Yes, my experience is that the "magnet holders" are locked, but can be freed with a suitable C spanner.
If you physically abuse these isolators, which can happen during de-commissioning, they become microphonic. The two adjusters can be screwed in to stop this problem. Re-adjustment is always necessary and isolation is always worse. The construction is like a clamshell with the adjusters clamping the magnet sandwich together inside. To move the frequency I assume that the internal spacers will have to be replaced on a select on test basis..... I fully agree with Eric, leave this one to Sinclair! G8PWE Walsall England www.gb3dx.com ----- Original Message ----- From: "Eric Lemmon" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Monday, March 07, 2005 12:25 AM Subject: Re: [Repeater-Builder] Retuning of Sinclair I2113A Isolator > > Scott, > > I have been down that road twice, coincidentally with exactly the same > Sinclair part number. In each case, I had a working isolator pulled > from Government service around 166 MHz that I wanted to use in the > Amateur 2m band. > > The "range" shown in the catalog for these isolators is really an > indicator of the manufacturer's capability to make the isolator, not the > tuning range of a particular unit. Once an isolator or circulator is > made for a particular frequency, it can only be tuned a very few MHz > either side of that frequency. > > It will cost about $250 to remanufacture your isolator to the new > frequency, which involves a considerable amount of precision work. This > is much cheaper than buying a new isolator, and it comes with a > guarantee. Be forewarned: Once you open the isolator, Sinclair may > refuse to perform the rework. > > 73, Eric Lemmon WB6FLY > > wn1b8 wrote: > > > Greetings, > > > > I have a Sinclair model I2113A isolator. The range on this is > > supposed to be roughly 130 to 170 MHz. It currently sits at 167.1 > > MHz. I want to put it on 148.8. I suspect that this requires > > retuning of the large magnets. I have removed to side stickers to > > reveal the outside of the magnet holders, but they appear to be > > locked with something like Lok-Tite. Has anyone experience in > > retuning these? How do I go about freeing the covers? Will a heat > > gun be adequate without damaging the inside components? > > > > Kevin's site has the instructions for field tuning these but that > > only covers the fine tuning within a 2-4 MHz. range. I need info on > > the coarse tuning. > > > > Thanks, > > > > Scott Madison, WN1B > > > > > > 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/
