Date: Tue, 23 Mar 2010 23:13:26 -0700
From: "Bill, W6WRT" <dezrat1242@yahoo.com>
Subject: Re: [Amps] Good engineering
On Tue, 23 Mar 2010 18:55:33 -0700, "Jim Thomson" <Jim.thom@telus.net>
wrote:
>## Bill , got any idea what 3 x NEW EIMAC 3CPX-800A7's
>cost these days? ##That's the tube line up used in
>the HF-2500E.. really >smart.
I suspect that was a marketing decision, not an engineering one. Some
hams want only Eimac tubes and will not buy anything else. especially
in an amp that costs an arm and a leg like that one does.
### RF parts list Eimac as being the only ones that even make a
3CPX-800A7 [3.6 kv rated] Eimac came out with a bulletin, urging
all commercial FM stations that use 3CX-800A7's.. to switch to the
higher vdc pulse rated versions.
## chinese 8877's are abt $550.00 For $100.00 more, you can buy
a real tube. All my tubes can be rebuilt. I don't buy throwaways...
except for 3-500Z's.
>The 12 ga wireroller inductor,used in the 10 kw palstar ant tuner is a joke,
>along with SO-239's,and the mickey mouse balun on the INPUT
>of the tuner.. which will explode.
Really? I had a Palstar 5 kW tuner for a couple of years and it worked
fine. Nothing burned, nothing melted, nothing exploded. Of course, I
was running ONLY 1500 watts. :-)
## The original palstar tuners used real edge wound ribbon rollers.
Then they went cheap, and now use 12 ga tinned wire. If Palstar
rated your tuner for 5 kw.... do you think it would handle 5 kw....
it won't. And their 10 kw tuner won't handle 10 kw. I already
posted the pix of blown up palstar input balun on the other group.
## If palstar or anybody else wants to advertise products as
rated to handle XXX watts, they should handle that. 10 x yrs
ago, I was going to buy a Mosely PRO-96 yagi.... rated for '5kw'.
Turns out, the '5kw' rating was INPUT power to the amp. They
also assumed 60% tank eff = 3 kw out. Then they also assumed
a 20% duty cycle on SSB ! 20% of 3 kw = 600 w CCS CXR.
'Engineer' at Mosely explains this all to me in great detail. He tells
me the mosely will handle 600 w RTTY... but only in the low swr portion
of each band ! So inside of 15 mins, it went from 5 kw... down to 600w.
A buddy literally set his Mosely on fire, when on 20m ssb one day. A neighbour
pounded on his door, telling the ham that it was raining down burning glop,
onto his roof. [ Henry 4 k] So no Mosely for Jim.
But it was RTTY.
## yeah, well don't run 1.5 kw RTTY with an Ameritron AL-1200/1500 on
160m. You will melt it. Now rauch claims they 'tested' it in the lab with a
1.5 kw
cxr on 160m, and it was fine.... but field reports came in after the fact,
complaining
of melted coils, etc. Apparently, they thought no ham would run RTTY on 160m !
Later........ Jim VE7RF
73, Bill W6WRT
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|