Thursday, October 29, 2020

Video: Talk on Band Pass Filters for the HF Bands by 5B4AGN

The Mid-Ulster Amateur Radio Club are continuing their successful lecture series for 2020 and on Tuesday the 27th of October, they had a presentation by Bob Henderson, 5B4AGN on band pass filters.

The video of the talk which is about 1hr 40m in length can be seen below...

06:30... This is the start of the slideshow and Bob outlines some basic configurations.

20:40... This section of the talk outlines the use of the ELSIE programme for designing band pass filters.

33:20... In the main section, band pass filters for the HF bands are covered and it is mainly aimed at those interested in contesting and expeditions.

1:03:34... This is the start of the Q&A section.

* * * * *

The 5B4AGN Band-Pass Filter is shown above and there is a lot more information available in the links below.


Wednesday, October 28, 2020

Postage Stamps for the first 50-Years of Irish Broadcasting - 1926 to 1976


On the 5th of October 1976, the Irish postal service issued special stamps commemorating the 50th anniversary of broadcasting in Ireland.

The first day cover shown above is courtesy of Paul Logan, MI3LDO from Co.Fermanagh.

A close up of the stamps is shown below...

Sunday, October 25, 2020

Video: Mid-Ulster ARC lecture on SDRPlay receivers


In the past, traditional good quality superhet receivers have tended to be somewhat expensive as they required a fair amount of hardware in terms of mixers, amplifiers and filters. In the last decade, modern software defined radios have turned this on its head and now, a good quality receiver can be bought for a very modest price.

In October 2020, the Mid-Ulster Amateur Radio Club had a lecture about the SDRPlay range of receivers. These are generally well regarded in terms of performance and price.

The video can be viewed below. It is somewhat long at 1hour 38mins. 

The main presentation starts at 02:29 and runs until 49:30. After that, there is a Q&A session which lasts for another 50 minutes.

Saturday, October 24, 2020

Upcoming ZOOM presentation about the communications system for Ireland's first satellite - EIRSAT-1


EIRSAT-1 is due to be released from the International Space Station sometime in 2021 and this will be Ireland's first satellite in space. See previous post.

South Dublin Radio Club are organising a special ZOOM presentation with two of the EIRSAT-1 team members on Tuesday the 27th of October 2020 at 9pm Irish time (21:00 UTC).

During the presentation, they will discuss how they will communicate with the satellite from the ground station at University College Dublin and how others can listen in and contribute as well.

For  access to the ZOOM meeting, South Dublin Radio Club can be contacted here...

Friday, October 23, 2020

Virtual tour of the historic Swedish SAQ transmitter operating at 17.2 kHz


South Dublin Radio Club had an interesting Zoom presentation on the 20th of October 2020 about the historic SAQ transmitter in south-west Sweden.

This transmitter operated at the very low frequency of 17.2 kHz and was established in 1924 to send telegrams across the Atlantic to the USA. Not long after its opening, low frequency stations of this type were superseded by those using the more efficient short wave bands.

What makes SAQ unique is that it is the last surviving transmitter of its type in that it generated the radio signal by mechanical means. See the photo below...

The electric motor on the right provides the mechanical force. The gearbox steps up the speed by a factor of three. The RF generator on the left is an alternator operating at 17,200 Hertz or 17.2 kHz.

The transmitted power is then fed to an antenna which is 2.2 kms in length.

The one-hour presentation is now available on YouTube...


1) Grimeton SAQ website

Wednesday, October 21, 2020

TEP openings on 144 MHz between Brazil and the Caribbean - Oct 2020


With Trans-Equatorial Propagation (TEP), zones of high ionization occur either side of the geomagnetic equator in the F layer of the ionosphere. What makes the mode so interesting is that it can allow propagation on the VHF bands from 50 MHz to 144 MHz.

As the zones of ionization is roughly 400kms above ground level, the propagation paths achieved are in the region of 4000 to 5000 kms, much greater than what might be usual with Sporadic-E.

TEP propagation normally peaks around the equinox and there have been some interesting contacts made recently between the south of Brazil and stations in the Caribbean.

