ARCHIVE: Australian Ham Radio Discussion Forum ( AHRDF )

A historic contact was made on Sunday the 16th June 2019 when the Atlantic was spanned for the first time on 144 MHz.

From QRZ news

D41CV on Cape Verde Islands off the coast of Africa managed to work FG8OJ in Guadeloupe on 144.174 MHz using the FT8 digital mode. The distance was an incredible 3,867 kms.

To put that into context, the distance from the west coast of Ireland to Newfoundland is 3,000 kms.

Tropo prediction maps show a path right across the Atlantic and suggest that even more incredible contacts may be possible.

http://forums.qrz.com/index.php?threads/...hz.662689/

So it has finally happened. Hopefully VK6 to ZS or FR will be next.

73

Wayne VK4WDM

Hi

At the recent Nordic VUSHF Meeting Stefan, LA0BY, made a presentation about extreme tropo propagation: http://www.la0by.darc.de/190615_LA0BY_Tr...xtreme.pdf that is worthwhile reading.

Even though the Ireland to Newfoundland is "only" 3000 kms/s vs Cape Verde <-> Guadeloupe is 3867 kms/s my gut feeling is that the water is a lot colder at the more northern path.

Bo

 "Hopefully VK6 to ZS or FR will be next."

That assumes there are people at each end (1) transmitting; and (2) receiving; at the relevant times and on the same 2M frequencies !!!  

Using FT8 will probably be a lot harder than using WSPR to figure out if propagation exists over the path. The FT8 CQ process may be automated, even the to/from of the full QSO too, but there still has to be an operator there to actually manually log the contact to keep the details. That last bit is not automated.

(19-06-2019, 06:18 PM)VK4ADC Wrote: [ -> ] "Hopefully VK6 to ZS or FR will be next."

That assumes there are people at each end (1) transmitting; and (2) receiving; at the relevant times and on the same 2M frequencies !!!  

Using FT8 will probably be a lot harder than using WSPR to figure out if propagation exists over the path. The FT8 CQ process may be automated, even the to/from of the full QSO too, but there still has to be an operator there to actually manually log the contact to keep the details. That last bit is not automated.

Exactly. Finding willing VK6 operators is an issue we've faced for a while.

WSPR is also at least 10-12dB more sensitive than FT8, so propagation paths can be probed way before a contact is possible on FT8 or maybe even JT65.
We need a WSPR beacon in ZS or FR as they have in Hawaii which points back to the US West Coast over a 4000km path. They hear the 70cm beacon regularly during openings. Who wants to build it and take a trip?? Or convince some VK6's?

Yes, finding willing ops and appropriate beacons is a problem not just on the Indian Ocean paths but others as well. Here in QLD we have UN-conquered paths (I think) on 2m, 70cm, 23cm to 3D2, H44, YJ and on some bands, FK8 and P29. To extend the dream even further, what about to KH2 and KH6? (JA has been worked from Nth QLD and I have heard, but not worked JA on several occasions). I guess I should do my bit by getting up and running on WSPR.

In southern VK, what are the chances of the mid-summer propagation discovered recently to South America on 6m extending to higher bands?

In IMHO, the demise of VKLOGGER has added to the difficulty of spreading the news about possible openings to rare places.

It obvious that interest in long-haul contacts on VHF/UHF, and activity overall, has waned in recent years which is a worry given the recent moves to eliminate, or at least reduce, ham access to the 2m band as reported in other posts. How do we change that around?

73

Wayne VK4WDM

I am guessing my 5/8 Flower Pot antenna and 40 odd watts aren't going to make the grade in pursuit of these distances.

 

Hi Colin

Maybe not across the Indian ocean, but I have worked plenty of stations right down into VK3 who are using equipment and power much less than yours when summer sporadic E is in. On one occasion a guy with an FM handheld standing in the Bourke street mall was easily workable with my vertical here in Townsville!

VK2, VK3 and VK5 stations on 144 SSB were often 59+ on 2m, but in the last five years or so I have worked very few DX stations. Sporadic E occurs every summer regardless of the sunspot cycle so lack of ops and activity is the reason not propagation.

Any obvious problem with working H44 and YJ is that the main centres of population are on the far side of the island from VK with mountains in the way and the E cloud would have to be in a very favorable position.

73

Wayne VK4WDM

The main population and majority of resorts in YJ are towards the southwest of the island Efaté in Port Vila.  Which apart from New Caledonia in the middle should give a clear path to Oz.

The attached is the take off angle from where we often stay in YJ pointed at Sydney.

I wonder if my Mrs would get grumpy if some radio gear found its way into my luggage next time...

Just had a closer look and the line of the balcony points exactly at my QTH (weird) and is 2456.64 km.

Wayne,

There is a replacement logger called VK Spotter just so you know, try a google search.

No offence to the few who communicate with us, but its almost like the majority of VK6's dont like to communicate with the outside world, its weird, cause u see VK4, 5, 3, 2, 1, 7 participate on loggers and forums like this, but VK6 ops are noticeably absent. 

VK4 to FK8 has been done numerous times on 2m. P29 has I believe via FM and repeaters. Not sure about the rest. 

There was a 2m WSPR path to 3D2 last summer I believe from Sydney. 
2018-12-27 03:14 VK2MAX -21 10W 3D2AG 2959 km (double hop E) This was only a one way report, but still amazing that it was even detected at all.
See forum thread - http://www.ahrdf.net/forum/thread-747.html

There is also a VK4 path you didn't mention, while its been done before its a potential record breaking path which could easily be reality if someone was listening. North QLD to ZL 3000+ km. Missed opportunities we've noticed last summer where no one was active.

