If I were making RF measurements everyday, I would have instruments far better
than the Bird 43P and Bird 43 here in my workshop. I would imagine that a
modern day manufacturer would also.
Although we have seen the specification sheets for both the Eimac tantalum
vertical finned 3-500Z and the horizontal graphite donut version, I have never
seen or been able to obtain the spec sheets for the Chinese version of these
tubes, which are at stated to be at least higher mu tubes. I wonder what B&W
would have found out about designing their amps if they had the opportunity to
use the higher mu versions. I note that today's manufacturers all use the
Chinese version.
I also have asked here in the past if anyone has the spec sheets for the Pride
(perhaps one of the major Chinese producers of the 3-500ZG) and no one seems to
have this information. I have also asked the distributors of tube for the
sheet and they can not supply one either.
I notice that some manufacturers, who do not use 3,500 VDC plus supplies rate
the output of their single tube:
Power Supply:
Circuit type: Full wave voltage doubler
No load voltage: 3100 V
Full load voltage: 2700 V
Full load current: .6 A
Regulation: >13%
Transformer: 26 lb. E-I lamination grain oriented
Capacitors: 26 mFd total, computer grade
Normal line current at rated CW output: 12 A at 120 Vac
Normal line current at 1000 watt PEP output: 8 A at 120 Vac
Power line current in standby: 1 A at 120 Vac
Tube:
Type: 3-500Z
Continuous dissipation: 500 watts
Warm-up time: 10 seconds
Estimated life: 12,000 hours ICAS
The above data is from the AL 80B. I wonder how they manage to measure their
RF power output at 1 KW. There are others that seem to rate the output from
the modern tube much the same way. I never questioned my results because they
were more or less identical to the above data. Interesting to note the 10
second warm up time for this instant heating tube. I'll be these guys have
some spec sheets that I can't seem to obtain.
73 and Happy DXing,
Mike
W2AJI
----- Original Message -----
From: "Tom W8JI" <w8ji@w8ji.com>
To: "Mike Schatzberg" <cherokeehillfarm@earthlink.net>; "Amps Reflector"
<amps@contesting.com>
Sent: Monday, July 17, 2006 6:00 AM
Subject: Re: [Amps] transformers
>
> > Well, I stated what I have used for measurement, and I
> > realize that the Bird
> > and Nye Viking are not a Hewlett Packard. I can accept
> > that both meters may
> > be off by 10%, even though their accuracy is supposed to
> > be about half of
> > that.
>
> One thing I have learned doing RF measurements almost every
> day for 30 years or more is RF measurements are tougher to
> do than most imagine.
>
> The accuracy of a Bird 43 meter, when properly calibrated
> and used, is + or - 5% of full scale anywhere on the scale.
> Since they do not manufacture a 1500 watt slug, the best we
> can rely on is + or - 125 watts at any power level with a
> properly calibrated 2500 watt slug. Many people would be
> surprised at how far off a new Bird 43 and slug combo can
> be.
>
> I know of several manufacturers that had great difficulty
> making 1500 watts (measured by accurate means) with pairs of
> 3-500Z's when only 100 watts of exciter power was available.
> HV had to be over 3500 volts.
>
> 73, Tom
>
>
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