One such example was a recent contact on 144 MHz between FG8OJ in Guadeloupe and PY2PAL in Brazil. On the map above, the position of the actual equator is shown in Blue while the Geomagnetic Equator is shown in Red.

You can hear the SSB contact on 144.299 MHz below...

Note the curious warble on the signal. The distance was 4455 kms which is pretty impressive for 2-metres.

Saturday, October 17, 2020

ZOOM presentation about the SAQ LF transmitter in Sweden coming up on Tues 20th Oct 2020

The SAQ station in Sweden is a low frequency radio station that uses a mechanical alternator to transmit on 17.2 kHz. This was established back in 1924 to send telegram traffic across the Atlantic to North America.

It is a listed UNESCO site and it sends out a special transmission on this very low frequency twice a year.

On Tuesday Night 20th October 2020, South Dublin Radio club will be hosting an online meeting on ZOOM at 8pm (19:00 UTC). During it, Ola Hervall from Sweden will give a virtual tour & presentation of the SAQ station.

For  access to the ZOOM meeting, South Dublin Radio Club can be contacted here...

Friday, October 16, 2020

Videos from the 2020 RSGB Convention

Due to the ongoing COVID-19 pandemic, the annual RSGB convention was held online on the 10th of October 2020. They had two video streams going for 8 or so hours which contained talks on a wide number of subjects.

* * * * *

Video stream 1... 
An introduction to... This video stream is aimed at beginners and the timeline for the videos is shown below.

17:30 - Keynote address: Eric Swartz, WA6HHQ - From the K2, and a box of parts, to the technology and key features the K4. A behind-the-scenes look at a 22-year adventure of hard work, luck, technology and excitement at Elecraft. (Interesting look at the history of Elecraft. The main presentation is up to 52:15. Q&A lasts until 1:07:00)
1:14:20 - The small station: Joe Chester, M1MWD.
2:14:00 - Turning amateur radio into an adventure Kevin Richardson, G0PEK and Lauren Richardson, 2E0HLR
3:14:15 - The magic of six metres Chris Deacon, G4IFX
4:14:00 - How to get the most out of your dealer for your part-exchange Martin Lynch, G4HKS
5:14:20 - A pictorial introduction to data modes Mike Richards, G4WNC
6:14:10 - Antenna modelling with MMANA-GAL Steve Nichols, G0KYA
7:14:20 - Why radio and weather go together… Jim Bacon, G3YLA 

* * *

Video Stream 2...
Learn more about …This second video stream is aimed at a more experienced audience.

18:00 - Keynote address: Eric Swartz, WA6HHQ - From the K2, and a box of parts, to the technology and key features the K4. A behind-the-scenes look at a 22-year adventure of hard work, luck, technology and excitement at Elecraft. (Interesting look at the history of Elecraft. The main presentation is up to 52:45. Q&A lasts until 1:07:30)
1:15:30 - QRO Magnetic Loop Antennas Rael Paster, M0RTP
2:15:00 - VHF propagation and weather Jim Bacon, G3YLA
3:15:00 - Having fun with HF contesting Olof Lundberg, G0CKV
4:16:00 - Ionoscatter on 50 and 144Mhz Palle Preben-Hansen, OZ1RH
5:15:00 - VHF/UHF radios for contesting and DX-ing Alwyn Seeds, G8DOH
6:15:00 - DSP: Underlying Concepts William Eustace, M0WJE
7:18:30 - Take your CW to the next level Bruce Pea, N9WKE

Saturday, October 10, 2020

EI DMR registrations at the end of Q3 2020


The above chart shows the number of DMR (Digital Mobile Radio) registrations by EI stations for every quarter up to the end of Q3 2020. The first DMR numbers were issued in 2015 and this peaked with a surge of interest in 2017. After that, the number of registrations per year slowed and dropped by about 30% to a lower level.

It now looks as if 2020 has seen a rebound in the registration numbers with the numbers at the end of Q3 2020 already ahead of the total for 2019.

The first quarter of 2020 had 19 new registrations but 10 of these were for club call signs which will probably never be used. The second and third quarters were for individuals and show a renewed growth in interest and numbers. Even if the club calls are removed, it looks likely that 2020 will end up as the second highest year yet in terms of new DMR registrations.

