8 meter band

Lately there is quite a lot of attention for the 8 m band (40 MHz). Transmissions are done from Ireland, UK  and Denmark for example.

This band could be interesting to explore for various reasons:

The 8-meter band shares many characteristics with the neighboring 6-meter band. However, as it is somewhat lower in frequency it does display the better propagation mechanisms via the F2 layer normally seen at  HF. Also sporadic E-propagation is common on this band in summer.

After I performed the MARS modification, my FT-450 is able to receive 40 MHz signals. Of course the FT-450 input filters are not designed for this frequencies.

I am working on a 8 m bandpass filter / pre-amplifier for the FT-450 to increase the sensitivity for this band. 

Hopefully I will be able to tune in into 40.680 MHz - to receive FT-8 signals - soon.

First results;

                                                      Passive band filter under test

                                                             nanoVNA showing filter characteristic

Hardware

 For more than 10 years I have a piece of hardware in my junkbox that waits for an application:

It is an old school mechanical tuning device, most likely obtained from 'green' radio equipment. The tuning knob drives, tru a variety of gear wheels, a 100 Kohm potentiometer.

The only (German) inscription present says "Funk.stat.18.T"

This beautiful piece of mechanical art waits to be incorporated into a homebrew VFO (for example).

Off topic:

My QTH Zuidzijde, locator JO21dq from above. Photographed by a collegue in a Robin DR400, March 2022