Short Distance 500kHz Success

After a bit of discussion on 70 cm this morning, we talked through Spectran and WSPR settings and use. I was convinced that any wire antenna in an FT817 would produce some signals on 500kHz. With 6Km between us G3KAN had just got to see more than just a 30 second burst of my QRSS.

At 14.22 we made it, using just the wire in the rig, the signal -15dB.

2010-01-2814:42

G3ZJO

0.503820

-15

0

IO92ng

+17

0.050

G3KAN

IO92

26

A run of 4 Spots followed, then some screen shots by e-mail. It will be interesting to find out how long the RX was on for when we talk again. I am intrigued by the possibility that short periods of enhanced propagation bring signals up to a usable level on a poor antenna at short range.

500kHz QRPp

I decided to try QRPp on 500KHz. I have run my Low Power MEPT's with WSPR on HF and VHF / UHF with good results.
I then developed the XORgan which uses 2 Crystals and an XOR mixer to produce WSPR code at Audio frequency for PC Less and thus lower power consumption WSPR.

The XORgan led me to try the Hypersonic XORgan using the same method to directly generate WSPR, QRSS and Hellschriber at a very very high Audio frequency :-) 500KHz in fact.

I added a one chip Buffer / PA stage so that in just 2 chips I have a complete LF Transmitter with an RF Otput of 160mW. Existing stations on 500kHz were geting good results using 5Watts from their TX's and WSPR. I reconned I could get usable results with my 160 mW (15dB less power) so that was the basis for my Experimental Permit.

Quite rightly some advice said that on LF if you have a little Antenna Loss it is no great problem as you can just use a little more power to compensate. On the RX side there is little need for a super efficient Antenna. At my QTH I dont have the possibility for a very good Antenna so I have to make the small set up I have as efficient as possible. With QRPp there is nothing available to waste.
Up to now results have been quite encouraging. Antenna tests continue, more on that and the results later.