
Wide-Band WebSDR – Shortwave Radio on the Internet - sndean
http://websdr.ewi.utwente.nl:8901/
======
fr0sty
There are many more of these: [http://websdr.org/](http://websdr.org/)

Be sure to check several. Receive capability is not the same across stations
or between frequency bands on the same SDR.

~~~
riffic
it's a shame the author doesn't seem to be interested in opening up their
source code:

[http://www.websdr.org/faq.html](http://www.websdr.org/faq.html)

edit: previous HN discussion regarding PA3FWM's closed source stance:

[https://news.ycombinator.com/item?id=18571139](https://news.ycombinator.com/item?id=18571139)

~~~
bjakubski
For a very similar, but open source project have a look at
[https://github.com/jketterl/openwebrx](https://github.com/jketterl/openwebrx)

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wpietri
This is absolutely lovely. I used to mess around with a short-wave radio when
I was a kid, and there was a sense of mystery and discovery that was magic.
And for me at least it's still there. Just now I happened to find a Romanian
radio station, and discovered that about 70% of the time it sounds like
Spanish to me, with 30% incomprehensible.

And I love the lovely sounds one gets from trying various modulations and
tunings. It makes me think that whoever designed R2-D2's sounds must have been
a shortwave fan.

~~~
emmelaich
I found some intriguing music at 9700.00 AM.

Turkish I guess? But could be from anywhere from Eastern Europe to Arabia.

~~~
wpietri
That is indeed the Voice of Turkey: [https://www.short-
wave.info/index.php?freq=9700](https://www.short-
wave.info/index.php?freq=9700)

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state_less
I didn't know folks put their radios on the internet like this. Pretty neat
discovery. I found some folks by looking at the waterfall spectrograph talking
about toilet paper for $2.50 a roll on their CB near Orlando, FL.

[http://w4qed.hamshack.info:8073/](http://w4qed.hamshack.info:8073/)

Does anyone know if one of these radios can tune into satellite transmissions
or if there are any satellites that can be used as a relay?

~~~
coretx
The most popular satellite transmission receivable with that box is probably
the ISS when it passes over. When it comes to using satellites as relays i can
tell you that it's a popular practice to pirate unused US navy transponders.

~~~
SahAssar
This is probably the one you were thinking of regarding the relays:
[https://www.wired.com/2009/04/fleetcom/](https://www.wired.com/2009/04/fleetcom/)

------
mycall
Many other locations exist: [http://www.websdr.org](http://www.websdr.org)

~~~
sciurus
Another directory of receivers, all based on the KiwiSDR Wide-band SDR + GPS
cape for the BeagleBone Black, is

[http://rx.linkfanel.net/](http://rx.linkfanel.net/) (map version)

[http://kiwisdr.com/public/](http://kiwisdr.com/public/) (list version)

~~~
threeio
My kiwi is public and on the list.. its a fun device and has been super useful
to me over the years (I record shortwave radio shows, listen in on the ham
bands without having to go to my ham shack, etc)

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hanoz
Every time I see a post like this I get the urge to get myself a ham licence,
then always realise that realistically I'm never going to join a club in order
to do so. I wonder if the authorities might consider, in these interesting
times, letting people sit a foundation test online. Seems like it might be a
prudent idea.

~~~
apaprocki
Are you in the US? There is no requirement to join a club to take the test or
study for one. There’s an excellent iOS training app (written by Patrick J
Maloney), and after using that for two weeks (e.g., during commute) you’d
likely pass with no issue.

~~~
hanoz
Interesting, but no, I'm in the UK. We can sit a theory test online I believe,
but there's a practical test you have to pass first, which it seems can only
be done through clubs.

~~~
CraigJPerry
You can get the foundation with 2x 1hr visits to a local club. They absolutely
don’t want you to do this, they really want you to join but it’s possible.

I got my foundation in 2015, 10watts even in a solar minimum Like just now is
plenty.

I have a wire fan dipole strung up around inside my loft and i can do
everything i want to on 40m band or above.

I’ve had untold hours of fun with gnu radio and a hackrf.

