Friday, September 11, 2009
VHF QSO Party
http://www.arrl. org/contests/ rules/2009/ sepvhf.html
What follows is a 5-minute primer on how to get started in VHF .
Remember to get on and have some fun this weekend with the ARRL VHF QSO Party. All bands from 6m, 2m and on up are in play. Operate as much or as little as you like. USB mode is what 80-90% of the contesters use, with horizontally- polarized antennas.
Even modest horizontal loops will work stations out 50-150 miles. I know this because in my first contest (Sept. 2003) I had only horizontal loops for 6 and 2m, and I worked some stations as far away as 300 miles, without any special enhancement. Using headphones and keeping the squelch low is essential for digging out those distant, light signals. You'll be amazed how far some of those S1 signals will travel, if you listen carefully. Also be aware that on VHF/UHF bands, propagation is usually better after sunset and well into the morning hours. If I only had a few hours to spend, I'd operate from about 7-11pm, and then again from about 7-11am.
Those with beams and/or higher antennas (above trees and obstructions) can get out farther. Bread and butter VHF bands are 6 and 2 meters. At least 90% of us have one or both of those bands.
The basic contest exchange is callsign and grid square. Log the callsign of the station you worked, what band it was on, their grid square and the time of the QSO within a minute or two. Most QSO's are voice mode, but there is plenty of CW activity, as well. Each year, more and more ops benefit from using the various digital modes.
On 6m, you operate from 50.125 up to about 50.175 or so. If there's a good band opening, activity can spread above 50.200.
On 2m, the call freq. is 144.200, but tune around and call CQ between about 144.150-144. 250. Maybe more like 144.170-144. 230 if the band isn't that busy.
Avoid the temptation to use 144.200 too much. Far better to tune around and find some elbow room.
On 70cm, the SSB call freq. is 432.100 MHz. Hardly anyone calls CQ on 70cm because of the pointyness of horizontal beams. Standard practice is to do your CQ'ing on either 6 and/or 2 meters, and then "work up the bands" with the station you've contacted. Experienced hams will be happy to help you get your feet wet. VHF/UHF contests are far more casual than HF, and we can always use newcomers.
If you are limited to FM gear, then you'll find the most activity on 146.550, followed by 223.500 on the 1.25cm band. You may also find some activity on the 6m FM call freq. of 52.525 and the 70cm call freq. of 446.000. On FM, use vertical polarization.
VHF/UHF contesting levels in the entire Midwest have really improved the past year. 2010 should see continued improvement.
HOW TO READ PROPAGATION NUMBERS
The A index [ LOW is GOOD ]
- 1 to 6 is BEST
- 7 to 9 is OK
- 11 or more is BAD
Represents the overall geomagnetic condition of the ionosphere ("Ap" if averaged from the Kp-Index) (an average of the eight 3-hour K-Indices) ('A' referring to amplitude) over a given 24 hour period, ranging (linearly) typically from 1-100 but theoretically up to 400.
A lower A-Index generally suggests better propagation on the 10, 12, 15, 17, & 20 Meter Bands; a low & steady Ap-Index generally suggest good propagation on the 30, 40, 60, 80, & 160 Meter Bands.
SFI index [ HIGH is GOOD ]
- 70 NOT GOOD
- 80 GOOD
- 90 BETTER
- 100+ BEST
The measure of total radio emissions from the sun at 10.7cm (2800 MHz), on a scale of 60 (no sunspots) to 300, generally corresponding to the sunspot level, but being too low in energy to cause ionization, not related to the ionization level of the Ionosphere.
Higher Solar Flux generally suggests better propagation on the 10, 12, 15, 17, & 20 Meter Bands; Solar Flux rarely affects the 30, 40, 60, 80, & 160 Meter Bands.
K index [ LOW is GOOD ]
- 0 or 1 is BEST
- 2 is OK
- 3 or more is BAD
- 5 is VERY VERY BAD
The overall geomagnetic condition of the ionosphere ("Kp" if averaged over the planet) over the past 3 hours, measured by 13 magnetometers between 46 & 63 degrees of latitude, and ranging quasi-logarithmically from 0-9. Designed to detect solar particle radiation by its magnetic effect. A higher K-index generally means worse HF conditions.
A lower K-Index generally suggests better propagation on the 10, 12, 15, 17, & 20 Meter Bands; a low & steady Kp-Index generally suggest good propagation on the 30, 40, 60, 80, & 160 Meter Bands.
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