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SDR for beginners


#1

Hi all

A reference in this months Radcom put me onto this site.

http://websdr.ewi.utwente.nl:8901/

It is an SDR setup at the University of Twente in Enschede, Holland who have put an SDR radio on 20m, 40m and 80m which is independently tunable by people on the site. If you fill your call in the box, you are shown against the frequency you are tuned to. I have just been copying Klaus/DF2GN/P, Gunter/DL5WW/P and Jirka/OK1DDQ/P at much better signal strengths than from my FT1000.

Radio is in the midst of a huge evolutionary stage, whether we like it or not.

73,s
David/G4CMQ


#2

In reply to G4CMQ:

Many thanks for the link David - what a wonderful toy! Could play with this for hours! Whose going to be the first to look for their own signals (I’d have done it myself by now if the shack and the computer weren’t 20m apart…)

73 de Paul G4MD


#3

Hi All,

I haven’t had a look or listen to the remote RX site mentioned in the SOTAwatch forum but what a great way to copy your RST and callsign when conditions in the shack are poor making the station responding unreadable. You can then claim the points for SOTA or WAB etc. Fantastic, it’s so easy!

This is the best thing since sliced bread…and no one can tell that you are hearing the signals via an “internet HF repeater” as long as you don’t enter your true callsign!

I enjoy using SOTAWatch and DX Cluster on a daily basis to save time in finding wanted stations as I come and go from the shack, but using systems like the one at the University of Twente to listen to signals down your phone line is not amateur radio.

73 (a little tongue in cheek) :wink:

Phil


#4

In reply to G4OBK:

I agree with you 100% Phil and unfortunately there are some who will use it for exactly the reasons you quote above, it’s the thin end of the wedge and as far as I’m concerned it’s simply not cricket.

73

Mike


#5

In reply to G4CMQ:
Hi David

I believe it was these same guys who entered the 2007 CQ 160 CW contest; if you accessed their live internet link you could listen to them simultaneously on the Radio and on the Net - you could also hear how loud your signals were when you called them (the delay was about 4 seconds) - a real novelty spoiled only by the same stations sending them different callsigns just so they could listen to their own signals over and over again!

About a year ago I found this site (which you need to register with)

http://www.globaltuners.com/login

If you listen on (say) 30m on the Brisbane RX its amazing the different stations that can be heard - and how loud (or not) some EU sigs are.
Its no use for verifying reports though (thank goodness!) - there is about a 9 second delay between signals you can hear on your radio and what comes out of the remote RX.

73 de Cris
GM4FAM


#6

In reply to G4MD:

Whose going to be the first to look for their own signals?

This was the first thing I tried when the site first started up, but 80/40m crashed my broadband so that did not work and since the 20m addition I have never been able to hear myself.

This is a great tool for determining propagation and I have used it to follow an interesting conversation on 80m. One station was 5/9 on my TRX and I could not hear the other but he was 5/9 on the RX in the Netherlands.

You may have noticed that it is not covering the best sections of band for cheating at SOTA chasing due to the band coverage. eg It doesn’t go down to 7.032 or over 7.7ish on 40m, similarly on 20 & 80m, So it doesn’t cover the parts of the band we tend to use, however there are many on line scanners that do if you are willing to pay for access. These scanners do not however allow multi-user control of the frequency and are on a first come first serve basis.

I know of at least one station in Southern England who has a remote station in GM at his parents house linked by computer and when he is visiting them he can listen via his home station the same way. If you have the means and the contacts to do it the technology is there for remote receiver sharing on a massive scale, imagine what would that do for contesting? Where SDR makes thing interesting is the band spread and on this site the ability for multi-user access and control.

The band spread thing makes for other interesting ideas, because if you have a software defined RX (like the SoftRock) and a powerful enough computer you can record the whole band at once. So you could be working one station on say 40m SSB for the chaser point and simultaneously record 30 CW conversations for the SWL points. How about that one?

73 Steve GW7AAV


#7

In reply to GW7AAV:

It doesn’t go down to 7.032

On the face of it you are correct. However, during HB9CMI’s activation this morning, which was on 7032 according to my receiver and the SOTAwatch spots, I could clearly hear Peter on an SDR-indicated frequency of 7032.87. I presume that the frequency offset is a function of using the RX on CW rather than SSB.

I couldn’t hear my own signals though …

73 de Les, G3VQO


#8

In reply to GW0DSP:

Oh dear!! I did not post the link in order to re-start the ‘printing press debate’.

I make two points - you cannot cherry pick on progress. You all willingly accept the computer for DX Clusters and even SOTA spotting, so why not on copying signals. I agree it is not ‘radio’ per se. Are repeaters ‘radio’?
We accept the RSGB as the arbiters of all things to do with the hobby. They have an SDR section in Radcom. Huge sums of money are being invested in SDR. Would the commercial organisations be doing this if they did not feel it was the future? By all means use those parts of available technolgy which suit your own mindsets, but leave the mind open for new ideas.

PS It is possible to squeeze this site down to 7.032 if you push it carefully. I was copying the stations I mentioned in my original post quite comfortably but that is about the limit of its scope.

73’s
David/G4CMQ


#9

In reply to G4CMQ:

Hi David

My post was in reply to Phil G4OBK and I merely agreed with Phil on the issue that it is open to abuse, so I’m baffled why you quote a “printing press debate” and aimed your reply to me and not to Phil.

