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Title: Barker and Williamson Model 381C T-R Switch Post by: n0tjl on April 01, 2015, 02:40:21 PM I have a question about the Barker and Williamson Model 381C T-R Switch. I am wondering how you use the Tuning control on this unit. I found a manual copy for the Model 381 on BAMA but the 381 only has the Bandswitch and no Tuning control. I would like to use this unit with my r390a and HW Bandmaster.
Thanks, Tom N0TJL Title: Re: Barker and Williamson Model 381C T-R Switch Post by: WQ9E on April 01, 2015, 03:23:47 PM Tom,
The tuning control allows compensation/adjustment of the tuned circuit in the T/R switch and is adjusted for best gain when you change bands or it can be used to slightly reduce gain if desired. It is pretty broad tuning so in most cases you can just set and forget this control. As noted in the manual you will still need to provide a means of receiver muting, particularly if you plan to use your TBS-50 for AM operation. Title: Re: Barker and Williamson Model 381C T-R Switch Post by: W3GMS on April 01, 2015, 03:57:43 PM Hi Tom,
I went through my B&W archives that Jack Williamson of B&W passed along to me and found the attached document. Its based on an article that was written in QST from a former B&W engineer name Bob Myers. The enclosed documentation was documented by W3ZO - Boyd Cowan who is now an SK. I hope you find the attachments helpful. If you send me an email, I can send you additional information. Now to answer your question, the tuning control is used to peak the received signal. It basically parallel resonates the gain stage within the TR switch. It has no effect on TX operation. I see while I was typing this that Rodger has responded to your question---Tnx Rodger! 73, Joe - W3GMS Title: Re: Barker and Williamson Model 381C T-R Switch Post by: WQ9E on April 01, 2015, 04:51:15 PM Joe,
Thanks for posting the additional documents! More B&W equipment is taking up residence here so it is nice to have the information. I just picked up B&W 370 and GE YRS-1 SSB receive adapters to go with my TMC, RME, Eldico, Central, and Hammarlund adapters so I guess it will soon be the "battle of the adapters" here. :) Title: Re: Barker and Williamson Model 381C T-R Switch Post by: W3GMS on April 01, 2015, 05:10:24 PM Joe, Thanks for posting the additional documents! More B&W equipment is taking up residence here so it is nice to have the information. I just picked up B&W 370 and GE YRS-1 SSB receive adapters to go with my TMC, RME, Eldico, Central, and Hammarlund adapters so I guess it will soon be the "battle of the adapters" here. :) Very good Rodger! Just let me know if you need any B&W documentation since Jack gave me lots of stuff. I still have his engineering notes on a lot of it. I also have many of the catalogs they produced. I am just glad to share it with those that can use the material. The pictures of the factory while making the military gear are very interesting. Have fun with those RX adapters! Joe GMS |