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Author Topic: looking for a good receiving antenna  (Read 16247 times)

Posts: 42

« Reply #30 on: January 16, 2013, 09:51:54 AM »

Does anyone know how the HI Z triangle array performs in an urban environment with minimum (50 feet) spacing?  I would think nearby objects would affect the pattern/phasing although everyone's situation is different.  I too am always looking to improve low band reception.

Read the documents on the HI Z website. My reading of them suggests that a typical urban environment will powerfully affect the way such an array will work. Arrays need, for example, to be a minimum of 200 ft. from a transmitting antenna and any metal objects near an array will affect its performance.

Just did that.  I still wonder if anyone in an urban environment tried this with even a modicum of success.
73, Anthony

Posts: 2439

« Reply #31 on: January 16, 2013, 10:34:46 AM »

Since you have nothing now, I suggest you start simple to see what problems you have, if any.  A simple wire antenna will work.  There are many choices, and they are cheap.  Don't use an end fed or OCF antenna as those may pick up noise from the AC ground system.  If you discover you have noise problems, then you can decide what type antenna you need to solve that problem. 

All antennas designed specifically for receiving have some kind of limitations.  Most are frequency limited and are low gain.  Receiving antennas are able to obtain better signal to noise ratio by narrowing the receive beamwidth, or by providing a null centered on a single noise source.  That means you need multiple antennas or an ability to rotate a single antenna. 

Some, like small loops, have very narrow bandwidth and you have to retune them when changing frequency, even for small frequency changes.   Other receiving antennas like Beverages, BOGs, EWE, K9AY, flags, or pennants, may work over a range of frequencies, like maybe 160 thru 40 meters.  To get higher frequencies, you need to make them smaller or shorter. 

A small loop can reduce a man made noise source by turning the loop such that the antenna null aligns with the noise source.  If the noise is coming from more than one direction, a loop can't eliminate that.  None of the receiving antennas will remove noise if the noise source in the path of the signal being received.  Also none of the receiving antenna will work well if the noise source is right next to the antenna.

Atmospheric noise is difficult to reduce.  The only way to do that is to have an antenna with a narrow beamwidth.  Fortunately atmospheric noise is usually only a problem on 160, 80, and 40 meters.  A small loop won't work well for eliminating atmospheric noise because it doesn't have a narrow beamwidth and atmospheric noise comes from all directions.

Jerry, K4SAV
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