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RAMSEY ELECTRONICS

By Ross Goodall, WD4NJV

After over forty years of business Ramsey Electronics closed down their hobby kit division. These kits were well known by teachers, school children, scouts, and do-it-yourself hobbyists.  

Ramsey will be missed by many who enjoyed building electronic kits.
Ramsey was known for easy to understand assembly manuals that explained how to solder properly, step by step instructions, troubleshooting information and an explanation of how the kit worked.

Their first kit was a simple LED Blinky Light kit with only ten components and a sixteen-page assembly manual.

Other hobbyist kit retailers went out of business before Ramsey.  They included Heathkit, Dynaco, Knight Kit, Lafayette, South West Technical, and EICO because you can buy the items already assembled at good prices.

For example you would just go out and buy an 802.11 wireless router for about fifty dollars rather than spending time building one.

I enjoyed building Ramsey’s low-power FM stereo broadcast transmitter. The audio quality was excellent although the range was limited to just the home and the yard using the attached telescoping antenna.  

Over the years that I have been building kits, there have been major 
changes away from using 50 watt soldering guns and irons for point-to-point soldering of large components, terminal strips and tube socket pins.

Today, ICs use solder points close together with tight layouts and heat sensitive components which call for 20-25 watt pencil soldering irons and careful soldering so solder does not jump across to another point.

The remaining Ramsey hobby kits are now on Amazon and eBay.  

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Garage Door Opener Remote Transmitters
By Ross Goodall, WD4NJV

The garage door opener dates back to 1926.  Many people believe that the door opener provides the actual lifting power to open a heavy door but on a properly adjusted door the springs do most of the work and the opener provides only a small amount of power to open the door.  

The garage door idea came from remote bomb detonators used back to World War II. 

As more garage doors were installed in an area one may have had their door opened by someone else’s remote in the neighborhood as the same frequency was being used.  Next DIP switches were being used.   Next code grabbers were designed to record and retransmit or scanners were designed to transmit many codes in a short time to open unauthorized doors.  Next came remotes that had 3.5 billion codes with receivers with learn codes.  

Rolling code technology is used today in newer remotes.  When a remote sends a signal, a new code is generated for the next time use.  If a remote is sends a signal out of range and another one is sent later the receiver creates a look ahead code to solve this problem.  1

The frequency spectrum used on garage door remotes is typically between 300 to 400 MHz.  In the summer of 2004 many garage door openers around military bases were not responding due to be overloaded by strong Land Mobile Radio Service transmitters that had been authorized for decades 
earlier and were just beginning to be used by the Department of Defense.   Since garage door openers operate as unlicensed devices they must accept interference from LMRS services. 2

Door opener technology history:

1984-1993---8 or 12 position DIP switches 300 to 400 MHz.

1993-1997---Billion codes on 390 MHz.

1997-2005---security + rolling codes on 390 MHz.

2005 to present---security + rolling codes on 315 MHz.

2011 to present---security + 2.0 rolling codes on 310, 315, 390 MHz.
Finger print recognition technology is being added to remote keypads for ease of use by authorized access by children. 1

If you want to add more range to your garage door receiver clip off the small antenna and solder a coaxial cable onto the receiver and extend the cable outside the home and then solder the small antenna onto the center conductor of the coax.
References:
1         Wikipedia, Garage Door Openers

2         Wikipedia, Land Mobile Radio Service LMRS 


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