Friday, December 30, 2016

Old IRTS Newsletters now available...

The Irish Radio Transmitters Society is the national body representing radio amateurs in Ireland and they produce several newsletters for members throughout the year. While the newsletter isn't in the same league as say Radcom or QST, it is in many ways more relevant locally as it relates to Irish issues.

The IRTS have now put up an archive of old newsletters from 1988 to 2000 on their website.

Just go to their website... ... and look for the Publications Library.

Members of the IRTS also have access to all the IRTS newsletters from 2001 to the most current one as well. Taken together, the newsletters represent almost 30 years of the history of amateur radio in Ireland from the late 1980's.

The quality of the IRTS newsletter has changed greatly over the years. Before the late 80's, it was little more than some copies of typed text. With the advent of proper desk top publishing software, it improved hugely in the 90's before colour was finally introduced in mid 2008.

As of the end of 2016, some 27% of IRTS members opt for the PDF version which is available from the IRTS website. This does of course mean that fewer physical copies must be printed and posted out which results in a saving for the Society.

For me, I just prefer the digital version as it means I don't have a physical copy that I need to store or dispose of. I can also zoom in on diagrams and photos on the PDF document allowing me to see things in more detail, something which is of course impossible in the printed version.

I just upload the PDF version to my own private online Google Drive account where they are all available for easy access. This is a screenshot from that site...

Looking at the annual financial statements for the IRTS, roughly half of the Society's annual expenditure is spent on the publishing and posting of the newsletters to members. In an age of high speed broadband and smart phones, perhaps more IRTS members should consider opting for the electronic PDF version?

It seems to me an obvious way to help the IRTS to reduce its costs and help maintain the current membership fee.

Thursday, December 29, 2016

Good tropo conditions on 2m & 70cms...Wed 28th Dec 2016

The current high pressure system over the country resulted in some fine conditions on the VHF bands on Wed 28th December 2016. The local Cork repeater on 145.750 MHz seemed to be active with stations for most of the day while a few more distant repeaters were heard as well.

The opening seemed to favour the sea paths and the most consistent repeater all day was GB3WR at about 400kms. I heard this back in November but it was probably stronger this time around with a max signal of about 5/2 on my attic antenna.

A new one for me was hearing the F1ZEE repeater in Brittany also on 145.600 MHz. This has a very distinctive 'di dah dit' sound between overs with the 'dah' at a higher audio frequency compared to the two 'dits'.

The distance was 518kms which is the furthest 2m signal that I have heard so far in 2016. I was suprised to have heard it at all considering the antenna is in my attic.

According to QRZ, the repeater is at 300m ASL with a very good view towards EI.

Relais R0 de l'ARACA22  145,600Mhz en emission shift -600Khz , déclenchement 1750Hz
316m ASL installé depuis 1978 sur le site de Menez Kerespez , 22810 Plougonver, c'est le premier relais installé en bretagne. Antenne 6db COMET à 8m du sol. TX et RX Motorola MC Micro , 40w à l'emission. Responsable du site : F1LHC

It is also part of a larger repeater network in Brittany covering 10m, 6m, 2m and 70cms. Info here...

70cms.......There were two repeaters heard...GB3CH on 433.050MHz and GB3CM on 433.200MHz.

While GB3CH was just above the noise, GB3CM was pretty good at times and got up as high as 5/4. It was also the most consistent signal and was there for a lot of the day.

Other than listening, I had just one contact with GW0PLP in South-West Wales on 145 MHz FM. While Don had 90w into a 5/8 GP on his house, I had 50w into a Slim-Jim vertical in the attic. While we made a contact, the signals were at best 5/2 so it might be time to think about an outdoor antenna for 2017.

Thursday, December 22, 2016

Irish radio amateurs gain secondary allocation at 5.3MHz

The Irish Radio Transmitters Society have just announced that Irish radio amateurs can use the WRC-15 band of 5.3515 MHz to 5.3665 MHz with immediate effect. No application is necessary and the power limit is 15 watts. This is very good news for anyone with an interest in the 60 metre band.

The following was announced by Séan, EI7CD...

ComReg has just today published an amended version of the Amateur Station Guidelines in Document ComReg 09/45R2. The main revision is that the WRC-15 band of 5351.5 to 5366.5 kHz has been released with immediate effect on a secondary basis. No application or fee is necessary for this segment. The power is 15 watts PEP (12dBW) measured at the output of the transmitter or amplifier. All modes including digimodes may be used. The WRC-15 decision was for 15 watts EIRP and this will be taken up with ComReg. The Society recommends that USB be used for voice as has been the convention on this band and as used by the primary user and that the provisional IARU band plan be used:

5351.5 - 5354.0 kHz CW, Narrow band Modes
5354.0 - 5366.0 kHz All modes USB for voice
5366.0 - 5366.5 kHz weak signal narrow band modes.

