220 Mhz Yagi Antennas- The 7 Things You Must Know Before You Buy Your Next One.


by Gary Tootle - Date: 2010-08-31 - Word Count: 614 Share This!

Every year thousands of antennas fail due to high wind, heavy snow, ice loading and other severe weather situations. 220 MHz antennas, because of their large physical size, are particularly vulnerable to weather related failure.

That's not all: when you combine these reliability issues with your performance expectations (you want the antenna to perform reliably for many years, right?) your choice of antenna manufacturer for 220 MHz applications becomes especially important.

This clearly isn't the place to try and save $5 on an antenna or base your buying decision on "it's the brand we've always used" or because "the vendor's in our system".

Let's face it, antenna failures represent a totally unnecessary inconvenience and expense for system operators. The high cost of travel and manpower to replace a failed unit far exceeds any saving realized on the initial purchase of an 'economy' antenna.

You want to install the antenna once and forget about it. Right?

So to help make sure we get it right the first time, here are the 7 things you must know before you buy your next 220 MHz Yagi antenna:

1. Material. Insist on an aircraft quality 6061-T6 aluminum frame. This is strong and light. The boom (mast) should have a minimum of 11/2" OD material with heavy duty " elements and dipole. Remember, this antenna has to survive severe wind, often times with ice and frost build up.

2. Manufacturing. All components should be machined on CNC equipment for consistency and precision. This ensures every antenna is a clone of the next. You can depend on the performance to be exactly the same from antenna to antenna.

3. Construction. Insist on fully TIG-welded construction for the entire antenna. TIG welding provides vital strength and the antenna becomes electrically one piece. Forget bolted together antennas and antennas with bolted on brackets for this frequency.

4. Finish. Black anodized or black thermoset Polymer Coating (Powder coated). This helps reduce ice build up and protects against environmental degradation. Anodizing is the best here but the thermoset polymer is an excellent second. The black color absorbs heat and helps melt any ice or hoar frost that builds up on the antenna.

5. Feedline. Purchase your antennas with the correct length feedline built into the antenna right from the factory. Factory installed, sealed and tested integral feedlines offer many benefits and completely eliminate the requirement for field installed feed cables. This is especially wonderful for cookie cutter installations. You take the antenna out of the box and it's installed in less that 15 minutes. There's no feedline to build and install!

6. Mounting hardware. A heavy duty steel bracket that easily permits horizontal or vertical polarization should be included with the antenna. You also want a hot dipped galvanized bracket with minimum " galvanized bolts (not stainless steel). Remember, these are big antennas with high wind loading. A wimpy, light duty bracket can't cut it at the 220 MHz frequency.

7. Warranty. The Antenna should come with a minimum 5 year warranty. If it's built right then the manufacturer should stand behind it. If it doesn't have at least a 5 year warranty you should be asking: why?

(Free Bonus Tip #8) be sure to insist that each and every antenna is tested and certified by the manufacture prior to shipping! Nothing worse that getting to the install site and having a DOA antenna.

If you consider the above recommendations when choosing your next 220 MHz Yagi antennas, your end result will be drastically improved reliability and improved system performance. Besides, who needs a phone call on your day off, telling you that an antenna has failed and the system is down. I know you don't want to take that call and it definitely won't be you if you heed these recommendations.

Related Tags: 220 mhz antenna, 220 mhz yagi antenna, 220 mhz antennas

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