Any suggestions for improving the situation with our existing Q2220E duplexer?
We could turn the P/A down even further, but there's not much more room to work with with this 40 watt P/A from it's current 25 watt level without causing spurs... On Wed, Mar 25, 2009 at 3:44 PM, John J. Riddell <[email protected]>wrote: > *Re the Sinclair RES-LOC Q2220E Duplexer, they make a much better > version, * > *the Q2330E model.* > ** > * We use one here on VE3KSR, 146.970* > ** > *It has 100 Db of Tx - Rx isolation at 500 Khz and midband isolation of > 55 Db* > *as opposed to 30 Db in the Q2220.* > ** > *Power rating is 350 watts on each unit.* > ** > *The Q2330E** has three "cavities" on each side.* > ** > *73 John VE3AMZ* > ** > ** > ** > ** > ** > ** > ** > > ----- Original Message ----- > *From:* AJ <[email protected]> > *To:* [email protected] > *Sent:* Wednesday, March 25, 2009 4:19 PM > *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]>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 >> >> Cheers! >> >> Lee >> >> --- In [email protected]<Repeater-Builder%40yahoogroups.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. >> >> > >
