DI2AM reception on 505 kHz

The 500 kHz grabber is now set to two narrow frequency ranges, the "WSPR segment" and 100Hz around the frequency of DI2AM.

DI2AM reception seems to be there essentially all the time after sunset, albeit with some (expected) QSB, and WSPR signals coming and going.





Nice result with a "cheapo" frame antenna wound on a cardboard box 35x40 cm small.

A new somewhat bigger frame antenna (more than 70x70cm) will be made some time, but that will have to wait.

In the week end the construction of the 500 kHz TX should begin

500 kHz Receiving Antenna in the Make.

I have been looking into the options for receiving amateur signals on the 600m band (500 kHz). Since I live in an apartment size does matter, so looking for a small sized antenna I looked around and found this article from VK2ZAY , showing a simple 'frame antenna' made with a cardboard box.

Being close to all kinds of noise sources I think the loop is probably the best option for a receiving antenna on such a low frequency.

Since I intend to use the antenna indoors the support material does not matter much.

The box measures are on the small side - 35x40 cm (14x16 inches if you like) - but as a proof of concept I have put 25 windings with taps at 15 and 20 windings, as well as a single winding coupling loop.

Now I will be looking in my junk box to find a suitable variable capacitor to complete the project (this may take some time).

If this works out to my satisfaction I will try out frame antennas for 80m, 160m and 2.2km as well, at some time.

Since there seems to be an experimental license available here in The Netherlands I may even try to put out a 600m signal, yes, I am considering joining the experimental group. The decision, however, has to be made soon before the opportunity expires.

Idea box : 10.7 MHz spectrum scope (1)

I found a nice crystal frequency on eBay : 10.6875 MHz

Yes, 10700 - 12.5 kHz.

Combined with a 15 kHz wide 10.7 MHz FM filter and a direct conversion receiver this should make a 10.7 MHz spectrum scope with 15 kHz bandwidth, so :

10.7MHz signal from R7000 or similar receiver -->
possibly a preamplifier, in any case some termination for the filter -->
10.7MHz FM filter for 25kHz channel spacing (BW = 15 kHz) and 2nd termination -->
DC-mixer with oscillator frequency of 10687.5 kHz (possibly pulled up to 10690 kHz) -->
AF amplifier -->
output to PC running spectrumLab

Looks like yet another 'little' project.

should be good for looking at satellite transponders with (not too wideband) digital signals, and some Doppler tracking at the lower satellite frequencies.