Newbee question: My late father, left me a legacy of radar, radio, amplifier, signal & frequency equipment. Most of it from 1965 to 1988.
He did near-impossible things for the military, and was greatly influenced by N. Teslas works. I'm finding misc notes scattered in parts boxes about data/signal manipulation using an odd type of dbl full bridge rectifier. I'm no Electrical engineer, like him, but I dabble in simple diy board projects. Is it possible to strip hidden comm freq-bands off of data cables? And yet retain original transmissions? He also had a way to "capture" other freqs over older radar units, and separated them, but didn't have a way to store them back then. I just wanna finish some info he asked me to find after he passed.
Please advise, Dennis

 

Pictures of what (notes, devices equipment) you have would be nice? Questions like yours needs as much information as possible to give informed answers.
Influenced by N. Teslas is not a positive IMO for good radio technology as the guy was a total flake for much of his life and had little modern knowledge of RF technology and didn't even believe in modern EM theory.

Lots of things are possible but it's impossible to know what your late father was doing without a lot more info.

 

In response to that question: " Is it possible to strip hidden comm freq-bands off of data cables? And yet retain original transmissions?" It is possible to sense leakage thru the shields of cables, but seldom "simple" to do it. In addition, it requires that such a signal actually be present in a cable. A bit of understanding what the signal sought was will help a lot.

MANY long years ago I discovered that I could hear phone conversations that were capacitance coupled into our phone line from other pairs of conductors in the same big cable. All it required was a low leakage capacitor and a small audio transformer and an audio amplifier with a scheme to null out all of the mains frequency leakage signal. Not bad for a 13 year old.

 

https://hackaday.com/2021/01/18/tv-detector-vans-once-prowled-the-streets-of-england/

Most of the RF signal detection and decoding stories in the media and the public at large are complete fantasies. Made up BS for science fiction stories and movies about the evil government snooking agencies. The actual truth is so mundane that nobody talks about have hard it is to remotely receive and view Wim Van Eck type transmissions in the wild reliability. Sometimes you get very lucky but most of the time, it's a total bust. A simple 'bug' is a lot more reliable.

https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-577.pdf
Compromising emanations: eavesdropping risks of computer displays

https://en.wikipedia.org/wiki/Van_Eck_phreaking

 

We know that all conductors act like antenna and can radiate the spectrum transmitted according to the conductor leakage and effective radiation pattern and attenuation due to Friis path loss. This is detected using broadband dodecahedron antenna in far field (10m) radio emission field tests with Spectrum Analyzers according to specifications such as used by the FCC and other regional compliance directives. For the US military there were lower levels of emission testing required to be certified called Tempest tests. This was because it was known that the pixel data on CRTs could be detected from the high voltage beam emissions and the screen data could be reconstructed. This was of great interest during the “Cold War” era. When I was testing HDD ‘s in Paoli PA for Burroughs Inc, during the 80’s , guys performing Tempest Testing in another booth were surrounded by curtains to hide everything they were doing.

Previously when I worked in a different technology of broadband WANs, it was popular for cable companies to sell Pay TV and secure with some simple encryption or sync blocking method often using spare midband channels when they only had 200 MHz CATV distribution Amplifiers. It was also commonly known that cable TV companies needed to secure the revenue for this added service and could tell which channel your TV was tuned to by the local oscillation (LO) leakage from the TV tuner escaping back out the coax to the outside cable. This could be detected with directional antenna from the coax. leakage in the back lane for near the residence. Although I never knew anyone that the cable companies caught in the act of unauthorized Pay TV theft.

Much later after I retired, I met someone who wanted to start a business in Atlanta, Ga to support the privacy of individuals who were being spied upon by mobile GPS trackers added to fleet cars or surveilance devices added by Private Eyes or even the FBI. I used his portable Spectrum Analyzer (SA) and directional antenna to show how mobile device frequencies were detected that could broadcast vehicle tracking technology. This was of interest to some people who wanted to know if such devices were secretly installed on the vehicle they were driving.

The security agencies also used this same brand of SA to detect people who were stealing all the mobile phone signals nearby. There exists portable equipment to mimic a cell tower and host to intercept nearby mobiles locked onto that host for the purposes of recording conversations for whatever purposes.

I cannot tell what you are looking for but I have seen a lot of EMI in my career between R&D , Mfg and Test Engineering in my various careers in Aerospace, Telecom, HDD magnetic recording, wireless AMR, and contract manufacturing. Most of it is noise, but Ham operators probably have more interesting stories. Like a former RF Tech and collegue, Jack Askew , when I started in R&D at Bristol Aerospace, he had a certificate for establishing 2 way communication to all 5 continents by VHF bouncing his signals off the moon, using a large dish in his back yard. To him, fixing a 0.1 dB connector loss was a big deal. One day he said he intercepted a Japanese ship RF facsimile document being transmitted somewhere in the Pacifac, while we worked in a city located in the geometric center of North America. To you and me, it would just sound like an old telephone/fax modem white noise.

