As we continue to work our way through our archive of photos, we run across some that are a bit out of the ordinary.  They may be humorous or unique but they stand out from the other photos. We post new photos here monthly with the previous photos in the slideshow.

Our October Photo of the Month is an advertisement from the January 1950 issue of Electronics for the oscilloscope that was the primary competitor for Tektronix initial oscilloscope the Type 511. The Allen B. Du Mont Laboratory was America’s leading oscilloscope manufacturer through the second world war. Their leading product, the Type 248 oscilloscope, was introduced in the early 1940s. As stated in the ad, the 248 offered a 3 dB or better response to 5 MHz and was “useful” to 10 MHz. The oscilloscope consisted of two units, the 71 lb. indicator and the 126 lb. power supply. Note in the ad the power supply is shown much reduced in size in the white circle in the upper left. In reality it was roughly the same dimensions as the indicator.

At the time the 511 was introduced in 1947, the 248 sold for $1870. In an apparent concession to the success of the Tektronix 511, the ad announced a 27% price reduction for the 248, but Tektronix 511 was still $575 less expensive.

Key features of the Tektronix 511 over the Du Mont 248:

• 3 dB down at 10 MHz
• 65 lb. total weight
• One enclosure
• The 511A, introduced in 1950, was reduced down to 50 lbs. and incorporated an improved regulated power supply

Further, the 511 was sold with both time and amplitude calibrations from the factory. It also offered a continuously variable triggered sweep.

Photos of the Month:  Jan 2025 - Present

Photos of the Month:  Feb 2019 - Dec 2024