[Milsurplus] WTB: Hi Power Resistive (Dummy) Load (sort of OT)

[Christian R. Fandt]

Hi folks,

I'm looking for a 50 ohm dummy load to repair and maintain an industrial RF 
generator used to excite a 1 kW laser cutting system (namely, a Trumph TLF 
1000). I searched the usual suspects (Google, e*ay, etc., including Fair 
Radio). Finally found one used equipment outfit in California that lists 
several of them being available but doesn't bother to take the time to 
reply to my price and delivery requests. I'll try again, but . . .

The ideal would be a brand new Bird 8931-115SC13 with an optional 7/16 
connector installed (reference: 
http://www.bird-electronic.com/products/product.aspx?id=625 ). However, my 
friend who owns the shop that uses the laser almost passed out after 
hearing the $4400 price. It would be used once to repair the system and 
left setting until the next time, whenever that is. He just spent over $5k 
to replace the final tube per conclusion of a third-party laser cutting 
machine maintenance outfit. They reportedly said that was the problem 
causing the too high reflected power (the original problem that needs to be 
solved). Uh-huh! And the tech did not even have a dummy load with him to 
check the RF generator's performance and tuning after he came back to 
install the new tube. He left it back at the shop (~700 miles away) because 
"he didn't think he needed it".

My task is to isolate the source of the high reflected power between either 
the laser "resonator" (which is the laser itself), the RF generator, or the 
coax cabling between the units and attack the problem. Hard to know were to 
solve the problem without ruling out portions of the system which are not 
the cause.

Hence, my approach to these two groups for leads. You have been known to be 
a wellspring of information over the years.

The RF power output is 6.5 kW maximum at 13.56 MHz which means a 7.5 to 10 
kW load is needed. The connector is the 7/16 type (reference: 
http://www.amphenolrf.com/products/716.asp ) and I'd need to make an 
adaptor of some sort between whatever load I find and the system under 
test, if required. I work in a 2-way radio shop for my day job and I should 
be able to find components to make that up. We only know of loads available 
up to around 2 kW from all our sources; our typical max TX power we ever 
get into is 100-125 watts, even for base stations.

FYI: The 7/16 connectors are a DIN standard commonly used in Europe for 
high power applications.
FYI: 13.56 MHz is an unlicensed frequency assigned for use in industrial 
applications.

Please reply off list as this is not too on-topic.

Thanks very much for your help!

Regards,  Chris F.

NNNN

Christian Fandt,    Electronic/Electrical Historian
Jamestown, NY  USA      cfandt at netsync.net
         Member of Antique Wireless Association
         URL: http://www.antiquewireless.org/