 

Guess who gave Tempest tests? Guys like us.

 

Thank you, to all you Gents.
I'm a bit hesitant to reveal his notes. I gained a big hint from your input.
A past memory: when I was 10yr old, I received by mail a special order Plastic model, 1/72 Hawker Tempest.
I was ecstatic! When he got home from El Toro, I shouted to him "Dad, I got my Tempest in the mail!"
His face went pale, and he took my package swiftly and I thought "oh crap what did I do wrong".
Gave it back to me, never mentioned it again.

One of his notes mentions an attempt to pass a "comm" cable off-center through a vacuum tube. But couldn't find anyone to make the glass shell for this. I don't know what type of comm/data cable he meant. "Piggybacked signals stripped off with a synchronous filter pulse, leaving the original for normal translation". ( I noted Translation not transmission) Pre-entering the vacuum tube he had 2 fullbridge rectifiers linked with capacitors and a little rectangle labeled ChEBI dotted-line twards them.
I'm not trying to be cryptic, I have some security ratings. Just want to understand key points in my youth with the greatest man I never knew. Maybe just a fantastical idea he dreamed about.

Back ground info: ( My Father was recalled to active duty during the late '80s to convert an analog radar targeting system to digital.
He could only tell me so much. I know that a version of the A4m(2) skyhawk was adapted to test this system, it was very successful.
It looked similar to the image below but had round dish above the array. The A4, had an additional "pod" in the hump and the lower aft fuselage.
My dad said in later years it was a primitive doppler, only requiring small dynamic changes in hardware, "power-timing", and more power; which made it easy to convert current systems very very cheaply. ) (btw he had to make his own meters for reading these measurements my sister sold them at her garage sale) It looked similar to pic below:

 

I'm sure your Dad was a great guy but those notes don't point to anything special.

Translation means RF frequency shifting (intermediate frequency conversion ) in that context. Nothing special about that. We would often Piggyback ID or tracking (some encrypted) codes on the basic radar transmission carrier for long range systems and have filters to extract that baseband data.

Radar is a complex subject. Even these old systems would work wonders.

https://nps.edu/web/nps-video-portal/-/vr776ags7ksqslt79ujan9ywcuyj9aix

This radar lab looks at M.O.P.A style, pulsed coherent compression radar technology using the SPS-40 series radar. The focus is on the technology behind the radar.

 

I'm sure your Dad was a great guy but those notes don't point to anything special.

Translation means RF frequency shifting (intermediate frequency conversion ) in that context. Nothing special about that. We would often Piggyback ID or tracking (some encrypted) codes on the basic radar transmission carrier for long range systems and have filters to extract that baseband data.

Radar is a complex subject. Even these old systems would work wonders.

https://nps.edu/web/nps-video-portal/-/vr776ags7ksqslt79ujan9ywcuyj9aix

This radar lab looks at M.O.P.A style, pulsed coherent compression radar technology using the SPS-40 series radar. The focus is on the technology behind the radar.

Thank you so much for the link, It lead to even more information that showed me holes in this little bit of nonsense I'm puzzling over. You've saved me time in overextending my search efforts.
Thanx again, Djannjr

 

Sometimes the descriptions of those secrets just use vague terms. Years ago I asked a user of some of our equipment how fast the USMC tanks could actually go. The detailed answer was "Really Fast!!". That was good enough, I guess. We built testers for diesel injection systems and pumps, so I did know the max RPM and fuel flow. But the official statement was "Orange Line" for the RPM and "A Lot"for the fuel consumption.

As for detecting TV receivers, consider that the horizontal sweep system for a CRT radiated quite a bit at the 15, 7nn frequency. and with a good phase-sensing receiver, it is quite possible to determine which channel was being watched. Of course it was also simple to send out a signal to mask the radiated sweep signal.

 

We know that all conductors act like antenna and can radiate the spectrum transmitted according to the conductor leakage and effective radiation pattern and attenuation due to Friis path loss. This is detected using broadband dodecahedron antenna in far field (10m) radio emission field tests with Spectrum Analyzers according to specifications such as used by the FCC and other regional compliance directives. For the US military there were lower levels of emission testing required to be certified called Tempest tests. This was because it was known that the pixel data on CRTs could be detected from the high voltage beam emissions and the screen data could be reconstructed. This was of great interest during the “Cold War” era. When I was testing HDD ‘s in Paoli PA for Burroughs Inc, during the 80’s , guys performing Tempest Testing in another booth were surrounded by curtains to hide everything they were doing.

