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Archive for September 2008

The Riddle of Kit Building – why do they do it?

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The Riddle of Kit Building

The Heath Company

There is a popular book that you will see at Hamfests – Heathkit-A Guide to the Amateur Radio Products.  You can also find this book on http://amazon.com.

The Guide is a very good reference on all the Heath/Zenith products.  In fact, it’s a wealth of information on the history of the company, the products along with beautiful photographs, and a chronological history of the company from creation to decline and extinction.  The book is highly recommended if you are interested in the history of the Heath/Zenith company or details about their products.

Benevolent friend to Amateurs?

Without knowing the history of the Heath Company one might get the idea that the company had some sort of maternal instinct to Amateur Radio insofar as they created quite a popular and successful line of amateur radio products and test equipment.  One might think that the founders of the company had some benevolence for Amateur Radio and then built a company around this core concept and mission.

A good trivia question would be: “What is the first kit that the Heath Company produced?”  This answer is: a kit airplane – a kit airplane in which the founder of the company was killed.  That has nothing to do with Amateur Radio.

In the early history of Heath, the company was a generic profit making business in the sense that they had no core mission to develop amateur radio products.

Box-car loads of government surplus electronics

After World War II the Heath Company found that they could buy box-car loads of surplus electronic parts from the US Government at rock bottom prices.  So, what do you do with box-cars loads of electronic parts?

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Written by frrl

September 28, 2008 at 3:15 am

Inside the Black Box of Short Wave Radio

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Many people today spin the dials and twist the knobs on a radio without really knowing what is going on inside that black box.

You can be a person who likes to listen to radio and that is the real deal of why broadcast radio exists.

Growing in popularity are cable shows such as “How its made”,  “Batteries not included” and other shows that tell you how things work and how things are made.

As a kid you may have been one of those folks who liked to take things apart to see how they worked.  Parents sometimes did not like this.  One of our friends who has a son of about 10 years old asked “What’s inside Diamond?”.  Diamond was the family dog.

But now we are all adults and can take apart anything we want – but maybe not Diamond.

So what is inside the black box of shortwave radio?

We stumbled across a free ebook written by a retired Broadcast Engineer.  This is an excellent book on what is inside a glowing tube shortwave radio from a detailed technical perspective.

We like this book for a couple of reasons. 

First, there is considerable technical explanation in this book.  It goes a long way to teach you about electronics – just what you need to know – to understand how all the component stages of a radio come together to get the RF off he “air” and into your ear. 

Second, the book uses a real example – the RCA model 8Q2 Shortwave Radio.  This radio represents the common technology of the “All American Five” design used in radios from 1930-1960.  So this book is not a book on “theory” without practical application.  In fact, the book is so detailed that just about every component in the radio is explained.

The tile of the book is The Vacuum Tube Shortwave Radio: Understanding and Troubleshooting. 
The author is Richard McWhorter. 

The book is 212 pages in length provided as a PDF.

The PDF of the book is password protected.
The password is “allamericanfiveradio”

The authors download web site is: http://www.vacuumtuberadio.com/vacuumtuberadio/

In case that site disappears we snagged a copy here.

The author has a ton (81+) of electronics education and vintage radio videos on YouTube.
Check out the authors videos on YouTube – “AllAmericanFiveRadio”

Written by frrl

September 22, 2008 at 6:31 am

Life on HF – The MFJ-1796 6-Band HF Antenna for Limited Space

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For those folks who have constraints that do not allow you to put up a big HF antenna then take a look at the MFJ-1796 6-band antenna.  This antenna covers 5 HF bands and the 2 meter band.  HF bands covered are 40m, 20m, 15m, 10m, and 6m.

We’ve been using this antenna for about 8 years on HF with good results.  To have one antenna cover all these bands is a convenience.

At the outset we should say that this review of the MFJ-1796 is for a very special circumstance.  We have made a slight modification to the antenna and we use it in a slightly different position than recommended.

Look at the picture to the left. That is the antenna that MFJ will deliver.  But we have changed it a bit – read on.

The word from MFJ

The quote below is directly from the MFJ-1796 assembly manual and briefly describes the antenna structurally and electrically.

INTRODUCTION
The basic 40 meter quarter wave vertical antenna is 33′ tall and requires a reasonably good ground or counterpoise system to function properly. The usual way to eliminate the requirement for a complicated and space consuming ground system is to center feed a 1/2 wave (in this example a 66′ tall) antenna.

The six and two meter amateur bands are covered with the addition of four quarter wave decoupling stubs. The power rating of the antenna is 750 watts on six meters and 300 watts on two meters.

MFJ solved these problems by combining efficient end loading with a balanced center feedpoint design. The result is a physically small vertical antenna that gives good performance and does not require any type of RF ground system.

