Currently using the PM exciter - haven't had a chance to track down a PLL exciter yet. Didn't realize the noise supression figures were that different - Wow...
The receiver I currently has (as built, still surveying the system we've inherited) the UHS pre-amp in place... Guessing that isn't helping things much either LOL :) On Wed, Mar 25, 2009 at 6:01 PM, Jeff DePolo <[email protected]> wrote: > > Are you using the PM exciter or PLL exciter on the M2? If PM, switching to > PLL will reduce the transmitter noise supression requirement of your > duplexer by 22 dB. > > Otherwise, your best bet is to add another pass/reject cavity to each side > of the duplexer closest to the repeater equipment (i.e. don't add new > cavities connected to antenna tee). > > --- Jeff WN3A > > > > -----Original Message----- > > From: [email protected]<Repeater-Builder%40yahoogroups.com> > > [mailto:[email protected]<Repeater-Builder%40yahoogroups.com>] > On Behalf Of AJ > > Sent: Wednesday, March 25, 2009 4:20 PM > > To: [email protected]<Repeater-Builder%40yahoogroups.com> > > Subject: Re: [Repeater-Builder] Re: Sinclair Q2220E > > > > We have one in place right now on the 600 KHz split at 25 > > watts from a MastrII... > > Very noticeable desense... > > > > Not very happy with the setup... But we're doing the best we > > can with what was on the hill when we started... > > > > Oh well lol. > > > > > > On Tue, Mar 24, 2009 at 12:39 PM, ve7fet > > <[email protected] <yahoogroups%40woldanski.com> <mailto: > [email protected] <yahoogroups%40woldanski.com>> > wrote: > > > > > > Actually, the comment below isn't quite true. > > > > The Q2220E is a "Res-Lok" duplexer, but there are no > > machined coupling ports between the cavities. I just took the > > loops out of one to confirm. > > > > The coupling between the cavities is a function of the > > pickup loop inside the cavity, and the coax between them. > > > > However, in the C2034 type Res-Lok combiners, there ARE > > coupling ports machined between the bandpass section cavities > > (confirmed that too). > > > > Of interesting note on the Q2220E, the docs from > > Sincliar show two different harnesses available, presumably > > one for high split, and one for low. I have two Q2220E's > > here, one factory 143/148 and the other 152/157. They both > > have the same harness on them (320mm inter-cavity of RG400), > > and the pickup loops are the same size too (110mm). > > > > If you run the numbers for 320mm and a velocity factor > > of 0.695, you get a center frequency for the harness of 163MHz. > > > > If you wanted to optimize the tuning for the best > > response in the ham band, you may want to consider > > re-building the harness and changing the inter-cavity lengths > > to 355mm. I wouldn't change the lengths of the pickup loops > > as that is going to significantly change the response. > > > > Also note, the Q2220E makes a good candidate to modify > > for 220MHz... just ask Dave Cameron... > > http://www.irlp.net/duplexer <http://www.irlp.net/duplexer> > > > > Cheers! > > > > Lee > > > > > > --- In [email protected]<Repeater-Builder%40yahoogroups.com> > > <mailto:Repeater-Builder%40yahoogroups.com<Repeater-Builder%2540yahoogroups.com>> > , "Eric Lemmon" > > <wb6...@...> wrote: > > > Part of the problem is that the Q2220E > > > duplexer uses the "Res-Lok" design, wherein the > > coupling between cavities of > > > each pair is via a machined port between them, rather > > than a cabled coupling > > > loop that can be adjusted. > > > > > > > > > > > > > > > > > > No virus found in this incoming message. > > Checked by AVG - www.avg.com > > Version: 8.0.238 / Virus Database: 270.11.3/1970 - Release > > Date: 03/25/09 07:16:00 > > > > > > > > >
