New DMR repeater EI7FXD now operational in Cork - Dec 2020

The good news radio wise locally is that a new DMR repeater on 70 cms is now on air near Cork City in Ireland. It is co-sited with the existing EI7FXR analogue FM repeater at Farmers Cross near Cork Airport.

The callsign of the new digital repeater is EI7FXD and it has an output frequency on 430.250 MHz The input is 9 MHz higher on 439.250 MHz. This configuration is usually designated as DVU-R20.

The colour code is 1.

The Brandmeister ID of the repeater is 272015 should anyone wish to monitor the Brandmeister dashboard and hoseline.

Info from the Southern Ireland Repeater Group - DMR repeater for Cork City

A new 70cms DMR repeater was installed at Farmer's Cross near Cork city on Monday December 21st to provide DMR coverage to Cork City and surrounding areas. The set up consists of a Motorola DR-3000 repeater and the antenna is a CAT-C440 @ approx 50ft. It's the fourth digital repeater set up by the Southern Ireland Repeater Group and will complement our other three digital installations located at West Waterford, Waterford City and Mt. Leinster.

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.

Info about EI7FXD - the new DMR repeater in Cork on 70 cms

As outlined in a previous post, a new DMR repeater on 70 cms should be on air near Cork City in the next few week. It will be co-sited with the existing EI7FXR analogue FM repeater at Farmers Cross near Cork Airport.

COMREG has issued a licence call EI7FXD for the new DMR repeater with an output frequency on 430.250 MHz The input is 9 MHz higher on 439.250 MHz. This configuration is usually designated as DVU-R20.

The colour code will be 1.

The Brandmeister ID of the repeater will be 272015 should anyone wish to monitor the Brandmeister dashboard and hoseline, when it becomes active.

EI7FXD Coverage... The map below shows the approximate coverage out to about 60 kms.

A lot of the more distant coverage in Green is just the tops of hills so it's probably more appropriate to look at the close in coverage.

Some points...

• The Farmers Cross site overlooks Cork City so there should be saturation coverage there. Anyone with a DMR handheld should be able to access it.
• Anywhere in the shadow of hills is likely to have problems on 70cms. e.g Blarney, Inishannon, Bandon, Mallow, Fermoy, Glanmire & Passage West.
• The coverage on the N25 to the east should be good as far as the Youghal by-pass. After that, there is coverage from the Clashmore repeater EI7CDD.
• Coverage on the M8 motorway to Dublin is good until Watergrasshill. Once you crest the hill, coverage may be a problem.
• The same applies on the N20 north to Mallow. Coverage ends just north of Rathduff.
• On the N22 to the west, there should be good coverage until Lissarda. After that, screening from hills will be an issue.

It is expected that the new repeater will be on air before the end of 2020.

Noctilucent clouds visible from Cork... Sat 7th July 2018

I took this photo of noctilucent clouds from my house in Cork on the south coast of Ireland at about 23:08 UTC on Sat 7th July 2018. This was just after midnight local summer time and about 130 minutes after sunset.

To the naked eye, they looked a bit like a bright cloud on the horizon and a 5 second exposure on the camera was needed to bring out the detail shown above.

My location is just below 52 degrees north so they would certainly have been visible by anyone further north. I could still see them faintly at about 00:00 UTC which was 1am local time, roughly 3 hours after sunset.

Noctilucent clouds exist at a height of about 80 kms above the earths surface, way above where normal clouds exist. Some propose that they may have a bearing on VHF propagation on paths near the poles... example... Europe to Japan on 50 MHz.

Long distance reception of a Spanish station on Medium Wave during daylight hours

Since I did a previous scan of the Medium Wave band in March, I have found several other very weak signals buried in the noise. One of these however is just about audible and can be heard in the middle of the day. I built a very basic loop aerial with some wire would around a cardboard box (30 x 45 cms) and tuned it with a variable capacitor. The result was that I can now ID two of the signals.

The signal on 855 kHz was Radio Nacional 50kw transmitter near Santander on the north coast of Spain, a distance of 992 kms or 616 miles. As can be seen from the map above, the path is almost completely over the ocean.

The aerial mast in Spain is just 300m or so from the water while I am 10 kms from the south coast of Ireland.

Radio mast near Santander

The other signal heard was from the test DRM transmitter of France Blue (8kw) on 1071 kHz near Brest, a distance of 500 kms or 310 miles.

I was wondering if the signals were possibly sky wave but I don't think so. They are there in the middle of the day every day and they are really steady like you might expect from a ground wave signal.

The radio used was a very basic Sony radio which was indoors. The loop aerial was just sitting on top of it.

992 kms seems like a remarkable distance for a ground wave signal on the medium band. There are plenty of much closer transmitters in the UK that I can't hear but the sea path to Spain seems to be making all the difference.

