Monday, April 29, 2019

Example of Band 1 TV Tropo Signals at 66 MHz...

Someone left a comment on the blog about the early days of TV back in the 1960's and trying to receive signals from Wales in Ireland. Rather than just leave it as a comment, I turned it into a blog post as it shows the possibility of tropo propagation on the low VHF band around 60 MHz.

Band 1 TV
The first TV broadcasts in the UK used the 405 line system on Band 1 - 45 to 66 MHz. The last of these transmitters were turned off in January of 1985 in the UK.

This is an excerpt from Wikipedia about the 405-line service in Ireland to give the post some context...

Ireland
Ireland's use of the 405-line system began in 1961, with the launch of Telefís Éireann, but only extended to two main transmitters and their five relays, serving the east and north of the country. This was because many people in these areas already had 405-line sets for receiving UK broadcasts from Wales or Northern Ireland. Telefís Éireann's primary standard was 625-line; it began using this in the summer of 1962, more than two years before the UK had any 625-line channels.

The last 405-line relays, in County Donegal, were turned off in 1982; the main transmitters had been shut down in 1978 to free up frequencies for RTÉ 2.

https://en.wikipedia.org/wiki/405-line_television_system

Thanks to Desmond Walsh for providing some details about his experience of receiving TV transmissions at 66 MHz from a transmitter in Wales, a distance of roughly 300 kms.


"When I was much younger I lived in southeast Co Tipperary and was eager to get BBC TV from Wales ( before TE came on the air)


There were two possible channels , 4 and 5 (in the old 405 line +modulation with AM sound 3.5 MHz lower , from memory ) Channel 5 from Wenvoe (100KW) had a much higher erp than Haverfordwest Channel 4 (0.044KW).

So I obtained a 4 element yagi for ch5 (63 to 68 MHz ?) and braved going on the roof of the 2 storey house to erect it on the chimney. Definitely would not do it now !

Reception of course varied with different signal strengths but gave about 50% reception , up to a week at a time of tropospheric signals when high pressure was around.

An annoying QRM happened at times when the French 819 line system blotted out Wenvoe but that is tropospheric reception for you!.

Channel 8 HTV (St Hilary 100KW CH7?? Band 3) came later but suffered from overlap with RTE Ch F , Mt Leinster.

These cross-channel signals were stronger in the Waterford city area , 15 miles downstream of the River Suir.

Desmond Walsh"

Sunday, April 28, 2019

Sporadic-E on 28 MHz - Sun 28th Apr 2019

Like previous day, there was plenty of Sporadic-E about on 28 MHz on Sunday the 28th of April 2019. The band opened at about 07:30 UTC which seems a bit earlier than usual. The band also closed at about 14:00 UTC.

One thing I did notice was that one the Sporadic-E faded away, the propagation on the other HF bands like 17m, 15m and 12m really died as well. With the solar flux down around 70, the higher HF bands are very dependent on Sporadic-E for any propagation at the moment.

These are the FT8 signals heard on 28 MHz...


The propagation seemed a bit more southerly than previous days favouring the south of Germany, the north of Italy and Spain.

Only one double hop Sporadic-E signal was heard and that was in Ukraine.

There were some very weak signals later in the day but I didn't have the software running. South America? I can't be sure so I'll have to go with what I did hear for sure.

These are the beacons heard...
EI7GL 28205.0 DL0IGI/B 09:00 28 Apr IO51TUJN57MT Fed. Rep. of Germany
EI7GL 28227.1 IW3FZQ/B 08:56 28 Apr IO51TUJN55VF Italy
EI7GL 28257.8 DK0TEN/B 08:55 28 Apr IO51TUJN47NT Fed. Rep. of Germany
EI7GL 28285.0 DB0MFI/B 08:53 28 Apr IO51TUJN58HW Fed. Rep. of Germany

A list of 200 or so stations heard on FT8 on the 28 MHz band...

PSKReporter website passes 7 Billion reception reports


I noticed today (27th Apr 2019) that the PSKReporter website has just passed seven billion reception reports!

I can see from previous posts that I had that it passed four billion around the 21st of July 2018 and five billion around the 28th of November 2018.

The vast majority of those reports are of course FT8 and it just highlights once again how popular it is.

Saturday, April 27, 2019

Small opening on 28 MHz on Sat 27th Apr 2019

Saturday the 27th of April was a day when the 28 MHz band barely opened. It's easy to look at the map below and think it was a reasonable day but the vast majority of those signals were buried in the noise.



