Fox receiver for 2019

Fox receiver

Prototyp

It starts in the spring this year, I help Bo SM5CJW to do some small receiver board he work with.  I save some boards for own use and later I get updated info from Bo. So I will give it a try.  I build the HF board and an LF board, the  Lo Si5351 i was familiar with earlier, it was also published in Swedish ham magazine QTC. After some change of mixer it works grate with excellent  sensitivity  and low noise level. Bo also have same example on different antennas, and I start to try with loop antennas . I really like the result. I build prototypes with both loop and ferrite antenna and as I see it the loop is the winner, 1 more shape on minimum signal, 2 more quiet, ferrite  has a small noise I didn’t  here in loop, 3 a little bit higher signal level.

I decide to try this receiver build together with my earlier built electronic compass. This was the hardest bit to put in 3.3V cpu together with an sensitivity receiver (around 0.5 uV) many filters and try and error to get all thing to work.

I start to merge the code to one cpu but I couldn’t  get it small enough, so way not run the Lo with Bos code on Attiny85 and do the rest with an Adafruit board Pro Trinket 3V. So this Fox receiver has 2 cpu!

Here is the result.

Sensitive receiver.

Excellent Front back or side decision.

Integrated compass direction  in display and calibration status .

Frequency information in display.

Battery voltage in display.

Signal strange meter in display.

Attenuator 0-80 dB info in display.

Look forward to test signal strange in practise, difference so far  95dB 1m from Fox compared to 3.5 km from fox.

I am relay glad I start this work has learn a lot.

Thanks to Bo SM5CJW for the receiver part.