Category: TECHNICAL

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Solar Cycle 25 Producing Record High Sunspot Numbers

Record High Solar Cycle 25 Solar Maximum Sunspot Numbers Have Improved HF Propagation Since Mid-July and Possibly Bringing Worldwide 6 Meter F2 Propagation This Fall.

According to the NOAA Space Weather Prediction Centre (SWPC), Solar Cycle 25 likely reached its highest sunspot number yet of at least 299 on 8th August 2024.

The World Data Centre – Sunspot Index and Long-Term Solar Observations (SILSO) publishes near-real-time Estimated International Sunspot Number (EISN) reports based on its global network of reporting stations. Daily EISN reports during Solar Cycle 25 were consistently well below 200 until suddenly rising to 218 on 14th July and reaching 289 on July 18th, but then declining to 178 on 22nd July 2024.

While occasional brief daily EISN increases are not unusual during solar maximum, after only five days, the daily EISN suddenly rose to 212 on 27th July reaching a Solar Cycle 25 record high 297 on 8th August and remaining mostly well above 200 through this writing on 11th August. Daily EISN reports are likely to remain well above 200 during most days through late September and possibly much longer.

Since February 2002, worldwide 6-meter propagation has been mostly limited to sporadic occurrences of trans-equatorial propagation (TEP) near the equinox months and occasional sporadic-E propagation reaching many thousands of miles during June and July. Worldwide 6-meter F2 propagation may again occur — perhaps very frequently — starting in late October 2024 if daily EISN reports consistently remain well above 200.

More Information – http://www.sidc.be/SILSO/eisnplot and https://www.swpc.noaa.gov/news/solar-cycle-25-likely-reached-highest-sunspot-number-over-20-years

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FT-470 Repair – Colin GM6AWC

My experience with a faulty Yaesu FT-470 which was kindly gifted to me by another amateur may help someone else who owns an FT-470 2m/70cm dual band talkie that develops a similar problem.

When I initially tried out the talkie, I heard my TX on another radio, so it sounded like it was working, but in fact nobody else could hear me, not even a station just a couple of miles away.

I also noticed that RX was terrible as well and I could only hear very powerful signals, but even at that, it was with noise.

It transpired that the deaf RX and TX not getting out symptoms had something in common…

Once I got the top board separated and out of the cabinet, I noticed a very crusty looking solder joint below a stand off pin, which in turn was soldered, via solid core wire, to the centre pin of the BNC socket.

BNC Standoff Pin – CLICK To View

Things were a bit worse on the other side of the PCB once that had been removed from the rear cabinet.

Capacitor Separates – CLICK To View

A loose antenna socket had flexed the solid core wire soldered from the BNC socket to the stand off pin on the PCB, and in turn stressing the delicate print below.

Stranded flexible wire between BNC and stand off pin might have been better for preventing this from occurring.

I would add that the socket was not loose when the radio was given to me, otherwise that might have led me to the fault sooner, but looking at the scrape marks on the threaded, slotted circular BNC securing ring, it became obvious that the ring had been tightened with pliers at some point.

The PCB track leading to the stand off pin, that feeds the BNC, had separated from the board and from C2001 (470pF) which is in series with the antenna socket.

If you look closely at the photo (above), the fracture between cap and print can be seen.

When a 0.6mm soldering bit on a temperature controlled solder station was placed on this track, it fell off never to be seen again!

Oh well, not to worry, I’ll just solder to the end of the SMD cap then, I thought, given that it appeared to be ok in the photo.

Alas, no go – the capacitor had suffered from being pulled about too much by the flexing, and ultimately, broken print with the result that the antenna side contact of the capacitor disintegrated as soon as any heat was applied.

So a 470pf cap was now needed.

Doesn’t have to be SMD as it’s possible to solder one end of a “normal” cap to the board and the other end direct to the BNC at a push, although SMD caps are likely to be less inductive.

I managed to find a replacement 470pF cap on eBay which restored normal operation.

Effectively, I’d been TXing into no antenna!

Fortunately no other damage was done – I was initially fearful that the now rare and expensive Mitsubishi 2m and 70cm PA ICs might have failed.

One to watch out for, and the moral of the story is to make sure that the BNC socket on your FT-470 remains tightly secured otherwise this repair will become necessary at some point.

I trust of some interest and help if you experience a similar problem.