Looking at the PSKReporter website, the main Sporadic-E opening was over northern Europe centered on a region over the north of Germany and the south of Sweden. I could hear lots of weak signals and it certainly felt like I was on the edge of the opening.

In the afternoon, the only loud signals were from Iceland which were there for a few hours.

In the evening, the band opened to South America but the signals were really weak.

I listened several times during the day for beacons or other signals on the band but heard nothing.

These are the FT8 signals heard on 28 MHz...

The mysterious signal of KI5BLU on 28 MHz... 26th Apr 2019

Two days ago while listening to FT8 signals on 28 MHz, I heard the signal from KI5BLU in Texas... or so I thought.

On the 26th of April 2019, I saw the signal again while the band was open to South America. Note that the trace shows KI5BLU in Texas (locator square EM12). Note that I have Puerto Rico marked ...more later.


This is the traffic that I recorded on FT8 which shows KI5BLU working Ireland, Wales, England and Germany on 28 MHz...
160630  -1 -0.1 1058 ~  EI8GS KI5BLU EM12
160645  16 -0.3 1224 ~  KI5BLU EI8GS -01
160700  -2 -0.1 1056 ~  EI8GS KI5BLU R-11
160715  17 -0.3 1224 ~  KI5BLU EI8GS RR73
160730   1 -0.1 1055 ~  EI8GS KI5BLU 73
160930 -23 -0.1 1431 ~  KI5BLU MW0PPM R+03
161000 -18 -0.1 1431 ~  KI5BLU MW0PPM 73
161530 -14  0.1 1837 ~  KI5BLU G3ZQH IO92
161630 -12  0.1 1835 ~  KI5BLU G3ZQH R-01
161700 -14  0.1 1838 ~  KI5BLU G3ZQH R-03
161730 -15  0.1 1838 ~  KI5BLU G3ZQH R-03
161800 -15  0.1 1838 ~  KI5BLU G3ZQH 73
163645  -7  0.1  924 ~  DK4CF KI5BLU EM12
164400  -7  0.1  754 ~  <...> KI5BLU EM12

Suspicious...
If this was 14 MHz or even 21 MHz, I would have thought nothing of it. But this was April at the bottom of the sunspot cycle. East-West multi-hop Sporadic-E from Ireland to Texas on 28 MHz would be unusual this early in the season.

I then checked on PSKReporter to see who was hearing KI5BLU over a three hour period...


I then selected several of those... AM70E in Spain, G4HZW, G0LUJ, 2E0XXO, G8IXN and G7KFQ in England, MU0WLV in Guernsey, EI8GS in Ireland and F5OIH in France. I then checked what they had heard over a six hour period.

All nine stations as well as myself had heard KI5BLU but had not heard a single other station on FT8 on 28 MHz from the USA.

It's safe to say that KI5BLU was not transmitting from EM12 in Texas.

Initially I thought he was using a remote station as suggested by his QRZ page.... " Elecraft K3-mini for remotehamradio.com"

After a second search on Google, I found this...
KP4/KI5BLU - Palmas - Puerto Rico 04-22-2019
Thomas, KI5BLU will be active as KP4/KI5BLU from Palmas, Puerto Rico, IOTA NA - 099.
He will operate on HF Bands. QSL via KI5BLU, LOTW, eQSL.
Link

This would certainly tie in with the propagation paths that would seem likely to Europe on 28 MHz at the time. The problem is that he is giving out his locator on FT8 of where he lives in Texas rather than where he is in Puerto Rico. He was also not using the KP4 prefix.

This is what confuses people into believing the band is open to the USA when it's obviously not.

RTE radio service on 252 kHz to be extended


The RTE radio transmitter on 252 kHz on the long wave band has been flagged for closure for many years as there is adequate coverage on the FM VHF band around Ireland.

A sizable Irish diaspora in Britain however campaigned for the service to continue as many elderly people don't have internet access.

Located near Tullamore, it is one of the few radio stations transmitting on the long wave band. It does however suffer from a lot of interference from an Algerian radio station operating on the same frequency.



According to an Irish Times article in 2017, the service had been extended to 2019.

It now looks as if the mast is going to be upgraded and it will continue for another two years at least.

See the statement below dated Thurs 25th April 2019

More Sporadic-E on 28 MHz... Fri 26th Apr 2019

For the third day on a row, there was another good Sporadic-E opening on 28 MHz. It was perhaps a little bit more patchy than previous days but there was a very good opening to South America.

