Especially with the R7-A version. If you never noticed on my website, I have a production-prototype R7 I'm infinitely proud to call mine!!!
I also have a RACAL RA6790/GM which has a 10MHz external timebase oscillator input. One of these days I'm going to finally get my GPS Reverence actually setup-which as I understand it surpasses both Rubidium AND Cesium-Beam standards. IF you use either a WIN 98 (maybe '95) or WIN NT machine, you can actually compensate it for the delay in the coax (which HAS to be at least LMR400 from the external ANT to the SAT RCVR). It will have to be pretty near the '6790 since I have been told even the phase shift associated with any significant length of coax for the 10MHz messes with the accuracy. I have no idea how all of this winds up being affected by other crystals within the '6790. And yes I know: it's MAJOR overkill... but that's what the fun is about, isn't it?!!! LOL Ed Tanton website: http://www.n4xy.com All emails <IN> & <OUT> checked by Norton AntiVirus with AutoProtect -------------------------------------------------- Wag more / Bark less -------------------------------------------------- -----Original Message----- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Jim Shorney Sent: Monday, July 25, 2011 6:31 PM To: drakelist@zerobeat.net Subject: Re: [Drakelist] Yet another Drake TR7 X-Lock Implementation On Mon, 25 Jul 2011 08:36:05 -0400, Joe Pyles wrote: >It's not just the PTO in the TR7 that drifts. On the PBT/Reference board the are 3 crystal oscillators, 40 mhz, 13.695 mhz, and 8.050 mhz, and they all move around with temperature. The 40 mhz crystal moves the most and it not only is part of the synthesizer, it provides the 500 khz reference for the DR7 board. When you install the X-Lock you control the PTO drift but not the crystals. That's a very good point, Joe. Every time I open up one of my rigs, they all seem to be just a :"hair" off. After fully aligning both my TR-7 and R-7A, with the same frequency counter referenced to the same Rubidium standard, they are far enough off from each other after bing in service for a while that people notice that I am "off frequency" if I transcieve from the R-7A. There is an adjustment procedure for that in the R-7 manual that is reminiscent of the 4-Line (pre-"C") alighment. I woulda thunk they'd learned enough that the 7s wouldn't do that.... 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