73

Colin

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URESAT-1 – A chess playing ham radio satellite

“……………….One of the projects that is confirmed is a chess game that will allow radio amateurs to play having as an opponent the on-board computer sending FSK frames with the movements, to which the on-board computer will answer in its telemetry. Several radio amateurs are working on the project and if it is completed by the time the satellite is due to be delivered, it will be included………………” Read more – HERE .

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‘To The Moon And Back’ – The First Radio Attempts

Cindy Stodola Pomerleau (Author)

On January 10, 1946, the US Army successfully bounced radio waves off the moon–the first-ever extraterrestrial communication, the birth of radar astronomy, and the opening salvo in the Cold War. The author was just shy of three years old at the time, and her father, E. King Stodola, was Scientific Director of the team that carried out the experiment, code-named Project Diana.

To mark the 75th anniversary of this historic event, Cindy Stodola Pomerleau has written a series of essays using Project Diana as a lens for examining the transformations and dislocations occurring in the US during World War II and its aftermath. Nearly half the book is devoted to World War II, with particular attention to the history of radar at Camp Evans, starting with its fumbling beginnings at Pearl Harbor and culminating in its stunning success in Project Diana. The second section is devoted to King Stodola himself and an examination of the confluence of internal and external factors that made him the right man for the moment. The last section provides a sampler of Jersey Shore life (e.g., the boardwalk, the Neptune Music Circus), contemporary American life (e.g., Sears, nylon stockings), and the author’s little-girl activities (e.g., her parakeet Archie, her Islander ukulele).

Steeped in good humour and nostalgia, these wide-ranging narratives explore Project Diana’s historical, sociological, political, and scientific context, as seen from the perspective of the tiny coastal New Jersey community where fate in the form of Camp Evans deposited the author’s parents and their neighbours. The book is a unique eye-witness account of an event and an era that marked a turning point in American history.

Order from Amazon – HERE .

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All Our ‘Communications’ In One Basket

The recent storms to hit the northern half of the UK saw many without cellular, fixed landline and Internet access.

At the moment BT-Openreach still supply a ~48V feed via your fixed landline. Using a POTS (a plain old telephone (Service) – a telephone that doesn’t require a 230V feed) still provides a way of communicating when all else fails (unless of course your landlines have come down). From 2025 the requirement for BT-Openreach to provide this facility will be withdrawn. What then?

Have a read at THIS BBC News article.

I suppose from an amateur viewpoint, we still have good old RF point-to-point communication – in whatever form, but remember your still need power. Have a think about your standby requirements?

73 es keep communicating

Jack – GM4COX

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HAM RADIO GETS BRAIN TRANSPLANT

ICOM 245 Given A New Brain

By Al Williams

Old radios didn’t have much in the way of smarts. But as digital synthesis became more common, radios often had as much digital electronics in them as RF circuits. The problem is that digital electronics get better and better every year, so what looked like high-tech one year is quaint the next. [IMSAI Guy] had an Icom IC-245 and decided to replace the digital electronics inside with — among other things — an Arduino. Read MORE ……………

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SOTA Fun On Microwave

During ‘On-Air’ chats, members of WoSARS often hear me describe some of the fun that can be had on microwave frequencies; especially for myself 13cms (2.3/2.4GHz) whilst out Activating a SOTA summit.

These escapades evolved from the creation of the GM13 GROUP of likeminded amateurs in 2017.

CLICK – For Further Information

Following the successful launch and operation of OSCAR 100 in 2018/19; this has opened up the opportunity to predictably work distant stations around Europe, Asia, Africa and even South America. Using the Satellite’s 13cms UP and 3cms (10GHz)  DOWN translator; some of our hardy band of SOTA-microeers have put together kit to access this facility.

GM/SS-037 Hart Fell – G(M)4VFL- Microwave Kit (19/05/21) [PIC – G4VFL]

Andrew’s GM/SS-037 – LOG

Andrew G4VFL was an early adopter of this challenge (see WoSARS Web March 2020 Article – HERE ) along with his ‘partner-in-crime’ Nick G0HIK; they have been progressively ‘knockin’ off summits in LD (Lake  District) and SS (Southern Scotland).

G/LD-024 Pike O Blisco – Nick G0HIK Operating (19/05/21) [PIC – G0HIK]
Now not having quite the enthusiasm of the ‘twosomes’ as to lugging dishes up summits, I do however benefit from potential Summit-to-Summit’s S2S’s, utilising my 8 ele Bow-Tie and SG transverter (2W out) and the gain of the dishes at the other end.