This is the world map of the FT8 signals heard on 28 MHz on Friday 26th of April 2019.


The station KI5BLU shown in Texas was almost certainly not there and was giving out the wrong locator. See other post.

The opening lasted from about 09:30 UTC to as late as 22:30 UTC and the band was pretty much open for all of that time.

During the day, the coverage was more patchy than previous days. It did open to the south towards Spain but it wasn't great. It seemed much better towards the east for most of the day.

These are the beacons heard...
EI7GL 28271.0 OZ7IGY/B 15:55 26 Apr IO51TUJO55WM Denmark
EI7GL 28215.7 SR5TDM/B 14:19 26 Apr IO51TUKO01KX Poland
EI7GL 28279.0 DB0UM/B 14:14 26 Apr IO51TUJO73CE Fed. Rep. of Germany
EI7GL 28235.1 OY6BEC/B 13:59 26 Apr IO51TUIP62OA Faroe Islands
EI7GL 28245.3 DB0TEN/B 12:15 26 Apr IO51TUJO42UV Fed. Rep. of Germany
EI7GL 28269.0 SV6DBG/B 12:00 26 Apr IO51TUKM09KQ Greece
EI7GL 28251.1 ED4YAK/B 11:57 26 Apr IO51TUIN80FK Spain 
EI7GL 28227.1 IW3FZQ/B 11:55 26 Apr IO51TUJN55VF Italy

The beacon in Greece was double hop.

This is a closer look of the European stations heard on FT8 on 28 MHz...


Note the yellow line showing the rough limit of one Sporadic-E hop from my location.

There was some small amount of double hop into Greece, Ukraine and Russia. The suprise opening though was towards South America and the Carribbeean.

A list of stations heard on FT8 is shown below with those over one hop distance shown in bold...

Friday, April 26, 2019

Another big Sporadic-E opening on 28 MHz - Thurs 25th April 2019

There was another big Sporadic-E opening on 10-metres on Thursday the 25th of April 2019 and the band was pretty much open all the time from 08:30 UTC to 21:00 UTC.

It was pretty similar to the opening on the 24th of April except there seemed to be a bit more double hop Sporadic-E. These are the signals heard on FT8 on 28 MHz...


I have included a yellow dotted line on the map to show the extent of one hop Sporadic-E from my location on the south coast of Ireland.

As you can see, there didn't seem to be any double hop in the direction of the Baltic states of Estonis, Latvia and Lithuania. Further south though, there was double hop into the Ukraine, Russia, Romaniam Bulgaria, Greece, Turkey, Israel and Egypt.

I heard one lone signal from South America although I know others in the UK heard a lot more from there. I have a large hill to my south-west which blocks low angle signals from that direction.

These are the signals from Europe in more detail. Look at the big numbers in Germany!


Germany at 1000 to 15000 kms is pretty much the ideal distance for Sporadic-E from Ireland.

Like the previous day, I missed an hour or so but I think I caught most of what was there to be heard. In total, I heard 1163 stations in 47 countries which is pretty remarkable if you consider that it's 28 MHz.

These are the beacons heard...
EI7GL 28210.7 DB0FKS/B 14:23 25 Apr IO51TUJN49IT Fed. Rep. of Germany
EI7GL 28265.1 DF0ANN/B 14:14 25 Apr IO51TUJN59PL Fed. Rep. of Germany
EI7GL 28271.0 OZ7IGY/B 14:12 25 Apr IO51TUJO55WM Denmark
EI7GL 28277.4 DM0AAB/B 14:10 25 Apr IO51TUJO54GH Fed. Rep. of Germany
EI7GL 28279.0 DB0UM/B 14:08 25 Apr IO51TUJO73CE Fed. Rep. of Germany
EI7GL 28188.0 OE3XAC/B 11:42 25 Apr IO51TUJN78SB Austria 
EI7GL 28227.1 IW3FZQ/B 10:50 25 Apr IO51TUJN55VF Italy
EI7GL 28205.0 DL0IGI/B 10:48 25 Apr IO51TUJN57MT Fed. Rep. of Germany

FT8 signals heard on 28 MHz on the 25th of April 2019. Double hop in bold.

Thursday, April 25, 2019

Big Sporadic-E opening on 28 MHz - Wed 24th April 2019

After a quiet week and a half, the 10-metre band burst into life on the 24th of April with an extensive Sporadic-E opening. This is the world map of what I heard on FT8...


