how do i build a multi frequency RF detector

[Keymaster27]

I am looking to build a rf detector. I am fairly new to electronics so please be kind. I am a locksmith for a university and am looking to build a rf detector to test if a push button remote for handicapped doors or a wireless card reader is actually transmitting. The handicapped remotes transmit on a 433 MHz frequency and the wireless locks transmits between 903 and 922 MHz. Would love to build something that has a display for the frequency and a strength meter. Any help is much appreciated.

 

[Delta Prime]

Sorry, buddy, what you request is intermediate to advanced to build such a device from the component level. I suggest you purchase a handheld spectrum analyzer, which will display Power in decibels(dB) at a given frequency433Mhz to 1Ghz.
The example below is an spectrum analyzer use for reference only…

 

[Keymaster27]

Thank you for your input.

Sorry, buddy, what you request is intermediate to advanced to build such a device from the component level. I suggest you purchase a handheld spectrum analyzer, which will display Power in decibels(dB) at a given frequency433Mhz to 1Ghz.
The example below is an spectrum analyzer use for reference only…

 

[Harald Kapp]

Sorry, buddy, what you request is intermediate to advanced to build such a device from the component level. I suggest you purchase a handheld spectrum analyzer, which will display Power in decibels(dB) at a given frequency433Mhz to 1Ghz.

How do you match inexperience with using a spectrum analyzer?
Of course this will work, but is not a simple tool to handle for a layman.

Imho something like e.g. this key fob tester would be way more adequate - although it does not show the signal strength. It only indicates whether the signal source (doesn't have to be a key) does transmit and at which frequency. Probbaly good enough for the purpose.
You can find similar tools, more or less advanced, online (here's another example).

 

[Keymaster27]

How do you match inexperience with using a spectrum analyzer?
Of course this will work, but is not a simple tool to handle for a layman.

Imho something like e.g. this key fob tester would be way more adequate - although it does not show the signal strength. It only indicates whether the signal source (doesn't have to be a key) does transmit and at which frequency. Probbaly good enough for the purpose.
You can find similar tools, more or less advanced, online (here's another example).

Thank you for your response. I am really looking to build something due to keeping costs down and for hands on experience in building something that would be useful to me in my occupation. I am more of a learning by doing and learning from mistakes. Thank you again for your time.

 

[bertus]

Hello,

Here is a cheaper option than the first one that harald showed:

https://www.amazon.nl/Zeer-Nauwkeurige-Digitale-Display-sleutelhangerfrequentietester-Infraroodsignaaldetectie/dp/B0CJZ9C1MR/ref=mp_s_a_1_2?crid=3PHT17X7T2PC9&dib=eyJ2IjoiMSJ9.DGFhkFtqXTjmlI7qUNJdzxlw_TC-IuaD15o0HIQuKAL-cJH_L2HaVeFthKAMQL9HecVZ42lT2g9b8QBhl0Vxy33junpkqmuRALJ29gFzUOK5ctYFDOstajjypX1DsIKSisAAak2j7YlN4Fnqvttj3NYNTHTJfLnLq1FulO2MORp73y-PuejJNI32QsiG6unK4xUFa0RuDW7wnfSgZcR6Yw.buHzHuUU9a_awkUu5SuSyUhruoYqtSOfLpd1WCgeX98&dib_tag=se&keywords=key+fob+tester&qid=1768222986&refinements=p_85%3A16497054031&rnid=16497052031&rps=1&sprefix=keyfob+tester%2Caps%2C121&sr=8-2

Bertus

 

[Alec_t]

That one is for IR, not wireless.

 

[bertus]

Hello,

It is for both, rf and ir.
Here is an english link:

Amazon.com

Bertus

 

[Alec_t]

It is for both, rf and ir.

So it is. My bad.

 

[Delta Prime]

Imho something like e.g. this key fob tester would be way more adequate - although it does not show the signal strength.

In my not so humble opinion, you did not help the thread starter by addressing me…
You’ve just made my ignore list.
In the future, don’t even bother…

something that has a display for the frequency and a strength meter. Any help is much appreciated.