This allocation does not affect the availability of the existing channels centred on 5280, 5300, 5332, 5348, 5400 and 5405 kHz. Special authorisation is still required for these channels at an annual licence fee of €30. Lets hope for some more activity on 5 MHz to help our case for an increased allocation.

Seán EI7CD IRTS/ ComReg Liaison

Up to now, Irish amateurs had to apply to use the spot frequencies of 5.280 MHz; 5.300 MHz; 5.332 MHz; 5.348MHz; 5.400 MHz and 5.405 MHz

The relevant document can be downloaded from the Comreg website HERE

For the moment, the Irish allocation is different from our neighbours in the UK. See HERE

Tuesday, December 20, 2016

UK Radio Spectrum Review Shows Increased Noise on VHF Bands

Ofcom is the organisation that is responsible for radio regulation in the UK and they have just released a document for a review of the UHF spectrum from 410 to 470 MHz. While most of the report covers the UHF spectrum as expected, they do make a reference to the increase noise levels on the lower VHF bands.

In the chart below, 'Band 1' covers 55 to 68 MHz while 'VHF Low' covers 68 to 87.5 MHz.

In the past, the assumed noise floor for radios was -116dBm and the planned coverage area of a radio system was -104dBm, i.e. 12 dB over the noise floor.

What Ofcom have found is that the actual noise floor is currently 12dB higher than previously thought. As a result, the planned service signal level must now be -92dBm.

This higher noise level is likely due to a variety of sources. Just think of the extra electrical power lines, increased use of switch mode power supplies in electrical equipment and the vast multitude of computer and IT systems. Taken all together, they result in a large increase in electrical noise especially in urban areas.

What this means for amateur radio is that bands like 4 metres (70 MHz) and 6 metres (50 MHz) are likely to be much noisier than they used to be in the past. Higher VHF and UHF bands are not effected as badly. It's likely that the extra noise levels also extend down to the higher HF frequencies like 14 to 28 MHz as well.

This higher noise floor as announced by Ofcom is in contrast to what was said by Comreg, the Irish licensing authority. In response to a submission by the Irish Radio Transmitters Society, they said the following in a report published in mid-2016....

2:17 ComReg notes that no evidence was provided by the IRTS to support its assertion that the noise floor is increasing and, further, ComReg observes that its monitoring activities do not indicate a significant increase in the noise floor on the whole;

Perhaps the noise levels in the Ofcom report are based on the very large urban areas in the UK but it's hard to imagine that the noise levels haven't increased substantially in the various Irish cities and towns in the last 20 years.

1) Ofcom Strategic Reeview of UHF Band 1 and 2 410 to 470 MHz
2) Comreg Radio Spectrum Management Strategy 2016 to 2018

Wednesday, December 14, 2016

Opening to the Indian Ocean on 28 MHz...Wed 14th Dec 2016

Wednesday the 24th of December was another one of those days where the 28 MHz band seemed completely dead but early in the morning, I received 3 separate transmissions on WSPR from FR1GZ on Reunion Island in the Indian Ocean.

It's almost as if the North-South path is there on a lot of days but there just aren't any stations there to exploit it.

The Solar flux is down around 72 and the K index is a 1.

Monday, December 12, 2016

Proposed changes to the 70 MHz Band in Ireland

This is the current IARU Region 1 band plan for 70 MHz band...

The Irish allocation is from 70.125 to 70.450 MHz while the British one is from 70.0 to 70.5 MHz.

What it has meant is that the UK calling frequency of 70.450 MHz is actually on the limit of the Irish band. If any EI station were to transmit there on FM then their side bands would be outside the Irish allocation.

The most recent newsletter from the Irish Radio Transmitters Society carried details on submissions that had been made to Comreg, the Irish licensing authority. While many of the submissions were declined, it was obvious that Comreg was using European Common Allocations as their guide. i.e. if the European agreements said something about the amateur radio service then that's what they were likely to implement.

As regards to the 70 MHz / 4 metre band, they are guided by footnote ECA9 in the CEPT European Table of Frequency Allocations.

This is what the International Amateur Radio Union (IARU) said about ECA9 / EU9...

The 70MHz band is increasingly recognised as being appropriate for amateur allocations. In the CEPT area this progress is now recognised in the European Table of Frequency Allocations by Footnote EU9 which states:
EU9: CEPT administrations may authorise all or parts of the band 69.9-70.5 MHz to the amateur
service on a secondary basis. In addition it is worth noting that there is some experimental access on a national basis in the range 69.90 - 70.0MHz in cases where 70MHz is not available.

