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Archive for the ‘Technical Articles and Reviews’ Category

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

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Problem/Challenge:

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

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

Fun with FreeNAS – iSCSI – When a local disk is not local

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Read our related posting first –

NAS for Clunkers: How to turn that old PC into a high tech Network Storage, Web Server, and Torrent Server

“iSCSI uses TCP/IP (typically TCP ports 860 and 3260). In essence, iSCSI simply allows two hosts to negotiate and then exchange SCSI commands using IP networks.

By doing this iSCSI takes a popular high-performance local storage bus and emulates it over wide-area networks, creating a storage area network (SAN). Unlike some SAN protocols, iSCSI requires no dedicated cabling; it can be run over existing switching and IP infrastructure.

As a result, iSCSI is often seen as a low-cost alternative to Fibre Channel, which requires dedicated infrastructure.”

FreeNAS_Logo

The Further Adventures….

Further adventures with FreeNAS running on a PC Clunker tucked away in the basement…

I decided to try to get iSCSI to work in FreeNAS.  Both Windows Vista and Windows 7 has built-in support for iSCSI.

What is iSCSI?

What is iSCSI?  In a few words, iSCSI is the SCSI protocol over an IP network.

And what is SCSI?  SCSI is a protocol that a computer can use to talk to peripherals of all kinds.

The Apple Mac used SCSI a long time ago while PC people were fumbling with IRQ’s and DMA settings to get their peripherials to work.

SCSI is easy and Apple CEO Steve Jobs made a good choice to use SCSI attached peripherals for the Mac back in 1984.

What can iSCSI do for you?

So, enough of that.  What can iSCSI and FreeNAS do for you?  What it can do is make a chunk of storage on a network look like a local disk on your PC.  Why would you want to do this?  Keep reading.

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Written by frrl

August 25, 2009 at 6:59 am

NAS for Clunkers: How to turn that old PC into a high tech Network Storage, Web Server, and Torrent Server

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FreeNAS_Logo

Life for your old PC

What to do with that old PC.  What to do – what to do – what to do?  How about using it for a NAS device?

NAS is “Network Attached Storage”.  Better to use that PC for NAS than throwing it in the trash.  NAS requires only the most minimal PC resources to serve up Terabytes of storage and provide a huge number of other services across a network.

And what could be better than “free”?

FreeNAS

The goal of this posting is simply to get you to look at some free software.  The software is called FreeNAS and it can do some amazing things – for Free, and on a PC headed for the trash.

Bottom line on NAS is that it’s storage on the network.  It’s storage on the network that can be made available in a multiplicity of ways to just about any operating system (Mac, Windows, UNIX)

What do you need to set this up?

Here is the great part, there is an option of FreeNAS that does not require you to install any software at all.  FreeNAS can boot off of a Live-CD.  Configuration can be stored on a USB stick.  No software to install at all.

Doesn’t need keyboard, mouse, or monitor

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Written by frrl

August 23, 2009 at 2:40 pm

Second Date: Review of the Degen DE1123 DSP AM/FM/SW Pocket Radio with 1GB MP3 Player & Recorder

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Second Date:
Review of the Degen DE1123 DSP AM/FM/SW Pocket Radio with 1GB MP3 Player & Recorder

Read our related posting – Review of the DEGEN DE1123

DEGEN1123

Cheap Date

This a follow-up to my experience with the Degen DE1123 “do it all” AM/FM/SW radio, recorder, and MP3 player.

Now that I have had this “device” for a few weeks, here are some further thoughts and observations.

Overall, this is a very cheaply made device.  The slide switch on the left hand side is probably the weakest of the controls.  It is hard to move and position at the right setting.  The plastic case is thin and does not have a good feel.

The device packs a great deal of capability.  It can “do it all” for $79.  Here is what I use it for.

