Check Palstar and QRO, dont know what their specs are but a 3 holer "export"
model should do it.
Carl
KM1H.
----- Original Message -----
From: "Richard Solomon" <dickw1ksz@gmail.com>
To: <amps@contesting.com>
Sent: Wednesday, February 08, 2012 10:59 AM
Subject: Re: [Amps] Different amp recommendations
So, all this talk begs the question ....
What is available in the Ham Market that will do 1.5 KW for any length of
time.
I expect if such an animal existed, they would be selling a bunch of them.
73, Dick, W1KSZ
On Wed, Feb 8, 2012 at 8:46 AM, Rich <w9cin@comcast.net> wrote:
> I have owned many of the AL-82, Al-1200, AL-1500 series amps,, they
> all use the same
> power supply and the same tank ckt.
> did many tests on long time, high output . and found the amp is very
> good, for normal ham use
> but running at 1300-1500 watts out for 10 -15 min the tank circuits got
> so hot the solder got soft.
> asking any amp to do 1500 watts for 30 min. is asking a lot
> that's why they most manufactures rate them as "intermittent amateur
> radio service" .
> just my thought's
> "Rich"
>
>
>
> On 2/8/2012 12:29 AM, Jim Thomson wrote:
>> Date: Mon, 6 Feb 2012 11:47:42 -0600
>> From: Rob Atkinson<ranchorobbo@gmail.com>
>> Subject: Re: [Amps] Different amp recommendations
>>
>> I have doubts about the AL82 doing 1500 watts 100% duty cycle for very
>> long.
>>
>> Knowing the p.s. in that amp you'll be right at its limit, right at
>> the Ip limit of the tubes, right at or a bit above their maximum
>> dissipation...
>>
>> It's a "legal limit" amp only because Ameritron heaped up the Ep.
>>
>> But you can call almost anything "legal limit" with no time factor
>> considered.
>>
>> Your enemy is time. do you want to go for 10 minutes or more at 1500
>> w. on RTTY? Do you want to be able to forget about the amp and not
>> have to look at it nervously every 15 seconds to make sure it's okay?
>>
>> Personally, I like overbuilt stuff.
>>
>> you can beef up the AL-82 in some ways and settle for 1.2 or 1.3 KW,
>> homebrew an amp or keep looking with more money.
>>
>> 73
>>
>> Rob
>> K5UJ
>>
>> ## let's do the jr high school maths. The xfmr in the AL82/1200/1500 is
>> rated at 1.8 kva CCS. [32 lb]. To get 1.5 kw out, we require 1500/.6eff =
>> 2500w dc input.
>> When those dahl xfmr's are maxed out, the temp rise is rated at 55 deg C
>> over a 40 deg C
>> ambient. That also factors in another 10 deg C deep inside the core..for
>> 'spot heating'.
>> Deep inside the core, it will be 65 deg C over the outside 40 deg C
>> ambient.
>> Now 40 deg C = 104 deg F. Now the hottest it will get, deep inside the
>> core is 105 deg C or 221 deg F....which is hot.
>> On CW, with dashes at a 3.6:1 dash to dot ratio, this
>> xfmr will be fine. RTTY for hrs on end, yeah, I don't think so. A 46 lb
>> dahl is only good for
>> 2.7 kva CCS....and that would be the smallest size I would use in a RTTY
>> contest.
>>
>> ## If ur eff is lousy on 10m, like 50%... now you require 3 kw dc input
>> to get 1.5 kw out.
>> IMO, the initial extra cost of a slightly heavier xfmr is well worth it.
>> You save nothing
>> in the long run by under sizing pwr supply components OR tank components
>> like coils+
>> bandswitch's, etc. A bigger xfmr not only runs cooler, it will also have
>> way better V regulation.
>> IF you burn up a xfmr, it will have to be replaced with the 46+ lb unit
>> anyway, so now you
>> not only didn't "save" any money....you lost money ! IMO, build it [or
>> buy it] like a tank,
>> then never look back.
>>
>> Later... Jim VE7RF
>>
>>
>>
>>
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