The NAQCC December 2020 Challenge
All challenge info such as rules are now in the hands of Gary K1YAN. Email him with any questions in that regard at .
The results on this page are the responsibility of Hap K7HAP. Email him with any questions in that regard at .
SUBMARINE ELF COMMUNICATION
Trying to communicate with a submerged submarine poses a serious problem at normal radio frequencies. Seawater shields submerged boats from radio signals, cutting off vital communications. As transmission frequency decreases into the Very Low Frequency and Extremely Low Frequency spectrums, radio waves will penetrate seawater and support communication with a submerged boat. VLF frequencies of 3 to 30 kHz are capable of penetrating water to depths of about 10 to 30 meters. To utilize these frequencies a boat must rise to this shallow depth and risk detection. ELF frequencies of 30 to 300 Hz, can however, reach down to hundreds of meters allowing communications at preferred operating depths.
ELF operation is not without its problems. A half wave dipole for ELF would be around 300 miles long, so any physically practical antenna is very small in terms of wavelength and extremely inefficient. Antennas know as ground dipoles have been used. Resembling power distribution lines built on 40 foot poles, they are grounded at the ends of the 14 mile long legs and are in the shape of a cross with the transmitter in the center. For one installation, 2.6 megawatts of input power radiated only about 8 watts of ELF signal. Signal attenuation of only 1 to 2 dB per 1000 kM at ELF does, however, allow communication over half the globe with this low power ( QRP works ! ). The system transmits continuously, 24 hours a day, sending an "idle" message when not in use, so that submarines can verify they are within communication range. Shipboard ELF transmitting systems are not practical, so the communication is in one direction only.
As a result of the very low transmitting frequency, bandwidth for data transmission is very small. The resulting slow data transmission rate makes long text messages impractical. Because of this limitation, the system is used to perform a “ bell ringer “ function, alerting the submarine that there is a message for them. The boat must then receive their message using a different communications system.
The first day of the month 0000Z through the last day of the month 2400Z
Just make ALL these words from calls of stations you work subject to the General Challenge Rules. (Any spaces in the phrases should be ignored. For example the challenge phrase "INVERTED V ANTENNA" should be treated as if it is the single word "INVERTEDVANTENNA.")
EXTREMELY LOW FREQUENCY
30 TO 300 HZ
BELL RINGER FUNCTION
NARROW DATA BANDWIDTH
24 HOUR IDLE
The 89 total letters contain these 26 different letters and numbers : A B C D E F G H I L M N O P Q R T U W X Y Z 2 3 4 0
You can use each letter in a call TWICE. For example you could use K3WWP for 2 K's, 4 W's, and 2 P's.
Subsequent QSO's with the same station cannot be used for additional letters. For example, no matter how many times you work K3WWP, you can only use his call for 8 of the letters in the words.
See General Rule #5 for more details on what callsign letters can be used.
If you need some help with your alphabet challenge record keeping take a look at our Alphabet Tutorial page for everything from some great pencil & paper methods to fully computerized tools.
A certificate and Participation Point go to everyone making all the words and submitting their report before the deadline.
A Participation Point goes to everyone making at least 1, but not all the words and submitting their report before the deadline.
A choice of an item made by master woodworker Gregg WB8LZG as shown on our prizes page here goes to someone selected via a random drawing from all who participate and submit a report for this month's challenge. A person can only win once, then they become ineligible for future drawings.
For your report, list the words you made and the station used for each letter in the word. The number of stations listed must be the same as the number of letters in each word, even though you use the same station for more than one letter as in:
WORD - K3WWP N2OD WA8REI N2OD
NEXT - NF8M W8REI N8XMS K9EYT
(Note how N2OD is listed for both the O and D.)
You may also include comments about the challenge. Please preface any comments you want posted with "SOAPBOX:" so we will know what you want posted and what is private.
Send your results as text in the horizontal format shown above to:
E-mail: (You must type that address into your email program.)
Subject must read: (your call) NAQCC (month) Challenge
For example: K3WWP NAQCC February Challenge
All entries must be RECEIVED before the 10th of the following month at 2400Z.
All the above get a certificate and participation point.
All below get only a participation point.
Not eligible for a certificate or participation point for the following reason(s):
@ = Non-member
$ = QRO power