[Amps] Roller Inductor specs

[Carl]

The BC-375 was rated at a nominal 100W output as per the Army but hams 
routinely ran them up to 250W or so when 211's were dirt cheap. Power 
was frequency limited due to the archaic 1929 tube design. Look at it as 
the granddaddy of the family ending in the 572B.

Ive used that inductor at the 600W CW/AM level in an ATU back in the 
late 50's but havent used one in a TX tank. Tune in an ATU at the 100W 
level to prevent unnecessary heating and arcing.

In any case the form, wire, and roller should be given a good cleaning 
in the dishwasher before using to remove contaniments and oxidation. The 
Original Cascade works well to clean silver plating.

Carl
KM1H


----- Original Message ----- 
From: "Karl-Arne Markström" <sm0aom at telia.com>
To: <sacramento.cyclist at gmail.com>; <amps at contesting.com>
Sent: Monday, February 16, 2009 3:09 AM
Subject: Re: [Amps] Roller Inductor specs


On a "sunny day" the BC-375 put out about 60 - 100 W CW or AM carrier.

The roller inductor was part of a matching network that series-tuned
the aircraft wire antennas
at the lower HF frequencies. Rated "antenna current" at these
frequencies was 3.5 - 4 A.

As a "guesstimate", the wire size used in the BC-375 roller inductor
would be able to carry about 5 A RF current at HF frequencies. Heating
due to skin effect is the primary limiting factor.

73/

Karl-Arne
SM0AOM





----Ursprungligt meddelande----
Från: sacramento.cyclist at gmail.com
Datum: 2009-02-16 06:20
Till: <amps at contesting.com>
Ärende: Re: [Amps] Roller Inductor specs

Thank you all for the replies.

I'm still curious what power level a 5 amp rated (as Karl suggests)
inductor would be appropriate to use in.  A simplistic I squared R
calculation yeilds over a KW at 50 ohms, but I don't know what impact
skin effect or circulating currents have.

I also found contradictory info on the BC-375.  One source says it a
600-800 watt input transmitter, but other sources suggest a much lower
power unit.  I'm inclined to believe its in the 100 watt class given
its appearance.

      Dennis

On Sun, Feb 15, 2009 at 11:22 AM, Karl-Arne Markström <sm0aom at telia.
com> wrote:
> This is the roller inductor from the BC-375 airborne transmitter.
>
> If memory serves me right it is about 18 uH inductance with an
approx. 5
> ampere RF current rating.
>
> 73/
>
> Karl-Arne
> SM0AOM
>
>
> ----- Original Message ----- From: "Dennis Wade"
> <sacramento.cyclist at gmail.com>
> To: <amps at contesting.com>
> Sent: Sunday, February 15, 2009 8:07 PM
> Subject: [Amps] Roller Inductor specs
>
>
>> Good morning,
>>
>>      Could someone look at Ebay item  110349006314 , and tell me
>> what they might know about what piece of equipment this roller came
>> from, power level it was used at, etc.  I have three of these and my
>> impression is that they are fairly common.  I'm particularly curious
>> what the ratings of such an inductor might be (i.e. how big an amp
>> might it be used in.
>>
>>        Thanks for the info,
>>
>>        Dennis
>>

-- 
Dennis L. Wade
KG6ZI
Carmichael, CA
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