Audio character in DX

[RadioDaze]

I just responded to a thread about the Gain master and I use a GM antenna here in the UK and have only spoken to Australia once so far. I can remember the audio had a special quality to it. Of course audio quality can be different depending on power output, RF transistor drive levels, antenna, radio and mic (and drive) but do you highly experienced DX guys think you can identify a very, very distant DX signal when you hear it.

My only other really long DX contacts (+7,000 miles) have been Indonesia and Reunion Island (not bad for only having been on since March this year)

I wonder, can you almost sense from the audio quality that what you are hearing is extremely distant by the quality of the fading (QSB) or the tone in the audio. I think I have sensed a characteristic type of fading... long and very slow fading and also a very slightly hollow sound when the DX is so very distant. Hard to explain but almost slightly transparent and ghostly. Interested in your thoughts.

Whilst I am immensely interested in the technical side of DX and radio I find that the actually listening is a real window into a normally unseen world of unpredictable and slightly mysterious atmospherics which you can kind of contextualize after numerous experiences by visualizing what is happening in your minds eye. Picturing the F2 bounces and sea/desert hops. It becomes a little esoteric almost.

 

[Captain Kilowatt]

Audio has nothing to do with long haul DX signals. A signal from the opposite side of the planet can be loud and crisp and clear or low and fluttery. It depends on the signal path and type of propagation at the time. Grey line propagation from one area can have deep and rapid fading while normal F layer propagation can be rock steady even from the same station in the same area. If propagation is via aurora it will be fluttery and distorted even if it is from only 1000 miles away. If propagation is via multipath it can be fluttery with a slight hollow effect due to a slight echo. If the signal arrives direct as well as having traveled all around the world as well it will have a significant echo to it. In short, the quality of a signal is affected by the method of propagation and not where it came from. I have had middle of the night contacts with Australia and East Africa that were basically S-0 or S-1 and the audio was clear and precise. I have also had similar contacts that were stronger and with fading. Propagation is what it is.

 

[RadioDaze]

That makes sense.

But you do not sense any pattern of characteristics at all?... i.e. you kind of deduce that a signal from 5000 -7000 miles away is not Sporadic E or Auroral etc.

I am not experienced enough yet to have a knowledge/experience bank on this yet and just wondered. I suppose we can get a few cues sometimes before we get a division code if it is missed initially through QSB etc.

When I started back up I was rusty on the div codes and had to ask the station initially so was listening in part to the audio quality in order to gauge if it was distant, but what you say makes sense. That is probably why I am asking. I only use an omni so have never seen signals greater than an S0-S2 at such distances as yet. Maybe that will come but with a beam I suspect what someone might consider strongish skip hitting S5-S7 might be coming in significantly weaker for those using solely an omni directional antenna.

I guess I will just have to get some more contacts under my belt and it will probably follow what you have outlined.

 

[Captain Kilowatt]

That makes sense.

But you do not sense any pattern of characteristics at all... i.e. you kind of deduce that a signal from 5000 -7000 miles away is not Sporadic E or Auroral etc.

I am not experienced enough yet to have a knowledge/experience bank on this yet and just wondered. I suppose we can get a few cues sometimes before we get a division code if it is missed initially through QSB etc.

When I started back up I was rusty on the div codes and had to ask initially so was listen to the audio quality in order to gauge if it was distant, but what you say makes sense. That is probably why I am asking. I only use an omni so have never seen signals greater than an S0-S2 at such distances as yet.

OK now you are asking if you can tell by listening to a signal what method of propagation it has encountered. To a point yes......well no....mayb.......sometimes. A signal 5-7000 miles away is most definitely NOT sporadic E as that is not the nature of sporadic E propagation and sporadic E generally only happens on VHF from 6m and up. It does occur on 11m but is really quite rare. Often openings are mistakenly credited to sporadic E. Aurora propagation coincides with solar storms which tend to kill HF including CB but enhances VHF. Auroral propagation is characterized by distorted audio and CW signals often have a rough buzz sound to them rather than the nice pure tone. Often you can recognize multi-hop by listening to stations in one are that are fairly strong and suddenly a station from two or three times that distance away on the same beam heading will pop in for a short time. That is almost always multi-hop F2. One time I was working a station on Vancouver island about 2700 miles away. I cleared with him and a station on Midway Island called me from about 5700 miles away basically twice the distance and on the exact same beam heading. He was strong at first but faded out in just a couple minutes while the west coast stations were still strong.

Again, listing to the audio will not tell you the form of propagation however experience will. I know when an opening is likely auroral by watching space weather bulletins and if HF is dead and VHF is active it is certainly auroral or Es. If there is considerable distortion it is auroral. All bets are off however if propagation is F1 or F2 layer or multi=hop unless you listen to where other stations are coming from at the same time.

