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Electronics => RF, Microwave, Ham Radio => Topic started by: vk2seb on July 31, 2017, 11:12:42 am

Title: HP 141T Spectrum Analyzer LCD Upgrade
Post by: vk2seb on July 31, 2017, 11:12:42 am
Just a heads up to anyone else who owns one of these ancient 141T Spectrum Analyzer mainframes, I'm working on some firmware for an STM32F7 touchscreen development board to act as an upgrade for the display on it.

At the moment, I have:
- Real-time spectrum display with graticules etc, that works on the slowest up to the fastest timebase
- A waterfall display mode
- A normalization function that makes insertion loss measurements much easier.

Here's a video of it working (lots of other RF stuff too on my channel if you're interested):

https://www.youtube.com/watch?v=CwwRvqHGyts (https://www.youtube.com/watch?v=CwwRvqHGyts)

Code is available on github (very hacky at the moment): https://github.com/schnommus/stm32_hp141_lcd (https://github.com/schnommus/stm32_hp141_lcd)

Much more work planned for this (want to use all the extra data available on the tracking preselector connector on the back for more features).

I'll post updates in this thread :)
Title: Re: HP 141T Spectrum Analyzer LCD Upgrade
Post by: AF6LJ on August 03, 2017, 12:10:11 am
This is great, a baseband back end for an old workhouse.
I get a grin when I think of the half dozen PC boards and the 5602 processor in my 8569B that does the same thing. :)
Title: Re: HP 141T Spectrum Analyzer LCD Upgrade
Post by: KE5FX on August 03, 2017, 01:14:57 am
Very nifty.  What's your bootup time like? 
Title: Re: HP 141T Spectrum Analyzer LCD Upgrade
Post by: vk2seb on August 03, 2017, 06:55:19 am
Quote from: AF6LJ
I get a grin when I think of the half dozen PC boards and the 5602 processor in my 8569B that does the same thing.

Yep, it's ridiculous how much power you can get for a few bucks these days...

Quote from: KE5FX
Very nifty.  What's your bootup time like? 

Code is all bare-metal, no OS so it boots up in a few milliseconds, definitely faster than the old CRT took to warm up.
Waiting for the analyzer LOs etc to warm up to frequency is really the bottleneck though :P.
Title: Re: HP 141T Spectrum Analyzer LCD Upgrade
Post by: KE5FX on August 03, 2017, 07:02:55 am
Quote from: AF6LJ
I get a grin when I think of the half dozen PC boards and the 5602 processor in my 8569B that does the same thing.

Yep, it's ridiculous how much power you can get for a few bucks these days...

Quote from: KE5FX
Very nifty.  What's your bootup time like? 

Code is all bare-metal, no OS so it boots up in a few milliseconds, definitely faster than the old CRT took to warm up.
Waiting for the analyzer LOs etc to warm up to frequency is really the bottleneck though :P.

Ah, I see.  For some reason I thought you were running Arch Linux on the board at runtime, as well as to host your development environment. 

Do they offer a development kit like that one with a bigger/better LCD?
Title: Re: HP 141T Spectrum Analyzer LCD Upgrade
Post by: fcb on August 03, 2017, 05:09:45 pm
Very very cool.

I had a 141T and it was the HEAVIEST piece of kit I ever owned before my Fluke 5215A.

I seem to remember I had the matching tracking generator and it went upto 18GHz!
Title: Re: HP 141T Spectrum Analyzer LCD Upgrade
Post by: KE5FX on August 04, 2017, 07:42:49 pm
Just to be sure, this (https://www.digikey.com/product-detail/en/stmicroelectronics/STM32F746G-DISCO/497-15680-5-ND/5267791) is the board you're using?
Title: Re: HP 141T Spectrum Analyzer LCD Upgrade
Post by: Jay95 on August 05, 2017, 11:09:03 am
Nice work!

I knew I shouldn't have given away the 141T that I had  :palm:
Title: Re: HP 141T Spectrum Analyzer LCD Upgrade
Post by: AF6LJ on August 06, 2017, 08:35:50 pm
Very very cool.

I had a 141T and it was the HEAVIEST piece of kit I ever owned before my Fluke 5215A.

I seem to remember I had the matching tracking generator and it went upto 18GHz!
Yes it did.
There was also a preselector you could get also.