jeremy-ca wrote:
> However pulse rated tubes are often the most sought after for ham amps
> and are even used by the manufacturers.
>
> Examples are the 4PR1000A, 3CPX800A7, 3CPX1500A7, YC-156, and on and on.
However I think you will find most of these are *rated* for pulse, but
only have the 3CX800 and not the CPX version.
73
Roger (K8RI)
>
> They must provide extreme levels of linearity in medical service and
> are conservatively operated. In amateur service they are known for
> ruggedness and superb linearity.
>
> Bandwidth has nothing to do with it.
>
> Carl
> KM1H
>
>
>
> ----- Original Message ----- From: "Bill Fuqua" <wlfuqu00@uky.edu>
> To: "jeremy-ca" <km1h@jeremy.mv.com>; "Roger (K8RI)"
> <sub1@rogerhalstead.com>
> Cc: "Amps" <amps@contesting.com>
> Sent: Monday, March 24, 2008 11:59 AM
> Subject: Re: [Amps] What is this amp set up for
>
>
>> 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
>>> >>>>>
>>> >>>>
>>> >>>>
>>> >>>
>>> >>>
>>> >>
>>> >>
>>> >
>>> >
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>
>
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