Electronics > RF, Microwave, Ham Radio

Hughes 889H Traveling Wave Tube (TWT) Amplifier

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graybeard:
I picked up this Hughes at the W6TRW swap meet today.   The guy gave it to me for free after I spent $200 on attenuators, adapters, filters, amplifiers, and test cables.

I can't find any information online about it.  I hope someone on this forum might have some information.  I was hoping to see if it works.

Thanks . . . Chris

KE5FX:
Try the WA1MBA microwave list.  Some of the OTs on there have seen it all.

coppercone2:
yeah they go in rackmount boxes, I was wondering how hard it is to get a replacement tube for that thing, looks like you found one.

It is basically HV power supply with interlock (heat time) for tube and some monitoring. I noticed in general the voltage goes up when frequency goes up, that takes 2kV+

Don't start it without a load and find the correct sequence of power. 2 min warm up time on the tube and then not sure if the other rails need to be sequenced.

You have a 20W unit between 8-18GHz.

I have a few of them, one of them has blown up electronics. I replaced the transistors and noticed every single diode in the power supply was cleaved in two.  :D. A different unit had the main transformer smoke and blow a fuse.


https://www.axiomtest.com/documents/models/Hughes%208010H%20Datasheet.pdf

graybeard:

--- Quote from: coppercone2 on February 01, 2023, 05:09:27 am ---yeah they go in rackmount boxes, I was wondering how hard it is to get a replacement tube for that thing, looks like you found one.

It is basically HV power supply with interlock (heat time) for tube and some monitoring. I noticed in general the voltage goes up when frequency goes up, that takes 2kV+

Don't start it without a load and find the correct sequence of power. 2 min warm up time on the tube and then not sure if the other rails need to be sequenced.

You have a 20W unit between 8-18GHz.

I have a few of them, one of them has blown up electronics. I replaced the transistors and noticed every single diode in the power supply was cleaved in two.  :D. A different unit had the main transformer smoke and blow a fuse.


https://www.axiomtest.com/documents/models/Hughes%208010H%20Datasheet.pdf

--- End quote ---

Thank you.  I found this copy of the manual that shows the lead connections to the tube.

I have a 2KV 20mA supply, which is not enough.  I do not have a 8-16 GHz source (yet).   I have an HP power meter frequency counter that work in that range.-

0culus:
I have an HP 495A TWT amp that has a 1W Watkins-Johnson TWT in it. As other posters mention, that 495A box is mostly just power supplies plus a cathode current meter. You'll want to do your research before bringing your TWT up to avoid destroying it. Also, if it is really capable of 20W, be careful of legal issues and safety. 20W of microwaves directed into your remaining eye via open waveguide won't do that eye any favors. That said, very cool find!

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