In response to the IRTS proposal, Comreg said the following about 70 MHz...

"Comreg's work plan for radio amateur services is to make available the following bands:
. the 30-49 MHz and the 54 - 69.9 MHz and 69.9 - 70.125 bands to facilitate propagation beacons, digital amateur television repeaters and to align current allocations with those in the European Common Allocation Table: and 
. the 70.45 - 7-.50 MHz band to align it with the European Common Allocation Table.

So it looks as if they will be extending the Irish allocation so that it will cover 69.900 to 70.500 MHz. This is likely to be implemented soon...perhaps early 2017???

This is how the new Irish allocation will look now compared to other countries...

As can be seen, Irish stations will now be able to work other countries simplex without having to resort to split frequency operation.

Overall, a very positive result!

Additional info : 
1) Region 1 Band Plan...
2) 70 MHz website...
3) Comreg document 16/19 (See Page 69)...
4) CEPT European Allocation Table...

Sunday, December 11, 2016

Opening on 28 MHz...Sun 11th Dec 2016

With the ARRL 10 metre contest on this weekend, there was always going to be a chance that something would pop up. Even if there was a weak opening, there was a chance that contest stations running kilowatts of power might make it though.

I could see one of the big English stations spotted on the cluster and I could hear them weakly in the noise on SSB, probably as a result of some meteor scatter.

Around midday, I heard a weak cw contest station... GW5B or so I thought. Checked the cluster but no sign of that one. But ZW5B was spotted on that frequency and sure enough when I listened more carefully, that's what it was...ZW5B in Brazil! ...F2 propagation on 10m.

Within 20 minutes, more signals popped up on the band and some were pretty strong...up to s'7' at times. The following were worked on cw with 50 watts into the vertical...EA8AH & EA8CN in the Canary Islands and FY5KE in French Guyana. All of these were probably via F2 propagation. It seemed to be a pretty short opening...maybe an hour or two with the occasional strong signals for about 30 minutes.

Also heard were EA7ATX on SSB and the German beacon DL0IGI...both probably Sp-E.

I left the rig then on WSPR and heard the following weak signals via Sporadic-E during the afternoon on 28 MHz...

What was unusual was that I seemed to be hearing a lot more than the stations in England. Like yesterday, it was the fact that I was a lot further to the west than them which allowed me to hear the European stations shown above.

What I have also noticed about WSPR is that there are a lack of stations on 28 MHz. For example, today there were 4 from Spain, 3 from France, 3 from Italy and none from Poland. These are major European countries and very few were active. I was the only person in Ireland. Yet if you check say 14 MHz, there are plenty of stations there but it is questionable if a lot of those reports are of any real value to anyone.

Saturday, December 10, 2016

More weak Sporadic-E on 10m...Sat 10th Dec 2016

There was another weak Sporadic-E opening this afternoon on 28 MHz. Strange how there openings  always seems to be the afternoon and not in the morning?

No big signals, just weak WSPR signals buried in the noise.

The opening seemed a bit patchy as well. For some of the European stations, I was the only person hearing their WSPR transmissions as I am so far to the west in contrast to say the stations in the UK.

Weak opening on 28 MHz...Fri 9th Dec 2016

I left the rig listening on the WSPR frequency on 28 MHz on Friday and I heard the stations shown above. FY5KE in French Guyana was F2 while the European stations were via Sporadic-E.

All signals were weak and the DX cluster suggested that not a whole lot else was happening. I think to the casual observer, they would have thought that the band was completely dead all day.

The Solar Flux index is in the mid 70's at the moment.

Thursday, December 8, 2016

Dublin repeater EI2KPR heard

Last weekend, I heard one of the Dublin repeaters EI2PKR on 145.7625 MHz at a distance of almost 200kms. This is located on Kippure which is a 750m high mountain to the south of Dublin.

RX Freq: 145.7625 MHz
TX Freq: 145.1625 MHz
Offset: -600 kHz
CTCSS: 88.5 Hz
Locator: IO63UE

After looking at the path, it seems to thread its way through the mountains that are about 50-70kms away...A) Knockmealdowns B) Comeraghs C) Slievenamon.

The highest obstruction on the path was about 480m high although it may be that most of the signal came over the mountains with the lift conditions.

One interesting point is just how directional lifts can be. It's not a case of there being high pressure and all distant signals get stronger.

GB3PL in East Cornwall is on the exact same frequency. Last weekend, I was hearing EI2KPR with no sign of GB3PL. The previous weekend, it was the exact opposite with GB3PL being the only repeater on that frequency.

Tuesday, December 6, 2016

FY5KE worked on 10 metres

I had a listen to the 10 metre band late this afternoon and I noticed some weak cw beacons around 28.204 / 28.205 MHz. They were very weak but I could just make out the N3 callsign and the FN in the locators which meant the band was open to North America. Some F2 propagation at last!

