PI4 next generation VHF/UHF beacons?

Beacons have like other digital modes moved with the times, making use of the latest digital modulation techniques to improve detectability far beyond the human ear and CW.

The name PI4- PharusIgnis4 comes from the ancient words for a beacon, lighthouse and fire and is a digital modulation that is compliant with the IARU Region 1 VHF Committee accepted 1 minute mixed mode beacon sequence.

The sequence of events is illustrated below, and always starts on a full 1-minute cycle.0 to 24 seconds PI callsign


25 sends CW ident callsign and locator


carrier until 59.5 seconds


To decode the PI4 beacons you can download software PI-RX by Poul-Erik OZ1CKG or MSHV by Christo LZ2HV, they both report being compatible with Linux and Windows.

OZ7IGY beacons date back to 1957, and they are now QRV from 28 MHz to 24 GHz. You can review the dial frequencies and check the operational status online.

Frequency [MHz] USB dial* ERP [W] ASL [m] 99% accuracy [mHz] Year QRV
28,271 28.270.200 10 95 1 2009
40,071 40.070.200 10 97 1 2007
50,471 50.470.200 25 98 1 1990
70,021 70.020.200 25 100 1 2003
144,471 144.470.200 50 102 3 1957
432,471 432.470.200 75 103 9 1958
1 296,930 1.296.929.200 90 95 26 1978
2 320,930 2.320.929.200 30 98 46 1985
3 400,930 3.400.929.200 50 96 68 2006
5 760,930 5.760.929.200 50 98 115 1992
10 368,930 10.368.929.200 80 97 237 1999
24 048,930 24.048.929.200 20 97 481 2012

To support the PI4 beacon project, or to see a technical description of the modulation technique read more on their website.

Other becons to look out for.

PI4 + CW + carrier/Next Generation Beacons platforms
4O0BCG in JP92PK – 70,048 MHz
DB0HRF in JO40FF – 144,475 MHz
DB0IH in JN39HJ – 432,447 MHz
DB0JG in JO31HS – 432,412 MHz
DB0LTG in JO31TB – 1296,7435 MHz
DB0MMO in JN49RV – 144,455 MHz and 432,425 MHz
EI0SIX in IO63VE – 50,005 MHz, SBP 5/0
GB3CFG in IO74CR – 70,027 MHz and 1296,905 MHz
GB3MCB in IO70OJ – 50,443 MHz and 50,005 MHz SBP 5/1 and 3
GB3MHZ in JO02PB – 10 368,830 MHz
GB3UHF in JO01EH – 432,430 MHz
IW9GDC/B in JM78SD – 50,006 MHz (Later SBP 6/4)
KG4BYN in EM75RV – 28,2368 MHz
ON0EME in JO21JG – 10 368,875 MHz and 24 048,875 MHz
ON0SNW in JO21BE – 10 368,965 MHz
OX4M and OX6M in HQ90AL – 70,047 MHz and 50,047 MHz
OZ4BHM in JO75KB – 50,005 MHz, SBP 5/4, later also 50,466 MHz
OZ7IGY in JO55WM – 28 MHz to 24 GHz
PA0AG in JO32GH – 70,095 MHz (personal beacon, 07-21 UTC)
SK4MPI in JP70NJ – 144,412 MHz
TF1VHF in HP94AC – 50,457 MHz
UA1ZFG/B in KP69AK – 144,425 MHz
VA2NQ in FN35NL – 50,295 MHz, 144,491 MHz, 222,295 MHz and 432,302 MHz
Share this...Tweet about this on TwitterShare on FacebookShare on Google+Email this to someone

FT8 on 144 MHz

FT8 has taken the HF bands by storm, a bit like PSK did in the early 2000s. These days it seems the mode of choice for DX stations, allowing them to make a number of QSO is a short duration. If you haven’t checked out FT8 then I would suggest you head over to Joe Taylor website and have a look at some of the weak signal propagation modes available.

Connecting my Icom 7100 to Ham Radio Deluxe, and then WSJT-X to “Ham Radio Delux” works just fine for me. It should be possible to connect WSJT directly to the Icom radio, but a lot will depend on your operating preferences.


The agreed dial frequency is 144.174 USB and you will see activity most of the time, probably more in the evenings and weekends


Its quite common to see Germany, France, Belgium, Ireland, Wales and Scotland in a few hrs of monitoring under flat conditions.

50 MHz is also popular and works well under short sporadic E opening.

Share this...Tweet about this on TwitterShare on FacebookShare on Google+Email this to someone


I recently received back my Expert 1.3K-FA linear back from its holiday in Italy. I noticed some months ago that it would sometimes fail to start and require repeated presses of the power button. After a short holiday in Italy, the manufacturer replaced two relays, and I thought WPX RTTY was a good baptism of fire.

