Thermal Stabilization of an AirSpy mini SDR

[Alex P]

I have always had the SDR in a remote  box rather than running a long ( 25m ) coax. In the past, the SDR & USB Extender box had been on a shaded screen porch and was ( by chance ) somewhat temperature stabilized .

Over the past several months  I have been building and refining highly portable Disk Yagi antennas and for convenience, installed all electronics at the antenna.

What I  did not anticipate was that an AirSpy mini SDR is quite sensitive to temperature changes .   Not gain, but a significant change in spectral response : the filter shape changes .  

Moving forward , I've finally stabilized the SDR by installing it within a small insulated box.  June 9th  was the first test of the TEC cooled , Resistive heated  thermal control system 

I've never had such stable data .   An example is a spectrum plot set ( 135 ea) over 11 hours where the air temp changed from a morning low of 74F to a late afternoon high of  102F in the sunlit area around the SDR box ...

The large shift was due to the Sun transit within ~ 4 deg of the Declination +20 drift scan. It provides a nice separation of the 5 minute duration spectra scans.

Presentation Attached.

Regards, Alex

[Anthony]

Hi Alex, based on the non weatherproof equatorial mount this is a setup and tear down prior to rain, yes?

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[Alex P]

Yes  Fair Weather only  :)

[b alex pettit jr]

The goal was to have all the electronics at the antenna and to use a fiber optic data link .

This project was what it took to do so .

[Anthony]

😊 

On Sun, Jun 16, 2024, 12:43 PM 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com> wrote:

The goal was to have all the electronics at the antenna and to use a fiber optic data link .

This project was what it took to do so .

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[Marcus D. Leech]

On 16/06/2024 12:43, 'b alex pettit jr' via Society of Amateur Radio Astronomers wrote:

The goal was to have all the electronics at the antenna and to use a fiber optic data link .

This project was what it took to do so .

Presumably, that's a fiber-optic 100M/1G/10G *network* data link?

I've found that RF-over-fiber links are about 10-20 times the price of fiber-optic network links.  Which is kind of odd, since
  it's basically the same technology.

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[b alex pettit jr]

This Fiber Optic Link is digital, but not Ethernet . They are  a USB Extender set using WDM wavelength

division multiplexing ( 1310nm and 1550nm )  over a single fiber .. rated to 5Km.

They work to 3MSPS.

On Sunday, June 16, 2024 at 12:54:55 PM EDT, Marcus D. Leech <patchv...@gmail.com> wrote:

On 16/06/2024 12:43, 'b alex pettit jr' via Society of Amateur Radio Astronomers wrote:

The goal was to have all the electronics at the antenna and to use a fiber optic data link .

This project was what it took to do so .

Presumably, that's a fiber-optic 100M/1G/10G *network* data link?

I've found that RF-over-fiber links are about 10-20 times the price of fiber-optic network links.  Which is kind of odd, since
  it's basically the same technology.

.

[Anthony]

😊

To view this discussion on the web visit https://groups.google.com/d/msgid/sara-list/dfdf75ca-7f14-4bc3-8645-57dadbd27265n%40googlegroups.com.

[Mathew George]

Excellent work.

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[b alex pettit jr]

[Anthony]

Very nice Alex! 😀

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