Two electonics questions

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From: Stephen Walters (oddjob@cix.compulink.co.uk)
Date: Fri Mar 10 1995 - 03:03:00 EST


Two electonics questions
In the april ed of Practical wireless there is a circuit for a xtal
controlled, 1 transistor tx based on a 2n2222 (Borrowed from WiFB's note
book..). Can anybody suggest what would happen if this was replaced with
a Hitachi 2sc681a?

Secondly, does anybody know what UDN2949Z'S ARE? they look power trans or
regs with five leads?

tvm

oddjob@cix.compulink.co.uk
> From owner-qrp-l@netcom.com Fri Mar 10 03:51:11 1995
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> From: N5EM@aol.com
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> Date: Thu, 9 Mar 1995 20:27:08 -0500
> Message-Id: <950309202706_44742847@aol.com>
> To: qrp-l@netcom.com
> Subject: Re: CW Filter from RS crossover?
> Sender: owner-qrp-l@netcom.com
> Precedence: list
> Apparently-To: oddjob@cix.compulink.co.uk
>
> Folks,
>
> I believe that you can still order the toroid stack from Ed Weatherhold,
> W3NQN. This toroid stack comes from old telephone network loading
> coils and
> makes EXCELLENT CW and SSB filters. They have been extensively covered
> in
> the amateur literature, and the toroid stack has been available for
> shipping
> costs. In addition, Ed has made available in the past, matched sets of
> caps
> to complete the construction for about $5 per filter. All the builder
> had to
> supply, beyond these stacks and cap kits was the enclosure and a couple
> of
> 200 ohm to 8 ohm matching transformers.
>
> References:
> Write (include SASE!) to Ed Weatherhold, W3NQN
> 1426 Catlyn Place
> Annapolis, MD 21401
>
> See:
> ARRL Handbook, 1993 Edition, page 28-1.
>
> QST, December, 1980 and feedback, QST, January, 1981, pg. 43.
> Ham Radio, April, 1981
> Radio Handbook, 23rd edition, W. Orr, pg. 13-4.
>
> Forget the Radio Shack crossover network. Check out this article.
> These
> filters are computer designed and have been built by numerous hams and
> described in QRP literature.
>
> You're gonna like it a lot!
>
> Ed Manuel - N5EM
> n5em@aol.com
> Houston, Texas
>
> QRP - Its a state of mind, not just a power level.
>
> QRP ARCI #4914, G-QRP #1243, NORCAL #498
> (And soon to have a CQC number as well - couldn't resist their patch.)
>


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