ki4SGU

Heathkit returns!

2011-09-08T21:44:00.000+01:00

Heathkit, the fabled electronics kits company, is going back into that business after a two-decade hiatus. - LINK

Last earthquakes worldwide for the last 48 hours

2011-08-23T22:18:00.003+01:00

LINK see the Last Earthquakes Worldwide for the last 48 hours.

Antennas in Your Clothes? New Design Could Pave the Way

2011-08-22T19:14:00.000+01:00

http://www.sciencedaily.com/releases/2011/08/110822111742.htm

ScienceDaily (Aug. 22, 2011) — The next generation of communications systems could be built with a sewing machine. To make communications devices more reliable, Ohio State University researchers are finding ways to incorporate radio antennas directly into clothing, using plastic film and metallic thread.

a Retroencabulator for your Ham Shack

2011-08-18T21:16:00.000+01:00

Scientific Enrichment YouTube Video for the week – Swarmanoid Robots

2011-08-17T13:54:00.002+01:00

The Swarmanoid swarm consists of three discrete types of robots: Foot-Bots can grab onto other robots and move horizontally. Hand-Bots have manipulators and a sweet magnetic grappling hook that lets them move vertically. And Eye-Bots can fly, perch on ceilings, and direct the movements of the Hand-Bots and Foot-Bots with their cameras.

We've been watching these swarm-bot modules evolve since 2009, and the following video (which won an award for best video at the 2011 Artificial Intelligence Conference last week) is the first that we've seen showing all of the bots seamlessly and autonomously cooperating to execute a task:

QRP & a NAP - Baby Carriage Portable

2010-03-22T15:00:00.002Z

This weekend, the sun finally poked out so baby Isabella and I were out for a walk. As babies do, she took a nap (we were at a noisy ball field, so a long walk around the back end of park was a lot quieter for both of us.) Also on the back of the All Terrain Baby Carriage was my FT-817 and a MFJ-1899T with a counterpoise.

The MFJ-1899T, is is a fascinating mini-antenna for on-the-spot HF'ing. It is made by Waters and Stanton of the UK and imported to the US by MFJ Enterprises, I got mine at HRO.

This multiband rig is similar to a miniature Outbacker, with band taps along its lower helical winding section, a jumper lead for selecting bands (wander wand), and a top mounted pull-up whip. The base is fitted with a BNC connector to mate with the FT-817’s front socket.

The MFJ-1899T “Walkabout” antenna covers 80 through 2 meters in a single “break apart and carry anywhere” package. Fully extended, it measures 63 inches in height. Retracted and separated, the helical base section is 12 inches long and the pull-up whip is 7 inches long. Adding a BNC-to-PL-259 plus a right angle PL-259 adapter and connecting it to the stronger SO-239 socket of the FT-817 relieves strain. That same idea also works for adapting the MFJ “Walkabout” to other transceivers (FT-857). But dial it down the output below the antenna’s limit of 25 watts.

It is the counterpoise, that is the key to making this little antenna perform. -- The instruction sheet suggests it need not be 1/4 wave long. In fact, the info sheet suggests using the formula 180/F(in MHz) = Length (in feet) of the counterpoise. I use a 16ft section for 40m & 20m and seems to work well enough, I used stainless steel cable covered in Teflon available at HOME DEPOT.

Isabella, slept for a little over an hour and half. When she awoke, we walked back to where the rest of the family was enjoying the ball games. She was rested and I was very happy to have worked a few stations on 20m QRP.

NOTE: I also listened for k4ESA on 10m, but did not hear anybody local, just lots and lots of South American stations calling, 10m is working well in the afternoon.

New Amateur Radio Digital Mode - ROS

2010-02-22T15:25:00.002Z

ROS is a brand-new Amateur Radio digital spread spectrum mode with the first HF contact taking place this week. -- The first contact with ROS took place on February 18, 2010, at 20:56 UTC from Vitoria in Spain to the University of Twente in the Netherlands covering a distance of 1265 Km on 7.065 MHz.

Although it's only 4 days since the first HF contact with the new Amateur Radio data mode ROS, it's proving popular with plenty of activity on 14.101 MHz.

ROS is a digital spread spectrum mode but with a narrow total occupied bandwidth of about 2.2 kHz (similar to SSB Voice). The software has two Symbol Rates: 16 and 1 baud (the latter aimed at weak signals down to incredible -35 dbs of S/N) and can automatically synchronize any Symbol Rate.

Initial reports in Europe (See Caution Below for US based HAMs) talk of it being able to copy signals so weak that they don't show up on the Waterfall and there are early indications that it is several dB better than Olivia. However, HF with its Fading, Doppler, Multi-Path and Interference is a hazardous environment for digital signals and only time will tell how well it performs against the other modes.

... see my previous report on very robust signals -- http://ki4sgu.blogspot.com/2009/11/signal-to-noise-ratio-rainbows-in-dark.html -- (as you recall, WSPR will currently do -29db)

The HF frequencies currently used for ROS are USB 3.600, 7.053, 14.101, 28.300 MHz

To use ROS you just need your HF radio, a PC and a basic PC sound card interface, similar to PSK31 or WSPR.

The software for ROS is free and you can download it along with the User Guide and Introduction to ROS Spread Spectrum at http://rosmodem.wordpress.com/

A Word of Caution -- Here in the United States there the FCC specifies which modes Amateurs can use and where on the bands. Some USA Amateurs are concerned that FCC regulations appears to prohibit the use of Spread Spectrum below 420 MHz and ROS is a Spread Spectrum mode. It is a very narrow Spread Spectrum same as voice, but the devil is in the details. -- To be fair to the FCC they did try back in 1977 to change from a mode based band plan to one based on bandwidth. At the time the ARRL opposed the change and was successful in defeating it, as a result the development of digital modes was crippled for decades to follow. In recent years the ARRL has been trying to get the FCC to re-introduce band planning by bandwidth and hopefully they will be successful.

