Reading high frequencies around 100ghz

[hhhhh9887]

I was wondering why a meter I bought that was capped at 8ghz wouldn't read out for a frequency around 100ghz. I know barely anything about meters.

What type of equipment would be able to detect that high of a frequency? I'm wondering if anyone knows a public or private meter that I'd be able to use for scanning an object emitting a frequency in that range.

 

[ko6jw_2]

What are you expecting to detect? Designing equipment for that frequency range is very expensive. Also, any transmissions around 100ghz will be highly directional. There are amateur bands considerably higher than 100ghz including everything above 275ghz, but these are experimental. Unless you were in the signal path and using a parabolic dish you would hear nothing.

 

[pb_lonny]

What type of equipment would be able to detect that high of a frequency? I'm wondering if anyone knows a public or private meter that I'd be able to use for scanning an object emitting a frequency in that range.

What sort of object is it and what are you trying to find out?

 

[majoco]

Radio waves start acting like light when you get up to SHF frequencies - unless you stand directly in the beam you aren't going to get illuminated!

 

[jwt873]

In Canada, ~100 Ghz is allocated to radio astronomy, space research and radio location. So is much of the spectrum above the 74-76 Ghz amateur radio band.

I imagine it's much the same around the world. As a side note, I've got a ham friend that's done moonbounce on 47 Ghz..

 

[zz0468]

In Canada, ~100 Ghz is allocated to radio astronomy, space research and radio location. So is much of the spectrum above the 74-76 Ghz amateur radio band.

I imagine it's much the same around the world. As a side note, I've got a ham friend that's done moonbounce on 47 Ghz..

Hey, I know Barry! Nice guy, and very sharp.

 

[zz0468]

I was wondering why a meter I bought that was capped at 8ghz wouldn't read out for a frequency around 100ghz. I know barely anything about meters.

What type of equipment would be able to detect that high of a frequency? I'm wondering if anyone knows a public or private meter that I'd be able to use for scanning an object emitting a frequency in that range.

Detect how? There are spectrum analyzers out there that would allow you to detect such a signal. A Tektronix 492 is affordable on the used market but the external mixers required are unobtanium.

There are guys doing stuff at those frequencies in their garages, but it's beyond the abilities of anyone who knows "barely anything about meters".

What is it you're trying to do?

And looking at the OPs single post, I don't expect him to ever return to this thread.

 

[dlwtrunked]

I was wondering why a meter I bought that was capped at 8ghz wouldn't read out for a frequency around 100ghz. I know barely anything about meters.

What type of equipment would be able to detect that high of a frequency? I'm wondering if anyone knows a public or private meter that I'd be able to use for scanning an object emitting a frequency in that range.

At 100 GHz three things become serious problems that have to be addressed:
1. Bends in wire cause and inductance which acts like a resistance to an RF frequency and that increases with the frequency.
2. Capacitance to nearby conductors will cause those to act as more of a filter and absorb signal.
3. Diodes and transistors can only "switch" up to a certain frequency.

By the way, ordinary red light is about 430 THz (terahertz) and blue light about 770 THz, or 430000 GHz and 770000 GHz, respectively. And it is the "same sort of thing" as radio, that is, electromagnetic waves/photons. Accordingly, as the frequency gets very high, the electromagnet waves start to behave more like optical (light). (But sound of course is entirely something different and not electromagnetic waves/photons though many people seem to confuse that.)

 

[bob550]

I was wondering why a meter I bought that was capped at 8ghz wouldn't read out for a frequency around 100ghz. I know barely anything about meters.

What make/model of meter did you buy? I think you answered your own question as to why the meter won't detect 100 GHz frequencies by stating that your meter was "capped" at 8 GHz. If your meter is a RF frequency counter, it will most likely have a designed frequency range beyond which it would not receive, or at least not be reliable.

 

[jwt873]

Hey, I know Barry! Nice guy, and very sharp.

Yep.. That's him. - He got me interested in UHF. We chat every now and then on 432 SSB. There's a group of us that meet once a month at a local watering hole for an eyeball contact.

 

[hhhhh9887]

Detect how? There are spectrum analyzers out there that would allow you to detect such a signal. A Tektronix 492 is affordable on the used market but the external mixers required are unobtanium.

There are guys doing stuff at those frequencies in their garages, but it's beyond the abilities of anyone who knows "barely anything about meters".

What is it you're trying to do?

And looking at the OPs single post, I don't expect him to ever return to this thread.

Detect as in just know of an object's presence. That spectrum analyzer seems to be capped at 21ghz, would it just top out? Also what is it about that spectrum analyzer that might detect such a signal at 100ghz or above?

 

[hhhhh9887]

What are you expecting to detect? Designing equipment for that frequency range is very expensive. Also, any transmissions around 100ghz will be highly directional. There are amateur bands considerably higher than 100ghz including everything above 275ghz, but these are experimental. Unless you were in the signal path and using a parabolic dish you would hear nothing.

So imagine I could stand in the signal path, would you know of a place to read a signal at that frequency? Also I should clarify I think it should be 100ghz - 150 ghz.

 

[hhhhh9887]

What sort of object is it and what are you trying to find out?

It's a device I found on my street post and I believe it may be a camera. I'm trying to prove that it's transmitting a signal.

 

[zz0468]

That spectrum analyzer requires external mixers to see that high.

Ok, you just want to detect it. Get a piece of waveguide for the frequency rang of interest. Get a horn antenna that fits. Put a waveguide diode detector at the opposite end of the horn.

If the signal strength emmitted by the "object" is greater than the noise figure of the diode, a voltage will be seen at the detector. The waveguide will act as a high pass filter.

I sure wish you guys wouldn't be so vague when you come here for help with your college lab work.

Detect as in just know of an object's presence. That spectrum analyzer seems to be capped at 21ghz, would it just top out? Also what is it about that spectrum analyzer that might detect such a signal at 100ghz or above?

 

[zz0468]

So imagine I could stand in the signal path, would you know of a place to read a signal at that frequency?

As close to the source as you can get.

 

[hhhhh9887]

As close to the source as you can get.

Right I meant whether there's any suggestion for an actual place or type of facility with a meter or analyzer I could use capable of reading that frequency because I guess the hardware would be expensive to do it myself.

 

[pb_lonny]

If it is transmitting I doubt it would be that high of a frequency...

 

[jwt873]

If it is transmitting I doubt it would be that high of a frequency...

That's what I was thinking.. For a simple video link, 100 gHz would be pretty exotic. NSA stuff. If that were the case, you definitely wouldn't be able to see the camera...

hhhhh9887.. Can you post a picture of it? Someone here might be able to recognize it and shed some light on it's purpose.

 

[zz0468]

It's a device I found on my street post and I believe it may be a camera. I'm trying to prove that it's transmitting a signal.

This post wasn't visible to me last night.

What makes you think that it's transmitting on 100-150 GHz? That frequency range is simply not used in commercial products like that. There are some automotive radars for collision avoidance operating around there, I think, but not cameras on light poles. That's probably going to be a WiFi connection.

 

[bob550]

It's a device I found on my street post and I believe it may be a camera. I'm trying to prove that it's transmitting a signal.

How can you be certain it's not hardwired? Is there a visible antenna on this device?