I'm a bit worried about the reliability of the Chinese 8877s. One in
my Alpha 9500 started arcing internally after about 100 hours of
service. Alpha replaced it under warranty, and now the replacement
tube is doing the same thing. I worry that the factory may be having
quality control problems.
73,
Jim w8zr
Sent from my iPhone
> On Dec 28, 2014, at 6:20 PM, Yueh Hsu <hsu4qro@gmail.com> wrote:
>
> HiJim & Carl，
> Yes, Chinese 8877 is my option too.but in lower power level,for example
> 1000W,what is your option?
> a GU-74?or a pair GI-7B(GI-46B)?or a pair 3-500Z?I know pulse tubes with
> bad IMD specs.
> 73s Hsu
>
>
> 2014-12-29 7:26 GMT+08:00 rmorris <robrk@nidhog.net>:
>
>> Though the "R" was for "linear service"... Maybe more better IMD. Have
>> some.
>>
>> Sent from my iPhone
>>
>>> On Dec 28, 2014, at 16:59, Colin Lamb <k7fm@teleport.com> wrote:
>>>
>>> And, just to complicate things a bit, the 4CX250R is stated to provide
>> more output than the 4CX250B. I think it is rated for repeater usage,
>> although the bias and characteristics are different than the 4CX250B.
>>>
>>> 73, Colin K7FM
>>>
>>>
>>>> On 12/28/2014 1:34 PM, Fuqua, Bill L wrote:
>>>> I suspect when EIMAC came out with the 7034 they wanted to suggest
>> that they were a good replacement for the
>>>> 4X150A. Military particularly wanted to use the same part number when
>> replacing tubes in their radios, and I suspect that
>>>> EIMAC wanted to not only promote the 7034 they wanted to make one tube
>> type rather than 2.
>>>> There are subtle differences between the two tubes, besides plate
>> dissipation limit. The characteristic curves for the 4X150A does not show
>> any
>>>> area where there is a negative flow of screen current, while this is an
>> obvious issue some times with the 7034 and 4CX250B.
>>>> This could be a problem in some cases when interchanging these tubes.
>> There are other differences, one is that
>>>> when operating the 7034 at 500MHz it does produce the same output power
>> but requires 1/3 the drive power.
>>>> 73
>>>> Bill wa4lav
>>>>
>>>> ________________________________________
>>>> From: Amps [amps-bounces@contesting.com] on behalf of Colin Lamb [
>> k7fm@teleport.com]
>>>> Sent: Sunday, December 28, 2014 8:15 AM
>>>> To: Peter Voelpel; amps@contesting.com
>>>> Subject: Re: [Amps] Power from Pair of Eimac 4 x 150 a / 7034?
>>>>
>>>> "The Eimac data sheet does not confirm that
>>>>
>>>> http://www.r-type.org/pdfs/4x150a.pdf
>>>>
>>>> The RCA 4X150A/7034 data does:
>>>>
>>>>
>> http://pdf1.alldatasheet.com/datasheet-pdf/view/241849/ETC/7034-4X150A.html
>> "
>>>>
>>>>
>>>>
>>>> The RCA data sheet refers to a 4X150A only, which is a different tube
>> than the 4X150A/7034.
>>>>
>>>> 73, Colin K7FM
>>>> _______________________________________________
>>>> Amps mailing list
>>>> Amps@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>> _______________________________________________
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>>
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