So for now, this ham is in ROS/SWL only.

Re: Some of this information came to me via the south gate club.

[LxPeditionsAtlanta] 2nd Annual Mid Winter 10 Meter Lunchtime LxPedition is February 11th at High Noon

2010-02-08T09:26:00.001Z

OK Gents;

The snow and rain are gone, the ground hog has done its jig, and the Saints have won the superbowl. -- Mean while in the world of ham radio the 10 M band is opening some, time to dust off the LX 10M gear and have some fun at lunch.

This Year's 2nd Annual Mid Winter 10 Meter Lunchtime LxPedition is February 11th at High Noon. -- 28.430 main calling frequency, so it in Tech friendly part of the band, 12-1:00 pm. Turn on your rig and call. -- See who you can contact.

Mark you calendars and join us. If we are lucky the band will open and lots of fun will be had. After the event, please post to the group in an email where you were, what your gear was, who you heard and who you had a contact with.

Non LxPedition members can email me direct for more info, and remember, once you participate in an event you can join the Yahoo group to keep current on up coming events.

Monitor 145.410 as the the talk-in Frequency.

Pictures are from Previous Events

An Evening with Martin F. Jue, founder of MFJ Enterprises

2010-01-29T21:44:00.004Z

The Georgia Tech Amateur Radio Club and the Atlanta Radio Club are pleased to announce a community event that should be of interest to all hams:

An Evening with Martin F. Jue, founder of MFJ Enterprises

Thursday, February 25, 2010 at 7:00 p.m.

Georgia Tech
Van Leer ECE Building
777 Atlantic Drive, Atlanta

Everyone is invited. Come one, come all. Bring your friends.

There will be a Q&A session with Martin after his talk. Here's your chance to get your MFJ company or product questions answered by the ultimate MFJ insider, the MFJ of MFJ, if you will.

Admission is FREE and a FREE door prize drawing will be held for some cool prizes, including MFJ-259B antenna analyzers.

Refreshments will be served. // Talk-in will be available on the GTARC (W4AQL) and ARC (W4DOC) repeaters. // There may also be a few surprises. // Additional details, such as the event program, will be available in a few weeks.

Did you know that... The Georgia Tech Amateur Radio Club is celebrating its 100th birthday this year, which makes it the oldest radio club in the state of Georgia. The Atlanta Radio Club is a close second.

A VERY partial lunar eclipse will take place on New Year's Eve

2009-12-29T16:21:00.002Z

A VERY partial lunar eclipse will take place on New Year's Eve, December 31, 2009, the last of four lunar eclipses in 2009. Only a tiny sliver of the Moon will be in the Earth's umbral shadow, but there should be a distinct darkening visible over the Moon's surface at greatest eclipse.

When and Where -- Will the Eclipse Occur? More details here.

And although this is a Lunar Eclipse, I was wondering what effect if any can be observed on the HF bands during a Solar Eclipse??

Back on the Air - Ready for the New Year

2009-12-29T03:25:00.003Z

After putting away the Christmas ornaments, and doing other honey-do's around the house. -- I finally got around to getting the radio shack back in shape earlier today.

The antennas are back in the trees after the mid December storms had done their damage.

I've also added a second flat screen monitor to the main shack laptop computer.

2009 - HAM Radio Accomplishments; I got my EXTRA (Nov), Peak-2-Peak Golden Packet Appalachian Trail end-2-end effort (Jul). My First full length article in CQ /VHF+ (May)

2010 - HAM Radio Planned Goals; More CW, Dixie Pixie Project, and first SDR (Genesis Radio Kit G2030).

I look forward seeing you more of you on the radio this coming year.

Happy New Year de ki4SGU

US SENATE INTRODUCES BILL 1755 - Passed!

2009-12-17T03:16:00.002Z

On Monday, December 14, S1755 -- The Amateur Radio Emergency Communications Enhancement Act of 2009 -- passed the Senate by unanimous consent; the bill now goes to the House of Representatives for consideration.

U. S. Senators Joe Lieberman (D-CT) and Susan Collins (R-ME) introduced a companion bill to HR 2160 which was introduced to the House of Representatives by Representative Sheila Jackson-Lee (D-TX-18) in April 2009. Senate bill is S1755 is also known as “The Amateur Radio Emergency Communications Enhancement Act of 2009”. More complete information can be found on the ARRL website.

The Main items are;

The first includes; Include a review of the importance of Amateur Radio emergency communications in furtherance of homeland security missions relating to disasters, severe weather and other threats to lives and property in the United States etc.

The second is more interesting; Identify impediments to enhanced Amateur Radio Service communications, such as the effects of unreasonable or unnecessary private land use regulations on residential antenna installations; and make recommendations regarding such impediments for consideration by other federal departments, agencies and Congress.

These is key; if we are ever going to rid ourselves of the overly oppressive Home Owner Association and other antenna restricting rules. -- I highly recommend each of you write your senator and encourage him to explore ways that we can maximize this opportunity here in Georgia.

Our Senators

Sen. Saxby Chambliss
416 Russell Senate Office Building
Washington DC 20510
Tel: 202-224-3521
FAX: 202-224-0103

Sen. Johnny Isakson
120 Russell Senate Office Building
Washington DC 20510
Tel: 202-224-3643
FAX: 202-228-0724

73 de ki4SGU

A Tale of Two Repeaters

2009-12-10T17:16:00.007Z

On a recent midday drive to a meeting downtown, I snapped the following picture of the Bank Tower (home of the .820 repeater) and the AT&T Tower (home of the .410 repeater) both in downtown Atlanta, Georgia.

