[BC] Tube transmitters do better in lightning

[Robert Meuser]

Harveyesmith at aol.com wrote:

> Re "head examination" for keeping tube type transmitters in service past
> their prime...
>
>
> I sort of agree with you, but there are exceptions.  I experienced one...
>
> A brand new Harris SX-1 on lightning hill in Limon, Colorado.
>
> Over the 1st 5 years of service, the total cost of keeping that box on 
> line
> after lightning hits was over $40,000 parts and labor.



Sounds like some poor engineering practices to me.

>
>
> the SX-1 transmitter (running at the allocated 250 W daytime) was 
> replaced
> with a Gates BC-250 tube type running 810's (industrial heating and 
> diathermy
> still MFG. tubes)
>
> Which then ran successfully without out further lightning outages for 4
> years, till the station went dark.


Nothing like giving up rather than solving the problem.  The BC 250 was 
long an antique well before the SX series was developed. Could this be a 
case of not understanding the technology??

>
> Lets' face the obvious.... (the same truth that exists for continental
> electronics in their 1 MW medium wave and short wave transmitters) 
> also holds for am
> stations worldwide... tubes can take lightning, transistors cannot.
>
> Yes, continental still makes vacuum tube high power transmitters for the
> obvious reason   -lightning survival-  they will tell you this at the 
> NAB and
> proudly so.

Continental no longer makes MW or LW TX's that market has been taken 
over by Harris Nautel and Thales all who supply solid state TXs to 2 
megawatts and beyond. They work well

>
>
> And guess what is saving the HDTV industry...  the one tube solution 
> for 55
> kW output (the klystrode) with an estimated 40k hours of service per 
> tube...
> it seems there is no fighting success and proven durability.
>

Gee the last time I was in the WABC TX room on ESB, they had a solid 
state HD transmitter from Harris. Did someone miss the memo?????



R