For those getting serious about "wire" antennas there is some free antenna simulating software that I have used and found to be quite good.  It will calculate rabbit-ears, beverages, yagis, whips, wire loops, flags, moxons....lots.   If you are designing an antenna for the commercial FM band then it is very useful.  I used it for ham radio antennas and found that the performance of the real antenna closely matched the software predictions.  It comes with a number of example antennas which are useful for user training and as project templates.

The software runs on windows and is called mMANA-GAL.  It is available for free download from http://gal-ana.de/basicmm/en/  .  The download link is at the bottom of the (quite long) page. 

To use it, you need to specify the three-dimensional end points of each element (wire) and the element characteristics such as metal used and diameter.  You can put resistors, inductors and capacitors into the build - good for beverages and directional loops.  The software will show the resonant frequency(s), impedance, bandwidth, directional pattern, etc.  It even has an optimize function to do some of the donkey-work for you.

It is not good for magnetic loop antennas but there are a number of magnetic loop calculators that can be found using a search engine.

May your QRM always be below your noise floor,

Ray

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From: main@UltralightDX.groups.io <main@UltralightDX.groups.io> on behalf of Paul Blundell <tanger32au@...>
Sent: Wednesday, 8 April 2020 1:23 PM
To: main@ultralightdx.groups.io <main@ultralightdx.groups.io>
Subject: Re: [UltralightDX] Low Cost FM Aerial Testing – April 2020

 

Thanks for the reply Kevin.

I aim to undertake some more testing of this when I can get outside.

On Wed, Apr 8, 2020 at 1:25 PM kevin asato <kc6pob@...> wrote:

i tend to prefer rabbit ears myself as they are easy to rotate as well as position the antenna elements at different angles to aid reception - either flavor, HD or non-HD for those that care about package labels. RF does not make the distinction !!. In the extreme case, a large outdoor TV antenna works well, too. Obviously the outdoor TV antenna is just not as portable but aids in DX as the FM broadcast band in Los Angeles is full.

73,

kevin

kc6pob

On Tue, Apr 7, 2020 at 1:20 PM Paul Blundell <tanger32au@...> wrote:

Over the past few days, I have been testing a few different low cost / simple aerials for use on the FM broadcast band (87.5-108MHz).

 

All these aerials have a cost of under $10, the idea of this test was to see which one would do the best job of pulling in signals on a range of test frequencies, these are a mix of community stations and also some commercial stations from both the North West and South of the state.

 

The table below shows the results of each aerial on each frequency. All stations were checked on multiple radios at different times of the day and night to account for any differences, the results below are the best each aerial was able to pull in each station during these times.

 

Normal in-built whip

3M of wire hanging vertically from a window.

$6 VHF/UHF TV Rabbits Ears

1/4 wave whip

1/8 wave whip

FREQUENCY - STATION	Standard Whip	3M Wire	Rabbits Ears	1/4 Wave Whip	1/8 Wave Whip
087.8MHz - LC FM	0	5	5	3	3
095.3MHz - TAMAR FM	0	5	6	6	5
096.9MHz - MEANDER VALLEY FM	0	2	2	1	2
098.9MHz - 7AD	0	1	0	2	1
101.7MHz - SEA FM BURNIE	0	1	1	1	0
105.7Mhz - SBS Hobart	0	0	0	0	0
107.7MHz - SEA FM DEVONPORT	0	0	1	2	0

Overall, the four external aerials all preformed much better than the built-in whip. Both the Rabbits Ears and 1/4 wave whip performed much the same and tied for the best signal levels, the Rabbit Ears having the advantage of being smaller and easier to move around. The 3M length of wire was not far behind with the 1/8 wave whip being the poorest of these four, it still however pulled in four stations that were missing on the standard whip.

 

These tested were preformed at home (due to the current COVID-19 restrictions) I am planning on repeating these tests again in the future for a lookout and seeing what difference this makes.

 

 

 

https://ultralightradiodxing.blogspot.com/2020/04/low-cost-fm-aerial-testing-april-2020.html

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Paul - Moderator
UltralightDX

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Paul

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Paul - Moderator
UltralightDX