 

[vkrules]

Well covered CK.
Just like to add local signals can also multipath due to reflection,refraction etc. It can be to close to get sufficient delay to perceive it as a echo but will sound slightly garbled or with a buzz.Have you ever heard the signal flutter when a jet goes overhead.! So audio quality alone is not an indication of distance. Nor is signal strength or type of antenna, when the band is really open it is possible to hear stations 10,000 miles away sounding like they are parked in your drive.
Unfortunately you have missed this cycles peak and we are also at the seasonal minimum , with a bit of luck we will have better propagation in the next few months

 

[RadioDaze]

Often openings are mistakenly credited to sporadic E.

Just like to add local signals can also multipath due to reflection,refraction etc.

A couple of points to cover thanks for replies... yes I can now recall a town from me about 40 miles away that in terms of distance should boom in. But instead I get S-0's and fluttery audio. This town is behind a bank of 100-150M hills which would explain fluttering from multi-path.

I was under the impression that the short hop summer openings across Europe were all Sporadic E, that is what everyone on forums and on air calls them. So these could be other openings? That seems to go against common knowledge here in the summer months. Not sure if there is something geographical related to Europe going on but I always knew these summer opening here as Sporadic E. (short hops - within 2,000 mile hops) These "Sporadic E" openings can be weak or strong but rarely distorted, almost always very clear. Strong ones bring European continental stations in at 9+ with regularity and sometimes +30. It seems between months of June to dying off Mid August the predominant skip modes here seem to be Sporadic E.

Such openings as outlined above often allow stations in the south of the Uk to speak to norterly stations 2-500 miles north. I was speaking to a guy in Stornoway/Isle of Lewis_Outer Hebrides the other day like he was 1mile away. (approx 550miles from QTH) and then the longest QSO contact I attributed to sporadic E (rightly or wrongly) is southern Turkey at about 1,700 miles.

There does seem to be openings to S.America from around April onwards. In fact 2-3 months ago it was like a phone line direct to Brazil from my QTH I could hear 3div stations all day long. Which someone called Trans-equatorial skip. I can very regularly speak to stations in Brazil from my QTH spots. This being an obvious F2 opening to get 4,000-,5000 miles from the UK.

 

[Captain Kilowatt]

What you are attributing to sporadic E (Es) is most likely just regular E-layer refraction. Also trans-equatorial propagation generally tends to be pretty much inline north to south so I am not so sure about the UK to Brazil being TE propagation. Just because it crosses the equator does not mean it is TE propagation. It could be FIA or Field aligned Irregularities prop or another mode.

https://en.wikipedia.org/wiki/Radio_propagation

 

[RadioDaze]

OK thanks for explaining it may not be TE. A bit above my head that... never heard of "regular E-layer refraction" or "FIA or Field aligned Irregularities"

 

[Captain Kilowatt]

Check out that link above for a bit of info on the various propagation modes.

 

[vkrules]

If you get any openings put out a call on the forum chat, some keen DXers there.
I'm on the east coast of Australia some 3,500 kms from Perth Guys in the West have a better path to The Uk and Africa than we do. Funny though I chat to the Canary Islands long Path frequently. Like you said" like a direct line'.
Different perceptions ,I regard Perth as short skip and anything in Aus as a local. I guess 3500 km would get you all the UK and most of Europe.

 

[vkrules]

You might find this program interesting as well http://www.g4ilo.com/voaprop.html

 

[RadioDaze]

3,500KMS that is in essentially the entirety of the span of Europe. From here down to Turkey and beyond even.

Thanks, yes I was out calling today in fact 41 and 43 on T5 and QSY .570 but nothing heard. I did that because I saw some early contacts (09:34AM local time here) being made - 4 to be exact on a map from Northern Europe to Australia.

I have to assume those initial logs online are very high power stations with large beam antennas. The more I see the better the chances for a QSO to your side of the planet : )

It really is a matter of conditions as I spoke to someone who has spoke to someone in Australia on a mere 20W. So it is a waiting game. I will check that link out. I keep hearing the stories that a stations was using QRP and a short mobile whip and it was great. So I await better conditions !

Anyway by the time I got out there I could hear nothing. Very quiet morning even with good ears up a hill. I spoke only to Slovenia and someone giving a Yugoslavia div code and a few locals within 40 miles or so.

In fact today I got 3 aluminium poles under the antenna with ease so I know I can go 3 poles with the GM easily now and be set up in 15 mins.SWR of 1.2:1 spot on the T5.