Month: August 2017

On the back of A WSPR experiment for station evaluation I thought I would try a similar experiment on 30m in the quest for some meaningful results.

Given the lack of activity from credible stations on 40m, it seemed worth a checkout on 30m befor committing to the trial run, large download and data analysis.

So, I ran WSPR for a half hour just before 0000Z and observed the activity on WSPRnet map. I should note that my tx power was 0.1W and rx performance was impaired as there was a 20dB attenuator in line to achieve the tx power.

Above, the map after of the half hour of activity.

The encouraging this was that there were 12 stations active. Continue reading WSPR checkout on 30m

An experiment was conducted on 40m using WSPR to compare my own station transmit performance with others relatively close by.

The experiment was conducted around sunset on 01/08/2017, data was collected for the period 0600Z to 0900Z, sunset was at 07:17Z.

The experiment was unannounced as previous experience has been that if the WSPR community becomes aware of activity that does not accord with individual’s opinion of acceptable, the activity can be disrupted.

Data for analysis was fetched by downloading the archive which contained nearly 1,000,000 records for the day, and about 340,000 of those were 40m spots.

Factors shaping experiment design

The following is a discussion of various factors that weighed into experiment design.

Transmitters tend to cluster around the centre of the 200Hz WSPR band.

Above is a frequency distribution of tx frequency, and it is evident that the risk of interference is reduced by choosing a frequency near the upper or lower limit of the band segment. There was some activity just outside the designated band segment which might indicate care and competence of operators.

One wonders if randomising the tx frequency might not reduce collisions and improve decode rates. Continue reading A WSPR experiment for station evaluation

I was working recently on an antenna and a visitor was intrigued by a device I was using.

Above, the device is for tensioning a wire span, commonly called a come-along though that term gets applied to all manner for appliances for broadly similar purpose. A significant difference is that this was designed for smooth hard drawn copper wires, and has smooth flat jaws (70x6mm) and does not put a kink in the wire (as do most wire grips for more general fencing and FSWR use). This one has had the strap replaced, it came with a 1.25″ canvas reinforced rubber transmission belt which became hard over time. Continue reading Come-along from the past