Joe,
Actually, it's the opposite. The return loss will be maximum (highest
numerically) at the operating frequency, meaning that the minimum energy
is being reflected. It can be confusing to describe, because a proper
tuning of a circulator involves reversing the input and output for
making some tuning adjustments, and this reverses the readings. One of
the best procedures for adjusting a circulator is published by
Sinclair. I am sending you a copy in PDF.
73, Eric Lemmon WB6FLY
Joe Ciarcia wrote:
>
> Eric thanks. If I looked at return loss, would the circulator operating
> frequency be determined by the lowest return loss?
>
> Joe
>
> At 03:01 PM 11/21/2004, you wrote:
>
> >Joe,
> >
> >I suspect that RJ Communications is no longer in business, so finding
> >tech data on that circulator may be difficult.
> >
> >The typical ferrite circulator doesn't dissipate much power itself; it's
> >the load(s) attached to the reject port that determines its power
> >rating.
> >
> >It's important that a circulator be correctly tuned to operate
> >efficiently. The label 140-180 MHz refers to the range of that
> >particular design, and should not be taken to mean that it will work at
> >any frequency in that range. Nearly all of the circulators I have taken
> >out of service from the 152 MHz band would not tune more than 2 MHz
> >either side of the frequency marked on the unit. I had to send them
> >back to the manufacturer to be reworked for operation on the 2m band.
> >This rework involved an exchange of magnets, pole pieces, and a new
> >garnet ground to a specific tolerance.
> >
> >A network analyzer is a must for tuning a circulator, especially a dual
> >circulator, since some measurements look for transmission peaks while
> >others look for return-loss peaks. A spectrum analyzer will not suffice
> >for this tuning task, unless it is used with a return-loss bridge.
> >
> >73, Eric Lemmon WB6FLY
> >
> >Joe Ciarcia wrote:
> > >
> > > I have a circulator from RJ Communications Products Inc
> > > of Scottsdale, AZ. It's a model HC-152. It also has a logo
> > > on it marked IJ. It has a marking tape on it which indicates
> > > that the freq coverage is 140-180 MC. Can anyone confirm this
> > > and know what the power rating might be?
> > >
> > > Thanks, Joe
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
>
>
> Yahoo! Groups Links
>
>
>
>
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