2019-03-16

Greek hams get 5 MHz WRC-15 band


Local (SV) SSB net on 5365 kHz, abusing the WSPR sub-band the the upper band limit.

Last week Greek radio amateurs had a pleasant surprise. The Government published the new national frequency allocation table (FEK B'751/2019), with considerable delay, which harmonizes frequency allocation with WRC-15 decisions. The update includes a new secondary amateur radio frequency allocation on 60 m (5351.5-5366.5 kHz), which is particularly suited for NVIS regional networks during daytime. 

The first few days on the band brought in some interesting DX, including N. America in the early mornings. Most traffic is FT8 on 5357.0-5360.0 kHz, with some CW, especially near the low end of the band. Also WSPR is very active on 5366.2 kHz (USB carrier 5354.7 kHz).

At times parts of the band are affected by continuous 3-kHz wide military PSK transmissions and Over The Hrizon Radars (OTHR). 



2019-03-09

Potential problems for users of GPS receivers

 
 
 
081451Z MAR 19
NAVAREA XII 93/19(GEN).
POTENTIAL PROBLEMS FOR USERS OF GPS RECEIVERS.
1. USERS OF GPS RECEIVERS ARE ADVISED OF POTENTIAL
    PROBLEMS DUE TO GPS WEEK COUNTER ROLL OVER ON
    06 APR 19.
2. THE GPS SYSTEM TRANSMITS TIME TO GPS RECEIVERS
    USING A FORMAT OF TIME AND WEEKS AFTER THE START
    DATE OF 06 JAN 80. THE DATA FIELD IN THE NAVIGATIONAL
    MESSAGE SENT BY GPS SATELLITES CONTAINING THE NUMBER
    OF WEEKS AFTER THE START DATE IS LIMITED TO A MAXIMUM
    OF 1023 WEEKS.  WHEN THE GPS SYSTEM REACHES WEEK 1024,
    THE SYSTEM WILL REVERT BACK TO WEEK ZERO.
3. SOME GPS RECEIVERS ARE KNOWN TO BE UNABLE TO MAKE
    THE TRANSITION FROM WEEK 1023 TO 1024. IF THE GPS
    RECEIVER IS OUTDATED OR LACKS PROPER UPDATES,
    THE RECEIVER WILL REVERT TO READING THE WEEK ZERO
    AS AUGUST 1999. DURING THIS TIME THE INTERNAL CLOCKS OF
    THESE GPS RECEIVERS WILL EXPERIENCE A LACK OF ABSOLUTE
    REFERENCE AND MAY GIVE THE WRONG TIME AND POSITION OR
    MAY LOCK UP PERMANENTLY.
4. SOME OF THESE GPS RECEIVERS ARE REPAIRABLE WITH
    UPGRADES AND OTHERS WILL BECOME UNUSABLE. USERS ARE
    ADVISED TO CHECK WITH THEIR GPS MANUFACTURER REGARDING
    THE STATUS OF THEIR RECEIVER.
5. FOR FURTHER INFORMATION SEE:
    A. GPS WEEK ROLL OVER ISSUE
      www.gps.gov/cgsic/meetings/2017/powers.pdf.
    B. TIMING CRITICALITY & GPS 1024 WEEK ROLLOVER
      www.gps.gov/governance/advisory/meetings
      SELECT NOVEMBER 2017 AND THEN TIMING CRITICALITY &
      NOTE ON "GPS WEEK-ROLL-OVER"
    C. GLOBAL POSITIONING SYSTEMS DIRECTORATE,
      SYSTEMS ENGINEERING & INTEGRATION INTERFACE
      SPECIFICATION IS-GPS-200,
      www.gps.gov/technical/icwg/IS-GPS-200J.pdf.
6. FAILURE TO VERIFY YOUR GPS RECEIVER COULD LEAD
    TO SERIOUS NAVIGATIONAL PROBLEMS PLACING LIVES
    AND PROPERTY AT RISK. 
 
 

2019-03-04

G3USF's Worldwide List of HF Beacons



The last published version of the worldwide HF beacon list compiled by Martin Harrison G3USF was on May 23, 2018. I have saved it here: G3USF's Worldwide List of HF Beacons  for future reference.

The Low VHF (40-50 MHz) beacon list by G3USF is still updated regularly, you 
may see the latest version here: G3USF's Worldwide List Of 50MHz Beacons.

An alternative 28 MHz beacon list by Bill Hays, WJ5O, is also available and updated frequently here: 10 meter Beacon List.

 

 

2019-02-10

More SSTV images from ISS

ISS SSTV image on 201-02-10 at 08:42 UTC

During the past weekend (February 8-10, 2019) the ISS transmited once more SSTV signals on 145.800 kHz. The pictures were related to varuious space anniversaries. ISS transmissions used call sing RS0ISS.


ISS SSTV image on 201-02-10 at 15:14 UTC
The SSTV mode used was again PD120, which was developed by Paul Turner, G4IJE and Don Rotier, K0HEO (SK).

 

ISS SSTV image on 201-02-10 at 16:50 UTC


During Friday and until Saturday evening the signal strength of the SSTV transmissions was very weak and only stations equiped with specialized antennas managed to decode them. The situation improved later, it seems that it was caused by a bad connection to the ISS VHF antenna.



144-146 MHz bandpass filter

At my urban location my radio, an Icom IC7100 tranceiver, suffers from overloading on 2m, even with the preamplifier switched off. The occasional overloading degrades seriously SSTV images. Today I installed an old homemade bandpass filter, which I used in the days of packet radio (1993-1997) and the situation improved.

I received a few images, the best ones being nos 2, 9, 10 and 11 in the series.




2018-10-31

SSTV images from International Space Station

During the past weekend (October 27 - 29, 2018) the ISS transmited again SSTV signals on 145.800 kHz. This time they were related to the celebration of the 60th anniversary of NASA and both call signs RS0ISS and NA1SS appear on the images.

ISS SSTV image on 2018-10-29 at 09:02 UTC

The SSTV mode used was again PD120, developed by Paul Turner, G4IJE and Don Rotier, K0HEO (SK) and is described in Classic SSTV. MMSSTV, when set in Auto, recognizes PD120 signals immediately, even without an FSKID.

ISS SSTV image on 2018-10-29 at 04:11 UTC
I received a few images, including photos no 7, 10, 11 and 12 in the series, plus some out of series images. The best reception conditions were during the morning passes of October 29.


ARISS SSTV Award #110423
Today I received by e-mail the ARISS SSTV Award no 110423 for reporting images received on October 29, 2018 to the the ARISS SSTV gallery and submitting a request for the award on the Application for ARISS SSTV Award form page.