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Friday, February 18, 2011
20% off on Book! 35% off on T-Shirts!
http://soldersmoke.com/book.htm
Speaking of sales... We will soon be in T-shirt weather in the Northern Hemisphere. And hamfest season is approaching. Now is a good time to stock up on SolderSmoke T-shirts. CafePress is offering 35% off on all T-shirts now through Sunday. It's 15% off site-wide and you get another 20% off with the coupon code PREZ
http://www.cafepress.com/SolderSmoke
VFO = Very Frustrating Object
I immensely enjoyed Solder Smoke -- The Book, and have given it as gifts to several friends. It has rekindled the homebrewing spark, and I have been operating only homebrew gear this year as a result. My transmitter is a rockbound 40 meter rig, and I am using a HF regen receiver.
Tiring of QRM on 7.030 MHz, I decided to cobble up a VFO. Well, you know how that can take on a life of its' own. I decided to build a Hartley oscillator at 3.5 MHz, and then double it to 7.030. The initial stages of the oscillator and buffer went well, but then I ran into a brick wall with the doubler, which performed admirably as an attenuator, but nothing else. The circuit was simple enough, but it just wouldn't work. For a week I tweaked and tuned, to no avail. (as a result of all this effort, my wife said VFO must mean Very Frustrating Object). Then this morning I was going over the circuit again, and discovered that one side of the doubler tank circuit capacitor was grounded, and not supposed to be. It seems the knob shaft of the variable cap was in contact with the metal front panel, and being grounded out. I corrected the problem, and almost shouted EUREKA! when the doubler sprang to life and generated a big and perfect sine wave exactly at 7030!
I just wanted you to know that the story of your doggedness in tracking down the cause of harmonics on one of your homebrew rigs provided moral support to help keep me coming back again and again.
So, thanks again for the inspiration Bill.
Hey, I hope you are going to FDIM this year. If so, you should bring a good supply of SSTB. I bet you would go home with new junk, but no books.
73 de KD7KAR
Rob Pursell
Thursday, February 17, 2011
Geeks Without Borders and Random Hacks of Kindness
Geeks Without Borders +) GWOBorg is an international coalition of passionate problem solvers working together to assist people whose survival is threatened by lack of access to technology or communications due to violence, neglect, or catastrophe.
One of the things that GWOB does is called The Digital Mountaintop: This is a free, open communications hub, accessible via voice, text (SMS), plain old telephone (POTS), Skype, SIP, Google Voice, Twitter, Facebook, Email, Instant Messaging (IM)…and as many other networks we can connect to. In crisis situations, neighbors can ask for help simply by sending sending a message to the DMT, as long as they (or someone they know) can connect via any of the messaging or real-time communication methods it supports.
Wednesday, February 16, 2011
Down-Under Double Sideband WSPR
Peter Parker, VK3YE, is one of the real DSB Gurus. When I got started in the world of double-wide RF, I would frequently turn to his web site for ideas and inspiration. So you can imagine my delight in getting this e-mail from him (his DSB WSPR video is embedded above):
Hi Bill,
Discovered SolderSmoke a few weeks back and love the show.
You might be interested that another DSB WSPR station is on air.
A video demo appears at http://www.youtube.com/watch?v=2aUHNRgV7kw It's still very crude (eg manual T/R switching) and the receiver is getting false spots. However the transmitter is working very well, with some long distance spots.
73, Peter VK3YE
Tuesday, February 15, 2011
First X-Class Flare of Cycle 24 Carries Shark To Spain!
A big X-Class flare took place at 0200Z, which was probably just a few hours before Pablo was looking at the FAQ grabber. This pond crossing probably also coincided with gray line time at his location.
Paul, NA5N, puts it all in context (in a message to QRP-L):
Gang,
There was an X2 flare about 0200Z 15 FEB (about 2100 EST). This has caused HF radio blackouts on the sunlit side of the sun (not us!). As this
subsides, the E/F layers will be highly ionized for good reflection. This
event has already elevated the solar flux to about 113 (average lately about
80-85). While this doesn't do much for us right now in North America, it
could create some very interesting morning gray line propagation if you're
one of those morning people.
The X2 event didn't have much density to it, only creating a shock wave of
about 550 km/sec. However, the M6 two days ago had a shock wave of about 1200 km/sec. - enough to cause a geomagnetic storm when it is expected to arrive Tuesday morning.
What is important is to keep an eye on the sun for further activity at:
http://www.swpc.noaa.gov/today.html or other sites.
These active regions are near the center of the sun, meaning any further
flares will send shock waves directly at us. The active regions are highly
magnetized, meaning they are capable of generating further M or X class
flares. If another flare or two happens tomorrow (Tuesday) during daylight hours, it will raise the solar flux and the higher bands will be open for the duration of daylight.
Therefore, the upper bands may be open, but may be interfered with for a few hours if a geomagnetic storm is triggered. It's a matter of dodging the bad stuff (geomagnetic storms) to get to the good stuff (enhanced E/F
propagation).
The only question left ... is this a hiccup on the sun, or is it finally
waking up from hibernation?
72, Paul NA5N
Home of the Altoids!
For anyone who wants to find this on Google Earth, it is at the corner of Jersey Pike and Shallowford Road in Chattanooga Tennessee, near the intersection with the TN 153 freeway.