[Amps] Warm Coax question

[Doc Johnson]

Hi Steve,
The harness I have is from DB Products. I ordered it a few years ago cause 
the antenna was a few years old back then and "freshening it up" I thought, 
was a good thing to do. I must have been younger and had more motivation 
then. As far as the broadcast xmitter. I think if I could get my hands on a 
Gates/Harris FM1H with a 4cx1000 it would make a good conversion project. 
It does not use a cavity like the newer ones. I have not figured out if 
converting a cavity would be easier. I have had may offers of the older RCA 
xmitters but they used 2 of the 4-400 finals and were really old. Even had 
an offer of an older 10kw xmitter, but I looked at the rules and figured 
that I would probably get into trouble. Besides, I have problems running 
375 watts now. But until I figure out if the antenna is any good, I will 
keep running on the backup tx which is only 100 watts located at the site 
where the voter is 400' up a broadcast tower. The users of the system 
complain about not having a full scale at 40 miles away signal to listen 
to, but hey, its ham radio. I do not want to be smoking any more 8560s or 
rf decks.  Here is a pick of the db224 for your viewing edification. The 
beam is the uhf  rx for the audio feed from the 
voter.  http://www.qsl.net/smart/xmit.htm


At 04:21 PM 4/22/2002 -0700, you wrote:


> > Thanks for all the replies. I ordered the DB224 cut for the ham bands, so
> > the swr should be flat. I am going to take an antenna analyzer to the site
> >
> > and see what it says. I am going to replace the RG8 jumper with some 9913
> > and eventually some !/2'" superflex. I am not concerned with de-sense at
> > the site as I do not rx any vhf there,  I just rx the uhf link tx from the
> >
> > site where the voter and all the uhf link rx are which is 8 miles away.
> > The
> > 375w tx just hooks to the feedline and then to the antenna. I am using a
> > pl259 only because that is what Motorola puts on their 357 watt Micor amp.
> >
> >
> > ::Ugh.  The circle batwing strikes again.
> >
> > I have a brand new harness for the antenna so if the analyzer reports bad
> > news the harness will be replaced.
> >
> > ::Well, the harness is made of silver-plated, double-shielded coax.  I
> > hope that's what you have to replace the original one with!
> >
> >  Probably will do that anyway. At least
> > the antenna is on a building not a tower. I will look at the Bird site and
> >
> > make the correct length jumper so when I remove it the tuning should not
> > be
> > affected.
> >
> > ::As I recall, the "Bird simulator" section of coax is 4" long.  But of
> > course, if the VSWR were flat, then it wouldn't matter.
> >
> > Actually adding some remote metering would be cool and I could
> > just leave the meter line section in. There should be some remote metering
> >
> > equipment surplus by now.  Has anyone converted a 1kw commercial fm
> > broadcast tx to the 147 mhz range?... Another project. That way I can stop
> >
> > using a commercial 2-way tx.
> >
> > ::Vacuum tube units, yes.  Solid-state, no.  It would be quite a stretch
> > to pull even a 107.9 MHz amplifier up to 147 MHz without replacing circuit
> > boards.  But it's easy to change a few components in a tube amp and be up
> > and running quickly.
> >
> > ::WB2WIK/6
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps