QST de AA1TJ -- Please listen for Mike's Microwatts!

QST de AA1TJ...

I've a 150uW transmitter built from a single unijunction transistor currently running as a beacon on 3552kHz. If my New England amateur radio pals would be so kind as take a listen for it I'd be most appreciative!

Alan Wolke W2AEW Builds a Michigan Mighty Mite (Video)

We are honored to induct Alan Wolke W2AEW into the Colorburst Liberation Army.  And for his valiant effort to build and explain a MMM Low-Pass filter, he is immediately promoted to the rank of CBLA Two Star General.  Congratulations General Wolke.

As is the case with all of  his videos, this one has already had an impact far and wide.  Ian writes from far-off Western Australia:

Jan 27 at 6:19 PM

G'day Bill,Just in case none of your other correspondents have brought it to your attention, here is a great video W2AEW has put up showing really clearly the positive effect of a low pass filter on the output of the Michigan Mighty-Mite.

It made me appreciate the benefits of an LPF more fully. It's always been clear to me that the harmonics would get rolled off, but in my head I hadn't made the connection between that and the improvement to the beautiful smooth sine wave that we are working towards.

Anyway, I thought you, and your mate Steve "Snort Rosin" Smith may be interested.

Thanks to you and Pete for Soldersmoke, I'm sure you're responsible for keeping the flame alight in many a ham.

73,Ian VK6MIB

And Steve "Snort Rosin" Smith, the guru of low pass filters, observes:

Of course, to work properly in the land down under, the inductors must be wound in the opposite  direction as those in the Northern Hemisphere :-P .

Seriously, there is a lot to be learned from the lowly Mighty Mite especially regarding impedance matching; not to mention LC circuits, link coupling, amplifiers, oscillators, etc. .  What fun!

73.......SR

Humidity Data and the Zapping of my LCD Display

Sometimes the Radio Gods conspire against you.   Check out the chart above.  It shows relative humidity at my location.   I zapped my LCD display right around 2000 UTC on January 25, 2016.  That poor little LCD didn't stand a chance :-(

Right now relative humidity here is 79%.  No sparks now! 

I like the solution (!) proposed by Brendan, EI6IZ:

You can get an anti-static spray designed to treat carpet, upholstered furniture etc. This is a sensible thing to do if one tinkers with electronics and for the average hamshack a bottle will last for many years as it only needs to be applied lightly and infrequently.
For example http://ie.rs-online.com/web/p/esd-safe-clean-room-treatments-lotions-dispensers/0182893/ For cheapskates however, diluted fabric softener sprayed on the carpet and chair will work well for at least a few months but will require much more frequent application than the 'proper stuff'.

I give my car seat an occasional squirt in dry summers to stop the 'zap' when getting out on a dry day.

73
Brendan EI6IZ

An Electro-Static Bandaid to Protect Sensitive LCD Displays

After the big East Coast blizzard,  the atmosphere in my ham shack became very dry.  I sit in one of those desk chairs with little plastic wheels.  The shack is carpeted.  So when I roll from operating bench to workbench,  the chair, the carpet, the dry air and I all become a kind of Van de Graaff generator.  Yesterday, my hand brushed against the 16X2 LCD display on my new R2 phasing receiver.  The pretty glowing numerals in that display disappeared in a small spark, never to return.

I swapped out another display I had, so all is well.  But the repair was a pain in the neck, involving the soldering of some 16 LCD pins, so I don't want to do it again.  I consulted with Pete Juliano N6QW who told me that this kind of LCD carnage is quite common in dry environments.  He said he had cured the problem by placing a small piece of Plexiglas in front of his displays. 

This got me thinking about those static protective bags that Digikey uses when shipping many of its components.  Might the material from these bags prevent the loss of another display? 

I retrieved a couple of these bags from the garbage and did a little test:

First, I rolled across the shack in the chair with a small screw-driver in hand.   At the other end of the shack lies my well-grounded DX-100 transmitter.  I moved the screwdriver close to the metal on-off switch.  SPARK!  It was visible, and quite audible in the AM broadcast receiver nearby. 

Next I taped a small piece of this material over the switch and repeated the ride in the chair.  No spark. Nada.  I repeated this several times and always got the same result.

It appears that the material in the bag helps dissipated the static discharge over a wider area, preventing the spark.  I quickly taped a piece of this material over the two LCD screens in my shack.  It's not pretty, but it is temporary, and cheaper than a humidifier.

I'm not going to try this on the actual screens, but I do think these small pieces of material will help prevent another accidental frying of an LCD display.

Here is the Wiki on anti-static bags: https://en.wikipedia.org/wiki/Antistatic_bag

And here is the data sheet on the bags that I am using:
http://documents.staticcontrol.com/PDF/Static_Shielding_Bag_1000_Series.pdf

1936 Shortwave Listener QSL card

I found this today while rummaging around in the shack.  It is starting to fall apart so I figured I better digitize it before it turns into dust.

July 24, 1936.  7 am in Central Germany.  29.0 degrees Centigrade.  Clear skies?  German Shortwave Receiving Station DE 2518/F monitored W5AIR's contact with Irish station EI7F on 20 meter CW. The receiver was an OV2 Schnell tube (almost certainly a regen) fed by a 38.5 meter long antenna.  

Conditions must have been pretty good -- they were approaching the peak of sunspot cycle 17.

In 1954 W5AIR was assigned to Garold D. Sears.  He was probably the operator.

Listen to My R2 Phasing Receiver (formerly known as "The Frankenstein" )

I really like this receiver.  Thanks to all who helped. 

Blizzard Prep Priorities: Protecting the 160 meter L network!

I'd been meaning to build a proper cover for my improvised 160 meter L network. The approach of Winter Storm Jonas pushed me into action yesterday afternoon. 

First I mounted the variable cap (from an old Johnson rig) and the roller inductor on a suitably sized piece of wood:

Then I put the tuner inside an old cooler.  I drilled holes in the bottom for the coax and the antenna wire and the ground.

Here it is at the feed point.  Pretty cool, don't you think?

And here it is 24 hours later:

The blizzard has been quite impressive.  Early this morning it featured lightning and thunder!