I had a look on the DX Cluster and it was quiet enough. I noticed that FY5KE had been spotted on 28.030 MHz. When I listened, sure enough he was there but he was very weak. He was calling CQ a lot so it wasn't like he had a pile up.

I heard EI4KN call and work him with ease. Ronan is in Cloughjordan on the Tipperary / Offaly border, about 120kms to the north. That's a nice distance for a direct path on 10m. I don't believe it was backscatter as the band wasn't that good.

I had a look around the band and it was pretty quiet. Went back to 28.030 MHz and just left the rig there. After about 10 minutes, he came up out of the noise and I worked him first call with about 50 watts.

My first QSO on 28 MHz since I put the antenna up back in mid-November. It was also my first contact on 28 MHz since October 2012.

It was only later that I realised that FY5KE is actually at the Space Centre in French Guyana.

I had a look around the band and it seemed dead. I put the rig on WSPR and FY5KE popped up there as well.

It was hardly a huge opening but interesting all the same.

Sunday, December 4, 2016

New 70cms repeater in Co.Tipperary

A new 70cms repeater was installed on high ground near the town of Clonmel in Co.Tipperary on Sunday the 4th of December 2016.

Here are the basic details...

Repeater Callsign : EI7HXR
Output Frequency : 430.850 MHz
Input Frequency : 438.450 MHz
CTCSS code : 103.5 Hz
Power : 25 watts
Locator : IO62EH

The repeater is highly screened from the South by the Comeragh Mountains and Slievenamon casts a large shadow to the North.

This is the coverage to the East in more detail...

This is the coverage to the West....

Note that these maps are a guide only. If you are just outside the coverage area, you may be able to still hear it if you have a good antenna up high.

This repeater has been also linked to the Southern Ireland Repeater Network.

Reception reports to Hugh, EI2HI.

Additional info...
Tipperary Amateur Radio Group
Southern Ireland Repeater Network

Saturday, December 3, 2016

Digital Modes on the VHF bands in EI

Over the last few weeks, I have been reading up on the various digital radios on the VHF bands. It would seem as if there are three potential modes which could be a replacement for analogue FM.

1) Icom D-Star, 2) DPMR and 3) Yaesu System Fusion

While the digital radio network in the UK seems to be pretty well developed, it is still in its infancy in EI.

A recent news item from the IRTS outlined how the the Yaesu System Fusion was being introduced in Donegal and Limerick.

A key fact is that the Yaesu DR-1X repeater controller will work on both analogue FM and on the Yaesu C4FM digital system. This means that at worst, it will work away as an FM repeater even if no-one uses the digital system. It will receive digital signals and convert them to FM on the o/p so that everyone can hear them. e.g. Digital in, FM out. It can also relay whatever is on the input...i.e. FM in, FM out OR digital in, digital out.

It was mentioned in the news item that some people in the Limerick region have bought the following Yaesu radios...

There are some obvious issues with introducing this new system in EI...

1) As you can see, they're not cheap. Someone can buy an ordinary analogue FM rig for a lot less. A cheap Chinese FM handheld can be purchased for less than €50.

2) The level of activity on the existing FM network is pretty low. The Limerick repeater has very little traffic on it as it is so it's hard to justify buying an expensive radio.

It will be interesting to see how things develop. I suspect though that in Ireland, DPMR may well become the system of choice for those that want to experiment with digital as cheaper radios come on the market.

This video explains what the Yaesu Fusion System is all about....

This is a video of the new repeater in Donegal...

Thursday, December 1, 2016

Bandscan on 145MHz during Nov 2016

I have been scanning and listening on 145MHz for most of November 2016 so I now have a reasonable idea as to what the level of activity on the band is like. As expected, the level of local activity is very low and is mainly confined to mobile stations calling through the various repeaters.

The only real activity period is after the IRTS news broadcasts on Monday and Tuesday evenings.

This is a map of the repeaters that I have heard on 145 MHz under flat conditions...

These are the frequencies I have heard most activity on  while listening to 145 MHz FM. The set up was pretty modest with just a home made half wave vertical antenna. The signals in Purple are those heard under lift conditions.

Freq. Station
145.400 ... Used as a net frequency near Waterford city
145.450 ... Used as a net frequency in South Tipperary
145.475 ... Packet type signals from the Chinese Satellite Kaituo 1B. Norad ID 40912.
145.525 ... Used as a net frequency in Wexford
145.600 ... FM repeater. GB3WR nr Bristol. IO81PH. CTCSS F 94.8Hz.
145.6325 ... FM repeater. GB3DN. North Devon repeater. IO70UW. CTCSS 77Hz.
145.650 ... FM repeater. EI2DBR. Devil's Bit Repeater, Tipperary. IO62BU. Southern Ireland Repeater Network.
145.675 ... FM repeater. EI2HHR. Helvick Head Repeater. IO62EC. Southern Ireland Repeater Network.
145.675 ... FM repeater. EI2CCR. Clermont Carn Repeater, Co.Louth. IO64UB.
145.675 ... SSB on downlink from transponder on Chinese satellite XW-2A. Norad ID 40903.
145.6875 ... Digital repeater. No positive ID. Might be GB3WE? Weston Super Mare. IO81MH.
145.700 ... FM repeater. EI2TKR. Truskmore Repeater. Sligo. IO54TI. CTCSS 77 Hz.
145.700 ... FM repeater. GB3AR. Carmarthen Repeater. IO73VC. 110.9Hz.
145.725 ... FM repeater. EI2TAG. Tountinna, Tipperary. Limerick repeater. IO52TU.
145.725 ... Beacon on Chinese satellite XW-2B. Norad ID 40911.
145.725 ... FM repeater. GB3NC. North Cornwall repeater nr St.Austell. IO70OJ. CTCSS 77Hz.
145.750 ... FM repeater. EI2MGR. Mullaghanish, Co.Cork. IO51KX.
145.7625 ... FM repeater. GB3PL. East Cornwall. IO70VM. CTCSS 77Hz. ID is 'GB3PL Amateur Radio Repeater'.
145.775 ... FM repeater. GB3WW. West Wales repeater. IO81CP. CTCSS F 94.8 Hz. 
145.775 ... FM repeater. GB3WT. West Tyrone. IO64JQ. Nr Omagh. CTCSS 110.9Hz.

While this list is unique to my location, it should give a general guide as to what can be heard if you are living near Cork. You may well hear other repeaters but this is a good list to start with and it's a guide on where to listen.

Wednesday, November 30, 2016

CTCSS codes and frequencies

This post is for my own benefit as I want to put the CTCSS codes somewhere online that's easy to find.

CTCSS.....What is it? This is the description from Wikipedia...."In telecommunications, Continuous Tone-Coded Squelch System or CTCSS is a circuit that is used to reduce the annoyance of listening to other users on a shared two-way radio communications channel."

In more practical terms, it is a tone that you can't hear that is added to your transmission so that you can access a distant repeater. If you don't use the CTCSS tone then the repeater will ignore you. It should mean in theory that under lift conditions, you can open up one specific repeater as opposed to several at the same time.

The letters are used in the UK to ID the CTCSS tone required to access some repeaters.

Tuesday, November 29, 2016

GB3WR repeater heard on 145.600 MHz

This morning, I heard the GB3WR repeater on 145.600 MHz. It was pretty weak and was 4/1 at best but the CW id was clearly audible.

At just under 400kms, it is the furthest signal that I have heard this month. Considering I was using a home made vertical half-wave in the attic, I presume it would have been much stronger with say a beam outside.

Still though, it was interesting to hear a signal from that distance. The map above shows the locations and the key is of course the sea path.

Listening to the conversation this morning, the repeater antenna seems to be on a 200ft mast and the repeater site is at 1000ft above sea level on the Mendip Hills to the South-West of Bristol.

The repeater site is

Update 12:45pm: The repeater is still there in the noise. ID on CW is "GB3WR" and sometimes "GB3WR F". The repeater uses a CTCSS access tone of 94.8Hz which is tone 10 or 'F'. I presume the F in the ID is to tell people what the access tone is.

Update 2:45pm: GB3NC in Cornwall (298kms) was there as well at S'3'. CTCSS code 'C' which is 77Hz. GB3CM on 433.200MHz is in there as well. 
Update 9:30pm: Heard GB3WW near Swansea on 145.775MHz. Distance is 316kms. It gave out 'F' after the callsign ID which again ties in with the CTCSS code.

Sunday, November 27, 2016

Lift conditions on 2 metres...Sat 26th Nov 2016

I've been scanning and listening on a pretty regular basis on 145 MHz FM for the last two weeks so I am getting a good feel of what I can hear with the home brew Slim Jim vertical in the attic. On Saturday the 26th of Nov 2016, there was a reasonable lift and the following were heard on 145 MHz...

With the exception of MW0DEW, the rest were repeaters. Obviously most are on hills but it was interesting to see what could be heard with my current antenna. None were that strong but I could hear the CW identification every so often.

MW0DEW was a Welsh station I worked on 145.475MHz. He was using 30w into a vertical antenna just 4m above ground level. The distance was just short of 300kms, a nice distance for an indoor antenna.

