Can ANAN radios be used as spectrum analysers to test filters?

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vu2mb
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Can ANAN radios be used as spectrum analysers to test filters?

Postby vu2mb » Sat Mar 18, 2023 12:06 am

Hello,

Just curious to know if Anan radios be used as spectrum analysers to test say Low pass filters.
A decade ago there was a project called Cyclopes under test.

SDR Play has software for the spectrum analyser program. Do we have something?
Thank you,

73
Bhanu
VU2MB
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w-u-2-o
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Re: Can ANAN radios be used as spectrum analysers to test filters?

Postby w-u-2-o » Sat Mar 18, 2023 12:41 am

The panadapter IS a spectrum analyzer. And you can use the transmit side as an RF sweep generator, look at the tests tab in setup. Obviously it will only test HF filters. Be careful of your levels. Using a coupler to obtain a test signal when transmitting is the safe way.
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vu2mb
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Re: Can ANAN radios be used as spectrum analysers to test filters?

Postby vu2mb » Sat Mar 18, 2023 11:56 am

Hi Scott,

That's good news. Since I have never used scopes, a little hand-holding is required. I know it's too much to ask for but a mentor
must do it once and I would quickly learn. Is there a video on how to use it to test LPF for HF amplifiers? I could not find it.

A block diagram to connect Anan 200d/ sampler / Attenuator and LPF. and how to configure the test tab of Thetis setup for any of the ham bands of the LPF will be of great help.

The same should be part of the Users Manual of all Anan radios so that a non-engineer like me finds it easier to use it.

A picture is equal to 1000 words and a small video clip of a minute or two may be equal to a bible.

Thanks a ton in advance to the community who can do the needful.

73
Bhanu
VU2MB
Dell Alienware R10 AMD Ryzen 9 3950 PC-16 core @3.5 Ghz,
32GB Dual Channel HyperX(TM) F URY DDR4 XMP at 2666MHz
AMD Radeon RX 5700 XT 8GB GDDR 6
ANAN 8000DLE ANAN 200D ANAN 100D
Amplifier Mercury IIIS, Antenna Tuner: Palstar AT2K
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w9ac
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Re: Can ANAN radios be used as spectrum analysers to test filters?

Postby w9ac » Sat Mar 18, 2023 1:38 pm

Bhanu,

Just to be clear, the sweep utility under the "Tests" tab sweeps only audio frequencies at the VFO's carrier frequency. It does not allow for sweeping the RF carrier as is normally the objective when sweeping RF filters. The ANAN's RF carrier frequency remains fixed.

So, for HF filter sweeping, I don't see its value unless you are attempting to sweep an audio filter's passband response after demodulation. That said, the ANAN is still very useful as a spectrum analyzer but not as a spectrum analyzer with tracking generator capability.

An alternative is to use a manual or automatic RF sweep generator that's separate from the ANAN. Correct port termination is required to ensure minimum RF leakage that can otherwise color measured results, especially when sweeping a filter with steep filter skirts. Another alternative: if you have access to a 2-port VNA for S21 measurements, it contains an automatic RF tracking generator to easily sweep through the filter.

Paul, W9AC
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Re: Can ANAN radios be used as spectrum analysers to test filters?

Postby w-u-2-o » Sat Mar 18, 2023 2:08 pm

Paul is 100% correct. I misspoke about the sweep functionality. :oops:

In thinking about your requirements some more, you would probably be much better served to buy a NanoVNA. The NanoVNA is a wonderful, and wonderfully inexpensive, hobbyist VNA with performance that rivals professional models at HF frequencies.

A NanoVNA is a better choice because it is a purpose-built test instrument. And it's a much better choice for you specifically because the NanoVNA has a huge following and there are folks who have put out entire series of instructional videos on YouTube. So you have easy access to cookbook type instructions. And you can buy little test boards with a variety of circuits on them that let you learn how to use the device.

A link to uncountable videos on the NanoVNA: https://www.youtube.com/results?search_query=nanovna+tutorial

The only problem with buying a NanoVNA is deciding which one to buy. Since the design of the NanoVNA is super simple there are a multitude of Chinese factories churning them out, some better than others. You can find NanoVNAs for as little as $50. Some come with accessory kits, some don't. They come in two screen sizes. You can also get PC software to make them even more capable. I bought one a few years ago when they were just coming out so I have no idea which one is "best" at the moment. But I've been happy with my early example and I can only imagine the newest ones are even better.
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vu2mb
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Re: Can ANAN radios be used as spectrum analysers to test filters?

Postby vu2mb » Sun Mar 19, 2023 2:55 am

Dear Paul W9AC & Scott WU2O

Thank you very much for sparing time to respond to my post.
I Would be looking to import one of the NanoVNA.
Once I have it and done the test I will be reporting back here the results.

Thanks again
73

Bhanu
Vu2MB
Dell Alienware R10 AMD Ryzen 9 3950 PC-16 core @3.5 Ghz,
32GB Dual Channel HyperX(TM) F URY DDR4 XMP at 2666MHz
AMD Radeon RX 5700 XT 8GB GDDR 6
ANAN 8000DLE ANAN 200D ANAN 100D
Amplifier Mercury IIIS, Antenna Tuner: Palstar AT2K

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