Previously when I worked in a different technology of broadband WANs, it was popular for cable companies to sell Pay TV and secure with some simple encryption or sync blocking method often using spare midband channels when they only had 200 MHz CATV distribution Amplifiers. It was also commonly known that cable TV companies needed to secure the revenue for this added service and could tell which channel your TV was tuned to by the local oscillation (LO) leakage from the TV tuner escaping back out the coax to the outside cable. This could be detected with directional antenna from the coax. leakage in the back lane for near the residence. Although I never knew anyone that the cable companies caught in the act of unauthorized Pay TV theft.

Much later after I retired, I met someone who wanted to start a business in Atlanta, Ga to support the privacy of individuals who were being spied upon by mobile GPS trackers added to fleet cars or surveilance devices added by Private Eyes or even the FBI. I used his portable Spectrum Analyzer (SA) and directional antenna to show how mobile device frequencies were detected that could broadcast vehicle tracking technology. This was of interest to some people who wanted to know if such devices were secretly installed on the vehicle they were driving.

The security agencies also used this same brand of SA to detect people who were stealing all the mobile phone signals nearby. There exists portable equipment to mimic a cell tower and host to intercept nearby mobiles locked onto that host for the purposes of recording conversations for whatever purposes.

I cannot tell what you are looking for but I have seen a lot of EMI in my career between R&D , Mfg and Test Engineering in my various careers in Aerospace, Telecom, HDD magnetic recording, wireless AMR, and contract manufacturing. Most of it is noise, but Ham operators probably have more interesting stories. Like a former RF Tech and collegue, Jack Askew , when I started in R&D at Bristol Aerospace, he had a certificate for establishing 2 way communication to all 5 continents by VHF bouncing his signals off the moon, using a large dish in his back yard. To him, fixing a 0.1 dB connector loss was a big deal. One day he said he intercepted a Japanese ship RF facsimile document being transmitted somewhere in the Pacifac, while we worked in a city located in the geometric center of North America. To you and me, it would just sound like an old telephone/fax modem white noise.

Interesting information, as my dads' project involved atmospheric reflections with signal amplification from an aloft "station". (Does the term "parabolic bending" mean anything?) The 'Corps wouldn't give him the xtra power he wanted. But he managed to use what he had to separate corralations with SAM radar & comm signals, not unlike wildweasels, but more intense. His idea was stopped, and he had an early retirement in 1976.
I really really appreciate that info on that dish. Thank you very much.

 

Guess who gave Tempest tests? Guys like us.


View attachment 345212

Looking sharp in your uniform.

 

Looking sharp in your uniform.

I hated that Good Humor uniform during the late 70's.


I loved the classic Cracker Jack we wore before and after Ice Cream Man and so did my dad.

 

Thank you, to all you Gents.
I'm a bit hesitant to reveal his notes. I gained a big hint from your input.
A past memory: when I was 10yr old, I received by mail a special order Plastic model, 1/72 Hawker Tempest.
I was ecstatic! When he got home from El Toro, I shouted to him "Dad, I got my Tempest in the mail!"
His face went pale, and he took my package swiftly and I thought "oh crap what did I do wrong".
Gave it back to me, never mentioned it again.

One of his notes mentions an attempt to pass a "comm" cable off-center through a vacuum tube. But couldn't find anyone to make the glass shell for this. I don't know what type of comm/data cable he meant. "Piggybacked signals stripped off with a synchronous filter pulse, leaving the original for normal translation". ( I noted Translation not transmission) Pre-entering the vacuum tube he had 2 fullbridge rectifiers linked with capacitors and a little rectangle labeled ChEBI dotted-line twards them.
I'm not trying to be cryptic, I have some security ratings. Just want to understand key points in my youth with the greatest man I never knew. Maybe just a fantastical idea he dreamed about.

Back ground info: ( My Father was recalled to active duty during the late '80s to convert an analog radar targeting system to digital). He also was sent back to Great lakes Station as an "advisor"
He could only tell me so much. I know that a version of the A4m(2) skyhawk was adapted to test this system, it was very successful.
It looked similar to the image below but had round dish above the array. The A4, had an additional "pod" in the hump and the lower aft fuselage.
My dad said in later years it was a primitive doppler, only requiring small dynamic changes in hardware, "power-timing", and more power; which made it easy to convert current systems very very cheaply. ) (btw he had to make his own meters for reading these measurements my sister sold them at her garage sale) It looked similar to pic below:

View attachment 345226