GM/SS-142 Scawld Law – GM4COX’s 8 El Bow-Tie (19/05/21) [PIC – GM4COX]
Popping down to just below the 2.4GHz UP Oscar frequency (2399.950MHz), it is possible to work Point-to-Point (S2S) utilising the high gain of the dishes – with the majority of the contacts being made on FM (of course falling back on SSB/CW on marginal paths).

GM/SS-100 Croft Head – GM4COX Bow-Tie on Walking Pole (19/05/21) – see end of this Post for design information [PIC – GM4COX]
And Wednesday 19th (May) this week, saw us all heading out on a predetermined series of Activations; an LD for Nick (and Chris M0KPW), and SS’s for Andrew and myself.

Predicted Path Profile – G/LD-024 to GM/SS-037 [PIC – G4VFL – CLICK to View]
Path Routes – G/LD-024 to GM/SS-037,100, 142 [PIC – GM4COX – CLICK to View]
So why not join us. Just bring along your kitchen microwave to a suitable top – you never know who you’ll work. 🙂

And I’ll leave the last word to Nick:

“……… Hi Guys,

Thanks for the contacts today, it was staggering how strong you both were. I think GM/SS-037 was 110km and GM/SS-142 was 99km. Sorry we could not stay around for your 2nd one Jack …………..”
73
Jack(;>J
EDIT: 10/06/21 – The design for the 8el Bow-Tie has been added to the GM13 Site. If you would like a copy please email gm4cox@gmail.com (file size 4MB)
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FINAL DECISION ON VARIATION OF LICENCE(S) – CONTAINS IMPORTANT INFORMATION

Dear Licence Holder,

We are writing to you again as we became aware that two of the hyperlinks in our previous email did not work. The links to the Final Decision and EMF compliance flowchart have now been corrected. We would like to apologise for any inconvenience this may have caused.

As stated in our previous correspondence, we are writing to make you aware of some important changes to your radiocommunications licence(s) issued by Ofcom. The changes mean you may now need to take action to make sure your radio equipment complies with a new licence condition to protect the general public from exposure to Electromagnetic fields (EMF).

We wrote to you in March this year to let you know we were proposing these changes. They apply to virtually all licence holders. We gave licensees until 18 April to submit any representations they wanted to make about the changes. We have listened to licensees’ concerns and made some changes to the new licence condition and guidance document as a result.

Full details of our Final Decision are published on our website. The Decision means your licence has now been changed to include a requirement to comply with internationally recognised limits on EMF exposure.

Alongside the Final Decision we have published Guidance on what you should do to ensure compliance. We have also produced a simple EMF compliance flowchart which tells you whether or not you need to take action and, if you do, what action is needed.

To help further, we will also shortly publish an updated version of our on-line calculator which you can use to work out an appropriate compliance distance for your equipment.  We are also preparing a new simplified version of the full Guidance, plus specific advice for holders of amateur, ship radio and aeronautical licences. We expect to publish these documents on our website by 8 June.

All documents – plus other relevant information – can be found on a dedicated EMF webpage.

Licensees will have the following time periods to make sure they have up-to-date records in place:

a) Until 18 November 2021 for any equipment which operates on frequencies at or above 110 MHz.
b) Until 18 May 2022 for any equipment which operates on frequencies above 10 MHz but below 110 MHz.
c) Until 18 November 2022 for any equipment which operates on frequencies at or below 10 MHz.

To view and download your new terms, conditions and limitations please click the appropriate link below:

Amateur Radio Licence Terms, Conditions and Limitations

Ship Radio and Ship Portable Radio Licence Terms, Conditions and Limitations

Please note: if we make any further changes to licences in future, we may not contact licensees individually. For that reason we urge all licensees to subscribe to email spectrum updates by going to this page on our website.

If you have any questions about this change and what it means for you, further information can be found on the dedicated EMF webpage using the address provided above.

Yours faithfully,

Ofcom

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Cooperative Effort to Resolve Potential 70-Centimetre Interference Issue (US)

The FCC, and the US Department of Defense are cooperating in an effort to eliminate the possibility of amateur radio interference on 70 centimetres to critical systems at White Sands Missile Range (WSMR) in New Mexico. The Defense Department’s Regional Spectrum Coordinator contacted the FCC in March, seeking information on whom to contact regarding detected amateur transmissions it believed could pose a threat to a critical WSMR system operating on 70 centimetres. The FCC, in turn, asked ARRL to be involved in the discussion and any necessary remedial efforts. It is to be noted that the Amateur Radio Service is a secondary service on the band…………READ MORE  .

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