Genradio

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General Radio Interest


  • March 6th, 2011 Interesting Tip from Tigertek
    • Removing Copper Antenna Tarnish
      • Copper tubing or large-diameter bare copper wire is sometimes used to construct small VHF and UHF antennas of various types, because copper is a good conductor that is easy to bend and easy to solder. However, unprotected copper surfaces soon tarnish when exposed to the elements, increasing RF skin resistance. Furthermore, it is difficult to establish a low-resistance connection to tarnished copper if a copper antenna that has tarnished is subsequently modified. Tarnish can be sanded or scraped off copper surfaces, but sanding or scraping removes some untarnished copper below and it is difficult to sand or scrape cracks and other irregular surfaces. An easier method is to apply a generous coating of salt to a quarter-section of lemon and then rub the lemon over tarnished areas. Flood the copper and especially any insulators with water afterward to remove residual lemon juice and salt and you will have a clean, bright, and like-new copper surface. ©2005 Tigertek, Inc. All rights reserved.
  • January 18th, 2009
    • Interesting Factoid from Tigertek:
      • Why Copper Ground Rods? 'Copper ground rods' actually are copper clad steel, because copper rods would be too soft to drive in the ground and unnecessarily expensive. Most people probably assume that copper is used because of its high conductivity. That is a slight added advantage, but not the real reason. The resistance of the soil surrounding a ground rod is so high compared to the resistance of any metal that the series resistance of a rod and the soil surrounding it would be almost the same regardless of the metal used. The real reason copper is used is copper a noble metal that has high corrosion resistance. It becomes a cathode when joined together with a less noble metal such as steel in the presence of an electrolyte such as moist soil. The less-noble steel becomes a sacrificial anode that corrodes away first, leaving a relatively corrosion-free copper shell in contact with the soil.
  • November 25th, 2007
    • Going on a road trip? Don't forget your CB Radio
  • November 18th, 2007
  • November 10th, 2007 Ross (RC4455) - I've Been reading a lot of articles on the popularity of FRS and GMRS FM radio especially in emergency communications. There have been 10's of millions of these cheap handheld FRS and more recently GMRS radio sold in North America. What is most interesting is the exaggerated claims of range by the manufacturers. Recent articles in Popular communications magazine from REACT have shown that the organization has moved significantly toward FRS/GMS and amateur radio and away from their roots as a CB radio emergency organization. To me this is bordering on the patently stupid.
    • FRS and GMRS have severely limited range and are subject to line-of-site condition.
    • UHF frequencies don't penetrate vegetation or other obstructions very well
    • The power limitations are stiff - just 0.5 watts for FRS and 2 watts for GMRS in Canada (and no repeaters allowed either). No external antennas are allowed either. UHF FM is very quiet compared to an HF AM signal like CB AM however CB radio has some major advantages especially CB SSB.
    • For emergency communications use a cell phone. Really! Use a cell phone! But in those rare circumstances that cell reception is poor a mobile mounted CB radio even just an AM unit will be useful for 8-10 KM or more even at the noisy Solar Cycle peak. And every trucker on the road has a CB radio probably set to Ch 19. Where REACT is still monitoring CB CH9 base stations will easily picked up a signal for dozens of miles on AM. CB CH9 is an official emergency channel. FRS / GMRS has no official emergency channel.
    • REACT and other organizations should be encouraging CB SSB over CB AM, FRS and GMRS for several key reasons.
      • Single Side Band transmission is four times more effective at the same power level.
      • The noise level is half that of AM.
      • The legal power limit is 3 times that of AM, 12 watts vs 4 watts. 40Km mobile to base is not uncommon.

Obviously, a good CB SSB mobile rig and antenna cost more the FRS GMRS but then it's useful range and talk power are far greater. For personal communications at the park or the mall FRS/GMRS are great. I use them all the time for that purpose.

A lot of mention is made is made about CB that states that skip increases noise levels and therefore reduces range. This may be true when trying to talk to a specific person some distance away but in an emergency siutations you want to contact ANYBODY! Generally speaking in HF radio, if you can hear them they can hear you. And that's the whole point of emergency radio communications.

  • November 4th, 2007
    • Check out CB Radio Magazine online and read some interesting and informative articles all relating to CB Radio antennas, radios, operating issues and trends. Next online issue due mid-November.
  • September 24th, 2007
    • A recent blog on one man's history and current interest in 11m DX'ing from a European perspective.
  • September 9th, 2007
    • Here's a site from Europe of some hardcore 11m DXers.
  • September. 1, 2007
    • The Aurigids Meter Shower Photo Gallery,
  • CB Radio Short Stories by Jeff Alan - Interesting read about one man's experience in the hobby
  • The United States Radio Frequency Allocation chart
  • The Radio Amateurs of Canada website
  • NASA 3D Satellite tracking site JAVA plugin needed
  • Interesting Daily radio fact
  • Information by Industry Canada for Radio Operators
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