I can second this.
My organization (Stockholm Radio) runs several Collins 208U-10 10 kW amplifiers
for air/ground SSB services that used Eimac 4CX350A's in the driver chain.
During the final time before the driver chains were replaced with solid-state
broad-band amplifiers (1997-98) the average filament hours before replacement
(usually due to gassy tubes or low emission) was down to about 3000 h.
When we obtained the amplifiers (1988), the average running time was about a
year (8500 - 9000 h).
I have been told by Rockwell/Collins field engineering that the US Coast Guard,
another big 208U-10 user,
went through a 4CX350A evaluation program in the mid-90's and after this
selected Svetlana for all future replacements.
Today's short replacement cycle of 4CX350A's (and probably also the replacement
cost of the P-290A final tube) reportedly also resulted in the consignment to
the scrap heap of Greenland Telecom's quite large setup of Granger 172-2 MF/HF
transmitters. (A pity that they learned too late about the solid-state driver
replacement that extended the life of our Grangers by 8 years...)
73/
Karl-Arne Markstrom
SM0AOM
=============================
Senior Radio Engineer
Maritime Networks
Telia Mobile AB Nacka Strand Sweden
Phone +46-8-6017171
Mobile +46-706-636575
Fax +46-8-6017959
----- Original Message -----
From: "Alek Petkovic" <vk6apk@eon.net.au>
To: <amps@contesting.com>
Sent: Friday, December 06, 2002 12:36 AM
Subject: [Amps] Eimac vs Svetlana
> G'day form sunny Perth,
>
> I found out something interesting a few days ago which may be of interest
> to the assembled masses.
>
> A few mates and myself were lucky enough to pick up some decommissioned 1kW
> transmitters from VIP, our local government run marine coastal radio
> service station.
>
> These all mode AWA transmitters run 3 4CX350 tubes in the pa and one more
> as a driver.
>
> We got a few dozen used pulls in the deal as well.
>
> That was the gloating bit. Now to the point.
>
> The guys who run the transmitters told us that the Svetlana tubes were far
> better than the Eimac version. Typically, they get 2800 hours from the
> Eimacs before trouble sets in. From the Svetlanas, the average is 8000 hours!
>
> We were quite astounded at the difference. They also said that sometimes, a
> batch of Eimac tubes, are so bad, they send the whole lot back mostly
> unopened. The few that they had opened and tested were so bad, that they
> didn't even bother testing the rest.
>
> I don't know if all this is specific to this type of tube or if it is
> across the board. Is anybody else in this group involved in a similar line
> of work? Have you had similar or different experience?
>
> 73, Alek
> VK6APK
>
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