As many of you already now I love using and tracking repeaters. They are great places for idle QSOs while on long metro commutes which many of us endure. These two repeaters were, and in may ways still are the central hubs to much larger repeater systems, which have continued to dwindle due to the maturing of newer suburban repeaters and clubs.

The Buildings:
The Bank Tower looks and is a much larger building, after all Wikipedia ranks it as the 35th tallest building in the world and the tallest building in North America outside of Chicago and New York City, an impressive pedigree (it is about 1000ft tall).

Meanwhile the AT&T tower is a not meager 677ft. (206-meter), 47-story skyscraper is almost as tall.

On first blush it would seem the Bank of America Tower has a huge advantage as a repeater base, but one must take into account the that the antennas are not at the very top of the building, but closer to the 56th floor roof, the steel structure crowning the building adds height, but all of the antennas are not located at the very top of that structure.

Here is an excerpt from their website to that point; "Our primary antenna for two meters is now located at the base of the "spire" near the building's peak. From this location our antenna has a virtually unrestricted line of sight to most of metro Atlanta." -- There use to be a better picture on the site but I could not find it, and the web statement is barely true.

The Repeaters:
Both of these venerable Atlanta Metro Repeaters are well over 12 years old, and both are starting to show their ages in less than positive ways. Unlike the obvious possible pun from the opening line of a Tale of Two Cities, in the case of these machines I can not really say it "It was the best of times, it was the worst of times…". because in this case it closer to the later than the former.

The w4PME 2m repeater is a Motorola 5000 (tube type transmitter) running about 60 watts output, but capable of over 320 watts continuous! -- recently this machine is suffering some sort of slow death by meltdown, although it still has an impressive coverage area it has frequent temperature lock outs in mid QSO, and this makes difficult to use.

The theoretically equally potent w4DOC 2m repeater is a Vertex VXR-5000 repeater, controlled by a Link Communications RLC-3 controller hybrid with many receivers, a restricted-by-request transmit power of about 45 watts output (see ke4FOV's excellent presentation). -- Recently this machine has taken to not working very well, specially in wet weather. Its average effective range has shrunk to almost the size of the i-285 perimeter, on rainy days it's less.

Both machines have remote listener repeaters located at Sweat Mountain. This accounts for the extended northern lobes in their coverage map.

I wish to bring an awareness to these repeaters; which both seem to be running a fever, and are in need of dire medical attention. -- Please use them, and please contact the clubs that operate them. Upon contacting the clubs offer your support and your positive criticism of the recent decay of these once proud HAM pinnacles. Let them know we value and miss these repeaters.

Lets make it the "Best of times" again. 73 ki4SGU

This Thanksgiving Season remember the Amateur's Code

2009-11-27T03:36:00.002Z

CONSIDERATE...never knowingly operates in such a way as to lessen the pleasure of others.

LOYAL...offers loyalty, encouragement and support to other amateurs, local clubs, and the American Radio Relay League, through which Amateur Radio in the United States is represented nationally and internationally.

PROGRESSIVE...with knowledge abreast of science, a well-built and efficient station and operation above reproach.

FRIENDLY...slow and patient operating when requested; friendly advice and counsel to the beginner; kindly assistance, cooperation and consideration for the interests of others. These are the hallmarks of the amateur spirit.

BALANCED...radio is an avocation, never interfering with duties owed to family, job, school or community.

PATRIOTIC...station and skill always ready for service to country and community.

--The original Amateur's Code was written by Paul M. Segal, W9EEA, in 1928

A Sourthen Resource - Cherry Blosom Intertie Repeater System

2009-11-19T16:14:00.004Z

If you find yourself traveling south from Atlanta to Savanna, you might to tune into the Cherry Blosom Intertie Repeater System. A very friendly and very useful resource for the HAM traveler equipped with only a only 2m FM mobile radio.

Personally I was able to access this resource from atop 2 of Atlanta's Metro Peaks (Lost Mt & Pine Mt). I tuned into the network at Forsyth (147.315 no tone). It is the furthest north repeater in the intertie family and covers Monroe and parts of Butts and Henry Counties. From the metro peaks I was able to bring the repeaters with ease at only 5 watts and my standard 5/8 comet mounted on my Jeep. Next time, I'll try a HT with an aftermarket long duckie antenna, no guarantee but the mobile worked so well, I'm optimistic.

Here is a link to their excellent site. In the very near future, I will be updating my North Georgia 2m Repeater list to includes this fine addition.

73 ki4SGU

PS. I'm told there are more repeaters on the network, but are linked only temporarily (during nets, etc), and regrettably I do not have the locations or the frequencies.

Signal to Noise Ratios - Rainbows in the Dark - Part 3

2009-11-16T21:52:00.011Z

Not all S-Meters are calibrated, mine sure is not. Below you'll find a nice chart for the ideal S-Meter, a standard originally proposed by the Collins Radio Company 50+ years ago and it is now accepted as the de facto industry standard. (The original standard stated S-9 = 50uV, the rest are linear extrapolations)

S-Meter    Signal    dBm
S-9 +60db 50,000uV -13
S-9 +50db 15,811uV -23
S-9 +40db   5,000uV -33
S-9 +30db   1,581uV -43
S-9 +20db     500uV -53
S-9 +10db     158uV -63
S-9            50uV -73
S-8            25uV -79
S-7          12.5uV -85
S-6          6.25uV -91
S-5          3.13uV -97
S-4          1.56uV -103
S-3          0.78uV -109
S-2          0.39uV -115
S-1          0.20uV -121
S-0          0.10uV -127

The source of this chart is ARRL's QST Magazine DEC2009, Page 45

There many ways to calibrate your S-Meter, but that lies outside of the scope of this blog. For our purposes here relative measurements will more than suffice. So let say you are on 40 meters, typically the "noise" will be S3, or about -109dBm (your location and radio will vary, but work with me here). If your receiver has an MDS (minimum detectable signal) of -131dBm, it means you’re loosing 22dB of your dynamic range to the noise! (131-109=22dB). In this case, the S-meter is more-or-less giving you an absolute power DIFFERENCE between its MDS and the noise floor, in dB.

