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Re: [Amps] Attenuator needed

To: amps@contesting.com
Subject: Re: [Amps] