RADIO AMATEUR NEWS & VIEWS, OCTOBER 2011

RADIO AMATEUR

NEWS & VIEWS

OCTOBER 2011

IN THIS ISSUE...
SKYWARN HAM-CON Relocates JOTA October 15-16
NO VE ARRL SET Decibels Demystified II

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Next Meeting: SKYWARN

The October 11TH meeting will be a SkyWarn presentation by the good folks from the National Weather Service in Burlington. With winter fast approaching, this will be a good brush-up on what to watch and listen for and what the NWS needs from us. Plenty of question & answer time and the usual munchies. Come join us for this always popular presentation!

Octoberís meeting is our annual Call for nominations. Itís your turn to take a spin around the block, step up to the plate, etc, etc. If you care about the club, consider adding some new energy, ideas, and skills to the leadership mix. What would you like to see the club do? Take us there!

And keep in mind that if you don't show, you may find yourself nominated for something you really had not had in mind at all


HAM-CON RELOCATES

Pending the pen-to-contract, the 2012 HAM-CON will be moving to the Holiday Inn by I-89 Exit 14. The Holiday Inn is easy to get to, has a 2400 sqaure foot main room with easy vendor access, plus 3 smaller rooms for forums, relaxing and yakking, and whatever else we need them for. W1V will be set up in the hotel lobby which will be great exposure to the public. Final details still in the works, but we see this as a pretty good move and we expect a good show. Put February 25 on your calendars and plan to bring along lots of buddies, ham and other.


JOTA OCTOBER 15Ė16

Jamboree on the Air (JOTA) is the largest Scouting event in the world, pulling in Boy Scouts, Girl Scouts, and Girl Guides from all over the world.

The International Space Station NA1SS will be participating throughout the JOTA weekend. Astronaut Mike Fossum KF5AQG, who is also a Scoutmaster, will be on the air whenever possible during breaks from his schedule. The uplink is 144.490 MHz and the downlink is 145.800 MHz.

If you have the time during the weekend get on the air and participate in the JOTA by making QSOs with the many scouts looking for contacts. After all, with all the fuss and complaints about getting new blood into the hobby, here's a group begging for encouragement. Letís welcome them in!


NO OCTOBER VE SESSiON

Carl AB1DD

Just a note, there will NOT be a VE session October 14th. Everyone will be at NEAR-Fest, come join us!


ANNUAL ARRL SET

Paul AA1SU / Robin N1WWW

This yearís Simulated Emergency Test (SET) in Vermont will be held November 26th, the Saturday after Thanksgiving, from 9AM until Noon. Paul (Section Manager) and Robin (Assitant Section Emergency Coordinator) are putting together a scenario and other details. Vermont Emergency Coordinators and District Emergency Coordinators will be contacted soon with the SET plan and instructions. Once the nets are up and running that day, everyone is welcome to check in and play.


DECIBELS DEMYSTIFIED - part 2

BOB W1ICW

Oftentimes it is convenient to calculate our entire system gain or loss, and then we can come up with a single number to apply to the transmitter power. In my Moonbounce system, I have gains and losses all along the path out to the antenna. I can add and subtract as necessary, and apply the net result. Donít forget, a loss of power is minus dB, and a gain of power is plus dB.

For powers of ten, it gets even easier:

As you can probably guess, 60 dB is 1 million times (1 followed by 6 zeros) or one-millionth. And 63 dB would be 2 TIMES a million or 2 million times. Now for a tricky one: Suppose you wanted to figure out the gain in an HF amplifier that boosted your signal from 100 watts in, to 500 watts output. We havenít really talked about a dB number that is 5 times your power out, but you can probably guess itís a number between +6 dB (4 times) and +10 dB (10 times).

Well, we can work backwards (hereís rule number 5 from September: You can add or subtract dB values to get additional ratios as needed). We know that 1 kW would be 10 times the power out (100 watts times 10 would be 1000 watts) and we know that 500 watts is half or 3 dB down from that, so we subtract +3 dB from +10 dB and get +7 dB! If you do the math you will find out that this works. A change of 5 times your power, or one-fifth, is indeed + or - 7 dB.

So a decibel represents a CHANGE in value. But what about a dBm? A dBm represents a finite power level. More on that, SINAD, and more in Part 3, next issue.


CRYPTOGRAM ANSWER FROM SEPTEMBER

Einstein On Radio
ďI am often asked how radio works. Well, you see, wire telegraphy is like a very long cat. You yank his tail in New York and he meows in Los Angeles. Do you understand this? Now, radio is exactly the same, except that there is no cat.Ē

A=F B=X C=P D=M E=L F=U G=A H=V I=D J=S K=C L=G M=Y N=H O=W P=O Q=N R=Z S=I T=R U=B V=J W=E X=T Y=K Z=Q



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