Going back to HF for digital comms

I came across this via a link from the Extreme Shortwave Listening group and posted from the blog of nw7us.

There is an ITU paper which discusses the problems of reliable ship-to-shore comms using only satellites, and a design for moving them back to HF. The paper includes architectural design for the system, along with explanations of the type of transmission, in this case, OFDM or Orthogonal Frequency Division Multiplexing. No, me neither.

A few quotes from the paper:

The NAVDAT HF system can use a simple time-slot allocation similar to the NAVTEX system which could be coordinated by IMO.

That NAVDAT HF system can also work on single frequency network (SFN) as described in Annex 4. In this case, the transmitters are frequency synchronized and the transmit data must be the same for all transmitters.

The NAVDAT HF digital system offers a free broadcast transmission of any kind of message from shore‑to‑ships with possibility of encryption.

That last one is telling “a free broadcast transmission”. That reads to me that one of the reasons to return to HF is the cost of renting satellite time, whereas HF is “free to air” with no ongoing costs other than maintenance.

Its not a large paper, but worth the read. The link to the pdf file is here: NAVDAT

Advertisements

CHANCE OF STORMS ON OCT. 7-8

CHANCE OF STORMS ON OCT. 7-8: NOAA forecasters say there is a 75% chance of minor G1-class geomagnetic storms on Oct. 7th and 8th when a stream of high-speed solar wind is expected to hit Earth’s magnetic field. The storms could intensify to G2-class–that is, moderately strong. If so, sky watchers in the United States could see auroras along a line from Maine to Michigan to Washington. Arctic sky watchers are almost certain to get a good light show. The gaseous material responsible for the coming storms is flowing from a large hole in the sun’s atmosphere, shown here in a false-color UV image taken by NASA’s Solar Dynamics Observatory.

Image may contain: food
With thanks to Spaceweather.com

A few logs from today

Date

 TimeOn 

Call

Freq

Mode

RST_S

Name

QTH

QS

QR

QSL_VIA

2018-09-26 17:44 OD5VB 14.18 SSB 59           EA5GL
2018-09-26 17:32 CS7APD 14.209 SSB 57            
2018-09-26 17:29 OD5UI 14.244 SSB 56   Mohammed        
2018-09-26 17:27 CT1ASM 14.244 SSB 59            
2018-09-26 17:18 CU3AN 14.292 SSB 4,4            
2018-09-26 16:53 9W2SAF 7.145 SSB 56          

A new callsign logged on 40m. 9W2SAF managing a big pileup. 20m was also in good shape.

True Blue DXing

I haven’t looked at Eham.net news for quite a while, so I was interested when this caught my eye. An article about the True Blue DXers Club. From their website at tbdxc comes the following info:

“If watching a computer make contacts for you is not your idea of DX…

…you are a True Blue DXer!

LET US TELL YOU RIGHT AWAY: WE ARE NOT AGAINST ANYTHING, OR ANYBODY

Digital modes, particularly FT8, have literally taken Ham Radio by storm. We at True Blue DXers Club (TBDXC) applaud technical innovation, and we are glad that so many people have found a new avenue for their amateur radio passion. We wish digital operators every success and lots of enjoyment.

HOWEVER

We are saddened that such explosion of activity has come to the detriment of traditional, person-to-person modes of communication. Experience tells us that, even with poor propagation and rising noise, both high-level, competitive DX activity and leisurely ragchewing on CW and SSB are possible and highly enjoyable, even for stations with modest means. Yet, the CW and SSB sub-bands are often nearly deserted, whilst the FT8 “watering holes” literally explode with signals which would be perfectly copiable by ear.

THEREFORE

The TBDXC was founded in early June 2018 primarily to bring together like-minded operators who may feel that their ethos and approach to DX communication is dying off. Given the level of enthusiasm the Club has triggered in only its first week of existence, this is obviously not the case. Practically, the aim of the Club is to a) to promote the use of radiotelegraphy (CW) and radiotelephony (SSB) in long-distance communications on the amateur bands; and b) to encourage the continuous improvement and refinement of the human, personal skills needed to do so. If the first paragraph on this page was not clear enough, let us repeat that this is not a crusade against digital modes, their developers and users. It is a crusade for a certain type of ham radio activity. In particular: “……see more at the website

Sounds like my kind of club. I have tried digital in the past, namely PSK31, and whilst it was interesting for a while, the QSO’s I remember are those which were conducted on voice (SSB). I especially remember contacts on I think 40m, with a ham in Russia. We never had skeds as such, but the QSO was always interesting and entertaining.

Sadly, even on SSB these days, the vast majority of contacts see to be of the “RST 5*, many thanks for QSO, 73’s, next” pattern. It is quite rare to hear anyone actually exchange even rudimentary information about QTH or equipment in use. Its usually “see QRZ.COM for details”! All the above is fine when contesting, or especially when working a V/UHF opening as conditions seldom last too long. But for ordinary day-to-day operating, say around Europe on 40, there is no excuse for this ‘scalp-hunting’ mentality.

