Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Equipment for UHF monitoring

Status
Not open for further replies.

georges998

New Member
Hi,

I am a newbie to this site and to electronics in general. I need to monitor usage of UHF bands (400-800MHz). For this, I am planning to do the following:
1. Buy an omni-directional discone antenna
2. Hook it up with a frequency pre-selector box
3. Hook the output of pre-selector with lab style oscillloscope.

I want to monitor channels with bandwidth 6Mhz. Can you please check if my method is correct or not. Also, can someone please suggest me a frequency pre-selector box which will suit my requirements (6 Mhz monitoring in 400-800 Mhz range). I can hope to spend up to $1000 (as this is a funded project).

Also, can you please tell me if the off-shelf laboratory CRO would satisfy the requirement or not?
Thanks everybody.
George
 
What do you want to monitor the bands for? What type of observations do you want to make?

Generally you will need a low-noise, high-gain 400-800MHz amplifier to be able to observe anything with an oscilloscope. But an oscilloscope will just show a jumble of frequencies in a 6MHz bandwidth. It is unlikely you can make any meaningful measurements.

If you want to measure the particular frequencies active in each band, then a spectrum analyzer might be more appropriate.
 
What do you want to monitor the bands for? What type of observations do you want to make?

Generally you will need a low-noise, high-gain 400-800MHz amplifier to be able to observe anything with an oscilloscope. But an oscilloscope will just show a jumble of frequencies in a 6MHz bandwidth. It is unlikely you can make any meaningful measurements.

If you want to measure the particular frequencies active in each band, then a spectrum analyzer might be more appropriate.

I want to monitor usage in each frequency band. In particular, I want to see how frequently bands are used on a micro-level. For example, I may observe that transmitter sends for 5 secs. and then remains silent for 2 secs and so on. I am not interested in deciphering the received signals.

I see that Spectrum Analyzers are very costly. Is there a cheaper alternative within $1500 budget?
 
In the range 400 to 800Mhz there will be many different types of transmission.

Using the UK as an example (you do not state where you are, other than quoting prices in $, but that could be many places.), a television transmitter will occupy a 6Mhz channel, but a radio system will typically occupy a 25 or 12.5khz channel.
So, in one of your monitored segements, there could be 1 TV station or 480 radio transmitters (voice, telemetry etc).

So, what are you really trying to do, what is the aim of this study?

As for using an oscilloscope, not a hope.

Your best chance of producing any results at all would be to use a scanning receiver and have it scan the frequency range 12.5khz channel by 12.5khz channel and when something is received, increment a counter/timer or W.H.Y.
By the way scanning a wide frequency range will be slower than you may like.

JimB
 
Last edited:
Here and here are a couple of home-built spectrum analyzer designs.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top