyone interested in modifying these antennae for circular polarization, I have some simple guidelines on my web page to convert one of these rectangular BBQ dishes to a round, circularly polarized, dish.  I converted a 2' dish a few months ago and it worked out so well I have just left it up.  Please see:


and select the "2' Dish Mods" menu item.  If you have a different size dish, you can confirm the "focus" for your dish by inserting a Step 2a:  place the dish flat on the floor facing down and measure the depth (d).  The focus formula is:
focus = D^2 / 16d  (or or you FORTRAN old-timers... D**2/16d)
where D is the diameter of the dish and d is the depth.

The K5GNA dish I used had a focus of 10.33" and I put the back of the helix cup at 11" so the "phase center" of the helix was at the focus of the dish.  

If you use a patch feed, place the face of the patch at the focus.  I recently built a K3TZ patch for a small DSS dish and was very positively impressed (http://www.qsl.net/k3tz/index.html) with it's performance compared to a helix.  Coupled with a 3731 (already has an N-connector), it makes a compact, high-performance antenna feed.  See K5GNA for the downconverters.
Jerry, K5OE

In a message dated Sun, 17 Feb 2002 11:01:54 PM Eastern Standard Time, "WJ4W" <WJ4W@msn.com> writes:

> On monday, 4 Feb 02, I listed on the bb antennas I would/did have at the
> Orlando hamfest. As a result of that listing, I have received many
> e-mails wanting too know if I could ship the Conifer/Andrew's (bbq)
> 26T-2400 and 18T-2400 antennas. The answer is : yes, I can. These
> antennas were carefully uninstalled recently out of up-and-running mmds
> systems. These antennas will be ship disassemble. All necessary hardware
> for reassembling and mounting will be included. The dipole feed is not
> included; instead, stainless steel brackets for mounting the TranSystem
> ADIC type downconverters(3731, 3733) will be included.
> I will pack and ship the 26T-2400 for $75.00
> I will pack and ship the 18T-2400 for $55.00
> These prices are for the lower 48 states only. Other areas need to
> contact me.
> Payment methods are cashier check or money order.
> I will send a digi pic of either of these antennas too anyone upon
> request.
> I can be contacted at: wj4w@msn.com
>                                         or
>                                wj4w@amsat.org
> Lem----wj4w
> amsat #24409

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