I created a Geo Fizz drink to enjoy while watching Time Team, combine to your taste gin, elderflower liqueur, orange juice and seltzer. A caution! If you take a drink whenever you hear “geophys,” you might not make it to the end of the episode.
What a treat to come home to this after my overtime workday. Can I just say that I'm overjoyed you can drive the array around at least a bit now as well Jimmy! Dr Gater chose well in you. I always empathised with your work loads, glad you got that new setup!
This is great, I study a degree in geology and remote sensing in mid late 90s and John & his team taught me more about geo phys than my lecturers every did as Time team explained simply than the classes. And I swear with TT I would never had passed geo phys modules at uni
I hear this sooooo much in general that I sometimes wonder if it wouldn't be better to have a few basic classes and then go for learning things in the field. Seems studies are almost "never" really applicable.
I am from norther germany and yesterday we were watching a documentary on our equivalent of a BBC reginal channel. It was about old houses beeing rescued. One of those old farm houses by folklaw had an old castle on its grounds. So they invited the local achreology unit to have a look and by using geop phys thes got a pretty good plan of the complex. Complete with a moat and buildings. And I thought, just like time team :)
I’ve been a relative latecomer to Time Team, having only discovered the show after it ended. Thank goodness for RUclips. These deep dive programs provide such deep insight into all the different disciplines that go into modern archaeological discovery.
Thanks Jimmy for the info. Just waiting for the new TimeTeam to start this spring. It was always a good day watching Mick he was always was a gentleman 🌹
Whether your sharing stories or explaining technology, I’m hanging on every word. I bet you could write a fun book on all the inside stories from all those digs. It’s so neat to see how radar has evolved. Thanks for the video!
Great explanation of the data,and how you translate it into 3D images. I can't wait to see these new advances and how they inform the digs,and tie that into the drone surveys,and footage of the site and surrounding landscapes and we are in for some fantastic new Time Team Digs.
You provided answers in Comments to all the questions I was thinking of asking plus answers to questions I didn't know to ask. A real masterclass. Thank you very much.
Nice video, especially the bits showing the direct comparison between GPR slices and photos from the excavation. Are more videos like this to be made, and perhaps on other techniques?
Super fascinating! As an astronomer, I can relate to and love how technology is allowing us to study history (of people on Earth, and of space) better. Modern cameras on telescopes for example collect as much data in a few days of observing as cameras 20 years ago did in an entire year! Some collect so much that it needs to be processed in real-time as it cannot be stored!
Super video thanks for doing it. I was wondering what sort of frequency and PRF/PRI the machines operate at and if you had to alter that depending on the grounds moisture content?
For a lot of archaeological work 250-750Mhz is common. Repetition rate is dependent on the system design, I think for the ones used in these examples it is a few hundred kHz.
Thanks Jimmy! I enjoyed that masterclass! I’d enjoy longer ones also… So I have a question …. I thought I heard something like different materials reflect the GPR energy with different intensity. If I got that bit right …based on the strength of the reflected signal, can you make guesses about the type of material that’s reflecting the radar signal?
It's kind of right. The reflection strength/type is related to the material but it is more about the contrast in electromagnetic properties. So a sandstone block buried in hard-packed sand wouldn't give you the same response as that sandstone block buried in a more organic soil. So that causes problems on archaeological sites where a wall might run from natural through other materials like demolition rubble or midden material and the same wall could present a different response through those materials.
Not a huge amount you can do about it. You can tweak the processing and contrast levels in the plots but if the contrast ain't there in the first place you're not going to be able to generate it later. Trying an alternative technique that is responding to different physical parameters is usually the best option and actually the most complete interpretations will come from multi-technique surveys.
Brancaster was fantastic. The GPR data was so detailed that you could almost have done the whole episode based on 3D reconstructions of the GPR data. I gather Brancaster was very dry and that helped the radar? GPR results seem poor when there's a lot of moisture or clay? Great presentation!
Yes, anything that increases conductivity is bad news. In conductive ground, the GPR signal is attenuated (absorbed) very quickly and so you get very limited penetration. Fresh water is actually not a problem - we can image through ice and river/lake water - but normally water in the ground contains salts and minerals that make it more conductive.
Question - What is the maximum depth to which the GPR can reach? What do you see next generation instruments being able to do that today's instruments can't?
It really depends on the frequency of the antenna and the material you're looking through. High frequency signals get absorbed faster than low frequency. Electrically conductive materials absorb quicker than resistive, and if something is homogenous (doesn't cause many reflections) the energy will travel further. So GHz antennas will give a few centimetres in concrete, 25 MHz antenna over good soils might give 30m, low frequency antennas through ice can give 100s of metres. A lot of archaeological work uses systems that will return 1-4m of penetration.
Hi - what frequencies are used for GPR? For subterranean communications we have to use a few kHz rather than the GHz of ‘normal’ radars. Also the pulse duration must be extremely short to work over centimetres rather than kilometres? What kind of power is used - getting a high power T/R cell to work at ps speed must be a challenge?
Most GPR is typically running between 25Mhz and 2.5Ghz with lower frequencies for deeper (10s of metres) lower-resolution geological, landform mapping and higher frequencies for shallow (few centimetres) high resolution structural studies of concrete, surfacing material etc. The sweetspot for a lot of archaeology is in the 250-750Mhz range where you get a sufficient penetration for most environments at a decent resolution. Power is pretty low - partly because for most applications high power isn't required, and partly due to legislation on transmission of radio waves. Individual antennas are normally outputting less power than a mobile phone.
@@jimmyadcockABEM Thank you for the information! Are the pulses very short or do you use chirped FM signals? I had supposed there was a specific band (like ISM bands) but I suppose since the energy is mostly headed into the ground there is not much leakage, so you can operate at any frequency provided it doesn’t annoy the neighbours :-)
Yes, very short. These are pulse systems and I think the ones used here would have been firing pulses at a rate of 200+kHz (there are also stepped frequency CW systems available on the market). You're right about the frequencies but legislation varies country-to-country. In the UK you need a license from OFCOM to operate a GPR and that dictates the range of antenna frequencies you could use, also states it must only be used whilst transmitting into an absorbing medium (i.e. don't wave it around like a flag) and has special stipulations about working in sensitive areas (primarily within a certain radius of radio telescope facilities). You also must keep a log so if those neighbours do complain you can demonstrate whether or not you were likely to be the culprit of their interference. As far as I am aware, there have been no recorded instances of GPR upsetting other systems (and plenty of work gets done at airports) when being used correctly.
You'd probably be looking at 4 figures for a full day of survey. But time was normally the limiting factor on Time Team. We never did full days of just data collection because we had to balance how much data we collected with having the time to then process it, interpret it and position the next trench for the diggers.
Awsome explanations . Thanks very much. Omg If i knew this science was a thing, I would strongly thought about it. But then , land survey technician is also cool so , i have I no regret 😊
Sadly not - the ground just isn't quite solid enough. The sonar pulses are transferred by vibration, works in water and some waterlogged materials as there is no/very little compression to absorb the energy but just doesn't work through other media.
@@jimmyadcockABEM Thank you - I have wondered about that for ages. I still think sound waves could have wider use in Geophysics, if only to find an old Roman bridge in a river, for example.
We can actually use GPR for looking at material within river beds. We gave it a go in the Piercebridge episode but the bed was a bit too rocky. Fresh water is surprisingly resistive so we can use the GPR in the bottom of a boat and it will penetrate deeper than sonar into the sediments if the river bed. We also could use resistivity through the water, or even seismic - all would offer better penetration and decent resolution.
@@jimmyadcockABEM A fair point, but I have seen no discussion of such techniques prior to this. I attended a Computer-Assisted Archaeology seminar a few years ago, and nobody there could answer my questions, sadly I still think that there's scope for the drone idea, as we know that ultrasound is used for car 'radar'. Thanks.
There is story that 1000 years ago two chests with silver coins were hidden in valley. I think the only possible place is where there used to be pond. But that place is now dry grassland. Would it be possible to see "lumps" of silver at 1-2 meters deep in the ground? The chests were small enough for one man to carry both.
