John, I have already sent a copy to Mike for posting. I'm also sending you a copy directly.
73, Eric Lemmon WB6FLY "John J. Riddell" wrote: > > Eric, would you consider putting this info on the repeater builders web > page...? > > If that is not possible I'd like to have a copy ....thanks... > > John VE3AMZ > > ----- Original Message ----- > From: "Eric Lemmon" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Sunday, November 21, 2004 5:20 PM > Subject: Re: [Repeater-Builder] Help with circulator specs > > | > | 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 > | > > | > > | > > | > > | > | > | > | > | > | Yahoo! Groups Links > | > | > | > | > | > | > | > > > Yahoo! Groups Links > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
