I am based in Glenmoriston which runs aprox.westwards of Loch Ness.
I am completely surrounded by mountains-the skyline south of me is 30 degrees from the horizontal and to the rear of my house the first three hundred feet is nearly vertical granite.
There is a small window between east and south east where the hills are about 8 miles way but which peak at 4000 foot in the Cairngorms.
So I am assumning the only signal I am getting is reflected.
We are assuming that we are getting a signal from the same transmitter.
I am sure I read somewhere that Northwood uses a series of transmitters from Ascension Island northwards because Northwood itself is near Watford.
My antenna is a horizontally strung 45 foot length of 1.5 mm dia.6 strand twisted insulated wire commonly used for wiring up ceiling spots.Feed line is 70 ohm low loss satellite coax. because I have a load of it!
Also I use a low loss screened digital audio feed-a couple of £s on e bay
Today for a change I also tried the radios onboard whip.The whip showed a far poorer spectrum spike with progressive signal build up either end wheras the antenna has little either side of the spike.
Radio is set local and narrow band ssb.
The wind vector chart begins on the whip and swops over just about where I am in the Highlands ;the prognosis chart I received almost two hours after setting the system on auto running whilst I took my dog for a walk.
Origional pic quality far better than this jpg conversion at 100kbs-1.4 mb per pic.and as I recall about 24x18 inches as transmitted.
Last edited by ffiill; 06-04-12 at 15:51.
I can't match these yet, but today, after a year or so of messing about, I got this:
Degen Short wave radio. laptop, Offenbach (DDH) weatherfax on 7878.1 Mhz. Software, demo version of JVComm32.
Really messy, and hardly worth anything, but after months of trying to work out what all the jargon means, how the radio works, how the software works, and getting nothing but noise, I'm absolutely over the moon to see an Atlantic weather chart. I fiddled about, and got a much clearer image after this, but didn't manage to save it.
Anyway, this isn't about me, it's just to say thanks to ed for providing the original info, and the other contributors. Cheers, lads.
Was your laptop on mains
Did you have your laptop or radio plugged into the mains when you collected this chart? It looks very like the charts I was collecting...look back to post 56 and others.
In my many and various tests I found mains (left on by mistake) could cause this and setting the 'slant control' also helped, however, your chart seems all neatly lined up, just very 'dirty'.
I guess ensuring the radio is on narrow band tuning might help? Just been going back through my posts to see if I can find the moment I went from this kind of thing to a cleaner, readable chart.
I'm learning with every attempt. First time I did have the laptop plugged in. I had a reasonably clear fax sound on the radio, but huge interference when I plugged in the mic lead from the radio. So, as Ed says, don't do it whilst charging.
Originally Posted by iainhu
Then I read that you can use the fine tune dial on the Degen once the frequency is set. That affects whether the fax is translated as mainly black, or mainly white. I was fiddling with this whilst recording - hence the switch from white to black fax and back again.
I haven't yet worked out why I can get faxes from Offenbach (Germany) but not yet from Northwood.
Honestly, I don't care. Once I know I can do it, it's just a metter of time to get the best results, and I'm learning loads.
A black art
Yes it is all a bit of a black art. Look back as I struggled my way through to getting readable charts. However, having done so and being all set to use them trans Atlantic I could get *nothing* once on the boat...contrary to all predictions. Probably RF from the boat, so in the end it became a whole lot easier to use the sat-phone and download gribs, which worked fine, just failed to use my, I thought, new found skills to work!
This one is fun as well, RTTY from DWD on 10.1MHz. On JVcom if you go into configuration/RTTY and enter these..
Originally Posted by Alcyone
mode:Whatever memory you want to save it as.
# of bits : 5
you should get text weather from DWD in Germany. Strong signal usually.
Apologies, Conachair, I missed your post. I'll try that. Many thanks.
What time were these faxes done at?-all mine are during the daymid morning and late afternoon is best.
Just suprised how poor the quality is-I managed to get good quality within a few days of beginning to experiment.
Several points-fine tune the signal whilst watching the image so as to get it as clean as possible.
You can pick up a lot of spurious sound of the mains-I am in a rural area but can still get a lot of noise sometimes and find that internal batteries are better.
When I was experimenting on the west coast I was getting a lot of interference on some frequencies-perhaps military jamming.
Use a sheilded coax lead between radio and PC.
Always tune down from reccomended frequency.
Set to Upper side band?-if I dont use USB I get a lot of spurious noise.
I am wondering if there are issues with Northwood of being too close.
My signals are definitely ones bounced of ionosphere.
Finally I did manage to pick one up on my long wire aerial if a little unclear from Boston -4000 plus miles away.
Some useful hints, thanks :-)
For my part:
- I often did my reception in the evening, after dark, which is supposed to be better for signal reception so interesting to hear yours are in daylight
- I used a PC audio lead...not sure how much shielding that would have had
- I only ran both radio and laptop on battery except for one accidental use of mains which was very obvious
- I did all my recordings outside...not a hope inside!
- I did most of my recording with a retractable (16' I think) wire aerial stretched horizontally which helped 'a little'
- Yes, you need to tune low the get the upper side band
- Very impressed at you picking up Boston...makes me feel I should try that again!