Rule of thumb is that to detect something with GPR, its size needs to be at least one tenth of the depth it is buried at. So for 1-2m deep, you won't see stuff that is less than 10-20cm across. So probably not. Also too deep for a metal detector to be effective.
@@jimmyadcockABEM Yes, I knew that the metal detectors wouldn't reach it. Probably not worth special trip. Also considering the fact on map from 18something name the pond "Lucky Pond" so....someone got lucky there at some point, I guess. I just thought lump of English silver coins, 1 - 5 kg would be detectable at that depth. Perhaps after 20 years...
Ah yes, I missed that the story had them in chests; might well be big enough to find. Next consideration is the soil type - if it's clay-rich (not uncommon in former wet areas) that's an Achilles Heel for GPR as it absorbs the signal very quickly indeed, and you may not see deep enough. Then, finally, are there likely to be natural targets of a similar size - would be very difficult to distinguish between large stones and chests and you'd want to be sure before someone gets sent in, armed with little more than a spade and wheelbarrow!
@@jimmyadcockABEM Shame - here is the story. The last part in "Life" is about when he hides the treasure. en.wikipedia.org/wiki/Egill_Skallagr%C3%ADmsson
When I first started it was resistance survey (the 'zimmerframe') because that felt like "proper Time Team Geophys" from the episodes I'd watched before joining. Latterly it was anything you could attach to a vehicle. Software-wise, GPR-Slice was used for most of the Time Team models but the live stuff in the video was using our online software MALÅ Vision which actually has a free option for working with small datasets, so that's useful when you're first starting out.
I dont think so...he has been involved in the latest T T digs, and you see him regularly on the Patreon T T videos, talking, discussing, verbally beating up on Stuart!
Lidar measures the surface topography, i.e. Stewart's beloved "lumps and bumps", it doesn't 'see' into the ground because it works using light (in the form of laser). EM waves can transmit through soils and geology.
As someone that spends a lot of time in Norfolk (but lives in south Lincolnshire most of the time-it is definitely flat here) I get fed up with the amount of people saying Norfolk is as flat as a pancake! If you go to any coastal town or Norwich; you'll find many a hill. But yes norfolk is mostly flat. However, I did enjoy learning about the new geo phys equipment.
I miss Mick. I think I stopped watching: being able to, when he passed. All the joy that a child feels for archeology kind of died in me when he wasn't there with his rainbow colors and childlike smile to point out all the things I didn't know. That and his tactful handling of the Geo Phys team. Hmm.
![Noob To Max With DRAGON REWORK In Blox Fruits [FULL MOVIE]](http://i.ytimg.com/vi/LnBMOinoOvA/mqdefault.jpg)
I created a Geo Fizz drink to enjoy while watching Time Team, combine to your taste gin, elderflower liqueur, orange juice and seltzer. A caution! If you take a drink whenever you hear “geophys,” you might not make it to the end of the episode.
I like imported Gin like Tanqueray.
Did your father smell of elderberry? :)
@@davidandrew1078 No, but there may be hamsters in my ancestry.
@@davidrasch3082 I use Bombay gin.
laughing my ass off over your comment. love it.
What a treat to come home to this after my overtime workday. Can I just say that I'm overjoyed you can drive the array around at least a bit now as well Jimmy! Dr Gater chose well in you. I always empathised with your work loads, glad you got that new setup!
❤️❤️❤️Jimmy -always has a chuckle ready. No one can walk a stick across a field like Jimmy!
Hello stef how are you doing 👋👋👋👋👋
Hello stef
This is great, I study a degree in geology and remote sensing in mid late 90s and John & his team taught me more about geo phys than my lecturers every did as Time team explained simply than the classes. And I swear with TT I would never had passed geo phys modules at uni
I hear this sooooo much in general that I sometimes wonder if it wouldn't be better to have a few basic classes and then go for learning things in the field. Seems studies are almost "never" really applicable.
Hello Helen
Outstanding, my favourite so far. Another 15 minutes please.
