rf distance measurement...

[whit3rd]

On Friday, September 9, 2022 at 5:49:57 PM UTC-7, palli...@gmail.com wrote:

Clifford Heath wrote:
================


A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.

** The range of ultrasonic sound in air in measured in meters.

Your story seems completely fake.

No, just an artifact of what frequency range in the ultrasound is being
considered. A transducer for soft tissues (baby imaging) or for brain
scanning (blood flow doppler or imaging) use different frequencies, and
for air... you want to go low frequency by comparison. The lower the
frequency, the longer the range before the sound becomes thermalized
(heat energy).

 

[Phil Allison]

whit3rd wrote:
===========

Your story seems completely fake.

No, just an artifact of what frequency range in the ultrasound is being
considered.

** Fuck off moron.

FYI idiot , \" ultrasonic sound \" = f > 20kHz.

A transducer for soft tissues (baby imaging) or for brain
scanning

** You need one, cos you brain is missing or badly damaged.

 

[Jan Panteltje]

On a sunny day (Fri, 9 Sep 2022 21:08:22 -0000 (UTC)) it happened Hul Tytus
<ht@panix.com> wrote in <tfga06$ei9$3@reader2.panix.com>:

>Jan - did the requisite componets you mention answer your question \"why rf?\"?

All depends, you did not give the application info AFAIK.

There are so many ways to do \'long\' distacne measurements in RF
You can buy some thing that you can hang on your cat and your \'smart?\'phone will tell you where it is
same for your kids.. GPS.
In X aplication there is no reason you could not combine ultrasound for short range and that for long range.
And there is of course measuring from 2 angles,
2 medium wave transistor radios with ferrite antenna and a transmitter of a MHz or so in the object
Tune for minimum or maximum from 2 locations... what\'s it called ?triangulation?
Ham fox hunt

Cheapest is a piece of rope with markings, tied to the source and you reading the length.
There also exist binoculars with a range feature (bring the 2 images together or with laser range meter):
https://www.space.com/best-rangefinder-binoculars
maybe you could google for what chip those laser ones use...

The possibilities for distance detection are endless.

I get a bit turned off by design becoming / being reduced to: \'do you know a chip for?\'

I hope there are not going to outlaw discretes.
Anyways after WW3 due to EMP and no more production you will have to learn how to use basics to survive.
Hell even old diesel cars can still run and no new ones available due to \'sjip shorts\' or whatever

So, to make it more fun: WTF are you trying to do?

 

[whit3rd]

On Saturday, September 10, 2022 at 12:27:39 AM UTC-7, palli...@gmail.com wrote:

whit3rd wrote:
Clifford Heath wrote:

A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.

Your story seems completely fake.

No, just an artifact of what frequency range in the ultrasound is being
considered.

FYI... \" ultrasonic sound \" = f > 20kHz.

There\'s a lot of frequency range between 21 kHz and 9 MHz, and lots of attenuation isn\'t
always a killer. I worked on a machine that did doppler velocity measurement of
blood flow, inside the brain. The skull gets in the way, but... the signal pickup
gets all the benefits of phase-locked amplification, and gain is cheap.

Scale up the energy (we were using about 1/10 watt), and wait longer for the signal
to show up (we were refreshing a video screen a few dozen times per second) and
even 6000 dB loss isn\'t necessarily a killer. For raindrops, you\'d want a wavelength in air
of millimeters (for blood cells and doppler velocity measure, wavelength was about
80 microns in water).

 

[Phil Allison]

whit3rd wrote:
==============

A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.
Your story seems completely fake.

No, just an artifact of what frequency range in the ultrasound is being
considered.

FYI... \" ultrasonic sound \" = f > 20kHz.

There\'s a lot of frequency range between 21 kHz and 9 MHz,

** No fooling ?

> and lots of attenuation isn\'t always a killer.

** So you say.

I worked on a machine that did doppler velocity measurement of
blood flow, inside the brain. The skull gets in the way, but... the signal pickup
gets all the benefits of phase-locked amplification, and gain is cheap.

** So what ?

Scale up the energy (we were using about 1/10 watt), and wait longer for the signal
to show up (we were refreshing a video screen a few dozen times per second) and
even 6000 dB loss isn\'t necessarily a killer.

** OK - so YOU are FUCKING TOTALLY INSANE

I hope someone cuts you ugly head off and sticks it on a broomstick in front of your house.
AS a fucking warning.
You rabid schizo.


...... Phil

 

[Jeroen Belleman]

On 2022-09-10 11:33, whit3rd wrote:

[...] and
even 6000 dB loss isn\'t necessarily a killer.[...]

