SV: [AMPS] feedback sought: Ameritron AL-80
measures
measures@vcnet.com
Sat, 30 Oct 1999 07:36:24 -0700
>
>Hej all:
>
>I have in front of me an EIMAC data sheet of the 3-500Z ( 6-1-77) and HAM
>RADIO (1/77 ) - an article by W6SAI called "intermittent voice operation " (
>EIMAC publication AS 40 ) . The 3-500Z is said to deliver 890 watts of
>useful watts ( does this include output circuitry losses?? ) at 3500
>volts/400 mA and 40 dB 3rd order products. The 8873 ( inside same as 8875
>and 8874 ), mentioned in the HAM RADIO article, has a 350 mA maximum anode
>current. Still, EIMAC, in IVS service,allows 500 mA ( in short tune ups
€ very short. According to the specs, the max. on time for 500mA is
50-milliSeconds. In other words, you must use a tuning pulser for
tune-up.
>and
>SSB modulation peak current ) with still low 35 dB 3rd order distorsion
>products. The 8874 family has been been pushed to this limit in this IVS way
>in many amplifiers by HENRY, HEATHKIT, ALPHA with little problems in normal
>use. I also have seen many amplifiers using 8873 and 8874 after many years
>service still delivering almost full power with no harm and still almost
>normal distorsion products. Even when using PEP in cw service. My old HENRY
>using a pair of 8873s, nowadays used by a guy in cw contests, still works
>fine. It all depends on the operator, of course - the way he tunes up his
>amplifier and using it. RTTY, FM and long tune-ups is of course not possible
>in this IVS service unless you have a thick wallet,hi!
€ Indeed Hans. For a photo of what happened to some 8874 (oxide)
cathodes that were driven beyond this rating, see photos in ''Parasitics
Revisited'' in the Sept and Oct. 1990 issues of *QST*. However,
overdrive does not shorten the life of thoriated tungsten cathodes.
>----------
>>FrÂn: measures <measures@vcnet.com>
>>Till: "AMPS" <amps@contesting.com>
>>Ÿmne: Re: [AMPS] feedback sought: Ameritron AL-80
>>Datum: l–r 30 okt 1999 07.27
>>
>
>>
>>>
>>>Your mileage may vary, but from my own experience:
>>>
>>>I have owned all three: AL-80, SB1000, and AL80B. They all showed >850
>>>watts carrier into non-radiating (HA!) loads when measured with Bird 43 and
>>>2500H slug. They worked very well and, in my not so humble opinion, were
>>>great bangs for the bux. .....
>>
>>Obtaining such power from a single 3-500Z at this anode supply voltage
>>requires driving the tube to more than its Eimac and Amperex rating
>>of400mA max.. The result is increased splatter in SSB service. The
>>designer of this amplifier (Mr. Tom Rauch) claimed that he had a letter
>>from Eimac that increased the anode current rating to more than 500mA.
>>He never produced the letter.
>>- cheers
>>>
>>>At 02:27 PM 10/29/1999 -0700, Joe wrote:
>>>>
>>>>Hi,
>>>>I have come across an original Ameritron AL-80
>>>>amplifier. This is not the AL-80A or AL-80B. Runs a
>>>>single 3-500Z.
>>>>
>>>
>>>73 from NS1Z, FN44rn
>>>
>>>John Wilcox
>>>871 Route 120
>>>Rumford, ME 04276-3836
>>>
>>>fon: 207-364-2246
>>>
>>>--
>>>FAQ on WWW: http://www.contesting.com/ampsfaq.html
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>>>Problems: owner-amps@contesting.com
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>>>
>>
>>
>>- Rich..., 805.386.3734, www.vcnet.com/measures.
>>
>>
>>--
>>FAQ on WWW: http://www.contesting.com/ampsfaq.html
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>>
>>
>
>--
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>
- Rich..., 805.386.3734, www.vcnet.com/measures.
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