I remember my first exposure to GeoPhys on Time Team. Watching the technology develop through the Time Team programs has been fascinating.
Hello Mari
I am from norther germany and yesterday we were watching a documentary on our equivalent of a BBC reginal channel.
It was about old houses beeing rescued. One of those old farm houses by folklaw had an old castle on its grounds.
So they invited the local achreology unit to have a look and by using geop phys thes got a pretty good plan of the complex. Complete with a moat and buildings.
And I thought, just like time team :)
I’ve been a relative latecomer to Time Team, having only discovered the show after it ended. Thank goodness for RUclips. These deep dive programs provide such deep insight into all the different disciplines that go into modern archaeological discovery.
Thanks Jimmy for the info. Just waiting for the new TimeTeam to start this spring. It was always a good day watching Mick he was always was a gentleman 🌹
Whether your sharing stories or explaining technology, I’m hanging on every word. I bet you could write a fun book on all the inside stories from all those digs. It’s so neat to see how radar has evolved. Thanks for the video!
Great explanation of the data,and how you translate it into 3D images. I can't wait to see these new advances and how they inform the digs,and tie that into the drone surveys,and footage of the site and surrounding landscapes and we are in for some fantastic new Time Team Digs.
You provided answers in Comments to all the questions I was thinking of asking plus answers to questions I didn't know to ask. A real masterclass.
Thank you very much.
Nice video, especially the bits showing the direct comparison between GPR slices and photos from the excavation. Are more videos like this to be made, and perhaps on other techniques?
That was great. best of the videos so far! funny and informative.
Hello Sara
Loved this and learned so much. Such a really clear explanation Thank you Jimmy
Thanks for the explanation. You describe the process clearly.
Super fascinating! As an astronomer, I can relate to and love how technology is allowing us to study history (of people on Earth, and of space) better. Modern cameras on telescopes for example collect as much data in a few days of observing as cameras 20 years ago did in an entire year! Some collect so much that it needs to be processed in real-time as it cannot be stored!
Love all the new gadgets he gets to play with!
Excellent presentation, very informative.
Great information on GPR, thank you.
Oh wow, that point at 4:00 is just amazing, I love it.
Super video thanks for doing it. I was wondering what sort of frequency and PRF/PRI the machines operate at and if you had to alter that depending on the grounds moisture content?
For a lot of archaeological work 250-750Mhz is common. Repetition rate is dependent on the system design, I think for the ones used in these examples it is a few hundred kHz.
That 3D cube modeling is something else 👌💪
Nice to see good Swedish technology put to good use. 🙂
Thanks Jimmy! I enjoyed that masterclass! I’d enjoy longer ones also…
So I have a question …. I thought I heard something like different materials reflect the GPR energy with different intensity. If I got that bit right …based on the strength of the reflected signal, can you make guesses about the type of material that’s reflecting the radar signal?
It's kind of right. The reflection strength/type is related to the material but it is more about the contrast in electromagnetic properties. So a sandstone block buried in hard-packed sand wouldn't give you the same response as that sandstone block buried in a more organic soil. So that causes problems on archaeological sites where a wall might run from natural through other materials like demolition rubble or midden material and the same wall could present a different response through those materials.
@@jimmyadcockABEM Thanks Jimmy, you answered my question! Are there ways to resolve those low contrast situations?
Not a huge amount you can do about it. You can tweak the processing and contrast levels in the plots but if the contrast ain't there in the first place you're not going to be able to generate it later. Trying an alternative technique that is responding to different physical parameters is usually the best option and actually the most complete interpretations will come from multi-technique surveys.
Brancaster was fantastic. The GPR data was so detailed that you could almost have done the whole episode based on 3D reconstructions of the GPR data. I gather Brancaster was very dry and that helped the radar? GPR results seem poor when there's a lot of moisture or clay? Great presentation!
Yes, anything that increases conductivity is bad news. In conductive ground, the GPR signal is attenuated (absorbed) very quickly and so you get very limited penetration. Fresh water is actually not a problem - we can image through ice and river/lake water - but normally water in the ground contains salts and minerals that make it more conductive.