Apparently, these are the faulty items, now replaced under warranty. Linear was working flawlessly and allowed me to complete 218 QSO on 7 MHz.

Using the doublet antenna, I wasn’t able to find much DX, but using the club call MX0SNB did provide some interest on the bands.



Even after some prolonged CQ runs the liner was able to deliver 400w RTTY and remained under 50 C

Interesting to see the VSWR at 1.01 and the temperature at 50C.

Bands seemed busy, I opted to only operate on 7 MHz and so conditions provided mostly contacts to EU. I was able to work into the USA, and I did hear China and Indonesia although was unable to work them.

I put together this map showing QSO mostly over the EU.

I managed to work 45 countries, with the best DX being Peru.

Always nice to see the bands busy, and RTTY has never been so popular.

Share this...Tweet about this on TwitterShare on FacebookShare on Google+Email this to someone

Multi Mode Digital Voice Modem with HAT

Let’s start with the name, MMDVM (Multi-Mode Digital Voice Modem) with HAT(Hardware Attached on Top)

The HAT has been designed by Flo DF2ET and Mathis DB9MAT and is compatible with the Raspberry PI or PI W Zero. The board will support MMDVM so that’s DSTAR, DMR, P25 and Fusion using the excellent software by Jonathan G4KLX.

The Raspberry Pi zero W (WiFi)

The board that brings together the UHF module, the STM32F103 CPU that is plugged directly onto the smallest Raspberry Pi, the Pi Zero W. The hotspot can be configured on the dashboard to operate on any or all digital modes and to operate on the UHF frequency of your choice.

I have mine setup on to provide a digital access point on 435 MHz, but your allocated frequency will vary by local usage and regulations. It has around 10mW of power, so ample to provide access all around the house using a handy.

A close look at the MMDVM_HS Pi Hat

The screen can be anything of your choice, I opted for a small OLED screen but in hindsight, it should have been a little bigger as one’s eyes get older!

Blue OLED Screen

Craig W1MSG has produced some excellent video on setting up your hotspot and on setting up your DSTAR radio.

The project and parts are detailed on Github

Support is available in  Groups.io or Facebook 

Who is behind PI-Star

Here you can see both the DMR and DSTAR radio screen.
















Thanks to George M1GEO for help setting and configuring the access point, and John M0UKD for running over some of the local settings.

Share this...Tweet about this on TwitterShare on FacebookShare on Google+Email this to someone

Receiving HF Weather Fax

If you have spent time listening to HF you may have noticed the distinctive sound of HF Fax, something I thought had disappeared 20 years ago.

FAX seems like a very old technology now, although before the days of email the FAX machine was the only way to send near real-time images between people. HF Fax uses the same principle, but instead of squirting the tones down a phone line we modulate them onto an HF carrier.

It’s still very slow, but if you are on a yacht in the middle of the Atlantic its a very low-cost alternative to using a Sat phone and data. The charts are still transmitted from a number of locations around the world, using very high power 5 to 20 KW HF stations, so reception is easy even with a modest antenna.

How to identify Wefax on the HF bands 

The history of Radiofax

Worldwide Marine Radio facsimile broadcast Schedules

You can use one of the online KiwiSDR to display the maps, this allows you to select the FAX overlay option in the top right-hand box, then region and download the image.

FLdigi can also be used to display the images on your screen. Using the schedule of transmissions tune your HF radio to 4608.1 KHz USB and set up FLdigi to your sound card. You will need to set the OP Mode to WEFAX then WEFAX-IOC576,

If you miss the start of a transmission don’t worry, just leave the receiver and program running and it will sync and start decoding on the next image. The transmission schedule is quite extensive, so you never have to wait long to resolve an image.

Here is an example from 4608 KHz decoded at 12:58 Hrs on 1/1/18

The transmitted images change based on a schedule, one typical example is included below.


