Hamfest Report

Bert, WF7I, at Winterfest

I had a great time at the Vienna Wireless Winterfest. The weather was very nice, so I moved my sales operation out to the tailgate area. I managed to sell the Heathkit Twoer that I was trying to get rid of (the receiver is a REGEN). Also sold a bunch of old books, an old o'scope, and some other odds and ends. I picked up a few things I needed, including some solder wick, a replacement rubber band for my wrist rocket antenna launching sling shot and a backup mic for the podcast (just like the one you guys are so find of).

I met many podcast listeners. Bert, WF7I, and Mark, KJ7IEA, from the University of Virginia (the guys with the rhombic) were there and it was great to meet them. N3UMW, the designer of the SolderSmoke logo, was there at my sales table, but I didn't realize until after the hamfest that he'd been there - -I would have liked to have talked to him! Oh well, more 'fests in the DC area are coming up, and I still have some junk to sell.

SolderSmoke 131 should be out tomorrow.

SolderSmoke at Winterfest

I'll be at the Vienna Wireless Society's Winterfest hamfest tomorrow morning. I've gathered up all the unnecessary junk in the shack, and hope to replace it all with new and better junk tomorrow. I'll also have a few copies of "SolderSmoke -- The Book" for sale. I'll be at table D4 inside the facility. Hope to see many of you there!

Watching the International Space Station Fly Over

Thanks to a tip from spaceweather.com, Billy, Maria and I were in position to watch the International Space Station fly over the Washington area on the evening of 23 February. The map above (from heavensabove.com) shows the pass we saw. All times are local. Maria spotted it first. She seems to have a talent for this -- she last spotted the ISS six years ago (at age 4!) from the streets of Central London.

This was a very nice pass to watch. We were in twilight. We first saw the spacecraft as it flew past Jupiter's position in the sky. It was red at first, then turned bright white.

This time we felt a special connection to the ISS because the twin brother of Astronaut Mark Kelly is currently on board. We all met Mark (and his wife Gabrielle) when they came to London. Mark will be heading up to ISS himself in April. Godspeed to Mark and to his brother. And we're all hoping for the best for Gabrielle. They are very nice people.

LOFAR -- World's Largest Radio Telescope

Here is a really well-done video on the new EU radio telescope. Very interesting. They are listening as low as 10 MHz. (I hope my little QRSS shark fins don't cause any ET confusion!) The antenna elements pictured looked a lot like the devices that Paul, NA5N, has been working on out at the Very Large Array. One thing I didn't quite get in the video: the shot of Arecibo.

Anyway, check out the video. You will like it.

http://www.motherboard.tv/2011/2/22/listening-to-the-universe-the-largest-telescope-on-earth--2

Space Station and Nano-Sail D Visible This Week (From North America)

The folks at spaceweather.com report that the International Space Station AND the Nano-Sail D satellite will be visible from North America this week. They provide a very handy on-line tool that lets you know when and where to look:
http://spaceweather.com/flybys/?PHPSESSID=iem8ec1ep115mnga8hjhh5p8p0
Here is an amazing image taken by an amateur astronomer in Florida:

Mark Twain -- Amateur Astronomer

"I love to revel in philosophical matters - especially astronomy. I study astronomy more than any other foolishness there is. I am a perfect slave to it. I am at it all the time. I have got more smoked glass than clothes. I am as familiar with the stars as the comets are. I know all the facts and figures and I have all the knowledge there is concerning them. I yelp astronomy like a sun-dog, and paw the constellations like Ursa Major.
~ Mark Twain

OK, so he hung out with Tesla and Edison. Now this... Could Mark Twain have had a pre-radio case of The Knack?

Transistor: Heal Thyself!

On SolderSmoke Podcast #130 I mentioned that in the book "The Evening Star" by Henry S.F. Cooper, the author mentioned that during the Magellan mission to Venus, some of the chips on the spacecraft could somehow "heal themselves" after developing problems. Wow! Rigs that fix themselves. I don't know about that. That would kind of take us out of the troubleshooting game, right? Anyway, I was wondering how this "self healing" thing works. Hamilton, KD0FNR has some ideas:

Hi!

I just caught up on SolderSmoke and finished listening to episode 130. FB and great fun! Thanks! You asked a quesiton about logic circuits that had healed themselves on the Venus mission. I can't find an exact reference to it now, but when I interned at a particle accelerator during my MSEE work, engineers frequently talked about using gallium arsenide transistors because they were rad-hard and self-healing. Here's the idea as it was recounted to me in the early '90s:

Radiation can damage transistors by breaking the crystalline lattice inside the semiconductor. Self-healing transistors run very hot so that when a lattice site in the semiconductor crystal is broken by radiation it is 'fixed' by the crystal effectively melting around the broken site. It's similar to your halogen bulb/heat gun fix but on a transistor level and automatically.

I can't find an exact reference that confirms this explanation. The closest I could find was on wiki at: http://en.wikipedia.org/wiki/Radiation_hardening#Fundamental_mechanisms

Maybe other listeners can provide more detail.

Thanks for the mention of my QSO mapper on your show a few years ago! The mapper and my practice exams have continued to evolve and grow, and the latest of each can now be seen at:

http://copaseticflows.appspot.com/hamtest
http://copaseticflows.appspot.com/newqso

Thanks again for the great work that you do!

-- 73 de KD0FNR Hamilton http://copaseticflows.appspot.com http://copaseticflow.blogspot.com

K2ZA's DX-100 Arrives at SolderSmoke HQ

Today was big day here at SolderSmoke HQ. John, K2ZA, and his lovely wife Erika drove down from New Jersey bringing with them the Heathkit DX-100 that John's dad (now a silent key) had built years ago. John heard me mention my long yearning to once again own a DX-100 (I'd had one as a kid); he very generously decided to give me his dad's.

It's beautiful. And BIG: Shipping weight: Over 100 pounds. This, gentlemen, is the rig that they were talking about when they first started to refer to certain transmitters as "boatanchors."

After some time on a Variac, I plan on pairing this magnificent transmitter up with a suitable thermionic-based receiver. Maybe the HQ-100. Then I will put it on 75 meter AM and will attempt to establish myself as one of the plate-modulated, big signal anointed, perhaps even attaining "tall ship" status. We can dream...

Getting the DX-100 was great, but even nicer was meeting John and Erica. What nice people they are!

John and I recorded (in both video and audio) a short segment about the DX-100. I will plug the audio into SolderSmoke #131, and will upload the video to the SolderSmoke YouTube page.

Here's John with the Drake 2-B, the HT-37, and the INFAMOUS Astatic D-104:

Thanks John!

20% off on Book! 35% off on T-Shirts!

Lulu is running a President's Day sale on SolderSmoke The Book (and everything else they are selling!). Through Feb 21 use the coupon code Happy 305 at checkout and save 20%.
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

Bill,
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