This was really interesting! Thank you 😊
Good video. I enjoyed it, interesting and informative
Love this stuff. Are there any studies in terms of this type of work? I'd be interested.
Question - What is the maximum depth to which the GPR can reach? What do you see next generation instruments being able to do that today's instruments can't?
It really depends on the frequency of the antenna and the material you're looking through. High frequency signals get absorbed faster than low frequency. Electrically conductive materials absorb quicker than resistive, and if something is homogenous (doesn't cause many reflections) the energy will travel further. So GHz antennas will give a few centimetres in concrete, 25 MHz antenna over good soils might give 30m, low frequency antennas through ice can give 100s of metres. A lot of archaeological work uses systems that will return 1-4m of penetration.
Facinating, It would be so much fun to use the GPR equipment.
The opening was HILARIOUS 😂
Hi - what frequencies are used for GPR? For subterranean communications we have to use a few kHz rather than the GHz of ‘normal’ radars. Also the pulse duration must be extremely short to work over centimetres rather than kilometres? What kind of power is used - getting a high power T/R cell to work at ps speed must be a challenge?
Most GPR is typically running between 25Mhz and 2.5Ghz with lower frequencies for deeper (10s of metres) lower-resolution geological, landform mapping and higher frequencies for shallow (few centimetres) high resolution structural studies of concrete, surfacing material etc. The sweetspot for a lot of archaeology is in the 250-750Mhz range where you get a sufficient penetration for most environments at a decent resolution. Power is pretty low - partly because for most applications high power isn't required, and partly due to legislation on transmission of radio waves. Individual antennas are normally outputting less power than a mobile phone.
@@jimmyadcockABEM Thank you for the information! Are the pulses very short or do you use chirped FM signals? I had supposed there was a specific band (like ISM bands) but I suppose since the energy is mostly headed into the ground there is not much leakage, so you can operate at any frequency provided it doesn’t annoy the neighbours :-)
Yes, very short. These are pulse systems and I think the ones used here would have been firing pulses at a rate of 200+kHz (there are also stepped frequency CW systems available on the market). You're right about the frequencies but legislation varies country-to-country. In the UK you need a license from OFCOM to operate a GPR and that dictates the range of antenna frequencies you could use, also states it must only be used whilst transmitting into an absorbing medium (i.e. don't wave it around like a flag) and has special stipulations about working in sensitive areas (primarily within a certain radius of radio telescope facilities). You also must keep a log so if those neighbours do complain you can demonstrate whether or not you were likely to be the culprit of their interference. As far as I am aware, there have been no recorded instances of GPR upsetting other systems (and plenty of work gets done at airports) when being used correctly.
@@jimmyadcockABEM Thank you!
How much does a scan of one site end up costing, and has it ever been too costly?
You'd probably be looking at 4 figures for a full day of survey. But time was normally the limiting factor on Time Team. We never did full days of just data collection because we had to balance how much data we collected with having the time to then process it, interpret it and position the next trench for the diggers.
Hello Dori
great stuff. thanks.
Awsome explanations . Thanks very much. Omg If i knew this science was a thing, I would strongly thought about it. But then , land survey technician is also cool so , i have I no regret 😊
Hello 👋
Hello catfolk
Would Sonar in solid ground work as an alternative to GPR? I think that it could, in principle.
Sadly not - the ground just isn't quite solid enough. The sonar pulses are transferred by vibration, works in water and some waterlogged materials as there is no/very little compression to absorb the energy but just doesn't work through other media.
@@jimmyadcockABEM Thank you - I have wondered about that for ages. I still think sound waves could have wider use in Geophysics, if only to find an old Roman bridge in a river, for example.
@@jimmyadcockABEM I am also wondering about a drone-mounted ultrasound scanner, to assist with surface searches for pottery etc.
We can actually use GPR for looking at material within river beds. We gave it a go in the Piercebridge episode but the bed was a bit too rocky. Fresh water is surprisingly resistive so we can use the GPR in the bottom of a boat and it will penetrate deeper than sonar into the sediments if the river bed. We also could use resistivity through the water, or even seismic - all would offer better penetration and decent resolution.