Saturday, November 26, 2016

Three Eight Wave Ground Plane Antenna for 10 Metres

Over the years, I have collected many old magazine articles and it seems to be a waste to have them buried away in a folder. This one is for a 3/8 wave ground plane antenna for 28 MHz and hopefully it might encourage someone to experiment and build one.

The principle is pretty easy. A normal dipole in free space normally has a 72 Ohm feed point impedance. A quarter wave ground plane is half this...about 36 Ohms.

By extending the antenna from a quarter wave to a three-eight wave, the maximum current point moves from the base to further up the radiating element. This has the effect of lowering the angle of radiation which is a plus.

The longer three-eight wave antenna now has a reactive feed point (inductive) as it's too long. This is tuned out with a series capacitor and it should be able to get close to 50 Ohms.

This antenna would suit someone who can only put up a quarter wave ground plane for 10 metres and wants better performance.

The article from the March 1983 edition of Short Wave Magazine is shown below...

Friday, November 25, 2016

GB3CM heard on 70cms

25th Nov 2016...There seems to be a reasonable lift on the VHF bands today as there is a high pressure weather system over the country. I noticed it first late last night when I heard the West Tyrone repeater GB3WT in the noise on 145.775 MHz.

This morning, the Limerick repeater on 145.725 MHz which is normally S3 on my indoor antenna was up to S8 and I was able to have a QSO with  MM0RJJ and MI0ADX on it with just 5 watts.

Looking North from here this morning, I could see the inversion layer with the high pressure keeping the air trapped near the ground. It can be seen as that dark band on the horizon which is usually slightly pink/purple in colour and is in marked contrast to the clear air above....a classic sign of air trapped near the surface.

This inversion layer means good VHF conditions and it ties in with this tropo propagation map for this morning...

The biggest suprise this morning was hearing the GB3CM repeater in Wales on 70cms. It was up to s'8' at times and that is with a home made colinear antenna in the attic. The distance is about 286 kms, well in excess of the usual range for that repeater.

70cm (FM) UHF Repeater
94.8Hz CTCSS tone and the 'time out' is set to three and a half minutes
Operating on 433.200MHz output 434.800MHz input
Power 20w

As I don't have the 70cms rig programmed for that CTCSS, I didn't try to work through it. I'll have to dig out the manual again :o)

Additional info...
GB3CM...Website for the GB3CM repeater.

Thursday, November 24, 2016

Low Power Devices on 433 MHz

At the moment, I scan the 70cms band on a pretty regular basis and every so often, the radio will stop on  433.475 and 433.525 MHz. The signal sounds like a weak digital transmission and it's only there occasionally.

I thought perhaps it was due to an out of band signal and the receiver was being overloaded. Having said that, the Alinco 605E seems like a reasonable radio and the front end doesn't seem to be wide open like some of the handhelds.

After a bit of digging, I discovered that there is an allocation for low power device on the 70cms band. It's called LPD433...

This is the frequency chart which as you can see goes from 433 to 435 MHz.

I knew that some car key fobs and remote devices were using the band but I hadn't realised it was so extensive. Perhaps that is the reason behind the mystery signals?

What I didn't know was that in Europe, this allows licence free voice communications on 70cms.

"LPD hand-held radios are authorized for license-free voice communications use in most of Europe using analog frequency modulation (FM) as part of short range device regulations, with 25 kHz channel spacing, for a total of 69 channels."...from Wikipedia.

I noticed that Amazon are selling a dual 446 / 433 MHz radio as well...

Considering how easy it is to buy a radio, I wonder will there be more unlicenced operation on the 70cms band in future?

Tuesday, November 22, 2016

Southern Ireland Repeater Network...2m & 70cms

Since I returned to the radio, I have been listening to the 2m and 70cm bands. While the level of activity on FM seems pretty low, the repeater infrastructure on the bands is very impressive.

The largest of these is the Southern Ireland Repeater Network which links up multiple repeaters. i.e. a signal on one repeater appears on all the others.

The coverage is shown below....

2m Repeaters:

Callsign:   EI2DBR
Location:    Devil’s Bit, Co. Tipperary.
Locator:    IO62BU
Output:   145.650MHz
Input:   145.050MHz
Shift:   -0.6MHz
Access:   Carrier

Callsign:   EI2HHR
Location:    Helvick Head, Co. Waterford.
Locator:    IO62EB  
Output:   145.675MHz
Input:   145.075MHz
Shift:   -0.6MHz
Access:   Carrier

70cms Repeaters:

Callsign:   EI7MLR
Location:    Mt. Leinster, Co. Carlow.
Locator:    IO62OO
Output:   430.950MHz
Input:   438.550MHz
Shift:   +7.6MHz
Access:  156.7Hz

