tirsdag den 29. december 2020
tirsdag den 6. oktober 2020
I've used Network Time about 6 months. However, the PC clock deviation could be 500 ms or more during a day. This amount of drift is not acceptable - digital modes like JT65 and FT8 require less than 100 ms deviation in order to run smoothly.
A blog post by N1RWY directed me to BktTimeSync by IZ2BKT Capelli Mauro.
My configuration is shown in figure 1. Note that connecting to an NTP-server works only if the PC firewall allows traffic on port 123. "GPS Configuration" is not filled in as I don't use a GPS device as time source.
BktTimeSync should run automatically when the PC starts up. How to add an app to run automatically at startup in Windows 10 is described by Microsoft support.
Fig. 2. Message from time.is: You have the exact time!
Checking your PC clock can be done by visiting time.is. You'll discover if your PC clock is off. Figure 2 shows, that my PC clock has the exact time, and the deviation is just 6 ms.
I hope BktTimeSync will continue its excellent timekeeping on my PC!
Note december 2020: BktTimeSync is still running on my Win 10 PC. System time is updated every 20 min via europe.pool.nt.org. I am satisfied with it's performance.
73 OZ1BXM Lars
søndag den 27. september 2020
- Input power LED
- Output SWR LED
Fig. 3. Transverter and PA inside the alu-box.
torsdag den 16. juli 2020
|My 23 cm portable rig at Trehoje JO46HE.|
mandag den 18. maj 2020
I noticed noise coming from the speakers, when no audio signal was present. Changing USB-port did not help. I seemed like my USB ports were noise polluted! When I connected a power-bank (lithium-ion battery) to the speakers, the noise disappeared, but during pauses in the audio, the power-bank shut itself down!
I decided to build a noisefree 5 V DC PSU using a transformer with iron core and a 7805 which has 68 dB ripple rejection and low output noise. The 7805 is thermal overload protected and short-circuit protected. I had all parts laying around, so the building cost was nil.
|Figur 1. The noisefree PSU.|
|Figure 2. Noisefree PSU with open lid.|
|Figure 3. AC Adaptor.|
|Figure 4. Circuit diagram.|
|Figure 5. The circuit board seen from the bottom.|
Now I can enjoy music and speech without background noise - and a good feeling of having improved something!
73 from OZ1BXM
My homepage: http://oz1bxm.dk
tirsdag den 24. marts 2020
I had problems after I installed Meinberg NTP. Whenever I booted the PC, the system clock was set by Meinberg, but then time discipline was lost. After some hours, the system clock could deviate as much as 1 sec. It seemed like Meinberg could not control the system time. I worked with this problem for a while, and then I decided to uninstall Meinberg NTP and try another piece of software for time control.
I need accurate time keeping because I'm using weak signal digital protocols in amateur radio. A time deviation of less than 100 ms is required with JT65. I use JT65 when I'm bouncing radio signals off the Moon and back to Earth (distance 800,000 km).
Network Time was easy to install, and it worked right away. Under "Settings" I set "Update Interval" to 20 minutes because I wanted frequent updates. Remaining options were left at the factory settings.
Before installing Network Time I opened UDP port 123 (inbound/outbound) in Windows Defender Firewall. This port is used by the NTP (Network Time Protocol). I named the rule "UDP-port-123-time1", see figure 3.
Vy 73 from OZ1BXM Lars
onsdag den 12. februar 2020
|Figure 1. SDRplay RSP1A with a 20 dB attenuator.|
|Figure 2. Pierce crystal oscillator.|
|Figure 3. Measuring the crystal oscillator.|
|Figure 4. Screen-dump from RSP Spectrum Analyzer.|
|Figure 5. Measuring a band-pass filter.|