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Copyright: 1996 - 2024
    Kirt Blattenberger,


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...

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Innovative Power Products Couplers

Vintage Heathkit IM-2400 Handheld 512 MHz Frequency Counter Kit
Cool Product Report

Featured Product Archive

The inventions and products featured on these pages were chosen either for their uniqueness in the RF engineering realm, or are simply awesome (or ridiculous) enough to warrant an appearance.

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Vintage Heathkit IM-2400 Handheld 512 MHz Frequency Counter Winter 1981 Catalog - RF Cafe Cool Product

Vintage IM-2400 Handheld 512 MHz Frequency Counter in the Winter 1981 Heathkit catalog.

Heathkit catalogs can be found at World Radio History and Heathkit Catalogs.

These are the kits for which I have photos:

Heathkit HM−1002 RF Power Meter

My Heathkit IM−17 Multimeter

My Heathkit ET−3100 Design Experimenter

Heathkit GR−48 AM/FM Table Radio Kit

Heathkit DG−140 Two-Station Intercom Kit

Heathkit HD−1481 Remote Coax Switch

Heathkit AA-1250 Stereo Receiver

Heathkit GD−1380 Video Game Pong

Heathkit IG−5257 TV Post-Marker / Sweep Generator

Heathkit SA−2060A Deluxe Antenna Tuner

Heathkit IM−2400 Hand-Held 512 MHz Frequency Counter

Heathkit CR−1 AM Crystal Radio Receiver

Heathkit HW−99 Novice CW Transceiver

Heathkit SA−5010 uMatic Morse Code Keyer

Heathkit GD−1114 Intercom Speaker System

This vintage Heathkit IM−2400, 512 MHz Handheld Frequency Counter kit is one the latest unbuilt Heathkit kits which appeared on eBay. I have been saving the images in order to preserve the history. The constantly growing list is at the lower right.

The first instance I could find for IM−2400 being offered for sale was in the Winter 1981 Heathkit catalog, at a cost of $139.95 ($429.59 in 2021 money per the BLS) as a kit or $179.95($552.37 in 2021) assembled and tested. A comparable handheld frequency counter today is the TTi PFM3000 3 GHz Hand-Held Counter, at a cost just south of $200.

"The Heathkit IM−2400 brings quality to hand-held frequency counters - take it wherever you need to know the value of a frequency."

  • Uses 5 nickel-cadmium batteries (included) and line current with available eliminator/chargers
  • Batteries are housed inside the counter to provide TRUE portability
  • Wide 50 Hz to 512 MHz frequency range
  • See full description and video below

Heathkit products were well known for the completeness of its instruction manuals, with clearly illustrated instructions. During the writing and editing process, Heathkit employees were given pre-production kits to take home and build, while annotating any difficulties or errors encountered. Doing so helped minimize the situation where the writer inadvertently assumes his own familiarity with the process is shared by the customer. Having built a few Heathkit products myself in the 1970s when I did not have a lot of experience with electronics assembly, I can attest to the user friendliness of the instructions. Heathkit still sells many of its vintage manuals for around $15, which is what you would pay on eBay.

Heathkit IM-2400 512 MHz Frequency Counter Kit Parts

Heathkit IM-2400 512 MHz Frequency Counter Kit Parts
(eBay photo)

Heathkit IM-2400 512 MHz Frequency Counter Assembled

Heathkit IM-2400 512 MHz Frequency Counter Assembled
 (eBay photo)

Heathkit IM-2400 512 MHz Frequency Counter Schematic

 Heathkit IM-2400 512 MHz Frequency Counter Schematic
(eBay photo) 

Heathkit Winter 1981 Catalog Cover - RF Cafe

Heathkit Winter 1971 Catalog Cover
(worldradiohistory.com photo)

Heathkit IM-2400 512 MHz Frequency Counter Paperwork

  Heathkit IM-2400 512 MHz Frequency Counter Paperwork
(eBay photo) 

Heathkit IM-2400 512 MHz Frequency Counter Documentation

 Heathkit IM-2400 512 MHz Frequency Counter Documentation
(eBay photo) 

Heathkit IM−2400 Handheld 512 MHz Frequency Counter: Overview, Demonstration, Theory

"In this video, I introduce a unique piece of vintage electronic test equipment, the Heathkit IM−2400 Handheld 512 MHz Frequency Counter, which was introduced in 1980 and remained in the Heathkit catalog for 10 years. Unlike the various Heathkit bench frequency counters, this model is optimized for radio work, as it is only capable of displaying the tested frequency in MHz (even though it can test frequencies down to 50Hz). I cover the unit's history and features, show the unit inside and out, demonstrate its operation, go through the user's manual, and finally present a detailed 'theory of operation' while going through the schematic diagram." - youtuuba

Modern engineering and sub-miniaturization bring you the first hand-held Heathkit Frequency Counter - the IM−2400. The most compact Heathkit Frequency Counter ever combines in-the-field versatility with bench-standard accuracy. Use the IM−2400 in cars, trucks, aircraft, boats - anywhere you need an accurate frequency reading. Communications service technicians and Amateur Radio enthusiasts will find it ideal for servicing mobile radio equipment.