There were a few unusual signals in there.... Israel, Burkina Faso, Mauritania, Trinidad and Texas! Also heard but not shown was a station in Cyprus.

That one from 'Texas' was a real surpise but see the explanation here.

The band seemed to open at about 10:30 UTC and lasted until about 22:00.

What was unusual was just how long the opening lasted and how extensive it was. Usually with Sporadic-E, the footprint of the opening moves around. With this one, the band just seemed to be open all over Europe.

I was in a mini pile up for the Spanish AM70 stations on CW and I could heard people all over Europe calling them. It took a bit of work to get through in the end which just goes to show how many people they were hearing at once.

This is the European map of what I heard on FT8...


The ones of interest here are those in Sicily, the end of Italy, in Crete and in Greece. These were all double hop Sporadic-E.

I wasn't listening on FT8 all day, just most of it. I probably missed maybe 1-2 hours made up of small breaks. There were probably a few extra that I could have added if I was on FT8 all day.

These are the beacons heard...

EI7GL 28277.4 DM0AAB/B 19:53 24 Apr IO51TUJO54GH Fed. Rep. of Germany
EI7GL 28270.8 OZ7IGY/B 19:48 24 Apr IO51TUJO55WM Denmark
EI7GL 28298.1 SK7GH/B 19:11 24 Apr IO51TUJO77BF Sweden
EI7GL 28257.8 DK0TEN/B 19:08 24 Apr IO51TUJN47NT Fed. Rep. of Germany
EI7GL 28237.5 LA5TEN/B 19:06 24 Apr IO51TUJO59JP Norway
EI7GL 28207.1 ON0RY/B 19:03 24 Apr IO51TUJO20CK Belgium
EI7GL 28205.0 DL0IGI/B 19:01 24 Apr IO51TUJN57MT Fed. Rep. of Germany
EI7GL 28241.6 F5ZUU/B 17:20 24 Apr IO51TUJN24IL France
EI7GL 28235.1 OY6BEC/B 17:16 24 Apr IO51TUIP62 Faroe Islands
EI7GL 28218.0 IQ5MS/B 17:11 24 Apr IO51TUJN54AB Italy
EI7GL 28227.1 IW3FZQ/B 15:51 24 Apr IO51TUJN55VF Italy
EI7GL 28251.1 ED4YAK/B 11:45 24 Apr IO51TUIN80FK Spain

Always nice to hear the beacon from the Faroe Islands as it's a bit unusual.

Looking through my logbook, the contact with AM70S on CW was my first contact on 28 MHz since May 2018! I guess I listen a lot! :o)

FT8 stations heard on FT8 on 28 MHz on the 24th of April 2019...

Tuesday, April 23, 2019

Sporadic-E on 28 MHz - Tues 23rd April 2019

There were a few weak Sporadic-E signals today on 28 MHz. Now nine days since the last decent opening.

The one notable signal was that from EA8WU in the Canary Islands at 20:25 UTC and well after sunset. I'm assuming it was double hop Sporadic-E?


Txmtr Band Mode Distance Time (UTC)
EA8WU 10m FT8 2704 km 20:25:15
F5OHM 10m FT8 919 km 16:53:00
F5CUN 10m FT8 1109 km 16:31:44
MU0FAL 10m FT8 488 km 16:29:44
EA7DT 10m FT8 1715 km 16:26:31
G0OYQ 10m FT8 579 km 13:14:29
PD1DL 10m FT8 921 km 13:08:18
PE5O 10m FT8 879 km 12:34:15
DO3FRH 10m FT8 1100 km 11:46:30
PD7RB 10m FT8 868 km 11:46:30
G4YBI 10m FT8 592 km 11:08:18
M0SSK 10m FT8 608 km 10:17:44
OM5CM 10m FT8 1934 km 09:55:14
DL1KFL 10m FT8 1096 km 07:42:14

On another note, the solar flux is down at 68 today which is about as low as it can go.

New FT4 protocol announced for Digital Contesting

On the 22nd of April 2019, a PDF document was released outlining the new FT4 Protocol for Digital Contesting. Link.... http://physics.princeton.edu/pulsar/k1jt/FT4_Protocol.pdf

Key points...

1) Transmissions last for 4.48 seconds as compared to 12.64 s for FT8.

2) Works at about the same speed as RTTY for contesting.

3) For a rough comparison with RTTY, it was noted that in simulated mid-latitude moderate conditions RTTY has been shown to yield character error rates less than 10% only when SNR exceeds –1 to +4 dB, depending on the software modem in use. FT4 offers a sensitivity advantage of about 10 dB over RTTY.


