Apache TX-1 "RF Hiccup" Puzzle

[Peter A Markavage]

I think there was a QST article or "Hinks" article or maybe in CQ's Ham
Clinic years ago that addressed this issue. I'll look around and see if I
have any info. You might try "regular" 6146/A/W/B's to see if the problem
goes away.

Pete, wa2cwa

On Wed, 23 Jun 2004 20:54:51 -0700 digital-conjurers at ADELPHIA.NET writes:
> Have an Apache TX-1 running AM only with an unusual problem:
>
> About 250 milliseconds after unkeying, there is a small "RF Burp" or
> small RF pulse of very short duration (100 ms or less), and small
> energy, that comes out of this transmitter.  This is especially
> puzzling, given:
>
> 1.  The finals seem perfectly neutralized
> 2.  Voltages, tubes, everything checks out as nominal
> 3.  Coax routing seems very orderly
> 4.  The complaint _slowly disappears_  as you tune the final tank
> circuit slightly off the resonance dip; i.e. if you're dipped at
> 200ma, and slowly swing up to, say, 240ma, the phenomenon goes
> away.
> 5. SWR is low; even does it on the dummy load.
>
> [BTW we're using 6293 industrials instead of convetional 6146's.
> (The primary difference between these and the "normal" 6146 is that
> the plate is much "heavier" in its construction. )]
>
> So, the sequence is:
>
> 1. Unkey, the Dowkey releases, all power meters swing to zero, 250ms
> later there's that >100ms RF "hiccup", then all is fine.
>
> Wierd.
>
> Ideas?
>
> Thanks to the group in advance,
>
> Lin/KJ6EF

-----------------------------------------------------------
Products bought, sold or traded here is the responsibility of the
parties involved.  This list and the City of Tempe are not responsible
for losses or misrepresentations of any kind.  Buyer beware!

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html