I am not against advancement of technology of any sort, maybe man will put a man on the moon some time in the future, who knows? but I am against plastic radio down a telephone line where the chase becomes extinct and there are those who would “cheat” (very tongue in cheek) by using it for weak sota stations.

It’s only my opinion and I am entitled to it. Like all other obnoxious contraptions, it has the benefit of an off switch;-)

73

Mike GW0DSP


#10

In reply to G4CMQ:

Actually we can and do cherry pick on progress, for example the kerfuffle every time GM crops turn up in the wrong place, or controlling “designer babies”. More relevant here is the way some guy designed a faster peddle bike only to have it banned from competitions, or the rigorous control of technology in F1.

Remote SDR rigs are a fine toy with lots of play potential, but I want nothing to do with remote rigs for every day enjoyment, I prefer my amateur radio up close and personal. That should not deter anyone else from enjoying the technology. However if it comes to the point where this remote technology can become advantageous in SOTA then we will have to discuss whether to allow a free for all or impose F1 style limitations. When that day comes I want a comfortable ringside seat, a large malt and a bag of scratchings - it should be fun!

73

Brian G8ADD


#11

In reply to G4CMQ:
I think all these computer innovations are great - but not all for me; the various remote RXs provide a completely different picture of what can and can’t be heard in Europe and elsewhere … fascinating!
BUT you won’t get me using Skimmer, Remote RX or any other computer-derived help for QSOs etc - in short, what goes in my log has been received and transmitted from this station (by me!).
We all know cheating goes on in all walks of life, whether professional or hobby, and amateur radio is not immune - thankfully (and increasingly thanks to the computer for checking) these cheats are being outed more frequently (especially in contests); even more satisfyingly they usually disappear from view and audible range having, in the end, cheated no-one but themselves.
But long live the PC in Amateur Radio - I just couldn’t imagine being without it for logging, spreadsheets, grey line, EZNEC for antenna construction, the cluster … an endless list.
73 de Cris
GM4FAM


#12

In reply to G4CMQ:

Oh dear!! I did not post the link in order to re-start the ‘printing press debate’.

There is something that looks like going full circle…

In the past - Why do we need a printing press when so few people can read?
In the future - We don’t need a printing press because no-one reads any more!


#13

In reply to G8ADD:

However if it comes to the point where
this remote technology can become advantageous in SOTA then we will
have to discuss whether to allow a free for all or impose F1 style
limitations. When that day comes I want a comfortable ringside seat, a
large malt and a bag of scratchings - it should be fun!

73

Brian G8ADD

If that day comes Brian it will definitely spell the end of Sota & RF radio. What next remote transmitters too, like a widebanded repeater? What would be the point in chasing when someone a thousand miles away supplies your reports? It will be Sota by mobile phone next, instead of a pile up you will get an engaged tone and have to keep re-dialling until you beat the pile up;-)

73

Mike GW0DSP


#14

In reply to GW7AAV:

It depends how far in the future you mean. I can see the day approaching rapidly when the computer will talk to us, but as far as I am concerned there is a huge BUT! I am a pretty fair speed reader, I can get through a 300 page novel in an evening, and process the written word much faster than it can be spoken. Until the day when the computer taps directly into my brain spoken interfacing with the computer will be inefficient for me.

Cris, are you referring to the guy in the PW contest whose linear cut in with a slight delay? Have a look at his web site, its a real laugh!

73

Brian G8ADD


#15

In reply to GW0DSP:
I know of a ‘top’ G DXer who works in the Middle East but works most of the DXpeditions from his home in G land by controlling his station from thousands of miles away; definitely not my idea of amateur radio but it goes on.
73 de Cris
GM4FAM (definitely in the Scottish Highlands - or so the last herd of zebras said not 2 mins ago!)


#16

In reply to GM4FAM:

I’m a little concerned about the use of the word “cheating”. Surely cheating can only occur if a breach of rules is committed. Currently SOTA has no rules that apply to this situation. Perhaps it should have, but that is a different debate.

What we have is technology that allows a hitherto impossible function to be easily accessible to all. I can understand the view of those who feel its use would devalue their own view of how SOTA, or any other facet of amateur radio, should be conducted, but they are under no obligation to use it, nor is their position under any threat from others that may choose to do so. Having tried it briefly, in parallel with actually listening on the home receiver, I feel that it is fascinating to play with, but far too unwieldy to use in the cut-and-thrust of pile-ups. No doubt further innovations will make it much more effective and user-friendly before very long.

73 de Les, G3VQO


#17

In reply to G8ADD:

Have a look at his web site, its a real laugh!

Link?


#18

Ahh technology… as Cris says, it is quite useful too. :slight_smile:

e.g. I checked why my chaser log from the weekend doesn’t have “stars” for a couple of QSO’s (using the computer, database, on-line activators log etc)

…and I find that my callsign was broken at the other end (twice) although I thought they were good QSO’s. So I have deleted 16 points worth of QSO’s from my chasing log.

Technology keeping me on the straight and narrow… and I have a clear conscience… :slight_smile:

73 Marc G0AZS


#19

In reply to GM4FAM:

You have zebras as well as the tree kangaroo? Well you learn something every day.


#20

In reply to GM4FAM:

I’m sure it does go on Cris and I’m equally as sure that a very small minority of Sota people would use it in the chase.

73
Mike GW0DSP (Still in and RX/TXing from CQ town)