----- Original Message -----
From: "Steve Katz" <stevek@jmr.com>
To: "'John Peters'" <pa5ms@qsl.net>
Cc: "'David Kirkby'" <drkirkby@ntlworld.com>; <amps@contesting.com>
Sent: Tuesday, February 12, 2002 4:23 PM
Subject: RE: [AMPS] Bird peak reading meter? Slightly off topic
>
>
>
> > Hi,
> >
> > Steve Katz wrote:
> >
> > > ::Nothing's amiss, it's a really old design using active
> > > differential amplifiers circa 1970's. <There is active circuitry in
the
> > > holdup amps.>
> > > -WB2WIK/6
> >
> > Be happy they peak-hold kit design is not from the same year as the
meter
> > is..
> > back in the 50's they did not know about op-amps certainly not a
(LM-324)
> > Quad
> > uA-741.. hihi How huge would it be when the should have used tuubes
> > instead...
> > not to mention the power consumption..
> >
> > But if you use a single 9V AC adapter you just have to add 2 470uF
> > capacitors
> > and 2 diodes in this way you make a voltage doubler, add some voltage
> > regulators and you'll never have to change batteries anymore..
> >
> ::The reason I use batteries is because my Birds are portable (see
> the little leather handle straps on top?) and rarely sit in one place.
Most
> of my measurements are "field" measurements, and no AC around...batteries
> are very nice. I don't leave a wattmeter in the line all the time at home
> -- my antennas are all matched, what else do I need to know? (It's
possible
> to tune your amp for maximum RFI to the stereo system in the next room.
If
> you have a really big amplifier, you can use instead the stereo system in
a
> neighbor's house, or maximum smoke detector activations in the
> neighborhood.) However, I did build a battery replacement for the 43P,
using
> two 9V wall-warts, a cube tap (3-way AC adapter) and two isolated DC
> connectors (coaxial mini-DIN). Total cost of the accessory was about $10.
You might like to look at K0XP's web site at:
http://www.qsl.net/k0xp/Technical/PEPMeter/PEPMeter.htm
where you'll find details of a 'modern' PEP reading modification for a Bird
43
which uses an LM324 quad-opamp and should run for weeks of a couple of
batteries. I'm just building two on stripboard for my model 43's.
Mike G8TIC/M0VHF
> -WB2WIK/6
> > 73! de John PA5MS
> > (changing batteries every 2 monthts too.....)
> >
>
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>
>
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