[Amps] Topband: B&W Filament Choke Query

[Kenneth Grimm]

EP Swynar wrote:
> Good Day All,
>
> Mining "...ye olden junque boxxe" here has yielded an undocumented, pre-historic Barker & Williamson type "FC-30" encased filament choke --- I  would be most appreciative if I might solicit some feedback from seasoned, experienced users of this device...
>
> Specifically, the unit has TWO pairs of terminals at EACH END (four per end, grand total of eight). I show continuity between any two terminals only, i.e. any one terminal on the LH side, & its immediate opposite on the other...
>
> Simple & logical enough, with two leads coming into it from a filament transformer, & two leads going out, to the tube's filaments --- but then why the extra four terminals, two per end? Is it because the "FC-30" is, in reality, a "dual" type "FC-15" filament choke, & in order to attain 30-amperes current capability, one must PARALLEL the terminals...?
>   
Yes, you guessed correctly.  From an old B&W catalog, "The model FC-30A 
is a twin dual-winding choke with a current capacity of 30 amperes.  The 
four-winding feature of the FC-30A makes it possible to use a separate 
filament transformer for each set of windings, and also makes it 
possible to meter each cathode circuit separately."
> Also, has anyone ever utilized one of these devices on a frequency band as low as 160-meters...? These things were manufactured back in the day when there was no real practical need of any kilowatt linear amplifiers on Topband, due to day time / night time power restrictions imposed by the old LORAN navigation system. Consequently, I wonder if this thing even has enough inductance on 1.8-MHz to effectively do the job...?
>   
The device is rated for 3.5 MHz to 30 MHz and an RF Voltage of 150 rms 
maximum.
> Up until now, ALL of my filament chokes were of the homebrewed variety, i.e. heavy-guage enamelled wire coiled around a ferrite rod...I have no experience whatsoever with this particular pre-manufactured unit, I'm afraid...but I do harbour thoughts of employing it into a dedicated 160-meter-only grounded-grid RF amplifier, utilizing a 4-1000A (still to be acquired!).
>
> Many thanks in advance, & my vy
>
> ~73~ Eddy VE3CUI - VE3XZ
>
>   

73,

-- 

Ken K4XL
k4xl at arrl.net

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-- 

Ken K4XL
k4xl at arrl.net

*** BoatAnchor Manual Archive ***
On the web at http://bama.sbc.edu and http://bama.edebris.com
FTP site info: bama.sbc.edu login: anonymous p/w: youremailadr