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Bode plot up to a few 100 MHz

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Martinn:
For characterizing amplifiers (for example an oscilloscope or DAQ frontend) I want to measure their frequency response. Mostly gain, but knowing the phase can't hurt. My RTB2004 does this nicely, unfortunately only up to 25 MHz.
What options would there be for BW up to say 100...300 MHz (I am not a RF guy, so antenna preamps and matching is not relevant for me).

I have used a VNWA for this https://www.sdr-kits.net/introducing-DG8SAQ-VNWA3 , but the installation is somewhat quirky. Very powerful instrument though.
Probably other USB VNAs would also do. With NanoVNA output amplitude does not seem to be adjustable, which makes amplifier measurement quite uncomfortable (needs fiddling with attenuator kit).
LibreVNA https://eleshop.eu/librevna-2-ports-full-vna-100khz-6ghz.html looks interesting.

I don't want to invest in a proper bench top VNA as I neither have the need for a multi-GHz unit nor the bench space.
DIY via SCPI controlled RF gen and scope would be feasible, but a lot of work I'd like to avoid. Also a proper RF generator (sine output and wide range attenuator) would set me back $2000 on top.

Any ideas? Thanks!

RoGeorge:
I've seen on ebay second hand portable VNA/SA (often used by service man for cellular towers/antennas).  The instruments were in working and sold for less than $500, with a calibration kit and some cables included.  A DIY would probably cost about the same and be less reliable.

2N3055:

--- Quote from: Martinn on October 03, 2023, 11:43:13 am ---For characterizing amplifiers (for example an oscilloscope or DAQ frontend) I want to measure their frequency response. Mostly gain, but knowing the phase can't hurt. My RTB2004 does this nicely, unfortunately only up to 25 MHz.
What options would there be for BW up to say 100...300 MHz (I am not a RF guy, so antenna preamps and matching is not relevant for me).

I have used a VNWA for this https://www.sdr-kits.net/introducing-DG8SAQ-VNWA3 , but the installation is somewhat quirky. Very powerful instrument though.
Probably other USB VNAs would also do. With NanoVNA output amplitude does not seem to be adjustable, which makes amplifier measurement quite uncomfortable (needs fiddling with attenuator kit).
LibreVNA https://eleshop.eu/librevna-2-ports-full-vna-100khz-6ghz.html looks interesting.

I don't want to invest in a proper bench top VNA as I neither have the need for a multi-GHz unit nor the bench space.
DIY via SCPI controlled RF gen and scope would be feasible, but a lot of work I'd like to avoid. Also a proper RF generator (sine output and wide range attenuator) would set me back $2000 on top.

Any ideas? Thanks!

--- End quote ---

Stick with the VNWA....

Martinn:

--- Quote from: 2N3055 on October 03, 2023, 01:09:50 pm ---Stick with the VNWA....

--- End quote ---
I don't own one, so I'd have to buy it. Feels a bit outdated though, installation by fiddling with USB audio codec settings is weird. But yes, tons of functions in the software and nice applications book available.


--- Quote from: RoGeorge on October 03, 2023, 12:40:17 pm ---I've seen on ebay second hand portable VNA/SA (often used by service man for cellular towers/antennas).  The instruments were in working and sold for less than $500, with a calibration kit and some cables included.  A DIY would probably cost about the same and be less reliable.

--- End quote ---
Would you have an example? I quickly scanned ebay and found nothing even remotely at $500. Range was more like $5k-$40k.

RoGeorge:
No example right now sorry, it's been a while since I didn't look on ebay.  You'll have to hunt for a long time until some major provider or factory renew its inventory, or got sold at an auction.  Could take months or years until such bargain deals occur.

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