TIME   Chart                                  Valid   I.O.C.
03:41  MSLP ANALYSIS FOR 00:00                00:00    288
04:31  500 HPA CONTOUR/TT (1000/500HPA) 
       ANALYSIS FOR 00:00                     00:00    288
04:40  MSLP 24-HOUR FORECAST (VT 00:00)       00:00    288
08:06  MSLP 48-HOUR FORECAST (DT 00:00)       00:00    288
08:12  MSLP 72-HOUR FORECAST (DT 00:00)       00:00    576
09:29  SEA/SWELL ANALYSIS FOR 00:00           00:00    288
09:35  SEA/SWELL 24-HOUR FORECAST             00:00    288
09:41  MSLP ANALYSIS FOR  06:00               06:00    288
10:00  500 HPA CONTOUR/TT (1000/500HPA)
       T+24 FORECAST                          00:00    288
10:10  SEA/SWELL 48-HOUR FORECAST             00:00    288
10:31  NORTH ATLANTIC INFERENCE               00:00    576
10:42  MSLP 24-HOUR FORECAST (VT 06:00)       06:00    288
14:12  UK SEA TEMPERATURE ANALYSIS            00:00    288
15:41  MSLP ANALYSIS FOR  12:00               12:00    288
16:02  NORTH ATLANTIC SEA ICE CHART           00:00    576
16:22  SCHEDULE: MARINE PRODUCTS              05:00    576
16:30  GENERAL NOTICES (if any)                        576
16:41  MSLP 24-HOUR FORECAST T+24 (VT 12:00)  12:00    288
17:08  500 HPA CONTOUR/TT (1000/500HPA)
       ANALYSIS FOR 12:00                     12:00    288
20:12  SEA/SWELL  ANALYSIS FOR 12:00          12:00    288
20:18  SEA/SWELL 24-HOUR FORECAST             12:00    288
21:41  MSLP ANALYSIS FOR  18:00               18:00    288
21:52  SEA/SWELL 48-HOUR FORECAST             12:00    288
22:22  MSLP 48-HOUR FORECAST (DT 12:00)       12:00    288
22:30  MSLP 72-HOUR FORECAST (DT 12:00)       12:00    288
22:41  MSLP 24-HOUR FORECAST (VT 18:00)       18:00    288
23:33  MSLP 96-HOUR FORECAST (DT 12:00)       12:00    288
23:40  MSLP 120-HOUR FORECAST(DT 12:00)       12:00    288
Share this...Tweet about this on TwitterShare on FacebookShare on Google+Email this to someone

6E beam for 70 MHz

70 MHz has become increasingly popular since Icom added it to some of their new transceivers. Since owning an Icom 7100 and enjoying the UKAC and portable events I decided to make a beam for the band.

I had some aluminium from a previous order at aluminium warehouse, and so decided to look around the web for a suitable design. Martin K7MEM website takes you to a javascript page that allows you to specify what material you have available. This is quite a flexible approach and gives you the ability to make something without being too prescriptive in the early design.

In my case, I had some lengths of 8mm and 10mm tube and a 25mm box for the boom. The website allows you the flexibility to specify the desired frequency and then select the required gain or boom length. Thankfully the design can be created in both metric and imperial measurements, you just specify the sizes in the design.

Program output.

The current design is an antenna for 70.2 MHz. It has 1 Reflector, 1 Driven, and 4 Director Elements. Estimated Gain is 8.917 dBd.

Antenna Dimensions

Spacing (mm)


Length (mm)



















Insulated elements

This is specified at the time of the design, it is interesting to see the design with and without insulated elements. Insulating the elements from the boom has the effect of shortening them slightly, but why not have a play with the calculator and see the difference. The insulators I used were 4mm ABS plastic, cut into strips but you can use anything to hand.

Driven element

Often the most difficult parts to complete, as it requires a split and insulation from the boom.


1/ Place a small plastic tube inside both parts of the driven element, thus making them rigid and then mounting this to the plastic insulator on the boom.

2/ Fix the driven element directly to the plastic insulator using 2 plastic clamps on each section. This should provide enough support to stop the element sagging or twisting.

3/ Commercial VHF style dipole centre.

Parts list / Supplier options.

Aluminium warehouse can supply lengths of aluminium in both imperial and metric sizes.

Black Plastic Nylon P Clips Mounting Cables Tubes Pipe Brake Motorcycle Car. These can be used to fix the elements to the insulator, they are available in various sizes. The clips allow the elements to be removed by simply pushing/pulling the element into the clip, and are therefore ideal for portable use.

Something more robust would be needed for a permanent solution.




Stauff clamps can be sourced online. These are more expensive than other options, but ideal for a permanent antenna build.





VHF dipole centre available from your local rally, eBay or junk box




Element insulator, search using 4mm ABS plastic sheet.




Closing thoughts

The antenna is a little quirky, the dip shows a good match at 70.200 and the bandwidth is wide enough to cover the entire 70 MHz band. The dip shown on the RigExpert is a little nonconventional, but it certainly has gain and good F/B ratio from the testing on site.

Alternative designs by DK7ZB

Audio clips from testing.

GM4NFC Alex 520 KM

GI4SNA David @530 KM

July 2017 70 MHz Trophy Cup.

Share this...Tweet about this on TwitterShare on FacebookShare on Google+Email this to someone
© 2015 Dave, M0TAZ