@@jimmyadcockABEM A fair point, but I have seen no discussion of such techniques prior to this. I attended a Computer-Assisted Archaeology seminar a few years ago, and nobody there could answer my questions, sadly
I still think that there's scope for the drone idea, as we know that ultrasound is used for car 'radar'.
Thanks.
More from Jimmy here: ruclips.net/video/VEs_zicLC18/видео.html
Jimmy!!!!
Donald!!!
@@TimeTeamOfficial Well now that we've all been introduced... 😉
🖐
OMG you and Henry are my favorites!
brilliant love it 🥰🥰🥰🥰
There is story that 1000 years ago two chests with silver coins were hidden in valley. I think the only possible place is where there used to be pond. But that place is now dry grassland. Would it be possible to see "lumps" of silver at 1-2 meters deep in the ground? The chests were small enough for one man to carry both.
Rule of thumb is that to detect something with GPR, its size needs to be at least one tenth of the depth it is buried at. So for 1-2m deep, you won't see stuff that is less than 10-20cm across. So probably not. Also too deep for a metal detector to be effective.
@@jimmyadcockABEM Yes, I knew that the metal detectors wouldn't reach it. Probably not worth special trip. Also considering the fact on map from 18something name the pond "Lucky Pond" so....someone got lucky there at some point, I guess. I just thought lump of English silver coins, 1 - 5 kg would be detectable at that depth. Perhaps after 20 years...
Ah yes, I missed that the story had them in chests; might well be big enough to find. Next consideration is the soil type - if it's clay-rich (not uncommon in former wet areas) that's an Achilles Heel for GPR as it absorbs the signal very quickly indeed, and you may not see deep enough. Then, finally, are there likely to be natural targets of a similar size - would be very difficult to distinguish between large stones and chests and you'd want to be sure before someone gets sent in, armed with little more than a spade and wheelbarrow!
@@jimmyadcockABEM Shame - here is the story. The last part in "Life" is about when he hides the treasure. en.wikipedia.org/wiki/Egill_Skallagr%C3%ADmsson
Very interesting!🌝
Hello Becky
Would love to know what your favourite piece of equipment is and what software you find the best.
When I first started it was resistance survey (the 'zimmerframe') because that felt like "proper Time Team Geophys" from the episodes I'd watched before joining. Latterly it was anything you could attach to a vehicle. Software-wise, GPR-Slice was used for most of the Time Team models but the live stuff in the video was using our online software MALÅ Vision which actually has a free option for working with small datasets, so that's useful when you're first starting out.
Hello Heather
So Jimmy, what’s your favored brand of trainers?
Onitsuka Tiger - think they'll send me some?! 😄
@@jimmyadcockABEM They might. How good is your Oliver Twist impression?
Jimmy Adcock would probably be excellent in a mushroom soup, he seems to be such a _fun guy_
😎👍
Did John Gater retire?
I dont think so...he has been involved in the latest T T digs, and you see him regularly on the Patreon T T videos, talking, discussing, verbally beating up on Stuart!
Why would you not just use LiDAR...wouldn't acoustic wave be better the electromagnetic?
Lidar measures the surface topography, i.e. Stewart's beloved "lumps and bumps", it doesn't 'see' into the ground because it works using light (in the form of laser). EM waves can transmit through soils and geology.
As someone that spends a lot of time in Norfolk (but lives in south Lincolnshire most of the time-it is definitely flat here) I get fed up with the amount of people saying Norfolk is as flat as a pancake! If you go to any coastal town or Norwich; you'll find many a hill. But yes norfolk is mostly flat. However, I did enjoy learning about the new geo phys equipment.
Yep, sorry! Lazy stereotyping... I should know better, too: I surveyed a hillfort just 10 miles from Brancaster!
I miss Mick. I think I stopped watching: being able to, when he passed. All the joy that a child feels for archeology kind of died in me when he wasn't there with his rainbow colors and childlike smile to point out all the things I didn't know. That and his tactful handling of the Geo Phys team. Hmm.