Repeating the experiment? Hmmm. We were re-cabling a set of Sinclair duplexers for a 2-meter machine and had access to a high quality vector voltmeter. It took three of us Keystone Cops over 3 hours to make a set of 1/4, 1/2 and even a couple of 1 wavelength cables. Later, we repeated the process for a 220 machine and even though we had experience, it took about the same amount of time. My point? It ain't easy ! We just weren't ready to use the time and materials to add an inch to a set of cables and then make another set of short ones.
In both cases, things worked out great. Many hams who are delving in cavity alignment don't have a vector voltmeter, so we were in good shape. Plus, you have a warm fuzzy comfort factor if you know your cables are the right length when you start the job. If alignment ain't happening, you can say "I know it ain't the cables!"...right ! And I got some ocean front property here in western Arizona.... de WD7F John in Tucson <So my take is that there are critical cable lengths involved for adding a pure pass cavity to a BP BR duplexer, but I would be interested to hear from anyone aboard who has the necessary hardware kicking around to repeat that experiment and either replicate or refute the results I got. As I said, my sole cavity experience has been with Wacoms, but I find it difficult to believe that this parameter is OEM specific. K7IJ > -------------------------------------------------------------------------------- Get a sneak peek of the all-new AOL.com. -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.476 / Virus Database: 269.10.20/919 - Release Date: 7/26/2007 9:56 AM