As of the end of Q3 2020, a total of 229 DMR numbers were issued for EI calls. If the club calls and duplicates are removed then 192 individual EI stations have DMR numbers.

Thursday, October 8, 2020

Change of Irish Coast Guard Frequencies


This might be of interest to anyone who monitors or listens to traffic on the Marine VHF band.

The channels / frequencies for the Irish Coast Guard in the locations shown above are changing during the period of the 6th of October to the 14th of December 2020.

Video about EIRSAT-1: Ireland’s first satellite (NOT AMATEUR RADIO RELATED)

EIRSAT-1 is Ireland’s first satellite and a team of students in University College Dublin (UCD) are designing, building, testing and will launch this satellite as part of the European Space Agency (ESA) Fly Your Satellite! Programme.

EIRSAT-1 stands for the Educational Irish Research Satellite 1. It is a satellite about the size of a shoe box, called a CubeSat and will be controlled from a ground station on the roof of the UCD School of Physics and collect data from the three science experiments on-board.

The first experiment is a novel gamma-ray detector, GMOD, which is being developed in UCD. GMOD will detect gamma-rays from both cosmic and atmospheric phenomena. 

The second experiment, EMOD, consists of a payload developed with Irish company, ENBIO Ltd., to monitor the in-flight performance of their thermal spacecraft treatments, SolarWhite and SolarBlack. 

The third experiment, Wave Based Control (WBC), is a novel attitude control algorithm, developed in the UCD School of Mechanical and Materials Engineering, which will be tested for the first time in space on EIRSAT-1.

The satellite was due o be delivered to the European Space Agency (ESA) in 2020 but this will probably be delayed due to the COVID-19 pandemic. Once launched, it is expected to last 6 to 12 months.

The video below gives a good overview of the project...

Some RF info...

On-board Communications: The on-board CMC (Common Mode Current) transceiver is the space-qualified CPUT VUTRX transceiver supplied by ClydeSpace. The communications system uses UHF downlink (430-440 MHz) and VHF uplink (140-150 MHz) bands. The transceiver provides 9600 baud downlink and 1200 baud uplink, and implements a GMSK downlink and AFSK uplink configuration. The AX.25 protocol is used for uplink packets, while a CCSDS convolutional encoder may be used for downlink. 

ADM (Antenna Deployment Module): EIRSAT-1 will use a custom ADM designed and built at UCD which will be mounted on the -Z end of the satellite deploys two dipole antennas, one for UHF downlink and one for VHF uplink. Both dipoles are composed of two tape spring antenna elements, deployed from opposite sides of the module, as seen in many previous and COTS antenna designs. The elements are 5 mm wide, made from a Copper Beryllium alloy and attached to spring loaded doors at each side of the module. They are coiled inside the ADM before deployment, within the 7 x 100 x 100 mm overall dimensions of the module. When EIRSAT-1 is clear of the CubeSat deployer the ADM will activate a burn wire release mechanism allowing the module doors to open and the elements to uncoil into their operational positions and stay in that configuration for the remainder of the mission.

Wednesday, October 7, 2020

Radio amateurs in the USA to lose the 3.4 GHz microwave band


In a ruling issued on the 2nd of October 2020, the Federal Communications Commission (FCC) in the USA announced that the amateur radio service is going to lose access to the 3.4 GHz microwave band. It is proposed that the spectrum from 3.3 to 3.55 GHz be cleared for 5G networks.

Up to now, radio amateurs in the US had a secondary allocation from 3.3 to 3.5 GHz based on a non-interference basis to primary users. The FCC have now proposed clearing 3.4 to 3.5 GHz in the short term and 3.3 to 3.4 GHz at a later date.

Excerpt from the ruling regarding the amateur allocation...

Tuesday, October 6, 2020

The ADIF format now includes the new 5m & 8m bands


Amateur Data Interchange Format (ADIF) is an open standard for the exchange of data between various amateur radio software packages from different vendors. For example, it allows for the import and export of data between various logbook programmes.

In the most recent edition updated on the 2nd of September 2020, the new 5-metre (60 MHz) and 8-metre (40 MHz) bands were added.

