Amplifier for 80 Meter Rig

Here's the LTSpice schematic for an amplifier chain that I've been building. (It might be hard to see, but maybe you can download it and look at a larger version.) Four stages, all feedback amps. The first three are class A, the final is Class AB. About 45 db total power gain -- it takes the .0001 watt (peak) from my balanced modulator and amplifies it to about 3.2 watts.

So far it seems very stable. Notice that I don't have any decoupling networks on the first three stages (other than a .1 uF cap to ground on the +13V supply rail. I tried to continue without decoupling on the final, but I got instability, so I added a 10 uH RF choke and a cap to ground as a decoupling network to the final stage. Instability disappeared. Do I need more decoupling on the other three stages?

The last two transistors are disgnated at 2N3053 and 2SC2075. That's what I'm actually using, but I haven't figured out how to get these parts into LTSpice, so I'm actually using 2N2222 models in my simulation.

Here is the actual LTSpice file: Bill's Kickpanel amplifiers

I'll talk about this project on SolderSmoke tomorrow. Comments welcome.

IK0IXI's Homebrew QRP SSB XCVR (8 bands!)

SolderSmoke #94

http://www.soldersmoke.com

SolderSmoke #94

November 2, 2008
Halloween in Rome, Autumn rains
Building Class A Amps with Spice, Copper, SSDRA, EMRFD
Wes on oscillator output wave forms
Inspirational article in "Air and Space" Magazine
Book Review: "My Detachment" by Tracy Kidder
Autumn SPRAT
SPECIAL REPORT FROM G-QRP MINI-CONVENTION
Aliens on 80 meters
MEPT: Can you see me?
Softrock 40 Group tries to digitize N2CQR
Homebrew solar panels
Request for assistance.. .
MAILBAG:
Alan Yates in cahoots with AA1TJ
Les gets our logo on I-tunes
Paul WA1MAC gets 2 2Bs
Scott KD5NJR on KSC honeymoons
Bruce VE9QRP on new free QUCS simulator
Keith G0CZR on bubble wrap insulation
Bob KD4EBM on green laser dangers
John VK3AJG designs 80 meter SSB rig
Todd KE7KXI on Knack relapse, old electronics smell
Jerry NR5A BACK IN ACTION!
Bob N7ZF on SolderSmoke Facebook

Homebrew Solar Panels

I hate to tell you, but all you guys who are using STORE-BOUGHT solar panels are a bunch of APPLIANCE OPERATORS. Time to roll your own, and REALLY make your own electricity.
Woody, KF4TQJ, sent me this interesting link on how to make your own solar panel:
http://www.thesolarplan.com/articles/your-own-solar-panel-collector.html
Before you get carried away by homebrew enthusiasm, scroll down a bit on that page and check out the cost estimates for large scale application of this technology.

See if you can see my signal 10140055 Hz

If Italy is in daylight, you should be able to see my 50 milliwatt FSK signal on one of the European on-line grabbers.

IK0VVE has a nice grabber aggregator site that includes a sun clock. Here it is:
http://www.ik0vve.net/mept6.aspx

Just see if the sun is shining here, then scroll down and take a look at either PA1SBD's site or ON5EX's. Sometimes I can also be seen on I2NDT's.

You should see my signal around 10140055 Hz. It looks kind of like a square wave. Read the Morse along the bottom (my FSK is upside down).

For extra credit, see if you can see Paolo's solar beacon. It too looks like a square wave, but with no Morse. He's running 2.5 milliwatts.

Please let me know if you succeed in seeing our sigs.

Arduino -- Italian Open Source Hardware

Scott Haley in Tulsa alerted me to this very interesting article in Wired magazine. How do you say Knack in Italian? Check it out: Wired article on Arduino

Aliens on 80 meters!

Graham, G3ZOD, was looking at the 80 meter band using the on-line SDR receiver in the Netherlands (http://websdr.ewi.utwente.nl) This is what appeared on the screen. Looks like you can work some real DX on 80 these days. The big issue will, of course, be DXCC credit. And I imagine getting a QSL card might be a bit tricky.

