Friday, May 28, 2010
Thursday, May 27, 2010
Basically the Signalink and it's soundcard are like a modem. The information encoded into audio tones is fed to the transmitter by this device and ultimately radiated out into the ether. The shielded USB connection cable is not visible but it's there plugged into the back of the unit and drops down behind the table top. Here is where things get interesting and more confusing. The TX knob on the Signalink controls the amout of audio "drive" to the radio. To provide the most efficient and "clean" signal this drive has to be carfully controlled. The TX knob on the Signalink works in conjuction with the radio's ALC or Automatic Limiting Control. ALC limits the RF drive level to the power amplifier during transmit to prevent distortion. To adjust for proper operation I switch my rigs output coax to a dummy load. This is just a giant resistor that absorbs the RF signal and bleeds it off as heat instead of sending it on to an antenna. While transmitting a PSK signal I watch the ALC meter on the rig. If the TX knob on the Signalink is turned up too high one or more bars will show on the meter. Backing off the TX knob until no indication of ALC is evident on the meter lands you in the sweet spot and the ideal balance of drive power is met. This is why I like the Signalink USB. My laptop's operating system is quirky enough and I think it would be a real pain to minimize fldigi (digital mode software) and go to the control panel window and jump through those hoops just to make a small adjustment to the soundcard drive.
That's it! Once the ALC conditions are met and the output is switched back to an antenna all systems are go for digital radio fun.
Click on the picture for a close up view and look at the yellow signal on the waterfall display. You will notice two fine red lines that straddle the yellow strip. This is the tuning indicator and is movable by using the mouse. If you see a signal and click on it the two red lines will jump to that spot and the software will begin decoding. The same applies when transmitting. Find a clear space on the waterfall, click on it and where the red indicator rests shows the exact frequency of the transmitted PSK signal.
Last night I spotted a bright PSK signal on 30 meters. I copied the callsign that belonged to the trace and when the QSO was over I gave Jean VE2GHI in St Georges, Quebec a call. He responded and we had a pleasant textbook PSK-31 QSO. I am very proud of the unsolicited comment that Jean made concerning my signal. The tricky part with the digital modes is that you cannot see your own signal on the waterfall so you can't tell if it is overdriven. This is why monitoring the ALC is so important. With the system properly adjusted 15 watts is more than adequate to send a good clean signal just about anywhere.
Sunday, May 23, 2010
Saturday, May 22, 2010
Wednesday, May 19, 2010
USS Douglas H. Fox DD779
Image contributed by Howard Longstreth to the archive at http://www.navsource.org/
On May 14th I met Andy KB3IFK on 40 meters CW. Andy is retired and lives in Baltimore, Maryland. I was excited to learn as I decoded the beeps in my headphones that Andy was once a Radioman in the US Navy. I am always amazed and honored at the chance to work these professional radio operators on the amateur bands.
Andy enlisted in the Navy in 1961 and spent six months in "Radioman A" school where he learned Morse Code and RTTY (radio teletype). With training complete he began his career aboard the Destroyer USS Douglas H. Fox. The Fox had recently been outfitted with the days latest anti-submarine warfare equipment. After an honorable discharge in 1965 Andy settled into civillian life and never gave ham radio a thought as he had morse code ringing in his ears for years after leaving the service. He became a licensed radio amateur in 2002.
Being the ever curious history buff I looked up Andy's ship online and discovered some very interesting history. The Fox was already 15 years old when Andy went aboard. Commissioned in 1944 the Douglas H. Fox first saw action in May 1945 during the final campaign of the Pacific war. During the Battle of Okinawa she successfully thwarted a number of kamikaze attacks but not without extensive damage and the loss of ten brave crewmen.
During 29 years of dutiful service The Fox saw action in three wars, WW2, Korea and Viet Nam. The Douglas H. Fox was decommissioned in 1973.
It was a unique and rewarding experience to use ham radio to communicate with someone who served as a radio operator aboard this destroyer. Particularly cool to use Morse Code I might add.
Saturday, May 15, 2010
Wednesday, May 12, 2010
On Sunday I managed to get my support lines for the EFHW antenna wires much higher into the tree out back. The tree is a silver maple whose trunk splits into 3 smaller trunks about four feet above ground. After closely looking at the tree for a month or so I settled on a target support branch about 25 feet up in the only area of the canopy that was in the clear and free of smaller branches and foliage. I know it probably would not matter at my low power levels and the fact that the wire is insulated but it would bug me if the 40 meter wire was in contact with the foliage. I was going to climb the tree and attach a pulley system but it was a bit windy and I don't enjoy climbing trees quite as much as I did when I was 13.
One day at the local hardware I spotted a roll of very bright pink string. I also picked up a 7/8" nut that weighs an ounce or two to tie onto the pink string. I explained to my son how I would twirl the string with the nut and fling it up into the tree David and Goliath style and hopefully over the branch. I could tell by his expression he thought I was crazy. After ten or fifteen throws I got the string right where I wanted it and pulled up the black Dacron antenna cord. Wyatt was impressed. Showing tricks like this to my son is one of the little joys of parenthood that I really get a kick out of.
