Bow Tie antenna calculations

[Martin VK6ZMS]

Regards

Martin 

VK6ZMS

[Randall Wayth]

Good luck everyone with those 3rd, 4th and 5th significant figures on your mm measurements!

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[RavenX]

You'll need one of these Randall ! 😎

Renishaw XL-80 490 g Laser Measurement System-2.

Cheers

(VK6ST).

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[Denis Brown]

Hello Martin et al

While not a bow tie, I made a variant of the biquad which has demonstrated good performance.   Could be interesting to compare the performance of the two antennas.

My variation is to replace the square "quad" elements with the equivalent circular elements.   My reason for doing so was to be able to easily adjust the element dimensions.   I found that I was unable to achieve good VSWR by un-bending and re-bending the elements.   After a few attempts the nice square shapes had "wrinkles" at the corners.

Using circular elements meant that the exact dimensions could be achieved by desoldering and resoldering an element end into a slightly different location- longer or shorter as needed.

My BiQuad and the variant is based on Andrew VK1AD's 23cm antenna for SOTA work.   Mine uses the same double sided PCB as a ground plane.   If anyone is interested I may be able to find some photos of the finished product.   The Spotlight company had an ideal snap-on-lid rectangular plastic "food storage container" to provide waterproofing.

73

Denis

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[Martin VK6ZMS]

Hi Dennis,

It would be great to see it at WH if you’re in VK ?

I hope to be there next Saturday.

Cheers 

Sent from my iPhone 

On 11 Jul 2026, at 10:16 am, Denis Brown <kaneko...@gmail.com> wrote:



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[Denis Brown]

Thanks for your interest, Martin

Will see what can be arranged.

I am in JA for another 5 months but may be able to get 1st or 2nd harmonic to locate it and help to get it up to WH.   May be possible for next Saturday.

73

Denis

On Saturday, July 11, 2026, Martin VK6ZMS <vk6...@gmail.com> wrote:

Hi Dennis,

It would be great to see it at WH if you’re in VK ?

I hope to be there next Saturday.

Cheers 

Sent from my iPhone 

On 11 Jul 2026, at 10:16 am, Denis Brown <kaneko...@gmail.com> wrote:



Hello Martin et al

While not a bow tie, I made a variant of the biquad which has demonstrated good performance.   Could be interesting to compare the performance of the two antennas.

My variation is to replace the square "quad" elements with the equivalent circular elements.   My reason for doing so was to be able to easily adjust the element dimensions.   I found that I was unable to achieve good VSWR by un-bending and re-bending the elements.   After a few attempts the nice square shapes had "wrinkles" at the corners.

Using circular elements meant that the exact dimensions could be achieved by desoldering and resoldering an element end into a slightly different location- longer or shorter as needed.

My BiQuad and the variant is based on Andrew VK1AD's 23cm antenna for SOTA work.   Mine uses the same double sided PCB as a ground plane.   If anyone is interested I may be able to find some photos of the finished product.   The Spotlight company had an ideal snap-on-lid rectangular plastic "food storage container" to provide waterproofing.

73

Denis

On Sat, Jul 11, 2026 at 8:57 AM Randall Wayth <randal...@gmail.com> wrote:

Good luck everyone with those 3rd, 4th and 5th significant figures on your mm measurements!

On Fri, 10 Jul 2026 at 22:09, Martin VK6ZMS <vk6...@gmail.com> wrote:

Regards

Martin 

VK6ZMS

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[Dave VK6KV]

Also why is the first expression multiplied by 1000mm? That would give the width in m x mm, or some hybrid area unit??

If instead they meant multiply the wavelength by 1000 (unit-less) to convert from m to mm then why -not- for the other two dimensions?

Yes it’s trivial to work out what was meant in this example but it’s also pretty easy to get the maths right in the first place.

Cheers, Dave VK6KV

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[Mark Bosma]

A similar antenna is being used very successfully by SOTA operators in the East on 2m.  Dubbed the Hourglass Antenna, this very simple, light-weight and collapsable arrangement is fed on one blunt end of the bowtie - and in testing by a number of operators over this way, seems to have comparable gain to a 4 element Yagi, but with only a fraction of the bulk.  Here's the original design info:  https://dl3tu.wordpress.com/2026/02/15/the-hourglass-loop-antenna-for-2-metres/

The version being used over this way for SOTA consists of a couple of  wooden dowels pushed through a vertical insulator, with hook-up wire as the radiator.

...and.... dimensions to only three significant figures :)

Cheers,

Mark Bosma

VK2KI / VK6QI

Beautiful South Bowning NSW

mark....@icloud.com

bit.ly/CQQRSWebsite

0418161773

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