Night time scan of the Medium Wave band during April 2018

Following on from the day time scan of the Medium Wave band that I did back in March 2018, I have spent the last four weeks listening to the band at night. As before, I was using basic domestic radios at my house near Cork City on the south coast of Ireland.

I used the Silvercrest above which is a very basic and not so sensitive receiver to find a signal using the digital frequency readout. I would then use the more sensitive analogue Sony radio below to listen to the signal properly so I could identify it.

All of the signals were heard roughly 2-4 hours after sunset... approx 9pm to 1am local time. As you might expect, a lot more signals were heard during the hours of darkness and the full list is shown at the bottom of the page.

Some stats and figures....

a) Spain...A total of 109 different signals were heard and roughly 50% of those were from Spain. With the sea path to the south from Ireland, it was probably no suprise that the Spanish signals were so strong and numerous on the band.

b) Gaps....Tuning from 531 kHz to 1602 kHz, there were 35 channels where no signal was heard. It's not that there was no signal there, it's just that I couldn't hear one. In some cases, very strong signals tended to block out the adjacent channels.

c) Countries......The countries with the highest number of stations heard were Spain and the UK. The only signal heard from Eastern Europe was Radio Free Europe in Lithuania.

Italy...Some stations in the north-west of the country were heard at about 1400kms.
Algeria & Tunisia....Some high power stations were heard here along the north African coast at roughly 2000kms.
Portugal...Not too many from there.
France....Two signals....a monster 1 megawatt transmitter in the south east (~1500kms) and a digital DRM (Digital Radio Mondiale) transmitter from a site near Brest in Brittany (~500kms). The DRM signal could be heard as a hissing signal with no obvious pattern.

Belgium and the Netherlands...Not too many from there.

UK...The UK signals were by far the most interesting ones to hear. Many were buried in the noise and were only identified by listening to a particular song and then checking online to see what they were playing. I found that the online feeds were often 20-30 seconds behind the live radio signal.

Strong English Stations.....In terms of strong signals that could be listened to at night, these were the strong ones....
810 BBC Radio Scotland Westerglen??
882 BBC Radio Wales 100 Washford, Somerset, England
909 BBC Radio 5 Live 50 Clevedon, Somerset
1053 TalkSport 500 Droitwich, SW of Birmingham
1089 Talk Sport 2 Washford
1215 Absolute Radio 100 Washford, Somerset, England
1341 BBC Radio Ulster 100 Lisnagarvey, Belfast
1368 Manx Radio 20 Isle of Man

These were what I would call acceptable quality. Most of the others had too much interference with them to really listen to. I found it interesting in how on a band full of signals, I could only find seven English speaking stations that were worth listening to at night.

Interference...This biggest issue when trying to listen to some of the UK stations was the level of noise and interference. In many cases, there was a strong Spanish station on the same frequency and it was a case of rotating the radio and nulling out the Spanish station using the directional properties of the internal ferrite rod aerial. On one occasion, I could hear a Spanish station perfectly clear, I'd rotate the radio by 90 degrees and there was a perfectly clear English station on the same frequency.

Echo......Some of the UK and Spanish stations are using the same frequency multiple times in their respective countries. It probably sounds fine in the targeted service area but outside the service area, it results in a loud echo which makes it difficult to listen to.

2 second echo......This was an interesting one. There are two Smooth Radio transmitters listed on 1557 kHz.

1557 Smooth Radio 0.76 Northampton
1557 Smooth Radio 0.5 Southampton

It was impossible to identify which one I was hearing until I realised that I was actually hearing both of them with a two second delay between them! I'm not sure which one was first but I was certainly hearing both of them.

In conclusion...... It was interesting to do a detailed scan of the medium wave band to get a feel for what it is like currently. It is something I would have done many many years ago when I first started listening on radio.

What's pretty obvious is that a lot of stations in Central and Eastern Europe have now closed down their medium wave transmitters and have moved to VHF and digital. Looking at the various frequency listings and from my own observations, Spain and the UK are the two main countries in Europe that still use the medium wave band in a big way.

In the past, I would have listened to the band using a long wire aerial... great for bringing in the weak signals but it can't discriminate between stations. With so many Spanish stations on the band, it is really important to have a directional aerial so that some stations can be nulled out.

I was also suprised as to just how well the internal ferrite rod aerial in the Sony radio performed as it pulled in some of the lower power stations in the UK, especially the ones under 1kw. Prior to this, I would have assumed that I would need a long wire to pull in the low power ones but that doesn't seem to be the case.

The full list of station heard is below...

New website for the Duhallow Repeater Group

The Duhallow Repeater Group operates the 70cms repeater EI7SMR and the 4 metre Simplexer EI4SMR on Seefin in County Cork. I have put together a basic website for the group which gives some details about their systems.

You can visit it at http://duhallowrepeatergroup.blogspot.ie/