The Flea: Minimalist QRP from Catalonia

Here is a really interesting little rig from Joan, Ea3FXF, and Eduardo, EA3GHS. They have a very nice web site with more info, including SPICE simulation files and SPICE waveform results.
Check it out: http://ea3fxf.googlepages.com/flea

Lasers, LEDs, Tin-foil Hats, and QRP

Yesterday I got a very interesting message from Rye, K9LCJ. The map of Tasmania comes from the Modulated Light DX portion of the KA7AOI site (below).

Hi Bill:

I really enjoy your Solder Smoke show and news feeds. Great stuff that has got me back into ham radio again. Your note about optical comms got me fired up enough to add some notes that you might not be aware of.

There is a substantial worldwide community playing with optical communications and they have achieved some amazing records using simple off the shelf components – mostly big Luxeon LEDs which have some (debatable) advantages over Lasers. The most sophisticated component in typical systems is the Fresnel lens – which can be obtained at office supply stores or ebay as “page magnifiers” for a couple of bucks.

There seem to be about four major groups:

The Radio and Electronics Association of Southern Tasmania has an active bunch and they have achieved some great distance records with (QRP) LEDs. They have also been bouncing signals off of geographic features to establish communications paths. They are also doing some cloud/sky bounce things that are quite amazing. The REAST web site has lots of well documented test data that’s really interesting to read.

K3PGP has an exceptional web page full of test reports and construction details. His K3PGP preamp/receiver (and variants) are the basic building block for most systems. It uses a $1.00 pin diode, a MPF103 FET and a handful of common parts to get some almost fantastic performance.

Yves, F1AVY has a strong theoretical background and has been doing interesting stuff in France for quite a while and his web page has lots of interesting technical details.

Clint, KA7AOI has a very comprehensive web page. Clint holds the record for long distance communications (173 miles) and describes much of his equipment and testing. There is also a bunch of historical material that is very interesting.

There are probably a bunch of folks I have forgotten, but all of them are noted in the many and varied links found on these web sites.

I think that the most interesting thing about the activities is how the teams have adapted available technology to an interesting problem. Much of the work resembles current amateur weak signal activities. In fact, Spectran and WSJT are part of almost every activity. Much of the work is unique outside of the academic community and might even be called groundbreaking in some areas.

We have a small group here in the Raleigh North Carolina area, but so far we haven’t done anything of note other than build equipment and play in the local park. The fact that this sort of thing must be done outside at night draws all kinds of attention – some of which is not necessarily good. …a bunch of strange looking guys running around in the dark with strange flashing red lights…. I have a special cap that I wear for the occasions.

Keep up the good work.

Rye Gewalt

K9LCJ

Laser QSO and Visual EME with laser!

Bob, Kd4EBM, sent me some really good info on laser safety. Bottom line: For the time being anyway, Billy will be limited to the <5mw href="http://www.earthsignals.com/Collins/0036/index.htm">http://www.earthsignals.com/Collins/0036/index.htm
Their rig is pictured above.

And here is one that is really mind blowing: A while back we discussed the laser reflectors left on the moon by the Apollo astronauts. Well, apparently there is an intrepid amateur out there who has been shooting his own lasers at the Sea of Tranquility, and seeing reflections come back. Visual EME. Check it out:
http://www.k3pgp.org/viseme.htm

Thanks Bob!

SolderSmoke #93

Oops, forgot to put this on the blog on Sunday:

http://www.soldersmoke.com

SolderSmoke #93

October 12, 2008
HB Pi Network Tuna (with mystery)
Hamfest report from Belgium
Space Hackers removed from YouTube
Verdict on Judica Cordiglia brothers
FB Italian ham magazines
I shift to FSK on 30 meters
Gimmick capacitors
QRSS QSY woes
SolderJoke
MAILBOX:
Jerry NR5A Back in action
Scott KD5NJR on Space Hacker controversy
Steve WB6TNL on the different flavors of solder smoke!
Paul WA1MAC labled PC boards with SSDRA page numbers
Ramakrishnan VU3RDD getting back on the air
Jim K9JM had 60 POUNDS of 2N2222
Jim AL7R listening from Yuma
Wes W7ZOI on plumbing washer toroids
Paul WA5WCP on laser safety
Terry G4GHU also went to KSC on honeymoon

The Da Vinci QRSS Code

Here is my 30 meter QRSS frequency standard using paper for insulation.