I.C. Changes from Previous Version
These changes from the previous version may necessitate application code or data changes:
Addition of the FST4 submode to the MFSK mode in the Mode and Submode Enumerations.
Addition of the 5m and 8m bands to the Band Enumeration.
Addition of ARRL-10-GHZ and WW-DIGI to the Contest-ID Enumeration.
(Released ADIF Version 3.1.1, updated 2020/09/02)

While this in itself is a small step, it is part of the process of having 5m & 8m accepted as new amateur radio bands.

(Thanks to Gintas, LY2YR for the heads up on this)


Monday, October 5, 2020

EI Digital Repeater Network on 2m & 70cms - Q4 2020

The amateur radio digital network of repeaters on the 2m & 70cms bands in Ireland is gradually changing and evolving and it is sometime hard to keep track of all the changes.

Steve Wright, EI5DD has very kindly put together an 'EI Digital Network Data Card' which makes things easier to follow.

The list of frequencies is shown below...

The one obvious gap in the EI Network is the lack of a digital repeater or gateway covering the Dublin area. It's an odd situation to be in as it might be expected that any new digital network would start in the capital Dublin and then spread out. It seems as if the opposite is happening.

For more information about amateur radio digital networks in Ireland, see this previous post.

Saturday, October 3, 2020

Successful 5.6 GHz ATV test in Cork Harbour

As part of the ongoing Cork VHF Group nets on Tuesday evenings, we hold an experimental night whenever there is a fifth Tuesday in the month. On a previous evening, we experimented with sending and receiving Slow-Scan TV pictures on 2-metres FM using apps on Smartphones. For the fifth Tuesday of September 2020, the group experimented with Amateur TV signals at 5.6 GHz.

For the experiment, Jim, EI8GS went portable to the town of Cobh and set up his ATV gear to point at Don, EI8DJ in Crosshaven. After discovering that there was no reception through a glass patio window, Don took his gear outside and successfully received an ATV signal from Jim at 5.6 GHz. The distance of the path across Cork Harbour was 4.7 kms.

The photo above looks a bit crude but it's a screenshot from my PC from a Zoom meeting of a phone pointing at another screen! What it shows are the lights from the oil refinery at Whitegate in Cork Harbour and the small string of lights to the left is the village of Whitegate itself. The tests were done when it was dark so the picture would be more relevant and clearer if it was in daylight.

The lines in the foreground are in fact superimposed by the camera. The unit is supposed to be used as an aid for vehicles reversing and the lines show the 'safe' distance areas. In this case, it was used for sending an ATV signal across Cork Harbour!

The photo above shows what Jim, EI8GS was using in Cobh. He was located at a well known viewing point high above the town allowing a good line of sight path across to EI8DJ in Crosshaven.

Jim was using 0.6 watts output power into a 40cm dish with a dipole at the feed point. 

Next it was Jim's turn to try and receive an ATV signal from Don. The receiver module is shown above and a photo of the signal received by Jim in Cobh is shown below.

Don sent a number of different test cards and this is another screen shot...

The photo below shows the set-up as used by EI8DJ...

The grey box (top left) contained a Raspberry Pi Zero which generated the sequence of test cards. 

The module in the centre with the display is a portable screen that is used by drone pilots. It has its own 5.6 GHz receiver built in.

The top right box contains the 5.6 GHz transmitter module and the antenna mounted on the outside of the box is a 4 element Bi-Square with a reflective plate behind.

The photo above shows the box containing the transmitter module with a microwave relay on the left for switching from receive to transmit. The PCB in the background with the toroid is a voltage upconverter to generate 28 volts for the coil of the changeover relay.

The FM ATV signal from the transmitter has a measured output of 0.6 watts.

In conclusion... The purpose of this initial experiment was more of a proof of concept than anything else - i.e. could an ATV signal at 5.6 GHz be sent over a line of sight path and over a modest distance of about 5 kms. The answer was a conclusive yes!

The next steps the group are looking at is maybe to look at increasing the distance and exploring more paths.

About 20 years ago, there was a small but active group on 23cms (1.2 GHz) using ATV in the Cork area. Hopefully these new experiments might reignite some interest in the mode.