~~~
hanoz
_> You can get the foundation with 2x 1hr visits to a local club. They
absolutely don’t want you to do this, they really want you to join but it’s
possible._

I know it's silly but it's exactly the prospect of this awkward situation
which is stopping me doing it. I can't bring myself to be saying to some old
timer: I'm interested in this hobby, you're _clearly_ interested, very
knowledgeable and keen to share, but actually I just want to do the test and
do my own thing thanks.

Not to mention I suspect every single member of my nearest club is about to be
subject to an over 70s isolation policy.

~~~
dll
I joined a university club to do the test even though I'm not a student. It
might be worth seeing if a local university has a club that would be happy to
help you?

------
jhallenworld
The MiniWhip antenna this thing uses is interesting all on its own, see:

[http://www.pa3fwm.nl/technotes/tn07.html](http://www.pa3fwm.nl/technotes/tn07.html)

I see they are widely available to buy.

------
phreeza
I recently learned that it is possible to buy shortwave airtime on reasonably
strong stations for around 30€/hour. I don't have a concrete project yet, but
I think there could be some fun projects to be done with this.

Here is an overview of stations that sell airtime:

[https://www.reddit.com/r/shortwave/comments/5mocm7/sw_statio...](https://www.reddit.com/r/shortwave/comments/5mocm7/sw_stations_that_leasesell_airtime/)

~~~
bobowzki
That seems very cheap. Like it wouldn't even pay for electricity...

I would set up a numberstation just to mystify people.

------
SL61
These can be fascinating. If you tune in at the right times on some American
receivers, you can hear the truckers communicate via shortwave. They chat on a
few different channels from hundreds of miles apart. It's like typical office
chatter, but when they say they're locations it'll be a driver in Louisiana
chatting with a driver in Ohio.

Then you can find the number stations (using
[http://priyom.org/](http://priyom.org/) to find their schedules), screaming
fundamentalist preachers, pirate music stations, ham radio (conversations can
get very weird), cults, etc.

It's a whole different world, and it's especially fun to browse through at 2
or 3 in the morning.

~~~
themodelplumber
You can occasionally hear truckers with ham radio licenses, too. :-)

If you're in the US there's a reasonable chance of finding the Cuban numbers
station on any given day. I pick it up from my back yard in CA all the time.
In fact, a bit more elusive and exciting to me are some of the trickier
stations like Radio New Zealand or NHK. Even North Korea is in many cases an
easier pull than those...

By the way, anybody interested in an easy and inexpensive on-ramp to listening
from your own radio, check out the Radiwow R-108 and XHDATA D-328. These are
less fiddly than SDRs, which can be a nice advantage for learning or
portability. The Eton Elite Mini is another one that's been really
surprisingly good in a small package.

------
marianov
How would one know the parameters to listen for example to maritime radio
("VHF" for me) LSB, USB, IQ ? What are those? I could only listen to local "MW
Broadcast" that I gess is AM radio.

Also: Any way to decode CW from a recorded mp3 or similar from this websites?

~~~
jimnotgym
LSB and USB are lower and upper sidebands. On the amateur radio bands it is a
convention to use LSB below 10Mhz and USB above. You can find the bandplan for
your country by duckduckgoing for 'bandplan usa' or wherever you live.

If you want to learn it in a little more detail, and join in, take your basic
amateur radio license. In the UK it is only a weekend course. I rarely
operate, but taking the first two amateur licenses was one of the most
interesting things I have ever done

~~~
wglb
What sideband to use on 10Mhz?

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peter_d_sherman
"In contrast to other web-controlled receivers, this receiver can be tuned by
_multiple users simultaneously_ , thanks to the use of Software-Defined
Radio."

Could someone please explain how this is possible?

Are there multiple SDR's present, with each user being allocated their own SDR
(which I would understand with no further explanation necessary), or is a
_single SDR being used to accomplish this_ , in which case, I would love to
understand how that works...

If the latter method (a single SDR) is being used... _would someone kindly
explain how that magic works?_

~~~
trothamel
Sure.

The hardware side of an SDR is a pair of incredibly fast analog to digital
converters, capable of tens of millions of samples per second. If you can
sample at 40 million pairs of samples per second, you've sampled every radio
signal in 20 megahertz of bandwidth, and moved it into a form where you can
computer.

