Demo of National HRO-50-1 receiver

This is a demonstration of a National HRO-50T1 receiver. This particular vacuum tube radio with plug-in coils dates from late 1951 or early 1952. It is an improved and updated version of the famous HRO receiver used by US and Allied forces during WW II.

The HRO-50 and 60 have exceptionally good audio quality for AM reception. This clip begins with a sample of AM broadcast reception on the 49m band, but the audio here just uses a cheap computer mic in front of the radio's speaker, and it cannot do justice to the AM audio quality. Using a very primitive antenna, it is shown that this receiver can still pull in distant amateur stations (Croatia and New Zealand) even though they are transmitting only a few hundred watts.

This receiver has the optional crystal calibrator, which allows the tuning dial to show the tuned frequency pretty accurately by the standards of 60 years ago. It is normal to calibrate in CW mode, but in this video, the receiver is in AM mode in order to also show the operation of the S-meter (signal strength meter). The S-meter on all HRO models with vacuum tubes works only when in AM mode.

When receiving CW (Morse Code), the bandwidth can be as narrow as 100 Hz, and this is demonstrated at the end of the video. This selectivity represents one part in 300,000 at the upper end of the frequency coverage.

This radio weighs almost 90 lbs if you include the extra plug-in coils, the wooden storage box for the coils, and the speaker. It is a true "boat anchor" receiver.
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Category:

Science & Technology

Tags:

• radio
• National
• HRO
• amateur
• ham
• general
• coverage
• bandspread
• communications
• receiver
• vintage
• boat
• anchor
• boatanchor
• vacuum
• tube
• thermionic
• valve
• wireless
• DX
• DXing
• shortwave
• short
• wave
• HF
• high
• frequency
• SWL
• listener
• telegraphy
• telephony
• AM
• CW
• SSB
• single
• sideband
• broadcast

[G8GT364CI]

I got an HRO-50R1 that I've had for maybe 5 years, it's complete in the rack and in great shape with only a few missing coils (black wrinkle and hard to find).

[imjustpassinthru]

This was REAL ham gear. These were solid built pieces of equipment.

[teamfab]

Just love the brute of a VFO knob..

Lovely looking radio...