FEBRUARY 2000

Floyd W9FX

President: Floyd Hofmann, W9EX
309-452-3612
Vice President: Rick Kempf, WD9HRU
309-828-8054
Secretary/Treasurer: Norman Huber, N9ZKS
309-378-4674

Submissions for the newsletter must be received by the 10th of the month and may be snail or e-mailed to the editor at:
Norm Huber
19268 E. US Hwy 150
Bloomington, IL  61704-5855

e-mail  nihuber@ice.net

Permission is granted to Amateur Radio-related organizations to reproduce contents of Short CIRCuits provided full credit is given.

Cherry Pie Deserts and Swap Fest
Don't miss it!

Bloomington Public Library
205 E. Olive
Bloomington, IL 61701

Dates for the year 2000 (Walk-ins are welcome)
Mar 11     1:30 PM
May 13     2:30 PM
Jul 15       1:30 PM
Nov 11     1:30 PM
Walk-ins are welcome.

Morton Public Library
315 W. Pershing
Morton, IL 61550

Dates for the year 2000 (Walk-ins are welcome)
Feb 19.
Apr 15
June 17
Aug 19
Oct 21
Dec 16
There will be VE testing at the Peoria SuperFest on Sunday September 17, 2000
Testing will begin at 10:00 A.M. Walk-ins are welcome.

73 & DX,

Gary - AB9M

EME    -   HIGH POWER AND BIG ANTENNAS  VS.  QRP AND GOOD RECEPTION
By        "WB9UWA Jim Shaffer" <wb9uwa@gte.net>

I find myself in agreement with AF9Y in an interview with him that appeared in QST a few years ago where he says that the state of the art should be developed to the point that small stations can communicate to each other via the moon. I may well choose to stay with a small antenna and legal amateur power levels to accomplish EME in a most challenging manor (remember the fun of QRP?). By staying at 1000 watts output, less rf interference is received by nearby appliances and I am encouraging all of you to take measures to advance the state of the art by developing, using, and optimizing EME receive techniques, hardware and software, in order to receive my small signal. Many more first time EME QSOs will then be made.

Using high power and big antennas may be a fun ego trip (which I wouldn't mind trying someday), but I think it could make me lazy or complacent and tend to cause me NOT to strive for great receive improvements. I would like to contribute to the advancement of the state of the art, but I need to learn the entire current state of the art and build from there. I know some of you are receiving at 2.7 kHz bandwidth on a speaker. I realize that the human ear is capable of 50 Hz bandwidth and can instantly tune to a new frequency, but if signals below the noise are to be detected (below 50 Hz bandwidth) then obviously something more is needed.

SM5BSZ is making great strides in receive techniques, but we need 50 more hams, just like him. In case I missed you, please introduce yourself. Xpol is not likely to go away soon and I feel it will quickly become an EME standard. I am disappointed that many EMEers with Xpol do not make optimal use of it, simply switching TX polarity at random, hoping to be heard. N1BUG seems to have a handle on polarity issues.

There is software out there that gives some DSP advantages. FFTDSP is my favorite. It boots up already running and allows me to locate a cw signal quickly. The sensitivity is outstanding. I rarely hear cw that doesn't show on the screen. It is functional in that it gives current antenna heading information (moon direction). I am curious of you FFTDSP users as to what level you receive CW at. Using the vertical bars at the right hand side of the screen, I find that I am copying code when the indicated peak s/n stays around 6db. When 10-dB s/n is indicated, copy is comfortable and sounds loud. This of course is indicated at 2 Hz bandwidth. I have spent hours and $$$ trying to get Hamview to run with no success. Spectran shows promise, but does not come up running and makes inefficient use of the screen area. I like having integration options, but have not seen any improvement over FFTDSP and when the integration is set similar to AF9Y's FFTDSP; the display bandwidth is too narrow to be useful for finding signals, without tuning the receiver. Spectragram is neat, because you can "see" the individual dots and dashes on the screen, giving a visual sense of what is heard. It is 100% worthless during an EME QSO because it must be filling the hard-drive with data while giving a real time display. It also suffers from insufficient display bandwidth.

