[ARC5] Why an UNUN?

[Mike Hanz]

The manual gives a range of values, John.  The upper limit is around 13 
ohms resistive, but it also expects a capacitive component.  See para 
1-28 in the ARC-5 manual, although the SCR-274-N and ATA manuals contain 
the same data, IIRC.

On 10/24/2012 6:06 PM, J. Forster wrote:
> Where did the 12 Ohms, resistive, come from? A manual? The value of a
> dummy load? Where?
>
> -John
>
> ===========
>
>
>> I gather, then, that the ARC-5 and SCR-274 transmitters
>> are designed to work into an impedance around 12 Ohms?
>> And therefore, addition of the 4:1 Un-Un will allow the
>> command sets to load properly into the usual dipole?
>>
>> * * * * * * * * * * *
>> * 73 - Mac, K2GKK/5 *
>> * (Since 30 Nov 53) *
>> * k2gkk at hotmail.com *
>> * Oklahoma City, OK *
>> * USAF & FAA (Ret.) *
>> * * * * * * * * * * *
>>
>>
>>> From: brianclarke01 at optusnet.com.au
>>> To: arc5 at ix.netcom.com
>>> Date: Thu, 25 Oct 2012 08:22:30 +1100
>>> CC: arc5 at mailman.qth.net
>>> Subject: Re: [ARC5] Why an UNUN?
>>>
>>> And a third reason, Dave,
>>>
>>> You can fit an appropriate Unun inside the BC-442 or equivalent.
>>>
>>> And the turns ratio of the unun will be 2:1 because you require 24 V
>>> across 50 Ohm to deliver 12 W. Using a small ferite core can allow this
>>> unun to cover most of the ham bands that Command sets can work - 160, 80
>>> and 40. So, no need for external components or any per set
>>> modifications.
>>>
>>> 73 de Brian, VK2GCE.
>>>
>>>> David Stinson <arc5 at ix.netcom.com> wrote:
>>>>
>>>>
>>>> Found a WiFi hot spot for my laptop. :-)
>>>>
>>>> Couple of reasons for using the series cap
>>>> and broadband UNUN:
>>>>
>>>> Assuming a resonant antenna, does not require
>>>> one to build and/or add an external tuning network.
>>>> More important: It's simple, easy and cheap.
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>
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