4) As many as 50 stations can operate in a 3 or 4 kHz passband with little interference, even when signal strengths differ by as much as 60 dB.

5) July 15th 2019: General Availability (GA) release of WSJT-X 2.1.0 and FT4.

From the document..."FT4 is a special-purpose mode designed for rapid-fire contest QSOs. It serves this purpose very effectively, but like FT8 the mode is not useful for more extensive conversations. FT4 uses much less bandwidth than RTTY and provides reliable decoding at much lower signal levels. Stations using low power and compromise antennas can participate effectively in a contest using FT4."

Thoughts... 
It will be interesting to see how this develops and what impact it will have. Will it help kill off RTTY? Will it be used outside of contests?

The software can be downloaded here... http://physics.princeton.edu/pulsar/k1jt/wsjtx.html

Update... See this video presentation about FT4 from Joe Taylor K1JT. The piece about FT4 starts around 14 mins...

New 434 MHz to 2.4 GHz Transmit Converter

The new OSCAR 100 satellite in geostationary orbit has a downlink in the 10 GHz band and an uplink at 2.4 GHz.

I was looking through the most recent edition of the Dutch Kingdom Amateur Radio Society  magazine and I noticed this transmit upconverter...


The price seems pretty modest for what it does although I don't know anything about its performance.

From what I understand, something like 2 watts into a 2.5-3 metre dish or 10-20 watts for a 1-1.5 metre dish is required for an SSB signal for the uplink at 2.4 GHz.

For more information, go to http://www.dxpatrol.pt/

Monday, April 22, 2019

Sporadic-E conditions on 28 MHz - Mon 22nd Apr 2019

It's been eight days since the last proper Sporadic-E opening on 28 MHz on Sunday the 15th of April. The conditions on Monday the 22nd of April 2019 was pretty similar to previous days with a modest number of stations heard...


G0OYQ 10m FT8 579 km 15:10:02
DL1REM 10m FT8 1071 km 13:40:33
PD5FK 10m FT8 1045 km 11:52:29
PD1DL 10m FT8 921 km 11:51:59
OM5CM 10m FT8 1934 km 11:46:29
DG5TF 10m FT8 1407 km 11:45:14
F4DJK 10m FT8 1051 km 11:44:14
DO9LC 10m FT8 1039 km 11:43:00
DO9REF 10m FT8 1121 km 11:18:45
G8UBJ 10m FT8 559 km 11:13:30
MU0WLV 10m FT8 488 km 11:00:14
DO3UW 10m FT8 1044 km 10:57:45
DH2DAM 10m FT8 1082 km 10:57:16
DK0MA 10m FT8 1037 km 10:36:31
PE5O 10m FT8 879 km 10:02:06
LA3QAA 10m FT8 1462 km 09:07:01

Sunday, April 21, 2019

Poor conditions on 28 MHz on Sun 21st Apr 2019

The last seven days of this week have been pretty poor on 28 MHz and I wouldn't consider any day to be good. That is in marked contrast to last week when there was reasonable Sporadic-E on five days out of seven.

My own date to watch is always the 23rd of April. It just seems to be a day when there is often an opening on 10m and 6m. This may have something to do with the fact that the Lyrid meteor shower peaks on the 22nd of April and that meteor dust is a vital component in the formation of Sporadic-E in the following days.

This is what was heard on FT8 on 28 Mhz on Sunday the 21st of April


CS7AKZ 10m FT8 1437 km 12:21:59
EI8GS 10m FT8 7 km 12:09:15
OZ1IKY 10m FT8 1433 km 10:47:14
DK0MA 10m FT8 1037 km 10:43:46
EA4WD 10m FT8 1447 km 10:11:14
OZ1PGB 10m FT8 1270 km 10:08:22

152700 -16 -0.3 1122 ~  CQ AM70C ... Special event station in Spain.

New IARU HF beacon list coordinator


For many years, Martin Harrison, G3USF has maintained the list of Worldwide HF Beacons. Martin has now stepped down as the IARU Region 1 HF Beacon Coordinator.

The official IARU HF beacon list will now be maintained by Dennis Green, ZS4BS.

The full list of HF beacons can be seen here... https://iaruhfbeacons.wordpress.com/

Saturday, April 20, 2019

Weak opening on 28 MHz - Sat 20th Apr 2019

Conditions on 28 MHz for the last two days have been poor although Saturday seems to have been the better day.

