Thursday, December 9, 2010

A Ham's Night Before Christmas

A pleasant video to share with your amateur radio friends. Wishing everyone a Merry Christmas and Happy New Year.

How to Use MUF

Maximum Usable Frequency (MUF) describes, in radio transmission, using reflection from the regular ionized layers of the ionosphere, the upper frequency limit that can be used for transmission between two points at a specified time. This index is especially useful in regards to shortwave transmissions.

Note: MUF is a median frequency applicable to 50% of the days of a month, as opposed to 90% cited for the lowest usable high frequency (LUF) and the optimum traffic frequency (FOT).

Operating near the MUF often gives excellent results because of absorption is lowest just below the MUF. Low takeoff angles also raise the MUF because the signals will need less bending to complete a hop. Here are two examples;
*If the MUF over a certain path is 19MHz, the best band for that path is 17 meters.
*If the MUF over a certain path is 25MHz, the best band for that path is 12 meters.

source used; Federal Standard 1037C, titled Telecommunications

My Stamp Collecting Blog

Counter Added January 1, 2011

free counters

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.

Terms of Service

[In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit, for research and/or educational purposes. This constitutes 'FAIR USE' of any such copyrighted material.]
I am not responsible for any thing that happens to your mental health, computer and all personal property because you visited my site.
This site is a collection of some things sent to me by e-mail, obtained from other blogs and the internet. If there is a picture or quote that is copyrighted to you let me know and I will remove your item .
Thoughts expressed in my blog are just that . I give My Opinion on the many events, products and how too, reported by the media and other web-sites.
Do not use this blog site to obtain weather events or disasters information. What I post may not be correct. Always get information from the proper media, weather (NWS)(NOAA)
Pacific Tsunami Warning Center and USGS sites