Vintage Law Enforcement Surveillance Radio

During Mike Murphy's (‪@MIKROWAVE1‬) career he had the opportunity to be involved with the design of law enforcement surveillance radios, and he met some of the colorful personalities who pioneered these controversial technologies. In this presentation Mike tells the story of the people and companies that created surveillance devices that remained secret for decades, some of which still haven't seen the light of day.
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[@mackfisher4487]

"Gentlemen don't read other gentlemen's mail." It's attributed to President Herbert Hoover 's Secretary of State Henry L. Stimson, who in 1929

[@joedoe4871]

Nice work 👍🏽

[@thelasercenterofmarin2514]

Very nice presentation. You mentioned my father, Leo Jones. He collected a lot of this equipment over the years and, while a lot of it is now in the San Jose Tech museum, I still have a some of it stored in my basement. You mentioned it can’t be sold on eBay, but is there another channel to sell this type of equipment?

[@Swamp-Fox]

Fascinating!

[@jimw7ry]

Well done Mike! Thanks

[@KevinMurray-TSCM]

Excellent and accurate presentation. Thanks, Mike!

[@GlendaleDailyPlanet]

telegraph register did NOT punch dial pulsesd it was inked onto the paper tape great program learned much Ed Sharp-e Archivist for SMECC

[@christophernetherton9389]

Very interesting content. Thakn you.

[@jimw7ry]

38:00 Looks very like the HT-220 construction and design... LOL! W7RY

[@MIKROWAVE1]

The brilliantly designed HT 220 used totem pole stage construction, that is the stages we're stacked, so the 12 VDC was producing current to feed each decoupled stage, 2 V for Rf, 3V for mixer, 4V for IF ect which is a power saving technique. In other words, the same 1 mA went through all of the series stages. Stacked stages made the 220 very difficult to troubleshoot. We are used to parallel powered stages with each stage getting the same voltage to ground using a lower voltage like 3V to save power. The 220 is totally alien to almost any radio design. But that is why it was ahead of its time. The Bell and Howell was 1 /2 the thickness of an HT220, so the Feds loved it for undercover.

[@Brooke95482]

Can you tell me some patent numbers?

[@MIKROWAVE1]

Here are a few of Sholly Kagan's Patents. First the Nielsen TV Viewer Reaction Monitoring System 4308554, 4107734, Video US3651252A, US3245332A, US3185056A, FR1428113A, Radio Stuff US2931034A, US2935606A, US3005093A, US3623064A, US3618070A, US3449684A, and more.

[@raymondmartin6737]

Now most Police frequencies are Encrypted as I have seen over my years of scanning since 1970, with crystal controlled analog scanners, to today's digital mode scanners. 😊

[@MIKROWAVE1]

Low Power Surveillance gear was intended for short range only, and was seldom repeated through a larger police communications system of any kind. Most of it was ordinary narrowband FM at this time.