>From my experience, an SWR bridge does indeed provide approximation; however,
the science of a simple device mirrors the more complex. In other words,
rocket science is not needed. For years I used a cheap CB matchbox on 10
meters in series with a Bird 43 wattmeter, just for kicks.
I discovered, to my surprise, the readings of SWR were identical. Minimum was
minimum no matter the device. Sure you can create higher degrees of precision
and limit the amount of interaction, but at the end of the day all you need is
a good dip when tuning -- another 1 or 2 db isn't significant.
73 de Phil - N8PS
-----------
Quoting geraldj <geraldj@storm.weather.net>:
>
>
>
> ---------- Original Message -----------
> From: ac9s@mchsi.com
> To: tentec@contesting.com
> Sent: Sat, 12 Dec 2009 18:26:50 -0600 (CST)
> Subject: [TenTec] Colliins SWR Bridge
>
> > Jerry,
> >
> > You wrote: "Many a ham SWR meter is a very rough approximation of SWR and
> even
> > when it shows matched, the impedance and reactance may be a ways from 50
> ohms
> > resistive. Birds aren't bad, Collins wattmeters I think have a much better
>
> > design. But then I'm biased, I have one of their reject designs
> > (I worked with the department that did ham gear designs in 1963) and its
> > plenty good but not good enough for their specifications. There's a lot
> more
> > shielding in their better design to control stray couplings that would make
>
> > the readings wrong."
> > > >
> >
> > Does the 312B-4 include the better bridge design?
>
> Yes.
> >
> > Thanks --
> >
> > Keith
> > AC9S
>
> 73, Jerry, K0CQ
>
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