HI For what you are doing, RG-6 Quad Shield is fine. Save the LMR-400 for other things.
Get a pigtail that will connect to the GPS board. It needs to be pretty flexible. That connector is not very study. Don’t bother with an adapter. Been there / done that, not a good idea. You need the mechanical isolation a thin coax gives you. Get one with an SMA, N, or F connector on the other end. The auction sites have tons of them. Consider that the best way to get things lined up is to divide the time base down to 1 pps and use the counter to watch what it does vs the GPS. You can get good accuracy without a lot of hassle that way. Bob > On May 5, 2015, at 7:35 PM, Tom Van Baak <[email protected]> wrote: > >> For reasons unknown to me, the body of the message was missing on the first >> attempt. > > Hi Bob, > > While we debug your mail problem, here is your post. > > /tvb > > ----- Original Message ----- > From: Bob Fleming > To: [email protected] > Sent: Tuesday, May 05, 2015 3:36 PM > Subject: The low budget UT+ newbie time-nut project: Frequency Reference > > > For reasons unknown to me, the body of the message was missing on the first > attempt. > > The low budget UT+ newbie time-nut project: Frequency Reference > Thanks to Bob Stewart’s generous offer I am now in possession of the heart of > my first time-nut project. > > My first stage plan is to make something for screwdriver disciplining the > 10Mhz reference on my frequency counter for work with ham radio. Bought on > ebay for a ridiculous low bid my Fluke 1953A -20 is synced to WWV as well as > propagation will allow. It was fading in and out over two minutes at one > point and that is good enough for ham radio but just good enough is not what > I desire and it took the better part of three days spare time fooling with it > to get it that close. (fail) > I have seen a reference to changing the 1PPS output of the UT+ to 100PPS > but if that is not applicable to my UT+ I will divide the 10Mhz by 100. In > either case my scope will be triggered with the UT+ to compare signals as > discussed here a few weeks ago. > > First thing I noticed about the UT+ is that the power/control 10 pin > connector headder on the UT+ looks just like internal USB headers on a > computer motherboard. In fact, a pair of 5 pin of USB header plugs fit > perfectly. > Second there is the antenna connector, the OCX. Apparently an MCX is > required and I have none. > Then there is wire selection for the antenna. Before I can buy an MCX > connector I better decide on the wire. I have plenty of RG6 quad shield, > enough LMR-400 that I was saving for another project and several boxes of > radio shack RG8 that I can’t find any use for. The rat shack RG8 is pretty > much hopeless but I haven’t recycled it yet. LMR-400 is too stiff to plug > directly in the tiny OCX without a pigtail of much more flexible wire and > extra connectors. > Input impedance of the UT+ is 50 ohms but I am tempted to use the RG6 because > my 20’ run will only lose about 2 DB not including impedance mismatch on both > ends. My limited experience with over 1GHz is that any connector will have > losses so I suspect that using 75 ohm RG6 coax won’t be much worse than the > LMR-400 with extra connectors, adapter and a pigtail. > Critique of my plans and/or guidance will be greatly appreciated. > I guess about a dozen of us will be building newbie time nut projects with > these. > Thanks, > Bob Fleming N5TX > >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
