David Welch wrote: > I was wondering with so many 10 mhz sources running.or even a single cesium > and gps receiver running, as I have now..and the 10 mhz is also routed to a > clock driver system (leitch).I cannot receive 10mhz wwv broadcasts at all > anytime,I am using a old radio shack sw radio on batt power..I tried even > almost 3 blocks away and all I get is my 10 mhz carrier..so even a rooftop > ant will not work ..I must have a lot of leakage somewhere to travel for the > signal to peg the radios meter blocks away.. > David One source is the interconnecting cables, hardline or similar has the lowest leakage. Another leakage path is via the mains (or other supply) leads, RFI filters on the mains (or other supply) inputs are advisable. The mains wiring can be a reasonably effective antenna at 10MHz. Bruce

I actually think that is where the prob is,I have tried much better sheilding on all the long runs with no change in leakage,I do not have an rfi filter on the power mains though,I also noticed when I use my plasma computer display, it is an old hitachi 25' I lose lock signal on my tru-time wwvb receiver. I assume due to the very close scan rate of vga 60 khz going back thru the ac line.----- Original Message ----- From: "Bruce Griffiths" <bruce.griffiths@xtra.co.nz> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Wednesday, February 13, 2008 5:21 PM Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison > David Welch wrote: > > I was wondering with so many 10 mhz sources running.or even a single cesium > > and gps receiver running, as I have now..and the 10 mhz is also routed to a > > clock driver system (leitch).I cannot receive 10mhz wwv broadcasts at all > > anytime,I am using a old radio shack sw radio on batt power..I tried even > > almost 3 blocks away and all I get is my 10 mhz carrier..so even a rooftop > > ant will not work ..I must have a lot of leakage somewhere to travel for the > > signal to peg the radios meter blocks away.. > > > David > > One source is the interconnecting cables, hardline or similar has the > lowest leakage. > > Another leakage path is via the mains (or other supply) leads, RFI > filters on the mains (or other supply) inputs are advisable. > The mains wiring can be a reasonably effective antenna at 10MHz. > > Bruce > > _______________________________________________ > 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.

Hi David, I am not sure where you are at, but your mail server appears to be on the East Coast of the US. I seriously doubt that it is your "in house" 10 MHz that is traveling 3 blocks. If it is then there are some serious issues to contend with. The first being, if you are in the US, that you are exceeding the FCC limits for unintentional radiators as defined under Part 15 of the FCC rules. For what would be considered a more or less sealed system (i.e., your equipment/cables), it is NOT normal to hear "the" signal beyond the first neighbor in any direction from the equipment location. Are you sure your "old Radio Shack" receiver is working properly ? I can still copy 10 MHz WWV mixed in with the local house standards at my location in the San Diego, California area. Of course I am using much higher quality receiver designed for the Amateur radio market. First I would turn everything off and then see what you hear. Then i would turn on & off each individual item and see how much (if any) contribution the item makes to noise floor in the receiver. After that I would turn on, in succession, the most important to the least significant and see who might be generating the strong signal. Something in that process should give you a clue as to which item may have a serious problem. In the end, if you have a real need to receive WWV on the HF frequencies, I would consider a much better receiver and, of course, an outside antenna. If I may suggest, the is a software defined receiver that appears to be of quality design covering from 500 Hz to 30 MHz for $499.99 that may interest you. Go to http://www.rfspace.com and look at the SDR-IQ model. I talked to someone who has one to test and he thought quite highly of it. It is of a very interesting design and includes software to run it. It plugs into the computer via a USB cable and is powered from that USB cable. The software includes bandwidth settings, a FFT spectrum and a waterfall type display as well. In addition, it handles CW, AM, LSB, USB, wide and narrow FM and perhaps other modes. Don't forget that WWV also transmits on 2.5, 5 and 15 MHz. 15 MHz is good during mid day and 5 MHz is quite good at night time. 2.5 MHz is only good at night and a little tough to copy unless you have a good antenna or are living quite close to it. Bill....WB6BNQ David Welch wrote: > I was wondering with so many 10 mhz sources running.or even a single cesium > and gps receiver running, as I have now..and the 10 mhz is also routed to a > clock driver system (leitch).I cannot receive 10mhz wwv broadcasts at all > anytime,I am using a old radio shack sw radio on batt power..I tried even > almost 3 blocks away and all I get is my 10 mhz carrier..so even a rooftop > ant will not work ..I must have a lot of leakage somewhere to travel for the > signal to peg the radios meter blocks away.. > > ----- Original Message ----- > From: "Matt Ettus" <boyscout@gmail.com> > To: "Tom Van Baak" <tvb@leapsecond.com>; "Discussion of precise time and > frequency measurement" <time-nuts@febo.com> > Sent: Wednesday, February 13, 2008 3:17 AM > Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison > > > On Feb 13, 2008 1:03 AM, Tom Van Baak <tvb@leapsecond.com> wrote: > > > To prevent, or at least detect, this effect I allow my 10 MHz > > > house reference to drift off-frequency by quite a bit (last > > > month it was 1.7e-12 off). That way there are no on-time > > > or on-frequency sources near the test setup. > > > > Tom, > > > > I think you might be the only person in the world who would consider > > 1.7 parts per trillion to be "quite a bit off" :) > > > > Matt > > > > _______________________________________________ > > 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.

