This has me thinking in new ways.... handheld has an ultra-low 50mw
output...
On Dec 22, 2007, at 2:34 AM, skipp025 wrote:
> Hi Cort,
>
> Just something to keep in mind...
> You can use a regular radio as a signal generator just as you
> can use another for your receiver/detector function.
>
> Duplexer adjustment is more easily done with some RF-Pads
> (attenuators) placed on each coax port. I use some 3dB pads
> fairly easy to purchase off Ebay cheap enough. There are
> even some very nice low power step and variable attenuators
> found (on Ebay) for more than fair prices.
>
> I've even built basic 1 and 3dB pads from common values found
> in ARRL and similar Handbooks. Only a few resistors, a proper
> size box/tube (with connectors) and the time to construct them
> right... There's also a step attenuator in some ARRL Handbooks
> and FAR Circuits probably still sells the pc-board kit to make
> them.
>
> So... one might assume your portable radio has a low power
> output setting, which should be still be more than enough
> generated signal to see with your receiver.
>
> The key to all of this is to at all costs avoid transmitting
> anything more than a very low (fractional) power signal toward
> the receiver. Using enough of the right size series placed
> RF-Pads should be the trick.
>
> One "days of old when knights were bold" trick was to solder a
> very low value fuse inside with a 3dB constructed RF-Pad. Easy
> enough to replace a 1/8 or 1/16th amp fuse versus the front
> end of an early Service Monitor Output Section. Many a smart
> radio service shop had external RF-Pad boxes (with internal
> pico fuses) in series with the coax from the Service Monitor
> Signal Generator Port.
>
> One other thought might be to find/buy/borrow a small amplifier
> for your Service Monitor, which would be something like a Mini
> Circuits wide-band box. Once again cheap enough if you search
> Ebay at the right time & place.
>
> Many things are possible
>
> chow for now...
> s.
>
> > Cort Buffington <[EMAIL PROTECTED]> wrote:
> > Thanks Skipp025!
> >
> > I have an old Lampkin service monitor and I've been tuning the
> > duplexer by using my handheld as a receiver with the Lampkin as the
> > generator. It just doesn't have enough oomph for proper tuning of
> the
> > reject portion of 2 cans in series.... So I'm working "somewhere" in
> > the notch... not good enough. I'll be looking for use of a proper
> > service monitor, and probably keep using the MSR2000 unit -- it fits
> > my installation better than the Wacom.
>
>
>
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