Callsign:   EI7WCR
Location:    Carrickphierish, Waterford City.
Locator:    IO62KG
Output:   433.275MHz
Input:   434.875MHz
Shift:   +1.6MHz
Access:   Carrier

Callsign:   EI7FXR
Location:    Farmers Cross, Cork City.
Locator:    IO51SU
Output:   430.900MHz
Input:   438.500MHz
Shift:   +7.6MHz
Access:   103.5Hz

Callsign:   EI7BWR
Location:    Bweeng, North Cork.
Locator:    IO52OB
Output:   430.875MHz
Input:   438.475MHz
Shift:   +7.6MHz
Access:   103.5Hz

One obvious problem is that one conversation can tie up multiple repeaters but it doesn't seem to an issue as the activity levels are pretty low.

It's certainly a big change from before when there were just simple stand alone repeaters on 145 MHz that didn't connect to anything else.

Additional info..
1) The Southern Ireland Repeater Network website can be seen here...
2) The repeater list on the IRTS website can be found here..

Sunday, November 20, 2016

GB3RAL on 28 MHz via Meteor Scatter

On Friday the 18th of November, I had the rig turned to 28.2150 MHz, the frequency of the GB3RAL 10 metre beacon in the UK.

I was using Spectrum Lab on the PC with the microphone resting on top of the HF easy way to monitor a frequency while working away on something else. If there is anything there buried in the noise, it will usually show up on the screen.

I've listened to this back in 2008 and found it hard to get a positive ID. It seemed to be just a carrier without any CW.

This time around, I got 'AL' on cw within about 20 minutes so I knew I was hearing it. There were plenty of pings over the space of an hour and then at about 10:28 UTC, I got this fine 4 minute burst...

Right hand side shows the audio freq in Hz.

The tone was easy to hear at times as it transmitted "GB3RAL IO91IN". It certainly wasn't a huge signal...maybe 419 at best but clear all the same.

I'd imagine it would have been really easy to make a contact on a digital mode like JT65.

It was only afterwards that I noticed that the Leonid meteor shower peaks on the 18th of November so perhaps it was due to one of those.

On a positive note, it's good that the new 10 metre vertical seems to be working well.

Saturday, November 19, 2016

Signals on 28 Mhz...Sat 19th Nov 2016

With the Solar Flux index down at 78, there isn't much in the way of F2 propagation at the moment. However, there was some Sporadic-E today.

In the morning, I heard the beacon on the Faroe Islands which is always interesting as it's to the North.

EI7GL-@ 28282.5 OK0EG/B 10:38 19 Nov JO70weIO51tu Czech Republic
EI7GL-@ 28237.4 LA5TEN/B 10:32 19 Nov JO59jpIO51tu Norway
EI7GL-@ 28235.0 OY6BEC/B 10:26 19 Nov IP62oaIO51tu Faroe Islands

I also left the rig on the WSPR frequency for a few hours and heard the following.....

It was one of the days where the casual observer might say the band was dead but there were weak signals there all the same. As you can see from the list, some of these were running less than 1 watt.

Interesting Sporadic-E conditions for this time of year. It also suggests that the new 10m vertical antenna is working just fine.

Friday, November 18, 2016

CB Vertical Half-Wave for 10 Metres

The long process of getting back on the air continues. I've put up antennas for 2m and 70cms in the attic of the house so at least now I have something that might be considered semi-permanent. If I go off the radio again, it's not such a big deal to get going again and the aerials won't get destroyed by the weather.

In the last week, I checked the Westflex 103 coax cable going to where the old CB vertical used to be. Using my old home brew power meter and my old Yaesu FT-290R, I established that the loss for the 20 metres or so of Westlex 103 was about 2dB at 145 MHz. This means that it should be well under 1dB at 28 MHz and that includes having a back to back SO239 connector in line. So the coaxial cable is working fine and shows no sign of water ingress.

About a fortnight ago, I purchased a CB half-wave vertical from Long Communications in Donegal. The model was a Venom which I believe may be from a company called Sigma.

Considering it was only €35 with an additional €12 for delivery, it's hard to say it is in any way expensive. In contrast to some of the verticals for the HF bands, it's incredibly cheap.

Some of the specs should be taken with a pinch of salt.

Power Handling...1000 watts.....I doubt it. 100 watts is fine but I'd have my doubts about anything close to 1000.

Gain...4.1dB.....Sounds great but it's a half-wave! 0dBd or 2.15 dBi at the most and that's if you ignore matching losses.

Frequency....26 to 28 MHz.... My tests shown below suggest that it won't be resonant anywhere near 26 MHz. Without an antenna tuner, I think 27.0 to 29.7 MHz would be part of the spectrum that the antenna could be adjusted to.

