"Larry Jaques" wrote in message
...
On Thu, 11 Oct 2018 18:50:38 -0400, "Jim Wilkins"
wrote:

...
Hey, I designed and built my first computer and coded its operating
system and editor/assembler. By comparison making a hydraulic bucket
loader was quick and easy.

Har! I guess so. I remember flipping a sequence of toggle switches
on the (Altair?) computer to load the bootloader from the 14" hard
disc for the old Baird Gamma Camera from the '70s eons ago, so I
vaguely grok your design.


It was functionally similar to an Altair or PDP-8. The company was
very supportive of my effort to learn computer engineering and
programming and gave me the 8080 CPU and some samples of 6116 (2K x 8)
CMOS memory that I kept alive with NiCads so I wouldn't have to enter
the bootstrap loader each time. A Teletype saved programs on paper
tape until I built an FSK modem to store them on a cassette recorder.
The I/O ports were similar to an IBM PC's except the video which was a
monochrome version of the Radio Shack Color Computer's.

I bought an RSP1A at a hamfest last weekend.
https://www.sdrplay.com/
In the 90's at Mitre I built prototypes of software-controlled digital
radios like that but always turned them over to the engineers to play
with.

The free SDRuno program makes it a universal radio receiver for up to
2 GHz, and it can also be a spectrum analyzer over that range. While
it doesn't have the calibrated accuracy, wide scan width or tracking
generator output of my HP spectrum analyzer the signal display is
good, and looks much better on an HDTV.

On my suggestion the seller set up the demo to receive ADS-B data from
nearby aircraft and overlay their locations onto Google Maps as a
virtual radar, which had been a 90's Mitre project. ADS-B is at 1090
MHz, weather satellites are at 137 MHz. The aircraft band is 118-136
MHz. The Grants Pass tower is at 122.8 MHz, Cascade Approach is
124.3, and your weather (wx) is at 120.0. .

I bought a 25-1300 MHz discone antenna for it that I haven't set up
yet, since I spent yesterday helping a neighbor fix his garage roof.
The feed from my 50 foot high TV antenna was good enough to receive an
AM broadcast station at 900 KHz.

-jsw