You're definitely on the right track ;) It would be (theoretically) exactly as you describe: additional hardware would be necessary to divide the master clock down to a suitable rate for the antenna switch - and the rest is done in software!
Balint (VK2FUNK), myself (VK2TVK) and Nick (VK2DAP) were out getting dinner in Newtown, Sydney, when Balint and myself started discussing RDF and how the doppler could work in SDR. While we were talking about how to switch the antennas, Nick loudly proclaimed "HUFF DUFF!" in an enthusiastic voice. It stuck, however, because we were doing it on VHF/UHF (specifically UHF CB and GRN band) we dropped the HF part and it became DUFF DUFF. And yes, it must be proclaimed loudly in a boisterous voice!
Thanks for the interesting video. Do you really need to switch each antenna on and off in sequence? Would it not be possible to measure the phase difference from each one on a continuous basis?
Not specifically an Australian thing - more a variation on a theme for the higher frequencies. Should be said with great enthusiasm and conviction! There's always a first :)
Hi, great video! Is there any documentation, or public files for the GNU radio flow chart? I've got a USRP-b210 and would love to have a go emulating this project, but am struggling with the programming side
Hmm would there be a way to use the realtek 20 dollar dongle to do this if you could somehow get the clock out of it and into the switch? or does it just not have enough power for that.
At video time 02:20 "DUFF DUFF". Is this an Australian thing? I believe most places (at least most English/American speaking that I have dealt with) use the term HUFF DUFF for HF DF, but I don't think I have ever heard DUFF DUFF applied before.
I'd be tempted to have a couple of clock locked sdr receivers and note the received phase angle between them. Stereo headphones and aerials on head anyone? ;-) Gnu radio trickery to only show only the chosen phase signal (as received) while line of sight would be uber for signal cleaning on the noiser bands.
maybe breaking out the oscillators pins on the dongle and then feeding those into some signal processing to be able to switch the antennas at the same clock as the cheap radio module.
Balint, are you serious?....At 6:31 your explanation of audio pitch change is absolute BS. Indeed pitch slightly depends on sound level. The effect is so tiny that most people don't ever notice it in normal life. But in case of the mentioned siren pitch change, doppler shift is causing this phenomenon for more than 99%. Really...
Pity he was in OZ and the mic was in NZ. Why don't digital specialists know any thing about sound? Pretty grim sound track and frequently unintelligible. Every time he dropped his voice often and just 'wasn't there'. Pity, could have been a great video. And the constant rumble.... Oh Dear! Couldn't keep up the interest. Got sick of him 'throwing away' words. No doubt some clever devil will hound me for criticising. Doesn't make me wrong!
You're definitely on the right track ;) It would be (theoretically) exactly as you describe: additional hardware would be necessary to divide the master clock down to a suitable rate for the antenna switch - and the rest is done in software!
Balint (VK2FUNK), myself (VK2TVK) and Nick (VK2DAP) were out getting dinner in Newtown, Sydney, when Balint and myself started discussing RDF and how the doppler could work in SDR. While we were talking about how to switch the antennas, Nick loudly proclaimed "HUFF DUFF!" in an enthusiastic voice. It stuck, however, because we were doing it on VHF/UHF (specifically UHF CB and GRN band) we dropped the HF part and it became DUFF DUFF. And yes, it must be proclaimed loudly in a boisterous voice!
Thanks for the interesting video. Do you really need to switch each antenna on and off in sequence? Would it not be possible to measure the phase difference from each one on a continuous basis?
At 2:50 "Rotatable loop antenna is not correct. This is a crossed pair of loops and does not physically move.
Not specifically an Australian thing - more a variation on a theme for the higher frequencies. Should be said with great enthusiasm and conviction! There's always a first :)
Very nicely presented
Hi, great video! Is there any documentation, or public files for the GNU radio flow chart? I've got a USRP-b210 and would love to have a go emulating this project, but am struggling with the programming side
could you calculate bearing AND distance if you know the transmitter wattage and antenna type?
Hmm would there be a way to use the realtek 20 dollar dongle to do this if you could somehow get the clock out of it and into the switch? or does it just not have enough power for that.
hello i would like to know wich IC you used for the antenna switch
At video time 02:20 "DUFF DUFF". Is this an Australian thing? I believe most places (at least most English/American speaking that I have dealt with) use the term HUFF DUFF for HF DF, but I don't think I have ever heard DUFF DUFF applied before.
Interesting. Thanks for sharing.
Perhaps "duff duff" is taken from the sound as the signal comes and goes while duffing?
I'd be tempted to have a couple of clock locked sdr receivers and note the received phase angle between them. Stereo headphones and aerials on head anyone? ;-)
Gnu radio trickery to only show only the chosen phase signal (as received) while line of sight would be uber for signal cleaning on the noiser bands.
maybe breaking out the oscillators pins on the dongle and then feeding those into some signal processing to be able to switch the antennas at the same clock as the cheap radio module.
Dumb question time - does fake Doppler also work with an AM source?
Ben Potter Yes
Thank you!
Cool but it seems like it'd be easier to just get a conventional Ramsey kit
This would have been better if you'd taken out the background noise before posting. It's really annoying to those of us with high frequency loss -----
If it were background noise, I could agree but it's at least as loud as the knowledge himself. Had enough @12.59
Balint, are you serious?....At 6:31 your explanation of audio pitch change is absolute BS. Indeed pitch slightly depends on sound level.
The effect is so tiny that most people don't ever notice it in normal life.
But in case of the mentioned siren pitch change, doppler shift is causing this phenomenon for more than 99%.
Really...
But I know nothing about RF so I could just be terribly mistaken haha
Pity he was in OZ and the mic was in NZ.
Why don't digital specialists know any thing about sound?
Pretty grim sound track and frequently unintelligible.
Every time he dropped his voice often and just 'wasn't there'.
Pity, could have been a great video.
And the constant rumble....
Oh Dear! Couldn't keep up the interest.
Got sick of him 'throwing away' words.
No doubt some clever devil will hound me for criticising.
Doesn't make me wrong!