The ΒΌ wavelength should be to the bottom end of each coupling loop. Note that the velocity factor of the loop will be close to that of air.
73 Gary K4FMX _____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of James Sent: Wednesday, February 21, 2007 7:31 PM To: [email protected] Subject: Re: [Repeater-Builder] Wacom WP-641 cable type and lengths If I am not mistaken, you can use whatever you want (silver plated, doubleshielded teflon type is best) as long as it is electrically a 1/4 wavelength. To get what the proper lengths are for your frequency, you multiply the normal 1/4 wavelength of that frequency by the velocity factor of the cable. The end bandwidth (margin of error) is about 3% of your frequency (so if you have cables cut for 148 MHz, and want to use them at 144, then it will work fine. Goodluck in your endeavors! James [EMAIL PROTECTED] wrote: Don't know what is used in the 641 but the interconnect length for the WP-642 set up for N connectors is 12 3/8 inches for the 2 meter band. I don't think Wacom used RG-223U. Their UHF duplexers were supplied with RG-142 and the VHF cans used a cable which was labeled: "Modified RG-214 Double Shielded". They felt that using silver plated shields was an unnecessary expense that didn't provide any improvement in the cable characteristics. Their "special" cable is double shielded but both shields are unplated copper and are terminated with a captive contact UG-1185A/U with a gold plated pin. I've never experienced any shield noise flexing the Wacom interconnects but others aboard have reported broadband noise generated by unplated shields and are insistent on using a MilSpec RG-214 cable for this purpose. It's not cheap cable, but considering how little you will need for bottle interconnects MILSpec RG-214 would probably be the way to go. In a message dated 2/21/2007 2:30:23 P.M. Pacific Standard Time, [EMAIL PROTECTED] writes: Hi All, I have access to a WP-641 factory tuned to the ham band, but someone removed and misplaced the interconnect cables. Does anyone have a WP-641 that they could take the measurements from? I am also in need of the type of cable used. I think Wacom used RG-223/U. Thanks, Sean _____ AOL now offers free email to everyone. Find out more about what's free from AOL at <http://pr.atwola.com/promoclk/1615326657x4311227241x4298082137/aol?redir=ht tp%3A%2F%2Fwww%2Eaol%2Ecom> AOL.com.
