Electronics > Beginners
How to **Safely** and properly align a Transmitter with a spectrum analyzer
hfleming:
Siglent USA has an app note describing an input protection circuit.
https://siglentna.com/application-note/diy-spectrum-analyzer-input-protection/
fourfathom:
--- Quote from: The_Spectrum.A_idiot on August 14, 2019, 09:23:25 pm ---Dear fourfathom
thank you very much for the contribution and the idea
--- Quote from: fourfathom on August 14, 2019, 01:25:02 am ---Another test device I have is a -40dB tap. This has two BNC connectors with a direct "through" connection: one goes to the device under test, and the other to a dummy load (a cheap 100W unit). The third port is a SMA jack, with a 40dB "L-pad" attenuator, using a few low-power resistors. My simple construction gave me a flat response out beyond 100MHz.
--- End quote ---
hopefully soon I may try to make this so called (RF sampler lets call it ? ) although I would use N type all over for my convince although the response in my application is a bit more critical to go up to 500 mhz
--- End quote ---
The reason my tap was only flat to 100MHz was that I used 1/4/W resistors with long leads and paid no attention to high frequency layout. If you do it right (say smt resistors on microstrip PCB) there's no reason your tap couldn't be usable into the GHz range.
And *thank you* for responding so nicely! Many times someone gets an answer and then disappears. We like to hear how it all comes out.
vk6zgo:
If your sampler varies in output overa wide frequency range, it isn't the end of the world, as sometimes you only need a small part of that range when testing.
If you havd a tracking generator with a Spec An, you can determine if the range you need is fairly flat, prior to using it to test a transmitter.
Even if there is a bit of a "slope" you can correct for that.
This is how we did things back in the old days, when the flatnesss of equipment was not always a given.
The_Spectrum.A_idiot:
Dear All ,
I manage to find and order a Bird Model 4275 20mhz-1Ghz RF Sampler so now I even more safe with my measurements ,
I would like to thank everyone for their help and comments about this issue I had , and enlightening me :D
Thank you in advance
The_Spectrum.A_idiot
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