----- Original Message -----
From: "Roger (K8RI)" <sub1@rogerhalstead.com>
To: "jeremy-ca" <km1h@jeremy.mv.com>
Cc: "Bill Fuqua" <wlfuqu00@uky.edu>; "Amps" <amps@contesting.com>
Sent: Monday, March 24, 2008 3:23 PM
Subject: Re: [Amps] What is this amp set up for
> 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.
Huh? What is that supposed to mean? They either have the 3CX800 or the CPX
installed (or a Y version). Im not aware of any commercial ham amp that is
pulse rated.
Carl
KM1H
>
>
> 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
>>>> >>>>>
>>>> >>>>
>>>> >>>>
>>>> >>>
>>>> >>>
>>>> >>
>>>> >>
>>>> >
>>>> >
>>>>
>>>> _______________________________________________
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>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>>
>>
>>
>
>
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