I have gotten several 200 MHz power pulsed amplifiers from University
surplus sales.
These were used in MRI systems. One interesting one had a version of the
8877 with out
fins clamped in a 1/4 wave cavity. It had a solid state driver amplifier
that was also pulse rated.
I think a hint may be the spec. of 200 MHz plus or minus a few MHz and a
2kW pulse rating for
power. Pulse operation is usually not used in amateur work due to the wide
band width.
73
Bill wa4lav
At 08:52 AM 3/23/2008 -0400, jeremy-ca wrote:
>With 2M amps being not that uncommon the price is usually lower.
>
>With the only 222 amps being custom made or modified as that one they tend
>to be more in demand. And you know what happens on Ebay when the frenzy
>starts.
>
>Those holes look to be for extra air flow thru the cover after it got hot
>and deformed. I'd open it all the way and install a silicon rubber chimney
>with a non restrictive mesh on top. I had to do that with my 144 and 222
>amps; made a huge difference and no more tuning drift.
>
>Prices are even higher for a good 432 amp in the 8938 and 2x 3CX800
>category.
>I gave up finding a 8938 at a good price and wound up rebuilding a Collins
>USAF 350 MHz cavity amp with a GE 2500W dissipation monster tetrode. It was
>designed for a KW out as an AM linear.
>
>Carl
>KM1H
>
>
>
>
>
>----- Original Message -----
>From: "Roger (K8RI)" <sub1@rogerhalstead.com>
>To: "jeremy-ca" <km1h@jeremy.mv.com>
>Cc: "Amps" <amps@contesting.com>
>Sent: Sunday, March 23, 2008 2:18 AM
>Subject: Re: [Amps] What is this amp set up for
>
>
> > jeremy-ca wrote:
> >> When I first saw that listing it said modified; I see he has revised it.
> >>
> >> Thats not a bad price for smoke on 222 if the tube is perfect and
> >> trimming back the strip line should be rather easy
> > I would think it's too high even with a new tube. Really nice ones
> > unmodified on 2, or 6-meters have been going for around $1400 (give or
> > take) Look carefully at the top. It is bent in and has a circular row of
> > what appear to be holes. I have one on 2 that is *almost* mint. It
> > looked crappy when I purchased it at a swap. I figured I could use it for
> > parts and hoped for a reasonably good tube. A little cleaner and it looks
> > almost new with a good tube.
> >
> > 73
> >
> > Roger (K8RI)
> >>
> >> My own amp for 222 is a 8877 and I scaled down a 2M version and then used
> >> a VNA for final trimming. I built it in a partially built Henry 44-46 MHz
> >> box I picked up in a swap.
> >>
> >> Carl
> >> KM1H
> >>
> >>
> >> Carl
> >> KM1H
> >> ----- Original Message ----- From: "Roger (K8RI)"
> >> <sub1@rogerhalstead.com>
> >> To: "jeremy-ca" <km1h@jeremy.mv.com>
> >> Cc: "Amps" <amps@contesting.com>
> >> Sent: Saturday, March 22, 2008 9:19 PM
> >> Subject: Re: [Amps] What is this amp set up for
> >>
> >>
> >>> jeremy-ca wrote:
> >>>> Hmmm, his description says it is modified for 220.
> >>>
> >>> Isn't that "modifiable" to 220?
> >>> Although advertised as a 2-meter amp, "I'd guess" it's one of those that
> >>> was used for plasma or industrial heating at 200 MHz that can be
> >>> modified for 220. Some outfit has had a similar one in very nice shape
> >>> (with new tube)on there since last Fall with no takers. Their BIN price
> >>> has finally started down. Unless they find some one who really wants
> >>> (and can use) one for 220 both are basically parts amps.
> >>>
> >>> I purchased one all set up for the 2-meter band in good shape that only
> >>> required a good cleaning for less than he's asking for one that may
> >>> require a lot of work. I was learning about building filters for it on
> >>> here last summer.
> >>>
> >>> 73
> >>>
> >>> Roger (K8RI)
> >>>> Carl
> >>>> KM1H
> >>>>
> >>>>
> >>>> ----- Original Message ----- From: "Roger (K8RI)"
> >>>> <sub1@rogerhalstead.com>
> >>>> To: "Amps" <amps@contesting.com>
> >>>> Sent: Saturday, March 22, 2008 7:59 PM
> >>>> Subject: [Amps] What is this amp set up for
> >>>>
> >>>>
> >>>>> the amp listed on
> >>>>>
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350038955687&ssPageName=ADME:X:AAQ:US:1123
> >>>>> is listed as a 2-meter amp but the specs list it as 200 MHz +/-10 Mhz.
> >>>>> Also the output filter is far smaller than the one in my 2002A which
> >>>>> is
> >>>>> set up for 2-meters.
> >>>>>
> >>>>> 73
> >>>>>
> >>>>> Roger (K8RI)
> >>>>> _______________________________________________
> >>>>> Amps mailing list
> >>>>> Amps@contesting.com
> >>>>> http://lists.contesting.com/mailman/listinfo/amps
> >>>>>
> >>>>
> >>>>
> >>>
> >>>
> >>
> >>
> >
> >
>
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