Findings

  1. I found that it is an excellent voice recorder.  It has a build in Microphone and records at the proper bit rate for voice recording quality balanced against recorded file size.  I use it extensively for recording conference calls which I attend daily for 3 to 5 hrs a day.  I did not expect to use it for this purpose – and that it works as well as does is a surprise.
  2. I use it to listen to recorded audio books.  I read or listen to a couple of books a week.  The DEG1123 is better than my undocked Apple iPod Touch since the DEGEN has a much better speaker than the internal speaker in the iPod Touch. 
  3. Of course, the prime use for which I purchased the DEGEN was to time shift radio programs which were not available as podcasts and for which I am not able to arrange “appointment listening”.
  4. The ability to record 70 hrs of audio either directly from the radio (AM/FM/SW) or from the built-in microphone is the real real value of this $79 device.
  5. Transferring files to/from a PC with the supplied USB cable is fast and easy
  6. The AM/FM/SW radio section is acceptable.  I live near Chicago with power-house radio stations.  So reception on this radio is not a problem.
  7. With the supplied 3 x 650 ma batteries the run time is about 18 hrs.
  8. My biggest gripe is the audio record volume.  When recording directly from the radio the actual recorded audio when played back is only 1/2 the volume level when recording.  The only way to get around this is to plug the headphones in when recording and crank it up.  Alternatively, post process the audio with a free open source program like Audacity and increase the volume.

When “Cheap” is better than “Insanely Great”

As odd as it might seem the real value of this radio is that it is cheap and almost “disposable”.  That is, I would never think of taking my $200+ Apple iPod Touch for a bike ride – but I will take the DEGEN.  The batteries in the DEGEN are 3xAAA – you can change them on the fly – not so with the Apple iPod Touch with its internal proprietary battery pack.  The playback on an undocked iPod Touch through its internal speaker – can’t compare with the DEGEN front mounted large speaker.

The face-down smash test.  I accidentally dropped the DEGEN 1123 from a height of 4 feet on to a hardwood floor.  The DEGEN landed perfectly face-down causing the battery compartment cover to fly off.  The 3 x AAA batteries were ejected and rolled across the floor.  I retrieved the batteries and put them back in the compartment.  It radio worked.

Bottom line, sometimes cheap and disposable with good capability is better than “Insanely Great”.

Go buy a DEGEN 1123 and enjoy a cheap date.

Here is the Manual for the DEGEN 1123 – https://frrl.files.wordpress.com/2009/07/degen1123_manual.pdf

DEGEN1123_Kaito

Written by frrl

July 31, 2009 at 5:44 pm

Small Transmitting Loop Tuners from MFJ

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Small Transmitting Loop Tuners from MFJ

MFJ-936B_image_frontThis is from the “I’m not paying attention department”.  When I wrote the article on the AES IsoLoop I didn’t know that MFJ Enterprises has a wide selection of small transmitting loop antenna tuners.

The biggest challenge in building the small transmitting loop is not the wire loop – it’s getting the tuning capacitor.  The images I posted in the AEA Isoloop article showing homebrew loops showed that most of the capacitors used in those homebrew loops were “ham fest specials” or from the junk box.

MFJ Enterprises solves the problem of getting the capacitor for your loop antenna.  They have an number of loop tuners from $160 to $260.

The $160 model covers 160m to 10m and handles 50 watts.  The $260 model which also covers 160m to 10m can handle 300 Watts and has a built-in SWR Meter as well as loop current meter. I don’t know what significant parts are inside the $160 model other than the tuning capacitor but $160 seems like a lot of money for a box with a capacitor and a few other parts and no tuning indicator (loop current meter).

I can’t remember exactly how much I paid for the AES Isoloop.  It was about $329.  So. for another $70 or so what I got in addition to the (expensive) tuning capacitor is the stepper motor which allows remote tuning.  Why remote tuning?  Watch out for the RF!

RF Exposure in Loop Tuning

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Written by frrl

June 7, 2009 at 12:30 pm

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