You then hear a CW (or any other kind) station calling CQ, and he has a S7 signal. Therefore S7-S3=S4 or 109-85=24db, so a +24db, that is a fairly clean and easy signal to work. Are you with me so far?

In my previous blog Signal to Noise Ratio - Rainbows in the Dark I created files of where I thought certain digital modes could be work under the noise level (SNR). With some digital modes listening and decoding signals that are much much harder than that. In my previous example file of about a -7db signal, I'm talking about a -109db+7db=116db or one S-Unit under the noise! By now, we have all seen that WSPR can do -27db (maybe less). In my last blog in this series, I posted that "CW@20WPM could only be done at -7db or better" (this was sure to draw fire from all camps)

I had a few folks tell me that they could do much better, one fellow whom I trust Dick /k2UFT, basically agreed with my -7db level estimates, but wisely suggested that I should re-do the files and embed a secret word with each file. In that way the testers would be blind and could then report what they heard and decoded.

So here is my new challenge, listen to the new files, preferably just once, just like a real QSO copy. Then please email me (or blog post) the correct secret word embedded in each. Never mind about -3db and above, those are easy, right? -- just focus on -5db and below. Since so many folk were so confidant that could do better than -7db, I have taken the time to create four additional files with even more noisier levels. (HINT: all of the words are 8 char long)

SNRtest_ki4SGU_091116_1_pos9.wav
SNRtest_ki4SGU_091116_2_pos7.wav
SNRtest_ki4SGU_091116_3_pos5.wav
SNRtest_ki4SGU_091116_4_pos3.wav
SNRtest_ki4SGU_091116_5_evn0.wav
SNRtest_ki4SGU_091116_6_neg3.wav
SNRtest_ki4SGU_091116_7_neg5.wav
SNRtest_ki4SGU_091116_8_neg7.wav
SNRtest_ki4SGU_091116_9_neg9.wav
SNRtest_ki4SGU_091116_10_neg11.wav
SNRtest_ki4SGU_091116_11_neg13.wav
SNRtest_ki4SGU_091116_12_neg15.wav

I know, I know... I can hear you thinking out there, "What if you use a computer?", knock yourselves out, FLdigi away and/or any DSP filter you'd like to use, remember just keep it like a real QSO. Also there is no prize for being right or first, so why cheat?

As an update, I also worked with Eric /ab3DI on PSK31 vs WSPR last week, we were not able to validate that a two-way PSK31 QSO can take place @ -10db (so for now this remains a guess-ti-mate)

For those of you that are only on SSB -- What value does this provide you?? WSPR can provide you a baseline, granted for voice SSB the SNRs have better be positive. If you like to check what your link budget is for a given path, simply have your station and the remote station fire up WSPR and let them run for a day or two on the given band and given power. This will reveal the observed SNR between those points (hourly). Please understand, time of day and time of year, WX, and solar activity will all be variables, but at least you'll know that on that day you had that SNR, albeit it will vary over time but if your net is always at the same time of day, chances are the numbers you observed will provide you with a "reasonable" estimate to base further decisions concerning moving your net to a different band or time. Also no need to do just 2 stations at a time, for a regional net have a bunch of the guys try it all at once, the WSPR database will sort out all of the link budgets at once.

Once last idea, if you have a program like VOAprop by g4ILO (an excellent program!) you can use your WSPR data (observed data) to calibrate your other VOA predictions (predicted data), and in the end be able to make better predictions.

73 ki4SGU

PS. This blog series has been mentioned on SOLDERSMOKE PODCAST 118 (QRP & Homebrewers Inspirational Incense)

Confused by all of the new digital modes when hearing them??

2009-11-13T16:33:00.003Z

If you have been the HF band lately listening in the digital portions, you will know that there are some very strange noises there. Some are more well known like the inviting sounds of CW, or the sweet double tones of PSK31. Others, like the difference flavors of RTTY or the numerous alphabet-soup of OLIVIA modes are harder to identify by ear alone. Just when it seems darkest, there is a solution right there on the programs you are already probably using.
- The solution is RSID

The Reed-Solomon ID (RSID) is a short 16-tone MFSK transmission which identifies the mode in use. The RSID transmission is about 180Hz wide and lasts for just less than two seconds. -- Reed-Solomon IDs - This idea was originally developed by Patrick Lindecker /f6CTE. -- You should enable RSID when using an 'exotic' mode such as Olivia so that users of programs with RSID support know what mode you are using. Your digital decoder program will then reconfigure itself to support that mode, not everybody uses this yet, but at least, now you know.

There are two ways to enable RSID (DM780 + FLdigi):

In Program Options select Modes + Ids and check the option to show the RSID button in the transmit toolbar,
Add the tag anywhere in the text being sent.

73 de ki4SGU

Decoding Digital Ham Radio Without A Radio

2009-11-11T11:00:00.004Z

Einstein once define radio this way;

"You see, [the] wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat."

Here is your your chance to do Einstein one better, no radio either!

Stuck in the Hotel room with no radio, because the airlines won't let you travel with your TS940?
Would you like to practice copying CW with Cyrillic alphabet but your QTH doesn't pull in Russian stations in the solar lull?
Test your new QRPp rig to see if you can be heard in Washington DC, or in the Netherlands.
Or how about, trying out Olivia or RTTY from your office during those brain numbing conference calls when you would prefer to listen to static?

