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August 12th 04, 12:29 AM

On 11 Aug 2004 19:59:04 GMT, (Len Over 21) wrote:

In article , Leo
writes:

On 11 Aug 2004 03:25:21 GMT, (Len Over 21) wrote:

snip

BTW, you mentioned in an earlier post that you have a Patent
registered to you, in the area od radio. Interesting - mind if I ask
what it was?

U.S. # 3,848,191 - Pulse Compression Receiver with AGC, granted
in 1974, assigned to RCA Corporation. Sole inventor on patent.
Missed two other applications due to being too close to prior art.

Basically it is a pulse processor and operating in an environment
of many different pulses, only a few of which come close to being
in synchronism with the system. The application was for SECANT,
an R&D project for 4 years at RCA, the acronym standing for
SEparation and Control of Aircraft by Non-synchronous Techniques.
SECANT was an aircraft collision avoidance system and in direct
R&D competition with a modified helicopter station-keeping system
done by Minneapolis-Honeywell. Both the RCA and Minnie-Honey
systems were flight-tested successfully in PA at the (former) Naval
Air Development Center (NADC). Flight testing local in PA, at the
Patuxent River range, and at Key West, Florida, observed by FAA
troops locally as well as USN and USA people. First air tested at
Kern County Airport #7, Mojave, CA...("Mojave International" in fun)
now the site for Scaled Composites, the first company to make it
into space privately.

SECANT worked at 1.6 GHz nominal bandcenter. The final version
(of three) in 1974 used 8 SAW (Surface Acoustic Wave) matched
bandpass filters done on quartz substrates (done at Sommerville,
NJ) at 1 MHz bandwidths centered between 55 and 64 MHz. I got
to play with the SAW filters and the final version IF-detectors plus
the pulse pre-processor. Al Walston, W6MJN, and I shared
responsibility for the Tx and Rx parts. Jim Hall, KD6JG, was the
engineering technical manager over the last two versions of
SECANT and all of RIHANS, another R&D program, again working
in L-band at the RF level.

The U.S. government scuttled any more testing funding in 1974 for
both the RCA and Minnie-Honey systems, opting for a less-tested
ATC transponder modification which is now in use, but only by the
air carriers and large executive aircraft.

TCAS? (now TCAS II)

Yup. MIT did their air testing in a couple of Piper Cherokees in MA.
Lovely picture they had in a magazine flying over the 'Haystack'
radome (unrelated project).

RCA's SECANT was tested first on a hired DC-3, Piper Aztec, in
Mojave in '71. [don't know what Minneapolis-Honeywell used]
USN air testing was in a C-117 (military version of "Super DC-3"),
Grumman S-2 Tracker, and Douglas RA twin jet...the latter sharing
duty of testing the prototype GPSS then called NAVSTAR (or
something like that). In PA, NJ, MD, and FL by the USN. It worked
just fine. So did the Minneapolis-Honeywell system. Would have
been interesting for the '74-'75 "electronic shootout" to see which
system was the better. Not so. U.S. gubmint decided in favor of
a largely untested system devised by highly-credentialled friends.

ATCRBS became TCAS and that was that.

Military doesn't use that
system. MIT had friends in higher places to sway gubmint opinion.

RCA Corporation began (well before WW2) as a place to hold
U.S. patents and try to keep control on the then-new technology
of radio. As a result, RCA built up a fantastic legal staff and pursued
patent filings aggressively. Back in '74 the average cost of any
electronic patent application cost about $6000, nearly all of it being
taken up by the non-patent-office Search costs. Corporate
employees of the lower levels would not get much chance to patent
anything unless a corporation had a large legal staff. I was lucky in
getting a sole patent award and don't sweat the other two at RCA
nor the one multiple-inventor patent turn-down at Electro-Optical
Systems (Xerox division). [sometimes good minds think alike! :-)]

Very impressive - thanks for the summary. I'd never heard of the
SECANT system before.

That would have been quite a challenge back in '74 - all discrete
components, no microprocessors, no CAD tools or circuit
emulators....real hands-on design work.