You\'ll want to think that over...

Jeroen Belleman

 

[whit3rd]

On Saturday, September 10, 2022 at 2:55:36 AM UTC-7, Jeroen Belleman wrote:

On 2022-09-10 11:33, whit3rd wrote:
[...] and
even 6000 dB loss isn\'t necessarily a killer.[...]

You\'ll want to think that over...

A TV signal at the receiver is a few microvolts, so in a 75 ohm system that\'s
10^-13 W. The transmitter is maybe 10 kW omnidirectional.
So, 170 dB loss, and you get a million pixels with good S/N ratio,
modulated each at 30 Hz.
If you only needed ONE pixel, 230 dB loss would work.
If you needed one measure per minute rather than 30 per second,
280 dB will do that. Now, instead of 4 MHz bandwidth, the
signals of interest only have 4 Hz bandwidth, so...the noise
floor gets smaller by a factor of 10^6 because you can use p hase-sensitive
detection; 340 dB should work.

Now recognize that the sender is NOT omnidirectional, nor is the receiver, but
has focusing of maybe a couple of degrees, 0.04 radians; the effective
signal/noise gets two factors of 4pi/((.04)^2), for another 80 dB
So, we\'re at 420 dB.

OK, unless the \'6000 dB\' number has a fault, it doesn\'t seem workable.

 

[Phil Allison]

whit3rd is FUCKING INSANE !!! :
============================
Jeroen Belleman wrote:
===================

even 6000 dB loss isn\'t necessarily a killer.[...]

You\'ll want to think that over...

A TV signal at the receiver is a few microvolts,

** Bullshit.
It is way more for a reliably good pic.

The transmitter is maybe 10 kW omnidirectional.

So, 170 dB loss,

** Bullshit.

YOU need to be fucking murdered.



....... Phil

 

[Ricky]

On Saturday, September 10, 2022 at 12:21:58 AM UTC-4, Hul Tytus wrote:

Bill - the coolrunner is an attractive device, especially for a fundamently simple circuit
as this. Unfortunantly it can\'t handle 500mc. If I remember correctly they are limited
to somewhere between 100 & 200mc.
The fpgas are, as you imply, a complex effert starting from scratch, but at least another
tool would be added to one\'s \"tool box\". Can you - or anyone else - suggest an fpga that
can handle 500mc and be in the $10, $20, $30 price range?
What\'s really needed is an 8 bit counter with a latch that can handle 500mc, ala the
20 pin ttl chips.

You just can\'t help yourself from top posting, can you? If you insist in top posting, I won\'t be responding further.

You are thinking too much inside the box. An FPGA can process the equivalent of 500 MHz, by processing in parallel. Please don\'t try to tell me a counter can\'t be parallelized, because that just means you don\'t understand what it\'s doing. Feel free to ask questions.

BTW, just how old are you? They had stopped using mc when I was in college and that was... 50 years ago!

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

 

[Ricky]

On Friday, September 9, 2022 at 4:52:04 PM UTC-4, Hul Tytus wrote:

Ricky - the delay you mentioned is along the lines I\'ve been thinking. Any
suggestions on search terms? TACAN would be likely. What else?

Please stop top posting.

TACAN is the military version. If you search on that you will get hits on the commercial version as well.

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209

 

[Ricky]

On Friday, September 9, 2022 at 5:22:56 AM UTC-4, Jan Panteltje wrote:

On a sunny day (Fri, 9 Sep 2022 00:08:39 -0700 (PDT)) it happened Ricky
gnuarm.del...@gmail.com> wrote in
ec0dd418-095c-4eba...@googlegroups.com>:
On Thursday, September 8, 2022 at 10:40:16 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Thu, 8 Sep 2022 22:39:52 -0000 (UTC), Hul Tytus <h...@panix.com
wrote:
Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot. The basic method of one device emitting a signal and another echoeing it
back would be attractive.
Any recommendations?

Hul
Reflections will be a big error source.

Not if an active transponder retransmits the received signal with a fixed delay. That\'s how they measure distance in the TACAN
system on airplanes. They use different frequencies which prevents an issue with echos.
Why use RF?
For 2 $ 50 centst you van get an ultrasonic distance measuring module on ebay
I have several.

For 500 feet, he is likely outside. Ultrasonic can be impacted by the wind.

--

Rick C.