Then check out Alex /oz9AEC excellently produced YOUTUBE video on how use a WEB accessible Software Defined Radio (SDR) and your headphone and/or your favorite digiMODE software. The video demonstrates FLdigi (my favorite too), but DM780, or digiPAN, or anything would work too.

click here LINK

Nice Job Alex! Here is a link to the WEB SDR ORG

DIXIE PIXIE BLOG created.

2009-11-10T20:33:00.000Z

Many of you may have already heard me talk about my plans to launch a group build on the local repeaters. The DIXIE PIXIE now has its own BLOGSPOT, please feel free to drop by and stay informed on its progress.

Stone Mountain Hamfest - Extra Extra - Read all about it.

2009-11-08T21:49:00.022Z

I recently attended the Stone Mountain HAM Fest near Atlanta, GA. This is the area's largest and best featuring lots of vendors and bone-yard tables.

The weather could not have been better, and I was able leisurely walk around slowly eying up lots of great deals on new parts for my JUNK BOX, and I also passed my EXTRA exam, DX here I come! So it is Mr. ki4SGU/AE if you please.

Among the electronics treasures I found, were four variable caps (3x 4-100uF & 1x 75-350uF), all less than $2 ea. I also stocked up on mono audio plugs for the upcoming PIXIE build, and some nifty multi turn 10K pots, and 2 new 10m ham-sticks for a ham-stick dipole for any future LX peditions.

The crowds were fairly large, even folks taking the Hams test numbered more than 40. With the testers and the all star VEC crew made for tight quarters while testing.

For all you Yaesu fans, they will be offering a new APRS & GPS dual band radio, the FT350.

For the Kenwood crowd, they will be offering two new models a new HT (a super new version of their popular Kenwood TH-D7AG Data Communicator) and a new HF (a super new version of the Kenwood TS-570SG). It is all hype now, but the booth guys were bragging about a k3 beater on RX. I was not able to find any pictures to share here, but I did find a video which I saw in person at the Kenwood booth, I found a version it here on YOUTUBE ICOM did not attend this year, but our old faithful friends MFJ and HRO were so busy, I did not fight the crowds to get a peak, or even a new catalog.

I also attended a very folksy and entertaining forum by the author of ARRL's Low Power Communication Guide, The Art and Science of QRP By Richard H. Arland K7SZ.

Ham Radio and Ham Radio Festivals are alive in well here in Georgia.

Signal to Noise Ratio - Rainbows in the Dark

2009-11-06T17:14:00.029Z

In analog and digital communications, signal-to-noise ratio, often written S/N or SNR, is a measure of signal strength relative to background noise. The ratio is usually measured in decibels (dB). If the incoming signal strength in microvolts is Vs, and the noise level, also in microvolts, is Vn, then the signal-to-noise ratio, S/N, in decibels is given by the formula;

S/N = 20 log10(Vs/Vn)

If Vs = Vn, then S/N = 0. In this situation, the signal normally borders on unreadable, because the noise level severely competes with it. In digital communications, this will probably cause a reduction in data speed because of frequent errors that require the source (transmitting) computer or terminal to resend some packets of data. If Vs is less than Vn, then S/N is negative. In this type of situation, reliable communication is generally not possible unless steps are taken to increase the signal level and/or decrease the noise level at the destination (receiving) computer or terminal.

And this was the world we lived in for most of time, but recently (last 40 years) even HAMs can communicate under the noise. As you may know if you have been following my blogs here, I have been smitten by WSPR and chalk up -30db contacts. PRIMER

Here are my findings to date (with the equipment at hand)

Mode Min SNR
CW@20WPM +3db (machine decoded by MFJ-461)
CW@20WPM +1db (machine decoded by fldigi or CWget)
HFpacket (300baud) +1db
RTTY45 -5db
CW@20WPM -7db (other claim like less, like -13db*)
PSK63 -7db
FELDHell -7db
PSK31 -10db
Olivia 64/2000 -13db
Olivia 16/500 -14db
WSPR -30db (maybe less)

NOTE: * some talk of minimum detectable signal (MDS), but I mean where one can actually decode it, not just hear it.

I prepared some files with simulated noise so I could judge for myself, now you can click on the links and judge for yourselves.

(I left them as .wav files because they sounded better, and are SMALLER than the .mp3 files)

Signal to Noise Ratio Files 091115 // CW string of 'ki4SGU em73ox' // CLICK TO LISTEN

So here is the deal, if you are using WSPR (and you should be by now), and you make contact with me, drop an email and lets sched up a real QSO using some digital mode CW, PSK31 or Olivia and see if my estimates are right, or just full of hot air. 73 ki4SGU

More on my RAINBOWS in the Dark Series...

2009-11-05T15:38:00.006Z

More on my RAINBOWS in the Dark Series... I am continuing to have a blast on WSPR

I was mentioned in g4ILO Julian's fine blog "WSPRing all night on 40" for a UK WSPR contact.

Other note worthy contacts were New Zealand and Australia.

Here is a LINK to complete log of 40m contacts @20w.

Of late, I've read some comments about the true worth of WSPR, in my humble opinion this is one hot mode, and is very valid and relevant. WSPR will probably bring-in and retain lots of new technically oriented blood into the hobby, as well as re-energize old timers, specially the QRPer and HOMEbrewers - And that is really a good thing. We need more true HAMs (Builders, HomeBrewers) not more "CBers with a GENERAL CLASS license that can't build, can't solder, do not know code" in a word "appliance operators". -- The WSPR software adds a dimension that was missing from traditional low power building projects, it collects and presents the performance data in an objective and easy to compare form.

New treasures from the east...

2009-11-05T15:23:00.008Z

New treasures from the East... have arrived at my home and another season of QRP building will have started in ernest.

