The R.O.L.B (Radio Operators for a LISTEN Breaktrough)

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Message 1917984 - Posted: 10 Feb 2018, 2:48:05 UTC

I was just thinking...

The beautiful story of Tabby's star and the citizen science project...
The picture of Jodie Foster with her headphones...
The Breakthrough LISTEN project were no one is listening...

I am an amateur radio operator and an ex marine chief radio officer and chief electro technical officer.
I am currently working as head end technicien for a major tv, internet, telephone, etc provider and I would
love to have a small part of the GBT antenna feed into my up coming high end DSP receiver... And I am surely
not the only one.

Think about it.

A live feed from GBT. (IP)
+
10,000 amateur radio operator each of wich are equip with a high end DSP receiver and an
allocated 1 MHz bandwith to listen to.
+
A good pair of headphones, A big tunning knob on the desk and a good spectrum analyzer.
+
Years of experience in listening to all kinds of signals and noises from 10Hz to 15GHz.
+
Familiar with polarizations, bandwidth, carriers, modulations, filters, interferences, doppler, etc (radio stuff)
+
Morse code operators that are familiar with CW and and narrow band signals.
+
a direct communication with SETI to report possible candidate signals (time, frequency, etc)
for further data analysis.

20,000 ears that are used to deal with extremely weak signals. Canada-Japan long path with 1 Watt ERP !!!
You guys at seti are good in physics. How many ┬ÁV at the receiving antenna assuming that the signal
bounced 2-3 times on the ionosphere before arriving at the receiver's 3dB gain antenna ? I know things are missing
in my ennonce and I know we are only talking thousands of KM here and not thousands of light years but my point is as follow ;

If an alien radio signal is strong enough to make his way into the GBT receivers and then be detect by a computer,
the same signal is, I think, strong enough to make his way into Jodie Foster's headphones. Assuming that a trained
radio operator is turning the knobs of a very sensitive and selective high end DSP receiver for her...

Computer method for searching technological radio signals is not perfect and they could miss something. The search
is exciting but too much computer oriented I think. I know we have only looked at a glass of water in the oceans so far
but how many MW of computing power in the last lets say 25 years ?
I have the feeling that this could lead somewhere. hours and hours that we amateur radio would dedicate to the task.
It would be a new thing and they would come by thousands. One should not underestimate the potential this enormous
pool of radio fanatics have. We talk to the International space station, we have our own satellites and we even use the
moon as reflector (moon bounce) !!! Aren't we the first to have tuned on and track Sputnik in Otober 57 ?
I was not born yet but what a thrill it must have been to ear Sputnik's radio beacon coming out of the warm and smelly
vacuum tube receiver for a few seconds...

I see it very well. The R.O.L.B (Radio Operators for a LISTEN Breaktrough) Dont know I might be totally dreaming...
As a matter of fact I am dead tired, but It would be really really fun.

Cheers and good week end to all !

Marc Verdoni
VE2MVE
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Message 1918036 - Posted: 10 Feb 2018, 12:19:53 UTC

I have to precise. I know the breaktrough listen project has nothing to do with ''listening'' for radio signals...
But my point is and can be confirm by anyone working in the radio field, any RF signal will produce a sound
on a radio receiver when properly tuned. Weather radio fax are not intended to be ''heard'' but if you tune a
side band receiver on it you will ear it. you probably wont know what are all these weird sounds coming out
of the speaker but you can tell right away if there is something there. What people dont understand is that
searching for triplets etc is what you do when you dont have anyone to listen... Computers are stupid and dont
know anything about radio noises. That is the only way for them to discreminate a signals in the noise. And it takes
a lot of time.

An example of that. Tune GBT on a local radio station. it will be record, split it in many pieces, sent to many computers
that are looking for triplets, sent back to seti, analyse, recombined etc etc etc. that takes time ok. Now. Take a radio receiver
and tune it on that same local radio station, you will hear right away that there is something there.
the problem is the amount of ''channel'' we have to monitor (bandwidth) one radio operator can not monitor all of it at
the same time. but suppose you have thousands of them !

Anyway I think my idea can only be fully understand by those who knows about radio stuff. really.
my post was kind of intended to be understood by those who understand radio basics. People here somehow thinks that
only computers are capable of detecting an alien radio signal. That is absolutely not the case. That is what you do when
you have no one to ''listen'' but at the same time have hundreds of thousands computer available.
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Message 1918055 - Posted: 10 Feb 2018, 14:26:54 UTC
Last modified: 10 Feb 2018, 15:19:01 UTC

OK. I have received a couple of private messages and I have to precise again.
Radio signals as for RF (radio frequency) signals. not as AM or FM broadcast
station. RF signals just like the one coming out of my wifi modem, cell
phone, gps satellites or voyager spacecraft.