I have not tried DSP Blaster. I understand its filter is useful, but its stereo RX is not useful for EME reception due to multipath distortion and frequency stability requirements. My current receive setup may accomplish some of what DSP Blaster intended with its stereo RX feature. My RX setup could easily be written into software using a soundcard and computer. I just wish it were easy for me. After bragging how good my receive (for my antenna gain) is, a few of you have asked me to describe my receive setup. I will describe it here and start with a bit of history so you can follow the development. I started with the Yeasu FT763r with the 600 Hz cw filter followed by my MFJ DSP filter (don't buy the MFJ filter) set to between 100 to 200 Hz bandwidth. Much more than 200 Hz lets in too much noise and much less bandwidth and my ears seem to loose a much needed reference point and the noise sounds like random cw signals all clustered close in frequency. Most of the successful contacts were made at 100 Hz bandwidth. FFTDSP always sees the full 600 Hz bandwidth. Before initial reception of signal I turn off the speaker and set the bandwidth to 2.7 kHz. FFTDSP is set to a bandwidth of 1.5 kHz. This has been sufficient at 2 meters and most stations start at between a 600 Hz and 1200 Hz tone. I decided to put a switch in line with my stereo headphones so I could listen in 600 Hz bandwidth, DSP filter output or 600 Hz BW left and DSP filter right. The stereo position is the one that always gives best copy. I can narrow the DSP filter down to 40 Hz bandwidth. This is much narrower than my ears can tolerate when used by itself. The 600 Hz signal on the left seems to give my ears a much-needed reference.

There is a small time delay in the MFJ DSP filter. I think this is key to the success of my stereo RX. My ears now have phase information for my brain to process. The narrowest setting or selectivity (40hz) gives the best copy. The presence of the 600 Hz bandwidth left channel makes the apparent ringing of the 40 Hz filter tolerable to listen to. Two factors give the receive advantage. Narrow bandwidth without objectionable ringing and phase information for my ears.

W5UN prefers the Autech audio filter to DSP filters. I had to wonder why. DSP filters don't ring. Audio filters do ring. Ringing = audio integration. AHAH! Copy is improved when time overlaps (integration). I don't own his filter so I built a simple fixed 8-pole filter with positive feedback to ensure sufficient ringing. It is set for 460 Hz center and about 75 Hz bandwidth. This filter has the added advantage of removing hiss and hum when it follows the DSP filter.

My latest refinement was to add a 375 Hz high pass filter to the left channel so I could further narrow the left channel by using pass band tuning without having too much low frequency response. With this latest setup, my left channel can be set to 200 Hz bandwidth while the right channel has 40 Hz bandwidth with ringing. My computer can be set so it will see the rig's audio or the audio filters output (right channel) so the filter frequency can be spotted. That is my current setup today. I welcome your suggestions for further refinements.

I would like to see an adaptive integration algorithm that follows the rules for cw and offers optimal integration when the code speed is known. It should provide various stereo mode outputs and display a variety of audio bandwidths and integration combinations in the usual waterfall display. There should be a wave editor that allows the received audio to be matched with known call letters either from sked information (one call) or a database (many calls) when a partial call is identified. This information could be taken from frequency bins on and near peak frequency after adaptive integration is performed. When 2.7 kHz and greater bandwidth audio is available, effective noise blanking could be done. SM5BSZ is making progress in this area with about 20 kHz bandwidth and polarity information available from xpol antenna. Perhaps with minimal modifications, CW detection using the rigs FM 15 kHz wide filter feed to the computer sound card with the proper software may prove useful. With true DSP at the IF level with, say 5 MHz bandwidth; great advances should be possible.

I don't know if this is the correct forum for this subject as I have not seen much on Moon-net battered about it in any great detail. Much seems to be known among the Moon-net group about tweaking the last .001 dB out of system receive by optimizing noise figure for a pre-amp and much amplifier and antenna knowledge is evident. Obviously scheduling contacts and reports of contacts are important to this group. If you can suggest to me a better forum for the subject of optimizing weak signal detection I would like to hear about it. If you have something to contribute that I didn't think about, I need to hear about that too. I welcome any web sites that you can suggest that will educate me on the subject of weak signal detection and DSP in general. Sorry for the length of this E-mail, but I lack the talent to say much in few words, so I use many words. Same end result perhaps more accurately conveyed.

I am interested in helping to advance the state of the art, but I must be current on what the state of the art is (but not to the point of being set in my ways) so I can build on what is known.

73, Jim Shaffer, WB9UWA, 4 W1JR/VE7BQH 8 ELEMENT YAGIS WITH ELEVATION AND
1000 WATTS on 144 MHz, MGF1302 preamp, Stereo RX, FFTDSP.

