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Heathkit HD-20, 100 kHz Universal Crystal Calibrator, for Parts or Repair #3

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MPN:
HD-20
Condition:
Used
Shipping:
$10.00 (Fixed Shipping Cost)
  • Heathkit HD-20 100 kHz Crystal Calibrator in excellent cosmetic condition. Provides strong 100 kc markers and harmonics from 100 kHz up to 54 MHz+ for precise dial calibration, band edge checking, and receiver alignment. Simple one-transistor design runs on 9V battery with adjustable output and fine frequency trimmer (easily zero-beats to WWV). Compact vintage Heathkit accessory ideal for any analog-tuned ham receiver, SWL rig, or vintage transceiver. Perfect addition to complete a classic Heathkit station or restore accurate frequency readout on older gear
  • Heathkit HD-20 100 kHz Crystal Calibrator in excellent cosmetic condition. Provides strong 100 kc markers and harmonics from 100 kHz up to 54 MHz+ for precise dial calibration, band edge checking, and receiver alignment. Simple one-transistor design runs on 9V battery with adjustable output and fine frequency trimmer (easily zero-beats to WWV). Compact vintage Heathkit accessory ideal for any analog-tuned ham receiver, SWL rig, or vintage transceiver. Perfect addition to complete a classic Heathkit station or restore accurate frequency readout on older gear
$9.99
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Description

Heathkit HD-20, 100 kHz Universal Crystal Calibrator, for Parts or Repair #3

 This calibrator does not have the 100 KHz crystal. I tested it with a good crystal and it is working, and you can hear the tone, but is a bit weak as compared to others I have.

 It is likely the transistor which is easy to replace as it has a plug in socket for it

 This Calibrator will work with any receiver or transceiver.

 A copy of the operation / Assembly manual is included

I am selling it as is, as described for parts or repair.

Heathkit HD-20 100 kHz Crystal Calibrator (introduced ~1960, produced until mid-1970s).
 
w6ze.org
This is a compact, battery-powered external crystal calibrator designed as an accessory for receivers and transceivers lacking built-in calibration markers. It generates a strong 100 kHz fundamental signal and rich harmonics, providing accurate frequency markers every 100 kHz across HF (and usable into low VHF). Hams and SWL operators use it to calibrate analog dials, check band edges, spot exact frequencies, and aid in receiver alignment.
 
rsp-italy.it
Key Specifications
  • Output: 100 kHz fundamental with strong harmonics from 100 kHz to at least 54 MHz.
  • Crystal: Quartz, fundamental mode, 100 kHz ±0.005% (can be precisely netted/zero-beat to WWV using the built-in trimmer).
  • Circuit: Simple single-transistor (2N409 germanium PNP) oscillator configured for rich harmonics.
  • Power: 9V battery (original NEDA 1600/1600D style; many units modified for modern rectangular 9V batteries). Typical draw ~3.5 mA. Battery life ~6 months intermittent use.
  • Controls: Simple ON/OFF switch.
  • Output Connection: 5-way binding post (red) on top — couple via a short wire near the antenna input or direct connection.
  • Size/Weight: Approximately 2.5" W × 4.25–4.5" H × 2.625" D; ~9 oz.
  • Features: Adjustable coil for max output; series trimmer for fine frequency adjustment.
     
    w6ze.org
Your unit in excellent cosmetic and working condition is a strong example, especially if it includes the original battery holder (or clean modification), crystal, and functions cleanly with strong markers.Compatible Radios / Intended UseThe HD-20 was a universal accessory intended for any receiver or transceiver without a built-in 100 kHz calibrator. It was especially popular with:
  • Heathkit receivers (e.g., HR-20, RX-1 Mohawk, AR- series, etc.)
  • Other vintage ham receivers (Hallicrafters, National, Hammarlund, etc.)
  • General coverage shortwave receivers
  • Early transceivers and homebrew gear
It couples easily to the antenna input of virtually any radio for marker injection.
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