If you are a QRP builder (or would like to be), you may have already noticed recently your local Radio Shack doesn't stock the parts you crave. - My secret is eBAY, with Keyword "HONGKONG" -- A paradise where 1/4w resistors are still a only .01$US and most items well under a buck. Happy Hunting

More on WSPR ... Rainbows in the dark.

2009-10-30T14:17:00.044Z

I'm continuing to enjoy WSPR -- Last night in a series of propagation studies I have been undertaking from ki4SGU studios, I explored the world of 80m internationally. A thought normally unheard of in these sunspot starved days.

I could not believe that Germany and Italy could be so easy worked on a low band. Studying the SNR data closely, I further believe that working these locations with traditional digital modes (PSK31, RTTY) would be easy, as would also CW but few try, hence few succeed.

(Click on Images to Expand)

Please pause and notice in this image that the Canadian HAM [ve6OG] is engaged in a WSPR QSO with a trans-Pacific station also on 80m.

Here are a few of the QSL cards that were sent electronically to me from Italians HAMs.

... a copy of my electronic log from the WSPR site;

Timestamp Call MHz SNR Drft Grid Report RGrid Km Az
2009-10-30 04:34 KI4SGU 3.594104 -10 1 EM73 NN6RF CM87uw 377 289
2009-10-30 04:16 KI4SGU 3.594090 -4 0 EM73 WA7KGX CN85 3484 304
2009-10-30 03:54 KI4SGU 3.594109 -23 0 EM73 IQ3AZ JN65qq 8003 47
2009-10-30 03:36 KI4SGU 3.594095 -16 0 EM73 KE0CO CN87tl 3476 308
2009-10-30 03:36 KI4SGU 3.594097 -27 0 EM73 G0DJA IO93if 6699 43
2009-10-30 02:34 KI4SGU 3.594093 -21 0 EM73 DL2NI JN48ul 7612 45
2009-10-30 01:54 KI4SGU 3.594099 +6 0 EM73 WB2LMV FN21ts 1314 42
2009-10-30 01:14 KI4SGU 3.594097 -12 0 EM73 VE6OG DO33fn 3164 324
2009-10-30 01:14 KI4SGU 3.594098 -20 0 EM73 AB3DI FM19ma 951 47
2009-10-30 01:14 KI4SGU 3.594095 -13 0 EM73 KC2RXS FN32bj 1391 41

Thereby proving that 80m is a TRUE world band, and that patience, persistence and curiosity are a healthy substitute for sunspots, as well as a welcome respite from the endless regional "ache & pains rag-chews" so common with US hams on the lower bands.

Then finally is an image from later this morning as the propagation faded, imaged captured remotely from work (a nice use of multi-tasking during those rather boring corporate conference calls -- And here you should wonder, How really boring these must be for a guy that likes to "listen to static" mind to wonder off into the ether. Numbingly Boring! - But I digress).

Have HAMs just grown lazy? ... Please quit waiting for the good propagation next year, HAM radio is about doing, action, and making waves. Please get on the air, on any mode tonight - And make your own Rainbows in the Dark.

Pssst.... Do want to know a secret? - Try WSPR!

2009-10-23T19:51:00.008+01:00

Last night in a bought of radio depression, I was motivated enough to try WSPR -- as I wasn't too motivated to do anything else -- the band conditions were dismal. I had held off on trying WSPR being loyal to PROPNET a similar venture that uses PSK31. I never do well in those Coke/PEPSI or BETAMAX/VHS sort of questions.... Well PROPNET is equal to BETAMAX, it is better in every way, but you guess it!, WSPR is more popular and hence the better choice. The idea of internet cross tabulating propagation reports is way cool, and more so when the whole world tunes in.. For a quick thrill on 30 watts or less try WSPR.

-- WSPR stands for Weak Signal Propagation Reporter, but it's pronounced "Whisper" - quite an appropriate name as it is all about sending and receiving signals that are barely audible. DOWNLOAD

The software is written by Joe Taylor, K1JT, a Nobel Prize-winning Princeton physicist. It was first released in April 2008. It uses a transmission mode called MEPT-JT. The "JT" stands for Joe Taylor, while MEPT stands for Manned Experimental Propagation Transmitter.

Consequentially, a very interesting interview with Dr. Taylor, k1JT can be found in this month's CQ Magazine - A link provided here.

The Emperor Has No Clothes - More on my infatuation with coils.

2009-10-16T16:23:00.012+01:00

As you may already know, I have developed a wholesale interested in coils. I have been trying to increase my personal understanding of coils as used for antennas (as baluns) and as they are used in band-pass-filters (ummm, as well ... coils) and all other things of an inductive nature.

After the normal frenzy of Google searches, I was lead to -- "Understanding, Building, and Using Baluns and Ununs" by Jerry Sevick, W2FMI -- This book is presented (ARRL, eham, and everyone else) to be universally touted as the pinnacle and the state of the art for those seeking a deeper understanding and actually building. I ordered it....

20 bucks and a few days later... I wish I could tell that it were true, in short they are all wrong and I would strongly suspect not one of them actually read the book. I found the book to be at best a loosely coupled collection of articles which seems to start in the middle of basic ideas, and seem to trail on and then abruptly end. To the say the book is badly written, I will not say, I'm no English major myself, and I'll leave that to others. What I can and will say is; I did not enjoy it, and I found it to be contradictory, weak and misleading. -- In many cases the author warns the reader of the evils of voltage baluns (probably a true statement), but then extols the superb benefits and divine merits of Ruthroff's work on the same. huh?!

