Gerald, have you considered running the filament black when not in use as
suggested by Siemens?
Is that $2500 in Germany or the USA?
And what is the going price for a decent one in Europe? My #2 son just got
confirmation of his Germany assignment today.
Carl
KM1H
----- Original Message -----
From: <TexasRF@aol.com>
To: <jtml@vla.com>; <amps@contesting.com>
Sent: Friday, August 28, 2009 5:33 PM
Subject: Re: [Amps] TH347 filament ramping
> Fortunately one was used and the other was a rebuilt tube. The filament
> went open like a bad light bulb when they failed.
>
> The price of rebuilt tubes has doubled over the past few years. They were
> around $1200 with a discount coupon now about $2500. While this sounds
> like
> a very high price, the tube is very capable of 3KW plus at 1296 MHz. If
> the
> filament issue is resolved, one can expect a lifetime of use at amateur
> power levels. This makes the $2500 price a bit more acceptable.
>
> So far so good with the relay scheme. That has been in use for a couple of
> years now.
>
> 73,
> Gerald K5GW
>
>
>
>
> In a message dated 8/28/2009 4:04:14 P.M. Central Daylight Time,
> jtml@losalamos.com writes:
>
> Gerald, that's unfortunate, I hope you didn't pay list price for those
> tubes and have them fail like that.
> Your relay scheme seems like it would have prevented problems. Did the
> filaments burn out or did they just short to grid and stick there?
> 73
> John
> K5PRO
>
>> I lost a couple of good TH347 tubes due excess filament current at turn
> on.
>> I thought there was sufficient turn on current limiting but apparently
>
>> not.
>>
>
> ----
>> 73,
>> Gerald K5GW
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|