WWVB reception on 60kHz

Having built the WA1ZMS loop, I was intrigued to see how low in frequency it would work without retuning. The lowest frequency signal I could think of seeing a signal was WWVB on 60kHz so i set the ANAN-10 to that frequency

There was a good signal and it did what WWVB should do (there is no voice or cw id on WWVB)

I then searched the internet for a decoder. There were a lot of hardware decoders but very few that could decode audio input to the soundcard. I then found clock1.1 from F6CTE which was easy to install and has a choice of time signals it can decode:-

One point to note is that after being installed the programme auto launches into a calibration routine for 3 minutes during which time there is no spectrum display. Make sure the frequency matches the frequency of the incoming audio tone. The following shows a complete time sequence reception:-

Admittedly this solution is not the most cost effective. Last year I picked up an Oregon scientific WWVB clock, with LCD display and alarm functions for $1 from the local charity shop!

Building a 477kHz receive loop

With the approach of the winter LF season it was time to look at building an LF receive antenna to put on the apartment balcony. My attention was drawn to the design by wa1zms A Simple Loop Antenna for 500 kHz. It looked straightforward to build. The half inch wood was available at the local hardware store. The hard question was how to cross the wood at the centre. Luckily Bob WA5YWC stepped in and milled the crossover portion to be a snug fit, solving that issue. Each arm had 8 holes (for the 8 turns of wire) spaced at 0.5". The two arms were secured with a brass screw to allow dismantling

I had found some 10/46 Litz wire on ebay. It soon became very apparent that this was too fragile to use as it snagged and broke with ease. A further internet search revealed a supply of the more robust 10/26 Litz wire from scotts electronic Parts It was not cheap but it would do the job. The wire was mounted on the frame easily and terminated with two brass nails. I measured the inducance and found it was 65uH, meaning around 1700pF would be needed to resonate the loop at around 475kHz. This value was soldered across the brass pins.

A visit to the local emporium produced all the components for the preamp including a box and stripboard. This was assembled and attached to the mast with adhesive backed velcro and a 9V battery attached. . I hooked it up to the ANAN-10 and took a listen around 475kHz.  but I noticed that the PowerSDR software was indicating an A/D overload. The preamp was acting as a wideband power oscillator! I re-examined the wiring finding a couple of extra short circuits which were fixed. Reconnecting it to the receiver I could hear the WG2XIQ on 475.7kHz and the antenna showed the expected very sharp nulls

131028 0152  25  -7  0.3   0.475663  WG2XIQ EM12 30
131028 0156  24  -8  0.5   0.475663  WG2XIQ EM12 30
131028 0200  23  -9 -2.0   0.475663  WG2XIQ EM12 30
131028 0208  10 -21 -1.4   0.475663  WG2XIQ EM12 30
131028 0212  10 -21 -0.3   0.475663  WG2XIQ EM12 30
131028 0216  11 -20 -0.2   0.475664  WG2XIQ EM12 30