The author constantly refers to the seminal publication of G. Guanella in the Brown Boveri Review in September of 1944 (PDF) but never really takes the time the explain to the modern reader the construction outlined in the article. The article also constantly referred to C. L. Ruthroff August 1959 equally seminal article (PDF) -- I'm sorry, I had missed that one too, as I imagine most modern readers will have (as in 'we were not born yet!?') and my subscription to the BBR is still in the mail. -- I have posted both of the articles above so that you may acquaint yourselves with their genius.

Like the little boy in Hans Christian Andersen's story, "The Emperor’s New Suit". I post this rather negative review at great peril to myself, because HAMs are a funny lot (as in not "ha-ha"), and are very similar to sheep, and do not take kindly to folks having a difference of opinion on something they hold sacrosanct. Flame On QRPers!

As to not become the Andy-Rooney-of-HAM-radio with my Casandra like opinions, I will share with you that I did find a few articles (Free PDF) on the web that are very helpful, and go a long way towards really being helpful.

C. Greene w1CG 2002.pdf (PDF) & C. Greene w1CG QRP 4:1.pdf (PDF)
and R. Bertran vk2DQ 2005 OCF dipole.pdf (PDF superd, must read!!)

I also share with you Jim Brown's J. Brown k9YC APR-2008.pdf (PDF), but with a warning. For it also seems to suffers from Current-vs-Voltage confusion affliction -- For the record the Guanella balun is NOT a voltage balun.

73 ki4SGU

Having Fun at the EAA's B-17 - Aluminum Overcast Event

2009-10-05T14:10:00.014+01:00

If you were looking for me this last Saturday, you would not have found me at home. For Mel /k4JFF, Ted /wb4CAB and I all headed towards the Gwinnett County Airport (Briscoe Field (LZU)) in Lawrenceville, Ga Lat 33.978 / -83.962 @1061Ft for the EAA's B-17 - Aluminum Overcast Event featuring their B-17. Although it is essentially an aircraft event, with guidance from Arnold /kc4ZUA we had lots of fun playing radio with various HF and CW displays. -- Here are some of the pictures from Dick /k2UFT.

And some more great Photos from Kevin /n5PRE on his "The Rocketeer's Photostream"

Electrons on Parade

2009-10-03T03:33:00.001+01:00

Treat yourself to this 1942 factory promo for RCA vacuum tubes. The short 18 minute video shows how they made metal-can octal base tubes.

A truly fascinating video of how incredibly complex and automated the manufacturing process was even during WWII. Electronics as an industry has lost something of its mystic with vacuum tubes becoming more and more rare, and America as nation, has truly lost something of its brains in the lost of minds like this that built these incredible factory machines.

http://www.youtube.com/watch?v=QCksgN7kiv4

Many tubes are only available now from places like China and Russia. I think I will begin to catalog and cross reference these to make them more available to other radio amateurs, who like me would like a cheap and simple access to these treasures.

Groovy Baby! Those Seventies were so Randy - GIRLS (Pretty Ones) !!!! On the Cover

2009-10-02T16:27:00.025+01:00

I have often commented to my more marketing savvy Ham friends -- Why don't HAM magazines have ads that appeal to men, and not just Hams. After all they are men first, and Hams second. -- Therefore, I would think that ads selling shotguns, sports cars, and dare I say it cigars and chewing tobacco! This would be not too dissimilar to Popular Mechanics or Sports Illustrated ads of today?? I also wondered why Hooters and Budweiser don't sponsor the local Ham Fest or VHF Rally's? Here again, there are parallels, VHF Contest's are a manly competitive sport like football or baseball? Surely from the sponsors point of view Hams are a very similar buying demographic to any male-dominated, testosterone-driven event.

But proving there is nothing new under the sun; I recently came into a bit of good fortune. I HAM colleague of mine needed more space in his basement office and needed to find a good home his super-duper collection of 73, CQ, QST magazines dating from 1955 to 1999, lucky me!

When I got them home, I set myself to organize and catalog them as best I could. I leafed through a few and looking at building projects filled with half a century of ingenuity and craftiness that Hams are famous for. But my eye was drawn to something I had never seen since I had been following Ham mags in the early eighties.

73's editor Wayne Green was one crafty business man, he reasoned most Hams are guys, therefore they would favor a magazine with a good looking gal on the cover. It is no wonder those were the good old days, and here I foolishly thought they were talking about sun spot cycles and glowing tubes. -- Maybe the hobby has gotten older, and lost a bit of its libido and zing!? Maybe we take ourselves a bit too serious? Maybe good old "Shep" /K2ORS and Wayne Green /W2NSD were right all along to say "Never Say Die!"

-- If the hobby is going to survive, let's make it fun. Be polite and welcoming on the air to new Hams, build something, try something new, quit whining about not using the repeater tones, and then complaining about kids kur-chucking the machine for fun.

When was the last time you just turned the dial and listened, really listened to some random spot on your dial and wondered --"Where in the world is that signal from?". I too find myself on internet led missions to this net or that special event without just spinning and grinning like a kid. After all, I have often said had what make my hobby fun, is the things we don't know.

In months to come I hope to share with you my impressions of some of those great articles, and build projects from my newly acquired collection of RF and dreams.

Virtually Change the World!

2009-09-30T02:00:00.003+01:00

Donate your computer's idle time, to projects that will truly benefit humanity!

check out the World Community Grid

They will provide the free software that does it all for you.

If you join the WCG, then be sure please join my Team 'Team World Radio'. I have already donated over 500 days this summer of computer time. I use older but dedicated computers setup in a VMware mini-Grid to maximize my efforts.

Reading for FUN // SolderSmoke - The Book!

2009-09-29T19:44:00.005+01:00

A book by Bill Meara N2CQR/CU2JL/M0HBR the host of the QRP classic podcast SolderSmoke.

