Paul,
Do you remember the boom length and the element diameters? It would be
an interesting exercise to model a Gotham exactly the way their
instructions said, and see what the results are.
Back in the early 60's, I was just about too poor for a Gotham ;-) I
spent my entire Novice career on 7184 kc (the only crystal I owned),
with a Knight T-60 and a bandspreaded BC-455 command set on rx - 15 kc
IF bandwidth, if I remember correctly. I did have a 40 meter dipole up
about 70 feet, so I worked everything near 7184! Those were the days,
indeed...
73,
geo - n4ua
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of Paul Christensen
> Sent: Tuesday, July 10, 2007 6:40 AM
> To: Jim Pruitt; towertalk@contesting.com
> Subject: Re: [TowerTalk] Gotham antennas
>
> >I remember Gotham quite well. I also learned the hard way that cheap
was
> > not necessarily good! I bought a 4 element 15 meter yagi from them
from
> > an
> > ad in QST. When I put it up I could work just as many stations off
the
> > front as I could off the back and sides and with no difference in
signal
> > strength! The SWR was 10 to 1 at the lowest.
>
> The beam antennas actually worked remarkably well although they
certainly
> were not "Plug-'n-Play." The building experience was more akin to a
> magazine construction project with Gotham supplying most of the parts.
> The
> gamma match simplified things for Gotham. There wasn't a single
component
> used that was custom manufactured.
>
> The instructions called for making the reflector 5% longer than the
DE,
> and
> the directors 5% smaller than the preceding elements which, were
spaced
> evenly on the boom. Without exception, the most difficult part of
> assembly
> for the beginner was creating the gamma matching section, finding a
> suitable
> tap point, and adjusting a series compression trimmer accordingly to
yield
> a
> VSWR of 1:1. Other than supplying a hose clamp, Gotham left the
design of
> the gamma section up to the owner. It was a shame, really -- so many
> beginners gave up like you did. At the very least, Gotham could have
> supplied thin tubing and an input termination point. No terminals.
No
> SO-239 connector. Only a set of instructions that told you to connect
> your
> coaxial able to the gamma section that YOU designed.
>
> Switching to the TA-33 from the Gotham was one of the happiest days of
my
> youth.
>
> Paul, W9AC
>
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
------------------------------------------------------------------------------------------------
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.
------------------------------------------------------------------------------------------------
[mf2]
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|