I have also had comment about the fact that we could not decode an alien
RF signals using headphones but I think our intention here is not to decode anything
but simply find an intelligent source of RF signals and It could be anything. Some kind
of alien radar technology using RF or micro waves could be detect here but how could
we possibly tell what that RF signals is for ? It just doest matter at this point.
How could any aliens ''decode'' and make sense of an MPEG4 encoded QAM modulated IP
porn movie.... ??? They would ''understand'' anything but they would know right away that
it does not have a natural source. Isn't it what we hare trying to do here ?

Well guess what ! when I put my wide band UHF portable receiver next to my wifi modem I can here
it because the RF signals makes his way into the receiver stages (heterodyn, Intermediate frequency,
detector, IF and audio amplifier and speakers all the way to my ears. Just like it would make a spike
on a spectrum analyser.

Anyway I think it could be a cool addition to the breaktrough listen project to give the amateur radio
community the possibility to Listen. It would be popular and symbolic. And why amateur radio only you might
ask. because we know how aircraft radar and meteor scatter ''SOUND'' like but we have never received an alien
radio signals. Listening to all kinds of RF signals is what we do. If A strong alien radio signal makes his way
over here and can be detected by computers, chances are the same signals would make his way into the audio
and spectrum analyser of any high end DSP receiver. Plug a pair of headphones into it, tune to the right frequency
and you will hear strange skeek beep beep tik tik tik noises. It does not matter what it is, you ear it.
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Message 1918077 - Posted: 10 Feb 2018, 16:22:45 UTC
Last modified: 10 Feb 2018, 16:29:18 UTC

And again... I am not proposing we should all stop crunching and go buy a pair of headphones !!!!
I am saying it would be cool and fun but mostly not entirely useless. Computers are essential.
I do know a little bit how difficult it could be to separate wanted and unwanted signals sometimes
and that ''listening'' to signals that have traveled very long distance in a stretching universe filled
with all sorts of natural RF sources is some other ball game than just tune on BBC radio international,
but I would and many others too, spend many hours playing with the ''knob''. Who knows what we might
find.

I would be curious to see what crazy idea would come out of a discussion between top SETI peoples and
top ARRL peoples... Guess what they would be talking about ?
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Message 1918096 - Posted: 10 Feb 2018, 18:28:44 UTC - in response to Message 1918077.  

How would you get the GBT feedhorn RF to the amateur listeners? I think you would have to digitize the rf and packet it off to the Internet. Even with the the best A-D converters, you still have to deal with quantization noise and linearity issues. Think you would have to preserve the original S/N ratio of the feedhorn RF. Don't know the numbers, but probably they have been published somewhere in an article explaining the sensitivity of the GBT antenna. Guessing its somewhere around -144 dBa. Anyone know the exact numbers or the web page for the antenna detailing its characteristics?
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Message 1918105 - Posted: 10 Feb 2018, 20:21:40 UTC - in response to Message 1918096.  
Last modified: 10 Feb 2018, 20:22:11 UTC

Yes you are right it would probably be difficult to sample the RF without affecting it somehow. I know nothing
about how the RF is transport to the receivers on a radio telescope (Coax, wave guide) etc. I am not a scientist
or an engineer but there is got to be a -20dB test point somewhere... I would be fine with that.

And yes I think you are also right IP would be the best If not the only way to transport it to the listeners. Dont forget
we are only sending chunk of the total bandwidth. each listeners could receive one channel of lets say 100 KHz wide.
Nothing that internet cant handle I think.

Do you know what kind of internet bandwidth would be needed to to broadcast the GBT feed ? It would not be free
thats for sure... I wish I could go there and plug my ''very noisy'' receivers, compare to the ones they have, directly into the feed,
picnic table under the dish, a beer in one hand and the other on the radio, Just listening, Jodie Foster style.
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Message 1918110 - Posted: 10 Feb 2018, 20:50:52 UTC

How many receivers at GBT ? If more than one they have to split the source somehow.
It might turn out to be very easy to do... And the more I think about it the more I am
convinced it would be very popular in the amateur radio community.
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Message 1918155 - Posted: 10 Feb 2018, 23:26:37 UTC - in response to Message 1918110.  

I can't seem to find the post describing the hardware at GBT, but I think the Alpha receiver at Arecibo had something like 11 channels or whatever.