There are then techniques that are used to recover individual signals. I'm not
really an expert in this, so forgive/correct me if I get this wrong, but my
understanding is that multiplying two signals at frequencies A and B is the
same thing as adding together a signal with frequency (A+B) and a signal with
frequency (A-B).

So for AM radio, if A is the carrier and B is the message, we can multiply
(A+B) from the original signal with a copy of A' we generate in the computer.
That yields (A+B)-A', which is just B - the signal we want to listen to. (Plus
high frequency signals that can be filtered out.)

The thing is, this last step can be done multiple times - as many times as the
computer can compute, since it's all done by the process. So that's how it can
listen to multiple signals at once.

~~~
peter_d_sherman
Fascinating!

"The hardware side of an SDR is a pair of incredibly fast analog to digital
converters, capable of tens of millions of samples per second. If you can
sample at 40 million pairs of samples per second, _you 've sampled every radio
signal in 20 megahertz of bandwidth_"

Yes, that makes _a lot_ of sense!

Never thought about that until now; you (and the other posters who have posted
virtually the same thought/thing) have expanded my mind as to what I
previously thought possible (but then, I'm a software guy who dabbles in
electronics -- not the other way around)...

But anyway, thank you! (and the other posters too!)

------
pizza
Off topic: I am looking for SDR project ideas for a signal processing class
(something to do during lockdown I suppose). Right now I'm thinking of doing a
pretty rudimentary auto-radio-remix project (ie sample multiple radio stations
simultaneously, trigger samples to form a song) or some augmented reality
plane flight vector visualization project (ie movement tracking using some
kind of sensor fusion between smartphone gps + smartphone camera + radio ads-b
data). Any more ideas appreciated!

~~~
jhallenworld
Do the inverse of the posted project: transmit an entire band, for example all
~110 channels of the AM broadcast band. Use an old AM radio to tune to around,
and hey every station is playing songs you like :-) It would be nice if this
was a UNIX command with paths to ~110 folders of MP3s or something like that.

What is the limit for something like this? I mean with a given DAC of N bits,
what resolution do you get with M channels without overflowing?

~~~
drmpeg
I've done ten channels of broadcast FM with GNU Radio. The limiting factor is
processing power. Here's a spectrum with all channels sending the same audio.

[http://www.w6rz.net/fm10.png](http://www.w6rz.net/fm10.png)

------
steveharman
It's a constant mystery to me why 90%of webSDRs have such terrible UIs.

Has nobody considered creating one which looks like, oh i don't know a digital
shortwave receiver?

~~~
droidist2
I'd love this, but it seems like these days people are against skeuomorphism.

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heyflyguy
This is an especially fun tool to play around with when SkyKing messages are
being broadcast!

[https://mt-milcom.blogspot.com/p/what-is-emergency-action-me...](https://mt-
milcom.blogspot.com/p/what-is-emergency-action-message-or-eam.html)

------
sakopov
This is so interesting. I just found a bunch of guys talking on a random
frequency in Russia. Spent about 10 minutes learning controls, tweaking and
adjusting and finally able to hear what they're saying clearly.

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michal_f
Another one [https://airspy.com/directory/](https://airspy.com/directory/) But
you need to download windows app Sdr#

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passthejoe
I love this service. I am really interested in learning how to do this myself.
And like others, it would be nice for all the code to be open source.

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jhallenworld
BBC on 882 KHz.. also on 198 KHz (no long wave in the US) it's interesting
what you get on AM broadcast from the Netherlands..

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timonoko
Bloody useless, because there is absolutely nothing to listen to. In olden
times every country has their own shortwave radio. And in many languages too,
you could heard Finnish from BBC, Radio Moscow, Soviet Estonia, Soviet
Karelia, Sweden and Voice of America. Sources were conflicting hugely, like
with "minor gas leak" from Chernobyl and "hooligans causing disturbances" in
Czechoslovakia.

~~~
jascii
While there are less public broadcasts on shortwave then there once were,
there is still plenty of utility stations, radio amateurs, and various other
uses. By no means "bloody useless"

------
geuis
Mobile version doesn’t seem to work on mobile Safari, or I don’t know what I’m
doing.

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punnerud
Is the number of users in from statistics at the bottom in thousand? Around
394.34 now.

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uranium235
This is pretty cool please keep it running

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loeg
Warning, autoplays noise.