-- Get 1,000 miles of free Supercharging
-- Tesla referral code - https://ts.la/richard11209

 

[Ricky]

On Friday, September 9, 2022 at 8:49:57 PM UTC-4, palli...@gmail.com wrote:

Clifford Heath wrote:
================


A friend worked many years ago on an ultrasonic method for measuring the
velocity of raindrop to look for windshear, microbursts, etc, for
aviation. They used an ultrasonic transducer at the focus of a 2.5m dish
(ex sat-coms) and got good results out to 6 kilometers.

** The range of ultrasonic sound in air in measured in meters.

Your story seems completely fake.


...... Phil

The troll raises he head and surveys the scene.

--

Rick C.

-+ Get 1,000 miles of free Supercharging
-+ Tesla referral code - https://ts.la/richard11209

 

[Jeroen Belleman]

On 2022-09-10 13:42, whit3rd wrote:

On Saturday, September 10, 2022 at 2:55:36 AM UTC-7, Jeroen Belleman wrote:
On 2022-09-10 11:33, whit3rd wrote:
[...] and
even 6000 dB loss isn\'t necessarily a killer.[...]

You\'ll want to think that over...

A TV signal at the receiver is a few microvolts, so in a 75 ohm system that\'s
10^-13 W. The transmitter is maybe 10 kW omnidirectional.
So, 170 dB loss, and you get a million pixels with good S/N ratio,
modulated each at 30 Hz.
If you only needed ONE pixel, 230 dB loss would work.
If you needed one measure per minute rather than 30 per second,
280 dB will do that. Now, instead of 4 MHz bandwidth, the
signals of interest only have 4 Hz bandwidth, so...the noise
floor gets smaller by a factor of 10^6 because you can use p hase-sensitive
detection; 340 dB should work.

Now recognize that the sender is NOT omnidirectional, nor is the receiver, but
has focusing of maybe a couple of degrees, 0.04 radians; the effective
signal/noise gets two factors of 4pi/((.04)^2), for another 80 dB
So, we\'re at 420 dB.

OK, unless the \'6000 dB\' number has a fault, it doesn\'t seem workable.

You got the point, that\'s good enough for me.

Jeroen Belleman

 

[Hul Tytus]

Bill - ECL does seem most likely but, since only 4 bits of a counter would be required,
its not so combersome. AC versions of the CMOS family could handle the rest. Considering
that a 12 bit counter conceptually would provide 2048 feet, the needs aren\'t great.
Practically though 16 bits would probably be needed to handle various delays.

Hul

Anthony William Sloman <bill.sloman@ieee.org> wrote:

On Saturday, September 10, 2022 at 2:21:58 PM UTC+10, Hul Tytus wrote:
Anthony William Sloman <bill....@ieee.org> wrote:
On Saturday, September 10, 2022 at 7:01:55 AM UTC+10, Hul Tytus wrote:
Anthony William Sloman <bill....@ieee.org> wrote:
On Friday, September 9, 2022 at 8:40:00 AM UTC+10, Hul Tytus wrote:
Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot. The basic method of one device emitting a signal and another echoeing it
back would be attractive.
Any recommendations?

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

Complex modulation and phase-sensitive decoding is popular.

The speed of light is about 1nsec per foot, so you are talking about round trip times of 20nsec, 200nsec and 1usec.

It\'s easy enough to create a 1nsec wide pulse, but detecting it after it has been reflected from something 500 feet away trickier.

Bill - the complex modulation & phase sensitive decoding along with multiple frequency direct are areas that would require a bit of study on my part.

Don\'t top post. It makes life difficult for your reader.

The 500mc clock required with the basic way with 2 transmiter/receivers is a problem too,

It\'s 500MHz and back in 1995 I was planning to buy one off the shelf (for about $100) which was based on a thinned-crystal oscillator.

There are a lots of faster options around today.

The whole point about the Tellurometer approach is that you don\'t need that kind of clock speed, but you do have to measure small phase differences pretty accurately, which isn\'t all that difficult. Twenty bit Sigma Delta A/D converters can be useful here.

https://www.analog.com/media/en/technical-documentation/data-sheets/2420f.pdf

is dead slow, but once you have used a phase-sensitive detector to convert the phase difference into a DC voltage you can measure it as slowly as you like.
Ingenious people get the phase difference to reverse from time to time which lets you cancel out any DC offsets

Whatever you do is going to take a bit of study on your part. The more study you do, the more likely you are to come up with a n approach that can be made to work. Coming up with an approach that is likely to work well will take even more.

probably an fpga. If some IC maker has packaged some portion of this approach the task might
be simpler.

A field programmable gate array is a fairly heavyweight device. Less ambitious programmable logic devices should contain enough gates to do the job.

