Hallicrafters SX-28A with BC-1031-C Panadapter

I ran a tap off the SX-28A mixer plate to 1st IF transformer circuit to the rear panel of the receiver. From there coax to the input on the panadapter.

The tap consists of a 10 pF capacitor in series with a 50K resistor for additional isolation, so as not to load down the mixer circuit. I then added a SO-239 connector on the rear panel after drilling a 5/8" hole in a safe spot. This was a very common mod during WW2 and you find many SX-28's with it already installed so they could be used with the panadapter.

The panadapter is like a mini spectrum analyzer, allowing you to see the rf as it passes through the IF passband at 455 kc. You get about a 100-200 kc spread either side of the tuned frequency.

This is ideal for signal monitoring in the frequency domain, and spectrum monitoring for signals adjacent to your tuned frequency. This allows you to see who else is out there and tune to them.

Fun stuff.

Greg
K6SRO

Category:

Science & Technology

Tags:

• Ham
• radio
• hallicrafters
• panadapter
• RF
• Signal
• receiver
• heterodyne
• superhet
• SX-28
• SX-28A
• HT-4