Dummies Guide to Digital Modes ??

[VK5AJ]

Could someone point me in the right direction for an intro guide to using digital modes on VHF / UHF ie JT65, WSPR etc etc

Thanks in Advance

Alan VK5AJ

[VK7XX]

Could someone point me in the right direction for an intro guide to using digital modes on VHF / UHF ie JT65, WSPR etc etc

Thanks in Advance

Alan VK5AJ

Leigh, VK2KRR has some info at http://www.vk2krr.com/jt65_message_procedure.htm
and there's "The Complete Bozo's Guide to HF JT65A" at http://www.pe2pe.eu/WSJT_on_HF.htm for starters.. I hope they help.

[VK2KRR]

I better update that with terrestrial process too soon.

I would also read up info at http://physics.princeton.edu/pulsar/K1JT/ the instruction manuals for the programs will help too.

Alan, maybe if you have some questions, we can just try and answer them for you here.

[VK2BLS]

I recently found this link. Some useful info on protocols etc. for the 'Digital Dabbler' - Clarified a few things for me. Thanks go to the originator.

http://vhfdx.radiocorner.net/docs/FSK441-Proc.pdf

[VK3YE]

Here's some quick notes jotted after my first few days of playing with WSPR (on HF):

Firstly some background

1. What is it? Weak Signal Propagation Reporter. Digital mode, narrow bandwidth, takes 2 min to send a callsign, location and power. Basically a beaconing system that can be heard well below the noise level. Most activity is on 30m, but during the evening I find 40m better.

2. What does it need? Computer with soundcard & HF gear. It helps if the computer is connected to the web to send and receive reports. You can use the same interface box as for SSTV & PSK31. Or in a pinch manual tx/rx.

3. How much does it cost? $0. Download here: http://www.physics.princeton.edu/pulsar/K1JT/wspr.html

4. Can you let the world know who you're hearing and see how well others are getting you? Yes. See http://wsprnet.org/drupal/ No logins or passwords - just tick a box in the above software to automatically report for later reading.

5. Can you build gear for it? Yes. See the W3PM 30m 1w Txcvr for a simple circuit http://www.knology.net/~gmarcus/

6. How much more efficient is it than CW/SSB? Hard to say but I'd say that milliwatts of WSPR are the equivilant to watts of CW/SSB. most operators use 1 - 5 watts.
Experiments

1. Receiving. Left the computer on overnight on 30m. Dozens of stations all around the world, but particularly Europe and USA were heard.

2. Transmitting. Tried various power levels, with results as follows (on 40m during evening).

5mW: VK1FOTO, VK2DDI, VK5DJW

100mW: Above plus VK6ZT and ZL2IFB

500mW: Above plus KL7UK, KH6CW, VK2BTS

10w (running this overnight): All Europe, North America & Japan.

3. Homebrew receiving. Used a crude direct conversion receiver feeding a soundcard (MPF102 mixer, BC548 audio amp, BC548 osc) and picked up several signals on it. Will be refined further, probably using a better detector like the W3PM circuit. I would not be suprised if I was not heard by making a transmitter and coupling a double balanced mixer straight to the antenna (output approx 1mW), though 100 - 500mW would be provide more reliable DX. UPDATE 3/2/2011: Been able to cut the receiver down to 2 transistors using a single balanced diode mixer. Still receiving DX.

It's not making QSOs but it's an amazing mode and the signal strength figures are instructive.

73, Peter VK3YE