[ARC5] Loctal Tubes

[Geoff]

Generator and alternator systems run at or a bit above 7, 14, and 28V...then 
and today.


----- Original Message ----- 
From: "Bill Cromwell" <wrcromwell at gmail.com>
To: "ARC-5 List" <Arc5 at mailman.qth.net>
Sent: Tuesday, May 01, 2012 8:21 AM
Subject: Re: [ARC5] Loctal Tubes


> Hi,
>
> I have accumulated and started using some of the loctal tubes in
> projects I intend to accommodate field use. There have been some
> comments about them that I would like to address.
>
> Loctal tubes are difficult to remove from the socket. Loctal tubes have
> a raised spot on one side. We are supposed to apply sideways pressure
> and slightly tip the tune from that side to UNlock them from the locking
> ring in the socket. That's why we call them LOCtals. They won't fall
> out.
>
> Some oxidation products get on the pins and cause intermittent
> connection failures. That is the same as for miniature tubes that have
> the same kind of pins. They need periodic maintenance to keep the
> contacts cleaned up. The occasional cleaning applies to loctals and
> miniature tubes. I have experienced the same thing with octal tubes,
> too. There doesn't seem to be a free lunch there.
>
> Voltage levels like everything else vary within specified limits. 6 volt
> and 12 volt and 24 volt automotive (or aircraft) battery systems are
> only rarely at 6.000000000000000 or 12.0000000000000 or 24.0000000000000
> volts. Fully charged batteries vary and are closer to 7 or 14 or 28
> volts. The charging systems are necessarily higher. The published heater
> ratings I've seen are the same 6.3/12.6 volts as many other tubes. I
> haven't seen the tube manual that specs loctals at 7 or 14 volts. I
> haven't seen the Taj Mahal either but I believe it exists. Given the
> allowable variation in those battery electrical systems 6.3/12.6 would
> include 7/14 volts.
>
> 73,
>
> Bill  KU8H
>
>
>
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