Any hoo, rant over! Lets hope the TBDXC brings a bit more chat back to the bands!

CQ WW WPX loggings

The CQ WW WPX SSB contest occurs every year on the last weekend in March. This year was no exception and was over the weekend of the 24th/25th March (last weekend). I usually try and do some logging as unusual stations that you don’t normally hear pop up on all bands. True to form I managed to log some new countries. Although conditions were not ideal (they seldom are!) there were hundreds of stations on the air. Obviously the die-hard contesters are there with their 1.5KW stations, but there are smaller powered stations who make it through the noise.

So the following is a list of stations I managed to hear, and overall I was very pleased as It was just casual listening.

24/03/2018 – 80M –                                                                                                                                                                  EF8R 5,9 PG90T 5,9+10                                                                                                                                    40M –                                                                                                                                                                  SI9AM 5,8 EV1R 5,9 LY4L 5,6 S58Y 5,7 OL9R 5,9+10                                                                                  15M –                                                                                                                                                                  PY5JR 4,6 CN3A 5,7 PP5JN 5,6 CE2LR 4,6 ZY2Y 4,5

25/03/2018 – 20M –                                                                                                                                                                 9H6A 4,6 4X7R 5,6 JT5DX 5,7 A61QQ 4,5 FR4QT 5,6 LZ25TRC 5,9+10 PJ4V 5,8                                     VE3UDX 5,6 CT3KN 5,7 EF9R 5,9 4Z5LY 5,9 VB3E 4,4 EB7DX 5,9 YM7KA 5,7                                         ED9E 5,9+10 KQ2M 5,9 4L2M 5,9 NR7DX 4,4 PZ5RA 3,3 Z37M 5,9+10 IF9A 5,9                                     PJ5Z 5,8

The CW CQWW WPX is on in May, so if Morse is your thing that would be worth listening to. Its nice to get some unusual ones in the log!

Snowy Shortwave Sunday

The snow forecast for Lincolnshire and other parts of the UK duly arrived on Saturday and continued into the small hours on Sunday (today). Total accumulation here was not big, about 4 inches (10 cm), but the wind made the temperature very low and most unpleasant to be out. The high winds had not done any damage to the antenna, so I settled back to do some SWLing. In between doing some other things, it was a very pleasant way to spend a Sunday, especially when the outside was so unpleasant. One station which I hadn’t listened to before was From The Isle of Music on 9400 KHz. This station transmits from Bulgaria and as I understand, features an eclectic range of music. Today it was Cuban Jazz fusion, and a very pleasant half hour was spent listening to this.

Another station not heard for a while was Furusato no Kaze from Palau, on 9975. Furusato no Kaze means ‘Wind of Home’ and is a special interest program for Japanese nationals abducted by North Korea.

As can be seen from the logs, most listening today was on the 25 Metre band. I find this band usually has something interesting to listen to, and even though the propagation predictions were not good, as can be seen, there was plenty going on! Its the reason that for me, Shortwave trumps any other form of information source. There is such a diverse range of stations and programs that it never gets boring. And there is always the thrill of the chase for that elusive station that you can just hear above the noise, but have trouble ID’ing.

And so, the logs.

5840 Khz Denmark World Music Radio 06:58 UTC Traditional Spanish sounding music.. ID at 07:00 followed by music from Bob Marley SINPO: 43323 2018-03-18

11775 Khz Taiwan SOH Xi Wang Zhi Sheng 09:38 UTC Chinese. YL and OM presenters. SINPO: 22112 2018-03-18

11970 Khz Taiwan SOH Xi Wang Zhi Sheng 09:46 UTC Chinese. YL and OM presenters. SINPO: 32222 2018-03-18

11555 Khz Northern Marianas Islands RFA 12:45 UTC Tibetan service. Sounds like an interview. YL presenter. SINPO: 33223 2018-03-18

11640 Khz Taiwan R Taiwan 13:53 UTC Chinese. Quite warbly at times SINPO: 33223 2018-03-18

11730 Khz Phillipines R Veritas Asia 14:20 UTC Bangla service. Music and discussions. ID 14:27 followed by jingle and schedules SINPO: 43333 2018-03-18

11740 Khz Singapore R Japan 14:32 UTC Burmese service. OM presenter SINPO: 44334 2018-03-18

11860 Khz Saudi Arabia R Sana 14:43 UTC Arabic. Discussion program SINPO: 33223 2018-03-18

9400 Khz Bulgaria From The Isle of Music 15:00 UTC Program featuring Cuban Jazz fusion music SINPO: 44334 2018-03-18

9335 Khz Phillipines VOA 16:09 UTC Burmese service. YL presenter. ID at 16:10 SINPO: 44334 2018-03-18

9975 Khz Palau Furusato no Kaze 16:22 UTC Japanese. YL presenter. Schedules and contact info prior to 16:30 sign-off SINPO: 43333 2018-03-18