Construction and Assembly.......All the parts come in a small plastic bag which includes two U-Bolts, three screws, three washers, 3 nuts, 4 jubilee clips and a small plastic seal for the top of the antenna. All pretty obvious and the antenna can be assembled in about 10 minutes.

There are Blue marks on the aluminium sections to show how far each section should be inserted into each other.

This YouTube below from someone in the UK shows what it looks like out of the box including the Blue marks for adjustments.

One of my biggest fears was that the antenna would be really flimsy once it was constructed. To be honest, it looks fine. I can't really say the construction matches the cheap price, it seems fine.

Tuning...I mounted the antenna on a 4 metre pole and checked the VSWR with the internal meter on the Kenwood TS690. When I had the lengths adjusted to the Blue marks, the centre point seemed to be around 28.0 MHz. I then shortened the antenna so that the VSWR plot now looks like this.

Some observations and notes....

1) As I shortened the antenna the VSWR curve below the centre frequency seemed to match that above. As a result, I have inferred the plot below 28.0 MHz as I cannot transmit there.

2) The 1:1.5 VSWR bandwidth is 1.3 MHz which seems pretty good.

3) The top section of the antenna must be adjusted by 4 cms to move the centre frequency by 100 KHz. So in other words, if you wanted to move the centre frequency up by 300 KHz then you would make the antenna 12cms shorter.

4) If the length of the antenna was assembled to the Blue marks then the centre frequency was 28.0 MHz. This means the VSWR was at or below 1:1.5 from about 27.35 to 28.65 Mhz. This might be an issue for someone who wants to use the bottom end of 27 MHz as there wasn't much scope for making the antenna much longer. It should tune up fine with an antenna tuner but I'd guess most CB stations would be unlikely to have one.

5) My antenna was mounted at 4 metres above ground level. The VSWR and centre frequency may well change if the antenna was at different heights.

Performance.....Too early to say but I am hearing local Churches broadcasting at the top half of 27 MHz from about 50-60 kms away so it seems reasonable. It is certainly no worse than the old CB half wave I used to have.

Overall.......Time will tell if it survives the Winter gales but the mechanical construction seems reasonable. If I had it way above the house then I suspect it wouldn't last long. But at 4m, I would expect it to last the first winter anyway. Other than that, the performance seems as expected.

Thursday, November 10, 2016

QRM from a Chinese satellite on 145.725 MHz

After my four year absence from the radio, the main task now is just to get some of the gear working again. Over the last two weeks, I managed to locate the microphone for the 2m/70cm dual band rig and I have put up a vertical half-wave in the attic of the house. Not perfect but at least it gets me on the air again.

Even though the aerial is indoors, I can hear some signals from repeaters and simplex stations from about 100kms away. One of those is the Limerick repeater on R5 (145.725 MHz) which is just over 100kms to the North.

The signal is about S3-5 which means it's clear and easy to listen to but I'd probably need the full 50w to work through it.

I have also managed to get the rig set up to scan both 145 MHz and 433 MHz bands which lets me see who is about. The level of activity is pretty low so it spends a lot of time scanning.

I have noticed though that it sometimes stops on 145.725 MHz with the unmistakable sound of CW coming through. It's not CW on FM but I can hear the white noise on FM getting pulsed by a CW signal. Sure enough, when the repeater opens I can hear the CW beating with the signal and the sound of the CW frequency changing slowly....a sure sign of a satellite.

I came across this a few weeks back when I went looking for info on the Cornwall beacon on 50.042 MHz. I ended up watching a video for the AGM of their Beacon/Repeater you do :o)

During the presentation, someone mentioned that there was interference to their local repeater GB3NC on 145.725 MHz from a new Chinese satellite.

Sure enough when I heard the signal today, I looked up the N2YO satellite tracking website and it was out over the Atlantic and within range. If you want to see where it is at any time or to see when it might be visible, go to

It seems that a bunch of Chinese satellites were launched in September 2015 and their up links and down links are shown below....

As you can see, the XW-2B has a beacon on 145.725 MHz which is the one I was hearing. The image below shows what it looks like with some specs...

– Micro-satellite architecture
– Dimensions: 250Lx250Wx250H mm
– Mass: 9kg
– Stabilization: three-axis stabilization system with its +Y surface facing the earth
– Antenna: Deployable antenna, one 1/4λ monopole VHF antenna with max.0dBi gain is located at +Z side and one 1/4λ monopole UHF antenna with max.0dBi gain is located at –Z side, close to the each edge of satellite 
CW Telemetry Beacon: 50 mW, 22 wpm

Essentially it's a 25cm cube with 50mW into a quarter wave whip on 145 MHz. It's pretty amazing to hear it with just a half-wave vertical in the attic.

I presume a lot of others must have noticed this?