Friday 19th April 2019... I wasn't able to monitor 28 MHz on Friday the 19th of April but looking at the PSKReporter website and what some of the regulars in the UK heard, it seems like it was pretty dead.

Saturday 20th April 2019... There were a number of FT8 signals during the day although not a great amount. The signals were pretty weak as well.



FT8 stations heard...
IZ0EGA 10m FT8 1930 km 21:15:59
F8DBF 10m FT8 477 km 20:02:32
F4IAA 10m FT8 1016 km 18:43:45
IU0MBJ 10m FT8 1925 km 18:23:59
EA8EE 10m FT8 2733 km 18:13:59
9A7JCY 10m FT8 1943 km 16:43:44
F4GEN 10m FT8 1087 km 16:34:59
DO4OW 10m FT8 1288 km 16:16:14
IZ0PMP 10m FT8 1976 km 16:15:14
PA7EY 10m FT8 899 km 16:14:14
EA5HEN 10m FT8 1616 km 16:10:29
EA4LG 10m FT8 1329 km 16:08:14
F8ZW 10m FT8 1183 km 14:12:47
PA9MD 10m FT8 936 km 11:03:29
PD1DL 10m FT8 921 km 11:02:44
EA1JAZ 10m FT8 1131 km 09:28:45

The most interesting signal was probably that of EA8EE in the Canary Islands at 2733 kms. It was most likely double hop Sporadic-E.

Looking at the PSKReporter website, it looks as if some stations in the UK were hearing South America but there was nothing here.

Friday, April 19, 2019

Another quiet day on 28 MHz... Thurs 18th April 2019

Even though I wasn't able to listen all day, I was still monitoring on and off for most of the daylight hours. This is what I heard on FT8...


F5RRS 10m FT8 1251 km 17:43:01
G4SWR 10m FT8 446 km 14:14:48
G4YBI 10m FT8 592 km 12:57:44
HA7XL 10m FT8 2034 km 12:55:14
DJ8QX 10m FT8 1058 km 11:40:59
CS7AKZ 10m FT8 1437 km 10:32:44

Looking at the logs of regulars on the band like G3XBM, GM4WJA and G0OYQ, it seems as if it was pretty dead all day.

Thursday, April 18, 2019

Quiet for a third day in a row on 28 MHz - Wed 17th Apr 2019

In marked contrast to last week, this week seems to be very quiet on 28 MHz with very little Sporadic-E about. This is the third day in a row with hardly anything heard.


Stations heard on FT8...
IW3QBN 10m FT8 1757 km 12:45:17
GI4SNA 10m FT8 334 km 11:23:59
G0OYQ 10m FT8 579 km 11:22:00

Wednesday, April 17, 2019

Another quiet day on 28 MHz - Tues 16th Apr 2019

Another quiet day on 28 MHz with just a few weak signals on FT8.


DO2HEY 10m FT8 1355 km 17:07:59
OE7FMH 10m FT8 1493 km 15:01:29
S52EN 10m FT8 1803 km 14:55:29
9A2WB 10m FT8 1949 km 14:48:45
DO5OT 10m FT8 1515 km 11:10:04
IU0MBJ 10m FT8 1925 km 10:32:44
G0OYQ 10m FT8 579 km 10:01:29
DG1PU 10m FT8 1096 km 09:47:44

Tuesday, April 16, 2019

SIGMA antennas for 43 MHz

From what I can tell, there are two main companies making antennas for the Italian 43 MHz CB market... SIRIO and SIGMA ANTENNE.

At the moment, SIGMA have three models...

GP 43
This is a basic quarter wave ground plane. Note that the gain is quoted as 2.5 dB but that is probably dBi as opposed to dBd.




BALCONY 43
This is very much a compromise antenna and is aimed at those with restricted space. It is probably slightly directional in the direction of the small radials.


TURBO 43
This is the five-eight wave ground plane and is made for 43 MHz. It's not obvious if there is enough tubing for it to made long enough to get down to 41 MHz.





The 1:1.5 VSWR bandwidth is claimed to be 1.64 MHz at 43.440 MHz.

At the slightly lower frequency of 42.0 MHz, it might be roughly 1.6 MHz which is pretty similar to the SIRIO model with 1.4 MHz bandwidth.

I suspect that like the SIRIO, the smaller GP43 might be better in terms of surviving high winds and for general listening around the low part of the VHF spectrum (30-50 MHz).