I've loved the show from the very beginning, hanging on every story. His stories are wonderful, and not because they are unique, but because they are our stories too. If you like I have been interested in the uber-geek pastime of Ham Radio then chances are you will find that many of Bill's childhood stories will resonant in a eerie sort of way with your own life. I recently picked up SolderSmoke - The Book! from LULU.COM and I'm planing to read it at work during my lunch break, in true SS style.

Also, If you have not had a chance to listen to SolderSmoke but are interested in QRP radio and other subjects of interest like Astronomy, CW & Electronics. Be sure to check out SOLDERSMOKE - The PodCast too. (It is free)

Coils and Inductors Chart

2009-09-29T19:04:00.005+01:00

As I got in my car this morning I was treated with a welcomed chill in the air. A very welcome chill indeed, after the heavy rains and muggy humidity which have lingered over the Metro Atlanta for the previous weeks.

Therefore, Winter must be near (or at the very least fall) and that really means only one thing, more time in the shack, building and operating radios. After many set backs last year with my QRP efforts, I thought I would start a fresh and get truly organized. One of those efforts is to better understand "inductance", I have always had a tighter hold on resistance and capacitance, but coils have always been somewhat more baffling to me.

After a few minutes searching around the web and QRP watering holes, I was rather unsatisfied with he current state of reference materials available for the amateur builder. I was able to find a few charts, but most with contradictory data, and a few helpful formulas. Using the formulas, I built a spreadsheet to help me, and presumably others with most of the more commons incarnations of toroidal and air coils. In weeks to come, I hope to expand the air coil document to include forms like Star Bucks coffee stir'ers and other item commonly found (preferably free) items.

I have put together a few charts to help myself to better build and catalog the different options available to me when building home-brew QRP rigs.

TOROIDS AIR-CORES

Although I have built many, I'm still clueless as how to calculate the values for Binocular Transformers and Bi & Tri-filar coils. - Maybe some helpful HAM would care to comment.

Sun Spots and Atlantic Storms Correlation

2009-09-15T16:43:00.014+01:00

In order to comply with the complaining about the low solar numbers quota that every HAMs must comply with as per of FCC rules, Earlier this week while driving I was amusing myself by dreaming about higher solar activity. -- Doesn't everybody?

In this particular day dream, I started to notice that there was an apparent relationship between solar activity chart in my head and the hurricanes I could bring to mind, please remember I'm driving, so my data was more than a little fuzzy. So this PDF is a result of an attempt to do a slightly less fuzzy back-of-an-envelope type of calculation.

I got my Solar Data and chart from the Solar Influences Data Analysis Center - (SIDC) http://sidc.oma.be/sunspot-index-graphics/sidc_graphics.php

and my Storm Data from the National Oceanic and Atmospheric Administration - (NOAA) - http://www.aoml.noaa.gov/general/lib/mgch.html (and a few others)

This seems so obvious that I knew I could not have been the first to notice, so a little google search turned a few references, but the best and cleanest seem to be this wiki entry. Where it names good 'le GATECH as the authors of just such an idea.

http://en.wikinews.org/wiki/Hurricanes_may_be_associated_with_sunspots

OK, so it is not a new idea, but an interesting one all the same. Notice the storms seem to ovoid the peaks (and troughs - except for Betsy). My original idea was that really large US hitting storms would only occur 18 mo ~ 24 mo AFTER the solar peak. This simple chart shows that is not exactly exclusively true. While it is true that storms do seem to follow that pattern, they also seem to happen 18 mo ~ 24 mo BEFORE the solar peak. This needs a little more work before any real conclusions can be made, but there does seem to be a pattern.

Tennessee Fire Tower

2009-09-14T15:23:00.010+01:00

The Tennessee Fire Tower article featuring n4AOW was in the Summer 2009 CQ VHF+ magazine.

Article

CQ-VHF+ Mag - ki4SGU AT Golden Packet Article

2009-09-14T14:59:00.009+01:00

Well after playing around with the blogspot software and interface this weekend. I think I am now ready for my next post, this time including a linked PDF. The trick was to upload the docs into my google docs area.

This article originally "aired" in the CQ/VHF+ Spring 2009 Edition, for the now completed APRS Golden Packet event. I am including it here now for completeness, since I am planning on making this my new home and cyber soap box.

AT Golden Packet Article

Where would Cloud 9 be, if it were a DX entity.

2009-09-11T21:14:00.003+01:00

This morning on my work I was discussing where is 'Cloud 9' might be if it were a DX entity, CL9 in Cuba came back one of the repeater's usual suspects (Dick /k2UFT). But searching my memory I could not remember ever working any CL9 from Cuba (or any where else). Most guys on the radio know I'm originally from Cuba, so naturally they think I know everything about the place, not so.

But the idea got me intrigued, when I got to work I wrote a few email to a few Cuban Hams I know and I quickly got my answer.

The prefix CL9, CM9 and CO9 belong to Radio Clubs or Hams authorized to operate from a Radio Club.

I also found out a little about their grid squares (super for 6m work, more on that soon), call signs and their license class system.

There Are 3 Ham's Classification:
CO - First -- HF/VHF/UHF/SHF bands & all modes, 2Kw HF. (Extra)
CM - Second -- HF bands SSB/CW and VHF bands FM, 500w in HF. (General)
CL - Third --- Segments on 160 & 2 Meters SSB, CW and FM. (Novice)

I had worked plenty of Cuban Stations in the past, but I guess I had not pay that much attention. OK, so much for Cloud 9 and my first official blog.

2009-09-11T20:48:00.003+01:00

OK I have decided to launch myself into the blogosphere. I have created this blog in an effort to be able to document the various points of interested that I am interested in, mostly Ham Radio, but I'm sure from time to time I will have other thoughts, however fleeting the may be.

I'm still new to the blog spot interface, so please forgive me if I commit any formatting sins.