I quite liked the Philips CMOS Coolrunner parts, which they eventually sold to Xilinx, They drew a lot less current than the competition (unless you clocked a lot of the gates really fast).

Nobody here has come up with an off-the-shelf part yet - I\'ve never heard of one, but that doesn\'t mean much.

You are still top posting. Are you another one Jake Isks pseudonyms?

Bill - the Coolrunner is an attractive device, especially for a fundamentally simple circuit
as this. Unfortunately it can\'t handle 500MHz. If I remember correctly they are limited
to somewhere between 100 & 200MHz.

The Tellurometer approach lets you get away with a slower clock.

The fpgas are, as you imply, a complex effort starting from scratch, but at least another
tool would be added to one\'s \"tool box\". Can you - or anyone else - suggest an fpga that
can handle 500MHz and be in the $10, $20, $30 price range?

What\'s really needed is an 8 bit counter with a latch that can handle 500mc, ala the 20 pin ttl chips.

TTL works really badly at 500MHz.

ECLinPS offers counters that can be strung together more or less indefinitely to create a synchronous counter working at 500MHz.

I did a detailed design that depended on such a part back in 1995. The modern part is faster, but it\'s unlikely to make 1.3GHz if you string a bunch of them together.

https://www.onsemi.com/pdf/datasheet/mc100ep016a-d.pdf

You really do need to go to ECL if you want to ship fast clocks and signal around - you\'ve got to treat your interconnects as terminated transmission lines.

Using the Tellurometer approach and measuring phase shifts is much easier.

--
Bill Sloman, Sydney

 

[Ricky]

On Saturday, September 10, 2022 at 11:13:47 AM UTC-4, Hul Tytus wrote:

Bill - ECL does seem most likely but, since only 4 bits of a counter would be required,
its not so combersome. AC versions of the CMOS family could handle the rest. Considering
that a 12 bit counter conceptually would provide 2048 feet, the needs aren\'t great.
Practically though 16 bits would probably be needed to handle various delays.

ECL is not needed. You need to understand FPGAs if you want to use them.

--

Rick C.

+- Get 1,000 miles of free Supercharging
+- Tesla referral code - https://ts.la/richard11209

 

[Tauno Voipio]

On 10.9.22 15.30, Ricky wrote:

On Friday, September 9, 2022 at 4:52:04 PM UTC-4, Hul Tytus wrote:
Ricky - the delay you mentioned is along the lines I\'ve been thinking. Any
suggestions on search terms? TACAN would be likely. What else?

Please stop top posting.

TACAN is the military version. If you search on that you will get hits on the commercial version as well.

For distance measurement, the ICAO standard system is called DME,
Distance Measurement Equipment. It is usually paired with a VOR
direction beacon.

--

-TV

 

[server]

On Sat, 10 Sep 2022 00:27:33 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:

whit3rd wrote:
===========

Your story seems completely fake.

No, just an artifact of what frequency range in the ultrasound is being
considered.

** Fuck off moron.

FYI idiot , \" ultrasonic sound \" = f > 20kHz.


A transducer for soft tissues (baby imaging) or for brain
scanning

** You need one, cos you brain is missing or badly damaged.

I used to be able to hear 22 KHz and I could walk past a house and
hear the 15K from TV sets. I\'m down to about 8 KHz now, but there\'s
not a lot going on above that.

 

[bilou]

Le 09/09/2022 à 00:39, Hul Tytus a écrit :

Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot. The basic method of one device emitting a signal and another echoeing it
back would be attractive.
Any recommendations?

Hul

Look at the design of radio altimeters.
Use of directional aerials on the source or/and the target can
improve performances a lot.

 

[piglet]

On 08/09/2022 23:39, Hul Tytus wrote:

Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot. The basic method of one device emitting a signal and another echoeing it
back would be attractive.
Any recommendations?

Hul

Don\'t know all the details but the Apollo ranging system used 1960s RF
technology to get foot scale accuracy across quarter million miles.
Loads of info should be on the web.

piglet

 

[Hul Tytus]

Worth a look, thanks.

Hul

piglet <erichpwagner@hotmail.com> wrote:

On 08/09/2022 23:39, Hul Tytus wrote:
Anyone know of any ICs designed for measureing distances with RF? I\'m
thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one
foot. The basic method of one device emitting a signal and another echoeing it
back would be attractive.
Any recommendations?

Hul

Don\'t know all the details but the Apollo ranging system used 1960s RF
technology to get foot scale accuracy across quarter million miles.
Loads of info should be on the web.

piglet