From ARRL Headquarters
Newington CT  February 15, 2000
To all radio amateurs

SB QST ARL ARLB010

Amateur Radio operators are responding in force in the wake of tornadoes that struck rural extreme southwestern Georgia this week, killing more than a dozen people and injuring many more. Georgia Section Emergency Coordinator Tom Rogers, KR4OL, reports that hams from nearby communities including Moultrie and Albany have turned out to help.
   Twisters late Sunday and early Monday leveled a housing development in the town of Camilla, in Mitchell County. The town was one of the worst-hit areas. The storm also tore roofs from houses and flattened mobile homes. The storm caught many residents by surprise since warnings were not issued until after they'd already gone to bed for the night.
   Georgia Gov. Roy Barnes has declared a state of emergency in Colquitt, Grady, Mitchell and Tift counties. Georgia Emergency Management Agency reports emergency shelters have been set up in Camilla and Moultrie.
   ''Shelters are open, and the Georgia Baptist Hams are setting up feeding locations and assisting with the cleanup,'' Rogers said.
   An HF emergency net is running on 3975 kHz to coordinate activities. Rogers advised all participating stations to monitor that frequency. If relief operators are requested, operators should coordinate through the emergency net on 3975 kHz before attempting to enter the disaster area.
   Thousands were left without power in Georgia and elsewhere. The storm that wreaked havoc on Georgia was part of a system that also struck Arkansas, Tennessee, Mississippi and Alabama before moving into Georgia, Northeastern Florida and the Carolinas.

The average life expectancy in the United States was forty-seven.
Only 14 percent of the homes in the United States had a bathtub.
Only 8 percent of the homes had a telephone. A three-minute call from
Denver to New York City cost eleven dollars.
There were only 8,000 cars in the US and only 144 miles of paved roads.
The maximum speed limit in most cities was ten mph.
Alabama, Mississippi, Iowa, and Tennessee were each more heavily
populated than California. With a mere 1.4 million residents, California
was only the twenty-first most populous state in the Union.
The tallest structure in the world was the Eiffel Tower.
The average wage in the US was twenty-two cents an hour. The average
US worker made between $200 and $400 per year.
A competent accountant could expect to earn $2000 per year, a dentist
$2500 per year, a veterinarian between $1500 and $4000 per year, and a
mechanical engineer about $5000 per year.
More than 95 percent of all births in the United States took place at home.
Ninety percent of all US physicians had no college education. Instead, they
attended medical schools, many of which were condemned in the press and by the government as "substandard."
Sugar cost four cents a pound. Eggs were fourteen cents a dozen. Coffee cost fifteen cents a pound.
Most women only washed their hair once a month and used borax or egg yolks for shampoo.
Canada passed a law prohibiting poor people from entering the country for any reason, either as travelers or immigrants.
The five leading causes of death in the US were: 1. Pneumonia and influenza, 2. Tuberculosis, 3. Diarrhea, 4. Heart disease, 5. Stroke.
The American flag had 45 stars. Arizona, Oklahoma, New Mexico, Hawaii and Alaska hadn't been admitted to the Union yet.
Drive-by shootings -- in which teenage boys galloped down the street on horses and started randomly shooting at houses, carriages, or anything else that caught their fancy -- were an ongoing problem in Denver and other cities in the West.
The population of Las Vegas, Nevada was thirty. The remote desert community was inhabited by only a handful of ranchers and their families.
Plutonium, insulin, and antibiotics hadn't been discovered yet. Scotch tape, crossword puzzles, canned beer, and iced tea hadn't been invented.
There was no Mother's Day or Father's Day.
One in ten US adults couldn't read or write. Only 6 percent of all Americans had graduated from high school.
Some medical authorities warned that professional seamstresses were apt to become sexually aroused by the steady rhythm, hour after hour, of the sewing machine's foot pedals. They recommended slipping bromide-which was thought to diminish sexual desire-into the women's drinking water.
Marijuana, heroin, and morphine were all available over the counter at corner drugstores. According to one pharmacist, "Heroin clears the complexion, gives buoyancy to the mind, regulates the stomach and the bowels, and is, in fact, a perfect guardian of health."
Coca-Cola contained cocaine instead of caffeine.
Punch-card data processing had recently been developed, and early predecessors of the modern computer were used for the first time by the government to help compile the 1900 census.
Eighteen percent of households in the United States had at least one full-time servant or domestic.
There were about 230 reported murders in the US annually.

If you haven't paid your dues OR YOU KNOW A PROSPECTIVE MEMBER here is a membership application.

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(  )VHF/UHF                             (  )  Administering Exams (VE)
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You can turn in your membership application at club meetings (4th Wednesdays at the Red Cross building in Bloomington) or mail it and a check payable to the Central Illinois Radio Club to:

Central Illinois Radio Club
P.O. Box 993
Bloomington, IL  61702-0993
 
 
 
 
 
 

Central Illinois Radio Club
February 2000 Newsletter
 
 
 
 
 
 
 
 
 
 

Central Illinois Radio Club
P. O. Box 993
Bloomington, IL  61702-0993