[ARC5] Why "Noodling" About Sweep Tubes?

[Ian Wilson]

I have a nice BC-375 manual - now I just need the hardware to go with it!

73, ian K3IMW


On Tue, Oct 22, 2013 at 9:07 AM, Kenneth G. Gordon
<kgordon2006 at frontier.com> wrote:
> On 22 Oct 2013 at 5:36, David Stinson wrote:
>
>> Some people have asked why I'm thinking about sweep tubes and
>> the BC-375.  I do use 211s in my personal rig.
>> However, there are a lot of 375s sitting around because 211s
>> have become so expensive. The least expensive I've seen are
>> the Sino chinese, which are going about $75 each.
>> $300 to get the old beast going is too much to ask for most people.
>
> Hmmm...well, I don't know how things are on eBay concerning 211s now, but
> a few years ago, by VERY careful shopping, I managed to buy quite a few
> 211s (or VT-4Cs) on eBay for an average price of $20.00. I shared most of
> them at my cost with other folks who needed one or more. I kept two and use
> them in my own P-P 211 TNT 1929 transmitter.
>
>> Worse- I finally got around to testing the big stash of 211 tubes I've
>> been accumulating for years.   Much more than half of them were bad-
>> most from gas.
>
> As you know, some of those can be reactivated by any of at least three
> different methods. Their filaments are thoriated-tungsten, after all. Some of
> such tubes simply need to be "re-gettered".
>
>>   Of the few that remain, some are low-emisson and will
>> work only in the oscillator stage.
>
> Low emission is about the easiest thing of those that can be wrong with
> tubes to fix.
>
>> This much-reduced stash is going to
>> have to last, since 211 prices aren't likely to come down. So I'm
>> trying to find an affordable substitute, not only to "stretch" my tube
>> supply, but in hopes we can get some of those 375s off the garage
>> floor and back among the living.
>
> Good project! I'd love to have a 375/191...if I had the room.
>
>> Sweep tubes with less-popular filament voltages, like between 10-14,
>> are not nearly as expensive.  They are good for high voltages and
>> currents. But I don't know enough about them to "narrow the field."
>> Thus, my appeal to the group's wisdom and experience.
>
> OK. Let's go to work to see what we can do here, folks.
>
> Ken W7EKB
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html