All discretes for sure, lots of prototype PCBs in the first two
versions, all hand-wired on Douglas boards (not the aircraft
company, but a then-new prototype PCB company in SoCal).
All the RF plumbing used mainly SMA connectors and purchased
uW components such as filters, couplers, etc. (we were short on
time and R&D budgets are not extravagant).

But...we DID have some CAE (although it was called "CAD" back
then). RCA Corporate had COSMIC, Computer Optimization of
Simple Microwave Integrated Circuits, and LECAP, the frequency-
domain analysis for any kind of circuitry...a much simpler version
of the original IBM ECAP. We did write some of our own programs
once we got accounts on the corporate time-share net (second
phase). I learned FORTRAN in '72 using Dan McCracken's book
on it and eventually contributed six programs to the corporate
program library. Was interesting and challenging!

To say the least. Compter programming was pretty mystical back then.
My exposure to Fortran came in college in '76 - the computer was an
old Burroughs B6700 (IIRC), and was absolutely massive.

While RCA Sommerville had just debuted their CMOS family and
was (half-heartedly) promoting COSMAC processors, they were a
bit ahead of time and facing the then-new Intel (and copycat Zilog)
CP/M micros for business applications. At RCA EASD we had to
produce quickly and went with discrete logic subsystems. Worked
out quite well and Bernie Case (not a ham) got at least 3 patents on
the threat-evaluation and tracking logic for SECANT, a couple more
on RIHANS (River Inland Harbor Area Navigation System), a highly
precise positioning system using shore station responders. That
was tested in the Galveston, TX, area in '74 (whole group was there
for the testing over 4 weeks). Following the NOAA survey team,
the positioning accuracy was BETTER than even military GPS of
the next decade. All that and massive amounts of multipath
reflections from all the steel in dockyards, etc., in harbors. RIHANS
worked in L-band also using low power RF pulses; range was only
about 30 miles (to radio horizon) and that suited harbor and roads
navigation very well. [it was so far back in time that ROMs were
limited to 8 KBits of storage...:-) ]

I remember those....worked with Rockwell's PPS-4 4-bit (!)
microprossessor system way back when....

Too bad that RCA Corporation was sold to GE and most of the
divisions parcelled out to other corporations. Was a heady time,
much accomplished in electronics and radio in the 70s, fun days
of pushing lots of performance envelopes. Most of the 3-decade-
old CMOS ICs are alive and well in production at many other IC
makers; Indianapolis division still makes color TV sets under the
RCA logo although Thompson CSF owns that division now.

It's too bad that RCA was not equipped with a some sort of financial
TCAS system when they took on the development of the analog VideoDisc
system..... :-0

No wonder you're getting so much heat here, Len - clearly, you are out
of your league. Are you aware that there are folks here who have
successfully assembled their own Elecraft kits, and built working CW
transmitters from plans? :-) :-) :-)

Yes, they've announced (sometimes with herald trumpets) their
fantastic Nobel-level accomplishments. Ave! :-)

Ad infinitum.

There remains an enormous area of electronics-radio exploration and
experimentation for anyone who wants to venture out from the known,
the already-accomplished a half century ago. Technologically and
operationally, the rest of the radio world has long-since surpassed
even the dreams of most amateurs. There's over 50 Million cell phones
in use in the USA and every one of them is a tiny two-way radio running
in the low microwave region. That's sneered at by the "radio pioneers"
(of the latter-day saints) busy keeping morse code alive and unhealthy
on HF.

That particular technology has been paying the bills (and then some!)
at the Leo household since 1985!

Financed my incursion into this hobby, too!

When every other radio service has either dropped morse code
use or never considered it from the beginning, it doesn't say much for
the pretend-ubiquitousness of that ancient mode.

It was once a mainstream form of telecommunications - but that was a
long, long time ago. Now, it's an interesting mode within the amateur
radio hobby. and the odd covert military organization, perhaps.

And Hollywood!

It's an exciting future for those who care to break away from half-century
old techniques and venture into largely-untried new areas. Only a few
dare. That's how it was in the 1920s. By the 2020s it would seem that
most amateurs want to recreate that time, to live a century back, and
feel "safe" re-inventing wheels because they have all the knowledge
recorded, all the successes and the failures of those early days. They
can neglect the failures because they never did the same thing.

Everything old is new again!

73, Leo