[600MRG] Pat Hammel

[Claude Baker]

Pat,

Despite being newly licensed, I am part of the over the hill gang; I was licensed about 18 months after I retired, although decided in 1956 that I wanted a ham license. Procrastination ya' know?

A few clarifications about WSPR on my system. First there is no A/D involved anywhere in the transmission process though there is a D/A in the signal path. The sound card resides in the transceiver and derives its sample rate frequency from the same reference oscillator that runs the DDS. The DDS of course sets transmit and receive frequencies.

The WSPR software generates the sine wave modulation mathematically and the modulation is actually FSK, not PSK. Each "tone" lasts approximately 0.6 seconds before switching to the next frequency. 


Reading the WSPR documentation, there is mention of the waveform being phase continuous. This is a description of how the waveform transitions between "tones", not the modulation type. As an example, let's say that were generating a sine wave that advances 10 degrees in phase between each sample. We're going to switch to a slightly higher frequency in which the phase advances 11 degrees per sample. When it is time to change frequencies from the 10 degrees per sample frequency, the next sample reflects a phase change of 11 degrees and remains at this rate until the next frequency change. The result is similar to applying a step input to an FM modulator. The process minimizes splatter during the step frequency change.

The USB connection does not affect the sample rate. The USB is very similar to a network connection in that it delivers bursts of data to a data buffer. The buffer (processor) in the radio delivers data to the D/A at whatever rate is required. Television or music over the internet uses the same process - so does satellite radio and CD players.


Thanks for the offer of wire. I have about 400' of 14 ga on hand but I've been thinking about ordering a 500' reel of coax and wrapping my backyard in a shielded loop. I'm thinking that the horizontal 2x4's on the privacy fence will support and conceal the coax - I'm in a single family home. 

Where do I find some reference to the information about changes affecting HOA's?

Claude, AC0ZL