Searching in my scrap wood box I found some pieces of 1/4" X 12" mahogany to wrap the cordage on to keep tangle free for future use.
I had doubled the height at the far end of the antennas. Back in the shack I noticed right away that the noise floor was lower and signals seemed louder. I believe I was picking up lots of electrical noise from the house. Incoming signals are not any stronger now, there is just less static in the background. As for any improvement in my transmitted signals I can't really say. I have made 7 contacts since the modification and the stations I am reaching are not reporting any difficulty hearing me. One ham I worked last night on 40 meters, Bob W0CAB (Been a ham for 60 years!) near Kansas City said the rig sounded great for only 40 watts.
Friday, May 7, 2010
Fridays after work I like to go for a bike ride. Last Friday, I celebrated Arbor Day with a mountain bike ride among the trees at Clear Fork. I rode about 5 miles with lots of short climbs on the blue trail. This Friday I was feeling like a bent ride. I started a few miles from the northern end of the B & O trail and planned on riding 15 miles south and turning back. Once I got going I noticed I might just luck out and get a tailwind push on the way back so I decided to run for time. A few miles into the ride a gentleman caught up with me riding a P38 Lightning. He was retired from commercial printing after 42 years in that industry. He has been riding recumbents for 9 years he said. I hit 15 miles at about an hour and 10 minutes and did indeed have a nice tailwind to help me home. The weather was beautiful and sunny but clouds moved in along with tornado watches for all the surrounding counties. I made it home long before the rain.
I have been trying to crack 2 hours for 30 miles on the recumbent. I have done 1:45 on my Lemond road bike and just under 2 hours riding the Ti general purpose bike when it was a single speed. I think this season I will reach my goal.
Ride Time: 2:09
Distance: 30 Miles
Average Speed: 13.9 MPH
Max Speed: 23.9 MPH
HP Velotechnik Street Machine GTE
Thursday, May 6, 2010
It took me about an hour to put the kit together. A well written and thorough assembly manual can be found online. Operation is EASY- push right for dots and left for dashes. Spring tension and leverage of the mechanism are fully adjustable. Doug Hauff, W6AME and his shop American Morse Equipment is a FB operation that specializes in QRP stuff like paddles and machined enclosures for electronic projects. They are located in San Luis Obispo, California.
The paddle's cord plugs into a Logikey K-5 Keyer. This device is a microprocessor that makes the string of dots or dashes. The K-5 is the gray box in the picture with 6 buttons and a single knob on the front beside the insulators. With the large knob the character speed of the morse code can be increased or decreased. Other functions such as memory are controlled with the 6 buttons. The keyer in turn is connected to the key jack on the back of the Transceiver. These two great American made components represent one of the latest designs in the 170 year history of telegraphic equipment.
Yesterday on 40 meters I called CQ and made contact with Tom, W8JI near Macon, Georgia. Tom is a great op who was keying with a vintage Vibroplex Lightning Bug. We had a pleasant QSO and I got to report back to Tom the difference in his signal strength as he rotated his Yagi antenna from the west to the north focusing his signal in my direction.
The paddle and keyer let me concentrate on what I am trying to say while the equipment works out the length of each character element and the spacing of the dashes and dots. Much easier than sending with a straight key or manipulating the bug which still requires you to regulate the start and stop and length of each dash. At slower speeds around 15 words per minute or slower straight keys are fine but as my copying speed has slowly increased I now enjoy sending with the paddle.
("FB" is an old land line Morse Code signal that means excellent or great. Fine Business.)
Tuesday, May 4, 2010
For Primary Power Distribution Circuits 2300 Volts. Also for 4600 and 4000-volt Y circuits.
An insulator of high dielectric and mechanical strength. Ideal for primary distribution circuits. Extra heavy constructions -- rugged and everlasting. New in design and material. Carefully annealed by special Hemingray process.
Voltage Rating _ _ _ _ _ _ 6,600 Volts
Dry Flash-over _ _ _ _ _40,000 Volts
Wet Flash-over _ _ _ _ _22,000 Volts
Leakage Distance _ _ _ _ _ _ 4 3/8 in.
Wet Arcing Distance _ _ _ _ _ _ 1 in.
Diameter of Groove _ _ _ _ _ _ 7/8 in.
Weight per Piece _ _ _ _ _ _ _ 20 oz.
Quantity per Carton _ _ _ _ _ _ _ 50
Weight per Carton _ _ _ _ _ _ 68 lbs.
Weight per 100, packed _ _ _ 136 lbs.
The new Hemingray Glass possesses extra mechanical strength and high dielectric qualities. These insulators are unaffected by rapid temperature changes. They are thoroughly tested for heat shock.
-From: Hemingray Bulletin D-1 page 4