I dont think there is any chance of the South American path being heard on higher bands than 6m. But anyone feel free to prove me wrong.

I dunno if we can say 2m activity has waned, maybe its moved or changed? There are more and more stations running full time on 2m WSPR, if you add up the hours its probably more 2m activity than ever, and discovery of paths that people have never known to happen before, are still being discovered because of this (and 6m WSPR). But, the sad part is, that I know there are capable stations out there who choose not to get a radio going and support activity and discovery. Even if its the station is RX only this still helps with monitoring and understand band conditions and paths. 

Having more stations on 2m & 6m WSPR in VK4 would have a big impact because its into VK4 that sporadic E will generally come from first into the southern states.  

A 2m & 6m WSPR beacon in Alice Springs area would also show a great deal of paths I feel too. I'm sure this can be organised if we could get a site. I think a Darwin site could also be of great interest too particularly with a yagi on 2m pointing Melb direction. I picked up Darwin FM radio and also Port Headland WA last summer. There is much potential, we just need more people with the drive to do what needs to be done to achieve it.

Kinda off the topic, but also kinda on topic if were talking about activity and long paths.

Edit - I should also add to this that with the advent of the IC9700 becoming stable enough for 2m WSPR with the GPS input, its helping get more people onto 2m WSPR.

Leigh - I have done ZL on 2m from here (QG56JR) Central Qld last tropo season , just under the 3000km , very rare we get tropo up here from ZL, so the further nth you go the harder it is , would need some extra coastal tropo extension for FNQ !!

Hi Frank,

Nice work re the QSO 

I noticed this missed opportunity for FNQ to ZL earlier in the year -
[attachment=325]

(22-06-2019, 05:59 PM)VK2KRR Wrote: [ -> ]Hi Frank,

Nice work re the QSO 

I noticed this missed opportunity for FNQ to ZL earlier in the year -

I have heard ZL several times on 2m SSB from Townsville and and have been heard over there but just could not get going in both directions at the one time

Wayne VK4WDM

(22-06-2019, 05:59 PM)VK2KRR Wrote: [ -> ]Hi Frank,

Nice work re the QSO 

I noticed this missed opportunity for FNQ to ZL earlier in the year -

Yes Leigh I monitored  that tropo event & called a number of times  ZL direction expecting a response ! but the silence was deafening ! I am wondering if the Attenuation factor on 2m tropo has a finite limit  distance wise in association with TXpower levels,  antenna gain etc ? because even on the times I worked the northern end of ZL, the  signals have never been above S5, whereas the Brisbane guys & the nth sunshine coast were giving S9+ reports ....  Maybe a 1kw amp is the answer with a high power permit of course ?  but if you can't hear them high power is not the answer ??

Wayne, thats certainly something to get excited about! 

Frank, I think it really depends on the characteristics of the tropo at the time, obviously not as far for Brisbane, but also the tropo extension up to you may well have had more loss over that section. 
And thats right, no point just one side having more TX power than the other, it would be a bit one sided.

As usual if it were me, I'd be running 2m WSPR across the path when ever there was a chance showing on Hepburn. Running it through the night to show up when the best times may be. A path like that is worth getting up early morning for.

(25-06-2019, 02:05 PM)VK2KRR Wrote: [ -> ]Wayne, thats certainly something to get excited about! 

Frank, I think it really depends on the characteristics of the tropo at the time, obviously not as far for Brisbane, but also the tropo extension up to you may well have had more loss over that section. 
And thats right, no point just one side having more TX power than the other, it would be a bit one sided.

As usual if it were me, I'd be running 2m WSPR across the path when ever there was a chance showing on Hepburn. Running it through the night to show up when the best times may be. A path like that is worth getting up early morning for.

Its worth remembering that the VK 2m record is VK4BFO (Mount Isa then I think) to JI7DMB, 6763 km on 15 April 1991. I have heard JA stations several times on 2m when there has been intense TEP on 6m. On one sad occasion I heard two of them chatting with each other but could not break in

2m SSB contacts used to be quite common between Nth VK4 and P29 but I don't think there are any stations in PNG now who are interested.

Wayne VK4WDM

Hi

"WSPR is also at least 10-12 dB more sensitive than FT8 ..." Well, this depends on the actual propagation. WSPR is good across smooth paths, but terrible when traveling across distorted paths. If it is only about sensitivity please choose JT9-30, Opera4H or WSPR15.

There is actually a rather interesting picture of the FT4 sensitivity vs. propagation, see https://physics.princeton.edu/pulsar/k1j...otocol.pdf page 5. Unfortunately, I haven't found similar simulations for the other modes. But the simulations clearly show that there is a dramatic loss of sensitivity vs. different propagation models, i.e. path irregularities. Also the duration of the mode negatively affects the sensitivity, if not subject to Additive White Gaussian Noise (AWGN). I have seen a similar set of simulations for FT8, but unfortunately I don't have the picture, that shows e.g. FT8 subject to highly disturbed ionospheric conditions has so poor sensitivity that the curve is flat all the way beyond 0 dB.

Here is a link to a presentation I made at the 2018 RSGB Convention about beacons and PI4 https://www.youtube.com/watch?v=jFcCncceSN4 A part of the presentation addresses the above path irregularities.

Bottom line: there is no single mode that is best for everything - it all depends.

Bo