Sunday, 10 July 2011

Delivery of Unobtanium

Crystals for 10140kHz have become very difficult to obtain of late. A lot of hams have become interested in QRSS, and this sub-band of 10m is a prime focus for the specialisation. I had to order from a supplier in the US, and yesterday they arrived, complete with a complementary ballpoint pen!

I will be taking time in constructing the next manned experimental propagation transmitter (MEPT), and the improved stability afforded by the new crystals is just one intended improvement. I also want to take advantage of a reception technique called 'stacking', where successive transmissions are overlaid in the grabber (software receiver), building up a stronger image of the transmission. The technique requires the transmissions to begin exactly 10 minutes apart, preferably aligned with the hour. Non-stacking grabbers receive the signal as normal, but those which can stack grabs will show enhanced images in their stack archive. This will involve use of the timers in the microcontroller; I use a PIC16F690.

I will be simplifying the format of the transmission. I will no longer transmit my locator, as just about everyone has access to and that makes the locator not just redundant, but possibly a little irritating for most users.

Next post will be a report on the success (or otherwise) of the new MEPT. Work begins tomorrow morning.

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