Thursday, 12 February 2015

Building the Ultimate-3S WSPR kit

I set aside a few hours to build the U3S from QRP kits.

The build went fairly well, the instructions are fairly clear. When I first applied power it was obvious that something was wrong. What I saw on the display was not what I expected to see.

I did some fault finding and came to the conclusion the 20 MHz clock was not functioning. I carefully removed the crystal and replaced it with a temporary 10 MHz crystal.

I then powered the U3S up and I was very pleased to see “Diagnostic mode” displayed on the display.

Tomorrow, I will try and find a suitable replacement crystal. Then hopefully I can set it up to WSPR to the WWW on 10m.

What a relief……

Start of build

This is a problem !!

Problem solved

Mainboard, display (not visible), synthesizer and 10m low pass filter

Wednesday, 11 February 2015

WSPR - Antenna performance evaluation

I believe WSPR is a great tool to evaluate station/antenna performance.

I used the WSPRnet’s data base and downloaded the 10m WSPR data for all stations decoded by myself and a fellow amateur, Kevin ZS6KMD located some 20 km north of me yesterday.

The graphic below reveals quite a lot of detail: Number of decodes, strength of decodes (min and max).

I was using a simple dipole beaming E/W at 8m agl, I think Kevin also uses a dipole, but I am not sure of the orientation and height agl.

IMHO this is a sure fire way of comparing apples with apples.

Info gleamed from this test:

The band opened and closed at about the same time (Duh...)

I decoded a few more stations than he did, 569 vs. 468.
The strongest signal decoded by me was +2 dB vs. -5 dB by Kevin.
Weakest signal decoded was -32 dB !!
It appears as if my antenna was performing slightly better (between 2 and 13 dB)

I should stop playing and build my Ultimate 3S WSPR beacon.....

WSPR ZS6A vs ZS6KMD 10m decodes