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moleculo wrote:

"Pertaining to helically wound antennas, I don't know where you're getting your material from. Long, skinny coils used in antennas have terrible Q and are terribly inefficient compared to better designs. A helically coiled antenna is just a long skinny coil. Here's another good reference: Topband: How Helically Wound Verticals Really Work"

the reference link provides no support for your argument. a single HWMA can exceed 70% efficiency if it is not "very short" and proper attention is given to the ground. as we're talking about 27 mhz. as indicated in the original posters reference to popular wilson antennas, how 'bout we stick to the subject. the topband article is a discussion of low freq. hf antennas and you can bet the physical dimensions are an appreciable fraction of what they would be at full length.

on the other hand, a 1/4 wave HWMA at say HALF the full physical length of a quarter wave (4.5 feet) @ 27 mhz. presents much less loss and higher efficiency than say an 80M HWMA for mobile application simply because the 80M HWMA is "very short" for the operating frequency in question, and in addition would not be much more than 10-15% efficient, best case scenario. and what is "terrible Q"?. within 3 db. markers the bandwidth of the 27 mhz. model referenced above is in excess of 700 khz..

if we ditch the fixed pitch and use a stepped-pitch tesla design in winding the HWMA using multiple (4) elements @ 3/8 wavelength we can also eliminate the need for link coupling at the feedpoint to achieve a match to 50 ohm feedline and present less than or equal to a 2:1 VSWR at the band edges across 1.7 - 2.2 mhz. of bandwidth and produce a stronger far field ground wave signal than a full size 1/4 wave whip.

that's how HWMA's REALLY Work.

<blockquote data-quote="freecell" data-source="post: 150080" data-attributes="member: 30">moleculo wrote:&quot;Pertaining to helically wound antennas, I don&#039;t know where you&#039;re getting your material from. Long, skinny coils used in antennas have terrible Q and are terribly inefficient compared to better designs. A helically coiled antenna is just a long skinny coil. Here&#039;s another good reference: Topband: How Helically Wound Verticals Really Work&quot;the reference link provides no support for your argument. a single HWMA can exceed 70% efficiency if it is not &quot;very short&quot; and proper attention is given to the ground. as we&#039;re talking about 27 mhz. as indicated in the original posters reference to popular wilson antennas, how &#039;bout we stick to the subject. the topband article is a discussion of low freq. hf antennas and you can bet the physical dimensions are an appreciable fraction of what they would be at full length.on the other hand, a 1/4 wave HWMA at say HALF the full physical length of a quarter wave (4.5 feet) @ 27 mhz. presents much less loss and higher efficiency than say an 80M HWMA for mobile application simply because the 80M HWMA is &quot;very short&quot; for the operating frequency in question, and in addition would not be much more than 10-15% efficient, best case scenario. and what is &quot;terrible Q&quot;?. within 3 db. markers the bandwidth of the 27 mhz. model referenced above is in excess of 700 khz..if we ditch the fixed pitch and use a stepped-pitch tesla design in winding the HWMA using multiple (4) elements @ 3/8 wavelength we can also eliminate the need for link coupling at the feedpoint to achieve a match to 50 ohm feedline and present less than or equal to a 2:1 VSWR at the band edges across 1.7 - 2.2 mhz. of bandwidth and produce a stronger far field ground wave signal than a full size 1/4 wave whip.that&#039;s how HWMA&#039;s REALLY Work.</blockquote>

[QUOTE="freecell, post: 150080, member: 30"] moleculo wrote: "Pertaining to helically wound antennas, I don't know where you're getting your material from. Long, skinny coils used in antennas have terrible Q and are terribly inefficient compared to better designs. A helically coiled antenna is just a long skinny coil. Here's another good reference: Topband: How Helically Wound Verticals Really Work" the reference link provides no support for your argument. a single HWMA can exceed 70% efficiency if it is not "very short" and proper attention is given to the ground. as we're talking about 27 mhz. as indicated in the original posters reference to popular wilson antennas, how 'bout we stick to the subject. the topband article is a discussion of low freq. hf antennas and you can bet the physical dimensions are an appreciable fraction of what they would be at full length. on the other hand, a 1/4 wave HWMA at say HALF the full physical length of a quarter wave (4.5 feet) @ 27 mhz. presents much less loss and higher efficiency than say an 80M HWMA for mobile application simply because the 80M HWMA is "very short" for the operating frequency in question, and in addition would not be much more than 10-15% efficient, best case scenario. and what is "terrible Q"?. within 3 db. markers the bandwidth of the 27 mhz. model referenced above is in excess of 700 khz.. if we ditch the fixed pitch and use a stepped-pitch tesla design in winding the HWMA using multiple (4) elements @ 3/8 wavelength we can also eliminate the need for link coupling at the feedpoint to achieve a match to 50 ohm feedline and present less than or equal to a 2:1 VSWR at the band edges across 1.7 - 2.2 mhz. of bandwidth and produce a stronger far field ground wave signal than a full size 1/4 wave whip. that's how HWMA's REALLY Work. [/QUOTE]

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