The IM−2400 measures frequencies from a large portion of the radio spectrum from 50 hertz to 512 megahertz, in two ranges. Accuracy and long-term stability are assured with a crystal-controlled 10 megahertz time base, The excellent typical sensitivity of 10 millivolts, RMS (as well as the guaranteed sensitivity of 25 millivolts, RMS) over the entire range of the IM−2400 means you'll be able to read weak signals, too. Measure frequency by connecting the IM−2400 directly to the component under test. Or, for counting without any connections, use the optional SMA−2400−1 Swiveling Telescopic Antenna (described below). Full voltage protection is built into the IM−2400 Counter for worry-free operation.

The big, 7−digit LED display is easy to read and gives you better resolution. Automatic decimal placement and zero blanking assure mistake-free readings. You get true portability with the Heathkit IM−2400 Hand-Held Frequency Counter. The batteries are located INSIDE the housing. There are no external battery packs to make handling the IM-2400 awkward.

Five rechargeable 1.2 volts DG, AA-size nickel-cadmium batteries are included with this frequency counter - making the IM−2400 an even better value. You'll be able to use these batteries over and over - up to hundreds of charges on the same set of batteries - to save on battery replacement costs. And use line current - and recharge the batteries at the same time - with the available battery eliminator/chargers below (PS−2404 for 120 VAC, PS−2405 for 240 VAC (one required for proper operation).

For bench use, the IM−2400 includes a pivoting stand which supports the counter at a more convenient viewing angle. Find out how portable a frequency counter can really be. Order the IM•2400 Hand-Held Frequency Counter today.

Kit IM−2400, Shpg. wt. 3 lbs. ..................................................... 139.95

SM−2400. Factory assembled and tested, Wt. 2 lbs. ................. 179.95

Swiveling Telescopic Antenna for IM−2400, IM−2410 Counters. Also use on many 2-meter transceivers. Chrome-plated brass antenna provides significant improvements in performance over similar antennas. Enhance counter sensitivity by tuning the antenna to the proper frequency - by extending or retracting the telescoping sections. Right angle version, with BNC connector included.

SMA−2400−1, Assembled, Shpg. wt. 1 lb. ..................................... 9.95

NEW! 120 VAC Battery Eliminator/Charger for IM−2400 Counter. PS−2404, Shpg. wt. 1 lb. ............. 4.95


Inputs: Frequency Ranges: 50 hertz to 50 megahertz, and 40 megahertz to 512 megahertz. Sensitivity: 50 hertz to 50 megahertz range - 25 millivolts, Root Mean Square (RMS) guaranteed, 10 millivolts RMS typical; 40 megahertz to 512 megahertz range - 25 millivolts RMS guaranteed, 10 millivolts RMS typical. Input impedance: 50 hertz to 50 megahertz range -1 megohm shunted by less than 24 picofarads.; 40 megahertz to 512 megahertz range - 50 ohms. Input Protection: 50 hertz to 50 megahertz range -150 volts RMS to 100 kilohertz, derating to 10 volts RMS at 50 megahertz; 40 megahertz to 512 megahertz range - 5 volts RMS. Time Base: Frequency: 10 megahertz. Setability: +1 part per million (ppm). Temperature Stability: +10 parts per million (ppm), from 0 degrees C to 40 degrees C. General: Gate Time: 1 second or 0.1 second [switch-selectable). Resolution: 50 hertz to 50 megahertz range - 100 hertz with time base set at 1.0 second, 100 hertz with time base set at 0.1 second; 40 megahertz to 512 megahertz range - 100 hertz with time base set at 1.0 second, 1 kilohertz with time base set at 0.1 second. Power Requirement: Five 1.2 volts DC, AA−size rechargeable nickel-cadmium batteries, 120 volts AC with optional PS−2404 Battery Eliminator/Charger; 240 volts AC with optional PS−2405 Battery Eliminator/Charger. Overall Dimensions: 1.63 inches H x 3.38 inches W x 8.38 inches L (4.1 x 8.6 x 21.3 cm). Net Weight: 0.81 pound (0.37 kilogram), including five AA−size nickel-cadmium batteries.


Contact Info

Heath Company (Heathkit)
Operations: PO Box 15, Ottsville, PA 18942
R&D/Mfg: PO Box 3115, Santa Cruz CA 95063
Phone: +1 (831) 480-4368
E-Mail: info.2015@2015.heath.company



Posted June 8, 2021

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