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Posts Tagged ‘how-to

How it works – Heathkit HA 14 Linear Amplifier tutorial

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The Heathkit HA-14, the compact kilowatt linear amp, is the lessor known of Heath’s linear amplifiers.

But, if one is looking for simplicity, then is the linear for  you.

Check out the video as Dave Larson, KK4WW  shows you the linear and explains the schematic diagram

Here is the full schematic –

Written by frrl

June 21, 2010 at 4:39 am

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Teardown Analysis of the Apple iPad – What’s inside and what does it cost to build?

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Materials for the iPad, which went on sale on April 3, include a touch-screen display that costs $95 and a $26.80 processor designed by Apple and manufactured by Samsung Electronics Co., according to El Segundo, California-based ISuppli.

Analysis by ISuppli indicates that components of the lowest-priced, 16-gigabyte iPad amounts to 52 percent of its retail price of $499. That leaves the iPad on par with other Apple products, including the iPhone 3GS. A high-end 64-gigabyte version of the iPad, which retails for $699, contains components that cost $348.10, according to ISuppli.

Much of the iPad’s component costs went toward making…

Read the full story –

Now see what’s inside –

And inside the inside –

More teardowns of popular products –

Written by frrl

April 7, 2010 at 4:52 pm

“Global” Communications 50 years ago

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Wow.  Try to explain this to a kid with an IPhone

Burt Fisher, K1OIK,  makes a contact from his 50 year old station, the Heathkit DX-40 and Hallicrafters S-76 receiver.

Written by frrl

February 14, 2010 at 6:10 pm

The Magic Bullet (uh Packet) for Remote Computers- Wake Up on LAN

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You have remote computers in you house, you don’t need to have them running all the time, but when you do need them you don’t want to have to go over to the remote location to turn them on.

How do you remotely turn-on a computer from power off state?

You can read a previous article on this site on how to turn a PC “Clunker” into a usable part of your home computer assets.

For example, using FreeNas and a clunker PC (a PC headed for the trash) with only a Hard drive and a CD-ROM drive (no keyset or monitor needed) you can turn this Clunker into a useful member of society.

For example, a home network can benefit, at least, from centralized NAS (Network Attached Storage).  Beyond this FreeNas can server up a Torrent service as well as FTP, iSCSCI, and a bunch of other useful network services that you can use on you home network.

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Written by frrl

January 24, 2010 at 8:25 pm

Wrapping your mind around SWR – the perfect match

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swr-reflected-forwardLast night I was listening to a couple of guys try to wrap their minds around SWR.  Very interesting.

New hams are seemingly after “the perfect match”.  An antenna tuner will make your radio happy but it provides no improvement to the natural resonance of the antenna nor the line losses of the transmission line.

And really, is a 2:1 or 3:1 match really that bad?  At a 3:1 match (depending on line loss) with a 100W transmitter you may only lose 20 watts in reflected power.  What is the difference between 100 Watts and 80 Watts at the receiving station?

On a modern radio, 1 S-Unit is 6DB.  A doubling of power is 3 DB.  So, to move an S-Meter at a receiving station 1 S-Unit one would need to quadruple the power.  So, given this, your 3:1 SWR taking your 100 W down to 80 W is not going to make any detectable difference – as long as your tuner keeps your solid-state rig happy by fooling it into thinking SWR is 1:1

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Written by frrl

October 27, 2009 at 4:05 pm

EVERNOTE – Save your ideas, things you see, and things you like: Comprehending the Business Model of FREE

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evernote_logo2The Challenge: Remember anything – make is searchable and available from just about any network connected device.

There are applications that come and go.  You download an interesting application, try it out a few times, and then, there it sits, idle on your computer, unused, just taking up space.

These unused applications will stay on your computer until you refresh the operating system.  They won’t be back.  You didn’t use it and you won’t install it again with the new operating system.

Many apps have not make it past these refresh points on my computers or Apple iPod Touch – except a few.

And one in particular that you should know about


Welcome to your notable world. Use Evernote to save your ideas, things you see, and things you like. Then find them all on any computer or device you use. For free.

The compelling feature of Evernote is that there is an Evernote application for just about any operating system and any networked device AND every thing you saved is on the network.  What this means is that Evernote can synchronize all your notes (ideas, things you see, things you like) in a central repository – over there on the Evernote servers – for free.

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Written by frrl

September 25, 2009 at 2:01 am

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Emergency Preparedness: 30 ft fiberglass mast and base for $40

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Emergency Preparedness: 30 ft fiberglass mast and base for $40

Need an emergency 30ft fiberglass mast, base, and stakes for $40?  Read on.

mastguy_kitThe Antenna Mast Guy

If you travel to hamfests in the Midwest maybe you have seen the “mast guy” or the “pole guy”.  This guy has been traveling around to hamfests (according to him) for the past five years selling this stuff.

He always has good sales.  He has the right product at the right price in the right market with customers lined up to buy.

I am not sure what the original use of these were, or where he got these from – but he always seems to have a trailer load full of them.  He will mix and match whatever you want.

What you can get for $20

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Written by frrl

September 20, 2009 at 7:18 am

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