Looking around for the GBT hardware post I stumbled on the Breakthrough Listen SETI website with some interesting information. The embedded video from Steve Croft on page 2 shows him demonstrating the NooElec SDR dongle and he moves on to how you could use a SDR for radio astronomy at 5:43 in the video timeline. The great thing about SDR's is the software gives you spectrum analyzer and waterfall plots. It it easy for our eyes and brain to pick up transient signals that way. Adding our ears to the sensory input only helps.

Breakthrough Listen at UC Berkeley

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Message 1918295 - Posted: 11 Feb 2018, 18:05:53 UTC

I would not have been good working at NASA I mix my acronyms all the time.
I often mix DSP and SDR...

Yes SDR would be the way to go of course with the spectrum analyser and everything.
Looking a t a few manufacturers though I cant find any for 1.2 GHz and up.
I had a look at Flex they don't have any receivers for the bands GBT is ''listening''
to.

Just for fun google image ''amateur radio seti'' there are a lots of miniature ''GBT''
antenna in back yards. That is cool. Great links I will spend some times reading and
learning SETI today.
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Message 1918304 - Posted: 11 Feb 2018, 19:04:20 UTC - in response to Message 1918295.  

Well this quote is from the Breakthrough Listen wiki page.

In April 2017, the project released its first set of results, covering the observations of 692 nearby stars at frequencies from 1.1-1.9Ghz (the L-band)

So all the SDR's that I am familiar with tune that band of frequencies. Most SDR's go to around 2 Ghz, some as high as 6 Ghz and then if you want to tune higher you just put a down-converter in front of the SDR receiver.
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Message 1918316 - Posted: 11 Feb 2018, 20:15:34 UTC - in response to Message 1918304.  

So all the SDR's that I am familiar with tune that band of frequencies. Most SDR's go to around 2 Ghz, some as high as 6 Ghz and then if you want to tune higher you just put a down-converter in front of the SDR receiver.
Thats the problem I am not familiar with any of them actually. Can you post a link to a SDR that would be great for the L-Band ? I could search again but since you seems to already know a few... I know that flex does SDR box that looks like a ''radio'' and I like that. https://www.radioworld.ca/flexradio-flex-6600-m That one is a transceiver but you get the idea.
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Message 1918322 - Posted: 11 Feb 2018, 20:38:04 UTC - in response to Message 1918316.  
Last modified: 11 Feb 2018, 20:50:53 UTC

Well, there are hundreds available on Ebay at the normal $20 dongle cost. Just search for RTL SDR on Google. I like my:
SDRPlay RSP2 receiver for $170

I like that it has 3 antenna inputs. Seems very well made. All you have to do is plug it into a computer or laptop and load the software of your choice and you are up and running.

There are lots of different software programs and the development community is very active.

You might want to start here with the beginners forum SDRplay Community Forum

Using a SDR radio is very different from spinning a tuning knob on a conventional receiver. And there are high-end SDR with actual knobs for their tuning interface.

[Edit] Just discovered there is a new SDRPlay SDR the RSP-1a which improvers on the RSP2 10bit ADC to a 14bit ADC and is only $120.
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Message 1918328 - Posted: 11 Feb 2018, 20:54:53 UTC

If we put a GBT dish like in space equip with an ultra wide band SDR receiver and and a 2GHz span on the spectrum what will happen when you
turn the dish towards the earth ? the spectrum analyser will be filled with bumps everywhere. It will look like a single giant wide band
transmission containing lots and lots of information. Why looking at narrow signals only ? I am just a technician but would it not be a good way
to search by just simply go from star to star ultra wide and when you pick one that has more bumps than average you investigate ?
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Message 1918331 - Posted: 11 Feb 2018, 21:03:06 UTC - in response to Message 1918322.  

Well, there are hundreds available on Ebay at the normal $20 dongle cost. Just search for RTL SDR on Google. I like my:
SDRPlay RSP2 receiver for $170
Wow I dont know what to say.
The last time I had a look at those receivers was like 10 years ago... They are so non expensive !!! Long time ago receivers needed to have only
3 qualities. Sensitivity, selectivity and fidelity. How do those little SDR performs in those matters ? They are software define so I guess one can
makes it the way he wants.
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Message 1918346 - Posted: 11 Feb 2018, 21:33:48 UTC

And BTW why arent we searching using 2 antennas (differential) ?
Point the 2 dish at the same star and ''look'' at the bumps. Those that appear
in just one antenna is for sure local. Local RFI problems solved. Must be a
budget and telescope time limitations I guess. It would be so much more
efficient. The scientists at SETI are far from stupid and I highly respects
them. I have watched a few Berkeley video on youtube and it looks like a
cool team. BUT ! If you tell me they have never thought about that I quit
SETI forever. No seriously it would be so much better to use two dish at the
same time.
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Message 1918357 - Posted: 11 Feb 2018, 21:56:43 UTC - in response to Message 1918331.  

