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Re: [TowerTalk] Modifying Comtek 4-square controller(relay unit) for a d

To: "'Michael Tope'" <W4EF@dellroy.com>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] Modifying Comtek 4-square controller(relay unit) for a different band?
From: "Tim Duffy" <k3lr@k3lr.com>
Date: Thu, 18 Nov 2021 15:58:27 -0500
List-post: <mailto:towertalk@contesting.com>
There is a reason DX Engineering/Comtek does not sell Comtek 4 square boxes 
above 14 MHz. The inductor and capacitor values are very low and losses can be 
a real problem. We are still trying - but it is not as easy as dividing down 
the values. Believe me - we tried.

73
Tim K3LR @ DX Engineering

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Michael 
Tope
Sent: Thursday, November 18, 2021 3:37 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Modifying Comtek 4-square controller(relay unit) for a 
different band?

Hi Mike,

I suspect the Comtek Hybrids look something like what is described here:

https://www.egloff.eu/index.php?option=com_content&view=article&id=4&Itemid=136&lang=en

If so, you'll need to change the L & C values accordingly to create a 90 
deg phase shift at 28 MHz instead of at 14 MHz.

73, Mike W4EF...............

On 11/18/2021 10:51 AM, Mike VE9AA ve9aa@nbnet.nb.ca wrote:
> To standardize my little vertical based antenna farm, I am wanting to 
> buy an ACB-10 for 10m, but they are no longer available and I cannot 
> find any other make/model of a 4-square system for 10m anywhere on 
> planet Earth, so is it possible to buy a 20m Comtek relay unit and put 
> it on 10m?
>
> If so, what all is involved?
>
> Anyone have any working knowledge of the outside relay boxes?  I 
> presume it must be something to do with the toroids, but I've never 
> had one apart, nor do I even have a schematic for the outdoor unit.
>
> Thanks !
>
> CU (all of a sudden!) in the next one.
>
> Mike VE9AA
> p.s.-my backup plan is just to build another K1WA/K8UR/K3LR/N6LF 
> vertical dipole array.

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