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Beacon Reception -- Any Interest?

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Avalanche

Wed Nov 29 2006, 11:49PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

well I've just won 100 crystals that are 99Khz too high, so if they arrive in time I'll try knocking them down by a few tens of khz, if that fails then I'll just make up a normal oscillator as stable as I can possibly get it... Either way I'll definitely be watching out for your signal, but I can't guarantee much judging by what I have now.

Wolfram

Thu Nov 30 2006, 06:04AM

Registered Member #33 Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971

Changing the frequency of crystals:

Steve Conner

Thu Nov 30 2006, 10:46AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Well, my web-enabled receiver seems good to go, so now you can join in the fun even if you don't have a radio! All you need to do is watch the web page (it updates every 20 seconds, I'll post a link nearer the time) and if you see Chris's signal, take a screencap and post it here. Don't say 4hv.org isn't good to you

The most likely times to receive the signal will probably be during so called "Grey line" propagation when it's morning at Chris's location and evening at mine or vice versa. So for a few hours around 1600 UTC and again at around 0800 UTC the next morning I guess. I never seem to get anything on 20m or 30m after dark.

Avalanche, if you get the crystal penning technique to work, please post and tell us about it! 99kHz is a long way

Dave Marshall

Thu Nov 30 2006, 01:39PM

Registered Member #16 Joined: Thu Feb 02 2006, 02:22PM
Location: New Wilmington, PA
Posts: 554

I'm going to try streaming the test via the icecast stream we set up some time ago. With the speclab winamp plugin, you ought to be able to decode straight from the stream, though I'm not sure what the compression is going to do to the signal.

I'll post the link to the stream Saturday afternoon most likely.

Dave

Chris Russell

Thu Nov 30 2006, 07:21PM

... not Russel!
Registered Member #1 Joined: Thu Jan 26 2006, 12:18AM
Location: Tempe, Arizona
Posts: 1052

Excellent. Not only can I send the signal out, but I can watch it come back via Dave and Steve's setups. I'll be sure to get screencaps of both.

Conner, or Dave, or anyone else using Speclab or Argo, you can set it up to take screencaps every so often, and store them in an incrementing number. It'd be quite nifty if you could store up an archive of screencaps. Given the slow speed at which QRSS10 moves, it shouldn't require more than a few hundred screencaps for the whole day. Argo tells me it'll take about 180, speclab should be even less because you can make the window physically larger.

Avalanche

Fri Dec 01 2006, 06:30PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

Thanks for the link Anders M, my crystals arrived today so I had a go at changing the frequency, and it does indeed seem to work. I was even able to achieve the 99Khz shift to 10.141Mhz but I admit the sensitivity to temperature changes is then pretty well 'amplified' probably due to all the ink.

Hopefully I'll have something working in time, the parents are going to get a shock when the halfwave dipole goes up tomorrow

Just thought I'd add, it didn't take much ink to achieve the shift, nothing like as much as shown on that page. I used 2 different kinds of permanent marker, 1 type did actually shift too much, then stopped the crystal from oscillating at all, but I was able to rub it off with some solvent when that happened and start again. My final technique was to apply too much ink, and then 'polish' it with a cotton bud to get near the right frequency. Just scratching the surface of the ink with the lead of a resistor shifted it by a few hundred Hz.

ShawnLG

Fri Dec 01 2006, 10:13PM

Registered Member #286 Joined: Mon Mar 06 2006, 04:52AM
Location:
Posts: 399

Nice job Avalanche. I may sacrifice some of my crystals to try that out. I am picking up a lot of ham activity now, you guys should listen in if your reciever is built.

Avalanche

Fri Dec 01 2006, 10:40PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

Just a tip to save you some crystals when opening the cans, don't bother trying to saw it off at the base. Even with a razor saw and lots of patience, I wasted 4 crystals by doing that, something went wrong every time and I broke the crystal. What I eventually did was to firstly grind the top off the can, and then grind each side away carefully, then fan out the two sides of the can and break them off.

Something else I found was that by adding too much ink at once, the crystal stalls and it will never oscillate again. By adding the ink slowly and letting it dry in between, you can slowly work down the band.

Hope this saves you some crystals!

Chris Russell

Sat Dec 02 2006, 04:53AM

... not Russel!
Registered Member #1 Joined: Thu Jan 26 2006, 12:18AM
Location: Tempe, Arizona
Posts: 1052

Wow, impressive stuff. Glad to see I'll have some listeners! Just remember, you want your crystal to be 10.140MHz, ideally. If you're right on top of my signal, you won't be able to see it, as the difference (and therefore the output) will be just a few hz or less.

Avalanche

Sat Dec 02 2006, 11:16PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

doh, I completely overlooked that but it makes sense now. Being as it's the beat frequency we're looking at, would it be ok to also go higher than 10.141? I'm only asking because my oscillator seems to have settled down on 10.1418Mhz.

As for my receiver, it's looking more and more unlikely that I'm going to have something working by tomorrow, the results of todays efforts is basically just a soldered mess that does nothing

There are too many 'unknowns' with my whole setup, hopefully I will stick at it and have something that works properly in time for the next transmission.

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