Well, there are hundreds available on Ebay at the normal $20 dongle cost. Just search for RTL SDR on Google. I like my:
SDRPlay RSP2 receiver for $170
Wow I dont know what to say.
The last time I had a look at those receivers was like 10 years ago... They are so non expensive !!! Long time ago receivers needed to have only
3 qualities. Sensitivity, selectivity and fidelity. How do those little SDR performs in those matters ? They are software define so I guess one can
makes it the way he wants.

Well you get comments fairly regularly that the SDR's don't match up to receiver sensitivity of older equipment. But if you consider my prior comment about how much 'quieter' the noise spectrum was back when I first started in ham radio, I don't think the receivers of those days would hold up all that well in today's noise environment.

With regards to sensitivity, they are maybe just a bit shy of the best in today's hardware. Regarding selectivity and fidelity, you can change those characteristics at will easily in the software. You can set up many different profiles depending on what signal you want to receive. The software selectivity settings for CW beat any 20 pole CW filter of the past hands down. When I tune to a FM station all I have to do is change over to a FM bandwidth to get full fidelity. The SDR's cover everything pretty well. And for what they cost now, it is amazing what the performance is.
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Message 1918359 - Posted: 11 Feb 2018, 22:03:52 UTC - in response to Message 1918346.  
Last modified: 11 Feb 2018, 22:09:43 UTC

And BTW why arent we searching using 2 antennas (differential) ?
Point the 2 dish at the same star and ''look'' at the bumps. Those that appear
in just one antenna is for sure local. Local RFI problems solved. Must be a
budget and telescope time limitations I guess. It would be so much more
efficient. The scientists at SETI are far from stupid and I highly respects
them. I have watched a few Berkeley video on youtube and it looks like a
cool team. BUT ! If you tell me they have never thought about that I quit
SETI forever. No seriously it would be so much better to use two dish at the
same time.

Primary reason is that only GBT is steerable for our current antennas. Arecibo is not. You would have to coordinate observing campaigns at each antenna. Also, we don't have exclusive access to the target observation star, we normally just 'piggyback' on the nights primary science target and have our receivers and recorders listen in as secondary. I do believe that many of the radio telescopes DO in fact do long baseline interferometry of observing targets. With bringing on the steerable Parkes array in Australia in the future there should be candidates at the celestial equator visible at both GBT and Parkes. So we theoretically could do differential listening if the hardware is compatible.
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Message 1918363 - Posted: 11 Feb 2018, 22:24:09 UTC
Last modified: 11 Feb 2018, 22:54:18 UTC

I am ordering one right now for real. I dont know why I dont already have one in my shack. Seriously.
I have not been active much in radio recently but boy I am late with new things.
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Message 1918368 - Posted: 11 Feb 2018, 22:37:06 UTC - in response to Message 1918359.  

Primary reason is that only GBT is steerable for our current antennas. Arecibo is not. You would have to coordinate observing campaigns at each antenna. Also, we don't have exclusive access to the target observation star, we normally just 'piggyback' on the nights primary science target and have our receivers and recorders listen in as secondary. I do believe that many of the radio telescopes DO in fact do long baseline interferometry of observing targets. With bringing on the steerable Parkes array in Australia in the future there should be candidates at the celestial equator visible at both GBT and Parkes. So we theoretically could do differential listening if the hardware is compatible.
Understood. So in a perfect world we would at least have 2 steerable dish in the northern and 2 in the southern hemisphere each pair in deferential mode with primary access all year long.
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Message 1918373 - Posted: 11 Feb 2018, 22:54:55 UTC - in response to Message 1918368.  

Primary reason is that only GBT is steerable for our current antennas. Arecibo is not. You would have to coordinate observing campaigns at each antenna. Also, we don't have exclusive access to the target observation star, we normally just 'piggyback' on the nights primary science target and have our receivers and recorders listen in as secondary. I do believe that many of the radio telescopes DO in fact do long baseline interferometry of observing targets. With bringing on the steerable Parkes array in Australia in the future there should be candidates at the celestial equator visible at both GBT and Parkes. So we theoretically could do differential listening if the hardware is compatible.
Understood. So in a perfect world we would at least have 2 steerable dish in the northern and 2 in the southern hemisphere each pair in deferential mode with primary access all year long.

Yes, that would be desirable. Add in the Murchison radio telescope array in Western Australia, or one in South Africa or India and there you go. Long baseline differential listening.
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