Re: [time-nuts] The low budget UT+ newbie time-nut project: FrequencyReference
Bob, I'm sure much more qualified nuts will chime in, but a few thoughts of mine. Over the years, I've collected enough GPS antennas from hamfests, online vendors and who-knows-where, all for prices from free to tens of dollars. Most of them came with anywhere from 3' to 10+meters of cable. Most of those cables have been terminated in SMA connectors. Not sure how long you think your cable run will be (mine is < 15', skylight to workbench) but I'd stay away from RG6 just as a matter of practice. The antennas are generally amplified, but still... MCX to SMA pigtails are cheap and plentiful. Once you are SMA, everything else is easy. To me, division is far better than trying to modify the UT+. Welcome to the asylum. The inmates all have good ideas! On Tue, May 5, 2015 at 7:35 PM, Tom Van Baak 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: time-nuts@febo.com > 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 -- time-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] The low budget UT+ newbie time-nut project: FrequencyReference
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 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: time-nuts@febo.com > 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 -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] The low budget UT+ newbie time-nut project: FrequencyReference
> 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: time-nuts@febo.com 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 -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
