Re: [time-nuts] Need help in test board pinout for SA22.c oscillator - thanks in advance

I remember when I started experimenting with Rb and I thought "why would I want to give it more cooling? That's just more contact with the outside world, and more chance for the room temperature variation to throw things off. I'll just put it on the desk, it'll be more stable that way." And then

Re: [time-nuts] Difference in antennas

Hi If you have a survey device like a Trimble NetRS then you *must* have a high gain antenna. If you want to feed it from the Trimble, you need an antenna that runs on 12V. It also needs to be an L1 / L2 antenna. If all you have a TBolt timing receiver, then you want a 20 db gain antenna

Re: [time-nuts] Difference in antennas

Most modern GPS receivers are very quiet even barefoot. So, one could argue that one should not have much more LNA gain in the antenna than required to make up for feedline loss, which should be easily calculable. While excess gain in the antenna can improve overall system noise figure a small

Re: [time-nuts] Difference in antennas

So concensus is, 50dB gain antenna is too much gain, unless feed line is too long, reception is poor, or there are other circumstances extra gain is desired? --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Thursday, November 21, 2019, 3:00:14 PM EST,

Re: [time-nuts] tracking position & orientation

Hi The “cheap” approach these days is to use a uBlox ZED-F9P https://www.digikey.com/products/en/rf-if-and-rfid/rf-evaluation-and-development-kits-boards/859?k=F9P along with one (or

Re: [time-nuts] Difference in antennas

John Ackermann N8UR writes: > One related question, especially with mixed systems -- how do you tell > if you have optimum signal level at the receiver? > > Most show some sort of SNR or Cn value. What should we look for? What > are the indication of *too much* signal? One issue in particular

[time-nuts] tracking position & orientation

I need another project like a hole in the head — but curiosity continues to nag me. I moved to Boulder CO a few months ago. The “curiosity” is to determine the position of two antennas at either end of my house and monitor it over time, with the idea that one could see plate movement in

Re: [time-nuts] Difference in antennas

Hi That is indeed the gotcha. Once you get past a certain amount of gain in the preamp, the C/N levels don’t change enough to notice. Looking today vs looking tomorrow is unlikely to be of any help if you are after a fraction of a db. About the only way to check would be to fast switch an

Re: [time-nuts] Difference in antennas

John Ackermann N8UR writes: > One related question, especially with mixed systems -- how do you tell > if you have optimum signal level at the receiver? I don't think you're going to figure out an _optimum_ gain without proper measurements along the whole signal chain. As a proxy, the reported

Re: [time-nuts] Difference in antennas

Bob, this is a great summary, thanks! One related question, especially with mixed systems -- how do you tell if you have optimum signal level at the receiver? Most show some sort of SNR or Cn value. What should we look for? What are the indication of *too much* signal? One issue in particular

Re: [time-nuts] Antique pendulum clocks

Heck as much as I like clocks I just want to see Adrians working HP 9815 calculator. Other comment for me at least is a good clock is a marvel by itself. Adding electronics removes the amazing engineering that went into the clock. By good I mean clocks few of us can afford. Though on time-nuts I

Re: [time-nuts] Difference in antennas

Hi Way back in time, the first gear out there to use what we now look at as “normal” antennas was survey gear. For various reasons they decided on a 12V power supply and 40 to 50 db of gain in the preamp mounted in the antenna. They also got into L1 / L2 pretty quickly. A bit later the cell

Re: [time-nuts] 90ms delay of time signal on phase-modulated carrier of BBC 198KHz transmission in the UK (was: DST change on DCF77)

Hi Steve, On Thu, 21 Nov 2019 at 01:00, Steve Allen wrote: > > The current version ITU-R TF.460-6 says that time signals should > not deviate by more than 1 ms from UTC. > > How can these broadcasts justify such a large offset? The signal is only used (as far as I am aware, a few Time Nuts

Re: [time-nuts] Difference in antennas

Like many things, price does not necessarily reflect a better antenna, however there are differences between antennas. One difference is in the quality of the filters in the antenna itself. This matters more when one is mounting an antenna at a communications site than say at a home timing lab.

Re: [time-nuts] 90ms delay of time signal on phase-modulated carrier of BBC 198KHz transmission in the UK (was: DST change on DCF77)

It can be justified very simply that the phase mod data on 198kHz is NOT intended as a standard time distribution. As far as I am aware only the frequency accuracy is covered in the NPL contract. Even that no longer seems to be monitored and offsets published. Time distribution is on MSF