Yes ,I am looking into a better receiver to test or a spectrum analyzer to find the source of the noise..I can receive wwv on 5 and 15 with no problem at the right times but have a lot of noise(just at 10 mhz.) the radio shack radio is a pll digital model and shows highest signal level at exactly 10mhz if I tune up or down the signal fades away..I did take the clock driver output (which is connected to unshielded cable out to the clocks)using smpte time code over two 22awg unshielded conductors..the signal is much less with this "antenna" disconnected.I just wonder why the 10 mhz generated in the cesium hp5071a is leaking through into the sempte out of the leitch clock driver which in turn radiates out through the clock lines..you think they would have better isolation in this (2003) very high end unit..BTW the driver is based on the leitch neo platform with two, main and backup cards installed..model CSD-3901..----- Original Message ----- From: "WB6BNQ" <wb6bnq@cox.net> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Wednesday, February 13, 2008 7:14 PM Subject: [time-nuts] David Welch's 3 block signal > Hi David, > > I am not sure where you are at, but your mail server appears to be on the East > Coast of the US. I seriously doubt that it is your "in house" 10 MHz that is > traveling 3 blocks. If it is then there are some serious issues to contend > with. The first being, if you are in the US, that you are exceeding the FCC > limits for unintentional radiators as defined under Part 15 of the FCC rules. > For what would be considered a more or less sealed system (i.e., your > equipment/cables), it is NOT normal to hear "the" signal beyond the first > neighbor in any direction from the equipment location. > > Are you sure your "old Radio Shack" receiver is working properly ? I can still > copy 10 MHz WWV mixed in with the local house standards at my location in the San > Diego, California area. Of course I am using much higher quality receiver > designed for the Amateur radio market. > > First I would turn everything off and then see what you hear. Then i would turn > on & off each individual item and see how much (if any) contribution the item > makes to noise floor in the receiver. After that I would turn on, in succession, > the most important to the least significant and see who might be generating the > strong signal. Something in that process should give you a clue as to which item > may have a serious problem. > > In the end, if you have a real need to receive WWV on the HF frequencies, I would > consider a much better receiver and, of course, an outside antenna. If I may > suggest, the is a software defined receiver that appears to be of quality design > covering from 500 Hz to 30 MHz for $499.99 that may interest you. Go to > http://www.rfspace.com and look at the SDR-IQ model. I talked to someone who has > one to test and he thought quite highly of it. It is of a very interesting > design and includes software to run it. It plugs into the computer via a USB > cable and is powered from that USB cable. The software includes bandwidth > settings, a FFT spectrum and a waterfall type display as well. In addition, it > handles CW, AM, LSB, USB, wide and narrow FM and perhaps other modes. > > Don't forget that WWV also transmits on 2.5, 5 and 15 MHz. 15 MHz is good during > mid day and 5 MHz is quite good at night time. 2.5 MHz is only good at night and > a little tough to copy unless you have a good antenna or are living quite close > to it. > > Bill....WB6BNQ > > David Welch wrote: > > > I was wondering with so many 10 mhz sources running.or even a single cesium > > and gps receiver running, as I have now..and the 10 mhz is also routed to a > > clock driver system (leitch).I cannot receive 10mhz wwv broadcasts at all > > anytime,I am using a old radio shack sw radio on batt power..I tried even > > almost 3 blocks away and all I get is my 10 mhz carrier..so even a rooftop > > ant will not work ..I must have a lot of leakage somewhere to travel for the > > signal to peg the radios meter blocks away.. > > > > ----- Original Message ----- > > From: "Matt Ettus" <boyscout@gmail.com> > > To: "Tom Van Baak" <tvb@leapsecond.com>; "Discussion of precise time and > > frequency measurement" <time-nuts@febo.com> > > Sent: Wednesday, February 13, 2008 3:17 AM > > Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison > > > > > On Feb 13, 2008 1:03 AM, Tom Van Baak <tvb@leapsecond.com> wrote: > > > > To prevent, or at least detect, this effect I allow my 10 MHz > > > > house reference to drift off-frequency by quite a bit (last > > > > month it was 1.7e-12 off). That way there are no on-time > > > > or on-frequency sources near the test setup. > > > > > > Tom, > > > > > > I think you might be the only person in the world who would consider > > > 1.7 parts per trillion to be "quite a bit off" :) > > > > > > Matt > > > > > > _______________________________________________ > > > 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.