with the amp inline as opposed to out of line, the swr could vary because of
the extra component between radio and antenna/antenna tuner. So to varify
swr after the amplifier is actually physically connected in line you have to
check after the amp and if you have a high powered amp that you wish to run
at full rf output while checking things to insure stability then a meter
that can handle the power is necesary...this is why naturally they rate
meters for power like 2000 watts instead of only 2 or 300 that the radio
could put out.
With the coax hooked directly into the radio from a tuner or direct to an
antenna the swr will likely be different then that when the amplifier is
physically connected in line..that was the point of what i said or i guess
why i refered to a higher power handling meter as something a little more
useful, at least for anyone running 625W plus.
It probably wouldn't change however if you just by-passed with a relay or
stand by/off switch on the amplifier because then the extra component would
still physically be there even though the unit is not being used..
Regards
Colin
----- Original Message -----
From: "Jerry Neufeld" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, February 19, 2005 8:54 PM
Subject: Re: Talking Watt Meter from LDG
> Hello Colin and others.
>
> It's not altogether clear to me why one would need a SWR meter for power
of
> the kind generated by a linear amplifier. With the amplifier out of the
> circuit, i.e., its relay in rest position, the exciter, unadjusted, looked
> into whatever standing wave characteristics an antenna has. Those
> characteristics, from my perspective, do not change, whether or not one
> tunes out inductance and reactance with LC adjustable circuits. In short,
if
> a 50 ohm antenna appears flat with ten watts forward, it will or should
> remain flat with a full thousand. If wide-spaced variable capacitors are
> used to tune out these things, as done in high power amps with tubes, then
> adjusting for maximum RF output is likely to be the optimal adjustment
> capable with that amplifier. If my presumptions are true, why look for a
> high power SWR meter, unless, of course, one wishes simply to look at SWR,
> once maximum RF out has been attained.
>
>
>
> Jerry, v e 3 q s o
>
> [log in to unmask]
>
> ----- Original Message -----
> From: "Colin McDonald" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Saturday, February 19, 2005 2:36 PM
> Subject: Re: Talking Watt Meter from LDG
>
>
> > nope, it only goes up to 54MHZ...but it will handle up to 2000 watts
where
> > as remy's meter only handles max 625 RMS.
> > When you are tuning an antenna with an amp you certainly want to make
sure
> > the swr between the amp and antenna or antenna tuner is right not just
> > between radio and amp.
> > So for anyone who wants to use over 625watts then the ldg meter would be
> > better.
> > However, since they dont offer a vhf version of the meter you would also
> > need remy's meter for that....also if you are real picky about
resolution
> > the ldg meter is accurate to 5 percent either way where as the other is
> > ten
> > to fifteen percent accuracy.
> > Regards
> > Colin
>
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