Friday, December 14, 2018

Reflecting the Geminides on 6m

With the passing Geminides meteor shower I though it would be a interesting experience to monitor the MSK144 frequency last evening and night. I never did meteorscatter before so I asked PE1BVQ Hans for some info since he is experienced in this kind of thing. He suggested I should take a look at ON4KST chat since meteorscatter most of the time is not random but a pre arranged sked via internet. So I logged in on the KST chat but really don't know what to do there. I see some amateurs chatting but don't see much about arranging skeds? In the mean time I decoded some signals that looked like a contest exchange and some CQs from several stations. Am I on the right frequency? Can't find anything on the internet about the region 1 frequency for MSK144 at all? Is it via MS or is it just aircraftscatter? I really don't know? I transmitted a few CQs and see I'm received in Schotland, England, Germany, Skandinavia and Netherlands. Some reports are above 00dB! But no one came back to me. However, I remember Hans told me that it could take some time before you get something back at all if lucky. So I went to bed and marked "SWL" in WSJT-X. When I woke up this morning I saw this:

Indeed I gave S58P a report several times but didn't see anything back to me. But it seems he tried to get back to me and I received the report much later. Unfortunately I already went to bed and was not at  my shack. I couldn't give him the 73. I don't know if it is important with MS? The QSO purist definitely tell me the QSO is not complete, although we complete the report exchange both ways!

So, what do you think?


John AE5X said...

Hello Bas,

I am thinking of trying this as well. What antenna were you using and how much power?

73 - John AE5X

PE4BAS, Bas said...

Hello John, antenna was my W2000 vertical @16m (52 ft) agl. Power was 50W. Good luck trying! 73, Bas

Photon said...

Good start, Bas! When the grids and signal reports are exchanged successfully, that is enough for an official QSO, in my view. A purist will of course sit there, sending 999 '73s' before giving up. But what is the point? The fact that someone is sending a '73' is a clear indication all information has been received.

The frequencies are a problem. They used to be quite focused at 50.230MHz, but I was getting almost all reflections (though there were not many) on 50.280. I think IARU R1 is meant to be at 50.320 and above now. Things here were more confused, as there was a 6m SSB contest on last night! MSK is so fast that even very brief 'glints' off an aircraft can give a decodable signal. It's amazing, actually.

PE4BAS, Bas said...

Hello John, so how can I determine if signals are reflected by a aircraft or by meteorite? Frequencies are indeed confusing, you can't find any on the internet. But most of the signals are on 280 since that's programmed in WSJT-X. I will be trying this night as well although I think the peak shower is already over. 73, Bas

Photon said...

Hi Bas,

I think it might be really difficult to tell the difference between short-lived MS and an aircraft scatter with these very high-speed modes, as the Doppler shift isn't readily apparent in most cases. I'm sure there's someone out there with a way to do it. Visual rates for the Geminids here last night were very good - some of the best I've seen in a while. Kids loved it!

John, EI7GL said...

Hi Bas, I think it has to be meteor scatter from PA to S5. After all, aircraft are only about 10kms above the ground so the range from reflections must be low, a few hundred kms.

The meteor scatter trails are probably up around 100kms so the range is much greater...out to 2000kms or more.

Hans said...

Hallo Bas. Leuk dat je MS heb geprobeerd en met resultaat. Bij MS is random erg moeilijk. Zeker als men niet exact op de frequentie zit voor random. Mijn ervaring is gewoon via de chat van ON4KST een vraag zetten wie er met mij wil scatteren. Met diegene die zich meldt overleggen we onderling de frequentie en wie het eerst start. Op 00 (first) of op 30 (second) van de minuut. Als dat goed is afgesproken wordt er gestart en kijken we of we ook ontvangen worden en b.v. met welke sterkte. Dat scatteren kan best een half uur duren, of nog langer. Het ligt er maar aan of er een goede meteoorregen op dat moment is. Uiteindelijk zijn over en weer de rapporten uitgewisseld en dan is het QSO ten einde. Het beste om het te leren is gewoon op ON4KST kijken en een qso volgen. Dan weet je hoe het gaat en zie je ook dat het niet direct tot een QSO komt.
Meer uitleg? Bel me maar. Goed weekend, Hans, PE1BVQ

PE4BAS, Bas said...

Bedankt Hans, het is me ondertussen duidelijk. Ik heb nog een avond en nacht getest en gelezen. Dit is niet echt een mode voor mij denk ik. 73, Bas

GM4FVM said...

Bas. That is a good QSO to me. I agree with "Photon" about 73s.
I suggest setting FTol to 100 or more and using a longer Watchdog time for meteor scatter. It can take a long time to receive replies as the meteors come and go.
Personally I do not like KST and I do not use it. Everybody has their own idea of course. When I was new to KST I found nobody was interested in newcomers.
Well done on meteor scatter.

PE4BAS, Bas said...

Tnx Jim, I wrote a newer post also on this blog were I changed the FTol settings as well. I use a omnidirectional antenna which is of course not so good for MS, but I managed to do many decodes anyway. 73, Bas