Oh, forgot to mention. If you turn your unit upside-down, you should see rubber plugs near the fed ends of each resonator. You can fine-tweak the taps through these holes. It's pretty easy to break a wire, so I wouldn't recommend you go in there and start twistin' and tweakin' with any significant amount of force. Adjusting the distance of the tap wire (center conductor) from the resonator will have a small, but measurable, effect on insertion loss and return loss.
3MB JPEG of a disassembled PD633: http://www.broadsci.com/foo/IMG_6010.jpg 3MB JPEG showing what happens when you mis-tune or over-power one of these duplexers (capacitive loading slug and teflon insulator fried) - they are NOT very forgiving: http://www.broadsci.com/foo/IMG_6031.jpg --- Jeff WN3A > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Jeff DePolo > Sent: Saturday, February 06, 2010 10:55 PM > To: [email protected] > Subject: RE: [Repeater-Builder] RFS TDE-7780A > > > > > I've disassembled and compared the ham-split PD633-6A-1N and > regular 450-470 > PD633-6A-2N. The resonators are identical; they're the same > length. The > difference is where they are tapped - the low-split model is > tapped about > 1/4" further up the resonator than the 460 MHz version. The semi-rigid > interconnect cables are slightly longer on the low-split > model as you might > expect. I took pictures and started writing it up as an > article but never > finished... > > --- Jeff WN3A > > > -----Original Message----- > > From: [email protected] > <mailto:Repeater-Builder%40yahoogroups.com> > > [mailto:[email protected] > <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of Joe > > Sent: Saturday, February 06, 2010 9:45 PM > > To: [email protected] > <mailto:Repeater-Builder%40yahoogroups.com> > > Subject: Re: [Repeater-Builder] RFS TDE-7780A > > > > > > > > I wonder what they do to the internal coupling at the factory > > when they > > tune them. Maybe it is something that can be done in the > field with a > > little surgery? > > > > Joe > > > > Eric Lemmon wrote: > > > Point taken. One factor that will directly affect how the > > subject duplexer > > > will perform at 70cm is where the original factory tuning > > was. For example, > > > if the factory tuning was in the 450-455 MHz band, such a > > duplexer will > > > likely perform better at 70cm than will a duplexer that > > originally was > > > factory-tuned for the 460-465 MHz band. The results I > > quoted were for a > > > duplexer in the latter class. > > > > > > 73, Eric Lemmon WB6FLY > > > > > > > > > -----Original Message----- > > > From: [email protected] > <mailto:Repeater-Builder%40yahoogroups.com> > > <mailto:Repeater-Builder%40yahoogroups.com> > > > [mailto:[email protected] > <mailto:Repeater-Builder%40yahoogroups.com> > > <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of Joe > > > Sent: Saturday, February 06, 2010 2:59 PM > > > To: [email protected] > <mailto:Repeater-Builder%40yahoogroups.com> > > <mailto:Repeater-Builder%40yahoogroups.com> > > > Subject: Re: [Repeater-Builder] RFS TDE-7780A > > > > > > > > > > > > Correct, but if I remember you were claiming 3dB loss at the pass > > > frequencies. I was seeing about 1.5dB loss. I claimed respectable > > > results, not perfect results. I think it is still > > acceptable for ham > > > use. Everything is a compromise when you push the equipment > > past its > > > limits, but the typical ham is frugal (aka me) and > accepts a little > > > degradation for economy. > > > > > > 73, Joe, K1ike > > > Another parsimonious Yankee ham. > > > > > > 73, Joe, K1ike > > > > > > > > > > > > > > > > > > No virus found in this incoming message. > > Checked by AVG - www.avg.com > > Version: 8.5.435 / Virus Database: 271.1.1/2640 - Release > > Date: 02/06/10 07:35:00 > > > > > > > > > > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.435 / Virus Database: 271.1.1/2640 - Release > Date: 02/06/10 07:35:00 > > >
