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 Post subject: Chinese Signal Generator/VFO/etc.
PostPosted: May Sun 15, 2022 6:13 pm 
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Location: West Concord, MA
https://www.ebay.com/itm/194812492342?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=vB5QHxRtT_y&sssrc=2047675&ssuid=ZrtCmwbDQMe&widget_ver=artemis&media=COPY

Sold as "10K-220MHz Qrp RF SDR Transceiver Vfo HF Signal Generator Radio debugger" or "Signal Generator RF Qrp Transceiver Vfo Homebrew S-Meter HF 10K-220MHz", mostly on eBay. Specifies a "Working Range" of 10kHz to 220MHz.

Intriguing. Wondering if anyone has experimented with these as a general purpose signal generator, or a VFO to drive boatanchor ham transmitters?


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 Post subject: Re: Chinese Signal Generator/VFO/etc.
PostPosted: May Sun 15, 2022 10:03 pm 
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Joined: Oct Sun 15, 2006 11:57 am
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Location: Liberty, Missouri 64068
Location: Liberty, MO 64068
I'd be interested to see a sweep of the output. I suspect its not all that clean, but it could be a surprise.

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 Post subject: Re: Chinese Signal Generator/VFO/etc.
PostPosted: May Mon 16, 2022 3:23 pm 
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Joined: Jan Tue 16, 2007 6:02 am
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Location: Lexington, KY USA
It is not clear to me from the description, but the output may be a squarewave.

This would be more suitable for some applications than for others.

The Si5351 IC definitely has only digital outputs. Getting from the squarewave to a clean sinewave over such a wide frequency range is not trivial.

https://cdn-shop.adafruit.com/datasheets/Si5351.pdf

Ted


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 Post subject: Re: Chinese Signal Generator/VFO/etc.
PostPosted: May Mon 16, 2022 9:59 pm 
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Location: Floral Park, New York
I like how they tell you to read the specs very carefully before making a purchase, but they somehow neglected to tell you what the output level is! I'd guess it is some high level and probably fixed, so an external attenuator would be required, along with an external modulator.

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 Post subject: Re: Chinese Signal Generator/VFO/etc.
PostPosted: May Mon 16, 2022 10:14 pm 
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Joined: Oct Sun 15, 2006 11:57 am
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Location: Liberty, Missouri 64068
Location: Liberty, MO 64068
Some of the Chi Com wonder widgets are useful rite out of the box, and some are pure junk, many are at least a starting point for some interesting projects.

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 Post subject: Re: Chinese Signal Generator/VFO/etc.
PostPosted: May Tue 17, 2022 1:06 am 
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Location: West Concord, MA
They seem to average around $50 on eBay. Some, like the one pictured, have a speaker grille (?) in the cabinet top. The rear panel inputs/outputs are mysterious. And the display I assume is meant to depict "presets" of some sort.


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