LadyBug Technologies LB5944A RF Power Sensor - RF Cafe

Webmaster:

BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:

AirplanesAndRockets.com

Cardboard Engineering & Science Slide Rule Calculators
The Original Mobile Apps™

October 2020 Update: Mr. Joseph Birsa, N3TTE, recently donated yet another of his vintage cardboard calculators to the RF Cafe collection. This one is the "Type B" version of the ARRL's "Lightning Calculator" series.

Long before there were smartphones and software 'apps,' engineers and scientists carried around portable 'apps' of another kind. These apps were made from printed heavy cardboard stock and typically had either a sliding section sandwiched between two outer layers, or a rotating layer on a fixed base layer. They even sported rivets to hold them together - like the original Levis dungarees. I and guys much older than me [ ;-) ] routinely carried them in our shirt pockets, securely snugged behind our plastic pocket protectors. You definitely always wrote your name on them in indelible ink since there was a tendency for those cardboard slide rules to sprout legs and walk away while you were at lunch or in the can.

These cardboard slide rule calculators used to be included on the Traditional Slide Rules page, but thanks to generous RF Cafe visitors who either sent me hard copies or high-res photos, the number has grown so large that they required their own page. You are invited to submit examples of your own collection for inclusion in the informal Cardboard Calculator Museum.

The American Radio Relay League (ARRL) sold a variety of these "Lightning Calculator" slide rules in the days before electronic calculators. This "Type B" version (copyright 1932, W.P. Koechel) calculates Ohm's Laws values for resistance, voltage, current, and power. As shown here, it indicates an alignment of 1 V, 1 A, and 1 Ω. The Lightning Calculators" were rather large at 8½" wide by 11" high. Being the size of a sheet of paper, it is surprising they did not come with holes for a 3-ring binder. There were six varieties of "Lightning Calculators," as shown in the 1939 QST magazine advertisement.

Thanks to Joe Birsa (N3TTE) for the donation - Added October 19, 2020

Thanks to Neil Blaho for the donation

(circa 1950s) Added July 6, 2017

Thanks to Neil Blaho for the donation

(circa 1950s) Added July 6, 2017

Thanks to Neil Blaho for the donation

(looks a little like the Starfleet Command logo)

Thanks to Neil Blaho for the donation

(Annapolis, MD, was my childhood home town)

Thanks to Joe Cahak for the donation

Thanks to Joe Birsa (N3TTE) for the donation

Thanks to Gary Steinhour for the donation

Smith Chart Side

Slide Rule Side

Thanks to Gary Steinhour for the donation)

I. Sea-Level Reduction (left), II. Altimeter Setting (right)

These were used by air traffic controllers back in the Stone Age This particular model was auctioned off when the Bedrock Airport closed

Thanks to Don Hicks for the donation

Sage Wireline/Wirepac Calculator

I have a spreadsheet available for the Wireline Calculator.

GE Mobile Radio, Range and Transmitter Power Calculator

Thanks to Alan Kealey for the donation!

Andrew Microwave Antenna System Computer

Classic Format Slide Rules

Pickett N600 ES Log-Log Slide Rule

(this is the same model that went to the moon w/the Apollo astronauts)

(wooden frame & bar w/metal ends)

K&E Model 4081-3 Slide Rule, S/N 087105

(wooden frame & bar w/metal ends)

Sterling 684 White Plastic Slide Rule

(I bought this for my first algebra class in 1976)

Skala Wilcza 32 Wooden Slide Rule (Poland)

Thanks to Alan Kealey for the donation!

Pickett N1010-T Slide Rule

(found in my father-in-law's basement)

Cleveland Institute 515-T Slide Rule (made by Pickett)

Send me an e-mail if you want a PDF file of a partial (10 pages) copy of the instruction manual.

[Buy the complete manual set here]

This advertisement appeared in the August 1967 edition of Electronics World magazine. The unique slide rule, leather case, and 4-course instruction booklet was "...deliberately underpriced at less than $25."