Scanned the 40m band now (2023-11-08 20:30-20:50 UTC) using my BITX40 and my 40m EFHW antenna in the attic. This is what I heard:

7.006-7.008 lots of CW
7.022 CW
7.036 CW
7. 049 FT8
7.078 some digi mode (FT8-like)
7.084-7.088 buzzing QRM
7.089 some digi mode (FT8-like)
7.090 "puff puff puff" QRM
7.119 constant tone
7.120-7.122 buzzing QRM
7.125.5 faint "digital-ish" mode (think RTTY)
7.139 AM carrier
7.145 AM carrier
7.151.5 AM carrier
7.156-7.160 buzzing QRM
7.161.5 AM carrier
7.162.8 AM carrier
7.165 AM carrier
7.169 AM carrier
7.177.5 AM carrier
7.182.7 AM carrier
7.185 DX pileup (faint)
7.187.8 AM carrier
7.190-7.195 buzzing QRM

The band seems to be closed this evening. Normally I hear human voices on pretty much all over the phone part of the band., but today I only heard voices on a single frequency.

It should be noted that the BITX40 has some known design issues. The one I have run into the most (apart from the LOUD 7.200 MHz birdie) is that 41m broadcast band is heard overlayed on top of the 40m amateur radio band.

Normally RF (7.0-7.2 MHz) plus LO (5.0-4.8 MHz) get mixed to IF (12.0 MHz). In this case, the fourth harmonic of the LO (20.0-19.2 MHz) minus RF (8.0-7.2 MHz) get mixed to IF (12.0 MHz). I figured this out when I identified that the station I heard on 7.1728 was actually broadcasting on 7.305 (a Chinese AM station I found using a WebSDR).

Since the band was pretty quiet I managed to figure out that the QRM I've been hearing for a long time seems to repeat every 36 kHz. Good to know!

#amateurradio #hamradio #bitx