Boonton makes some nice instruments. Just make sure
the RF probe comes with it (they plug in and are often
not included), and that the unit is guaranteed to be
working. You don't need to measure the exact
amplitude, you only need to detect the peak and dips
as you tune the filter coils.
The stations can be set up to repeat, do CW ID, and
even time out, if programmed correctly. On/off control
is the primary item you'll need to provide from the
outside world, and I don't think there was an easy way
to do it (i.e. they didn't just give you a signal you
could ground to disable the transmitter). I found it
was just easier to do everything with an external
controller, and this gave me the ability to put in an
audio delay module at the same time. However, I will
say that the interfacing is not as simple as plugging
something in and running with it; significant
technical prowess would be required to do the job
successfully. My station was a CXB that programs with
a PC and RSS, so changing parameters is a whole lot
easier.
Bob M.
======
--- Mathew Quaife <[EMAIL PROTECTED]> wrote:
> The unit that I got is the Boontoon RF
> Millivoltmeter Model 92E. Looks like it should
> cover what I need it to do. Thanks for the help,
> when it gets here, I am certain I will have more
> questions until this repeater is up and fucntional,
> and then comes the fun of tying in an outbord
> controller for the unit. Thanks.
>
> Mathew
>
>
> "Bob M." <[EMAIL PROTECTED]> wrote:
> There will be some loss in the filter (maybe 0.5dB
> per
> section), and about 30dB loss when using the tuning
> probe. If you're feeding in 223mV (0dBm), you would
> probably measure -30dBm using the RF voltmeter
> connected to the tuning probe, when the filter is
> fully peaked. This is around 7mV. However, even when
> the coil is mis-tuned, you'll still get some
> indication with the proper meter. It'll be harder to
> see with a spectrum analyzer because of its low
> impedance input.
>
> I use an old HP3406A sampling (RF) voltmeter. They
> show up on eBay once in a while, but you can't get
> parts for them any more, so if it doesn't work, it's
> difficult to repair unless a common part has failed.
>
> Mike (ILQ) please contact me.
>
> Bob M.
> ======
> --- Mathew Quaife wrote:
>
> > Hi Mike, did a little research and found one in
> > Chicago. I knew about the SM, just never thought
> of
> > one being outside the SM. So should have one here
> > in a few days, and then get back to working on the
> > repeater.
> >
> > Mathew
> >
> >
> > Mike Morris wrote:
> > At 05:13 AM 11/13/05, you wrote:
> >
> > >Sitting here looking at the tune up procedure for
> > the filter, it tells me
> > >to insert a rf millivoltmeter probe into J18 and
> > insert a 225 mV signal
> > >into the the output of the post filter. I did
> this,
> > and get nothing on
> > >the meter at all.
> >
> > It takes a LOT of level to force a signal past a
> > detuned filter.
> >
> > >Now I'm not sure if there is a difference between
> > my RS Volt-Ohm meter and
> > >an RF millivoltmeter.
> >
> > Your RS VOM does have an AC mode, but I'd be
> > surprised
> > if it responds to frequencies above 100khz. If it
> > responds to
> > 447MHZ RF at all, I'd be very, very surprised...
> >
> > An RF millivoltmeter is just that - a meter that
> > reads at RF
> > frequencies down to the millivolt (and frequently
> > microvolt)
> > levels.
> >
> > If you think about it a service monitor and a
> > spectrum analyzer
> > both have the function as RF millivoltmeters...
> when
> > you measure
> > receiver sensitivity you are injecting a low level
> > RF signal into the
> > receiver, and the RF millivolt / microvolt meter
> > section is reading
> > the result.
> >
> > Mike WA6ILQ
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