The reduction in size is accomplished by adding separate loading coils and capacitance hats at each end of the antenna for the HF bands. The efficient end loading coils are wound on fiberglass forms. The high quality materials and construction of the HF loading system allows a maximum power rating of 1500 watts on 40, 20, 15 and 10 meters. The continuous CW power ratings are 500 watts on 40 meters, 750 watts on 20 or 10 meters and 1000 watts on 15 meters.

Translation

So lets get to the bottom line on this antenna – its a balanced dipole with loading coils (not traps) and capacity hats at each end.  The length of the antenna is 12 feet as delivered from MFJ.  Its as simple as that.

The MFJ-1796 as delivered by MFJ is expected to be used as a vertical and mounted on the ground, on a tripod on a roof, or attached to a chimney.  Its a center-fed vertical dipole that is ground independent – that is, it does not require a counterpoise or grounding system.

Hatching the plan – going Horizontal

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Written by frrl

September 14, 2008 at 9:35 pm

How the RELAY got into the ARRL

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Note: You might want to read the historical content in our posting Amateur Radio Beginnings before you read this posting.  This posting picks up where that article left off on Amateur Radios beginnings in the early 1900’s.

The perception and image of Amateur Radio in early 1900’s

The reputation of Amateur Radio up to the 1920’s was not good.  Companies such as General Electric, Westinghouse, and Western Electric opposed Amateur Radio.  Private Citizens and commercial radio stations opposed Amateur Radio due to interference.  The Navy, at one time or another, campaigned against Amateur Radio.  Maritime companies lobbied against Amateur Radio being charged with interference with safe and consistent communication.  This is not to say that other groups and private citizens did not support Amateur Radio.

The point to be made is that significant powerful companies and parts of the government had no compelling positive image of Amateurs.  The Radio Act of 1912 restricted Amateur use of the RF spectrum and Amateurs were seen as hobbyists, experimenters, and folks that generally caused interference to other services.  There was no generally understood positive compelling image of Amateur Radio.

The need for a new Vision and access to legislation

What Amateur Radio needed was someone to champion the cause of Amateur Radio and create a better image of Amateurs.  What was also needed was a organization to bind all the Amateurs together.  Binding people together creates a synergy of collaboration and provides the possibility for a collective mission and purpose.

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Written by frrl

September 9, 2008 at 2:15 pm

Technology, History, and Commentary on Amateur Radio

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Discovery consists of seeing what everybody has seen, and thinking what nobody has thought.
– Albert Szent-Gyorgi

The most eclectic Amateur Radio site on the Internet

…One of the essays, by Susan J. Douglas, looks at the excitement set off by Marconi’s introduction of radio – the “wireless telegraph” – to the American public in 1899.

“Wireless held a special place in the American imagination precisely because it married idealism and adventure with science,” she writes.

Popular Science Monthly observed: “The nerves of the whole world are, so to speak, being bound together, so that a touch in one country is transmitted instantly to a far-distant one.” Implicit in this organic metaphor was the belief that a world so physically connected would become a spiritual whole with common interests and goals….

The rise of wireless also set off a popular movement to democratize media, as hundreds of thousands of “amateur operators” took to the airwaves. It was the original blogosphere. “On every night after dinner,” wrote Francis Collins in the 1912 book Wireless Man, “the entire country becomes a vast whispering gallery.”

Listen to Amateur Radio in real-time, now, this very moment, on-line here

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Written by frrl

September 3, 2008 at 3:12 pm

Posted in Uncategorized

Life on HF – DX Clusters using Spot Collector and DX View

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Note: Click on any image in this posting for full size in a new browser window

So there you are in front of your HF rig.  You could spin the VFO knob and randomly search for active frequencies – that’s one way to do it.  Or, you could leverage enabling technology of computer software, the Internet, and the community of HF operators on the air right now to find interesting QSO’s.

We came across a really great suite of software.  It’s called DX Lab.  At the time of this writing DX Lab contains seven integrated components.  Components can be combined based on your need.  Combine all the components and you have an extremely powerful tool to facilitate your HF activities.

For the purposes of this posting we’ll take a look at two of these seven components that work together.  We’ll use SpotCollector and DXView.   You use DXLab Launcher to manage the installation of any and all the components.

DX Clusters

Spot Collector is based on the concept of a DX Cluster.  DX Clusters have been around a long time – before the internet was public.  Before the public Internet, DX Clusters (or Packet Clusters back then) were available via Packet Radio using a protocol (AX.25) over standard VHF/UHF frequencies.  Sometimes these clusters were on the Internet available to government, research, and Universities.  Some folks linked AX.25 over packet radio on VHF to the Internet via Gateways.  All that is ancient history.

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Written by frrl

September 2, 2008 at 7:48 am

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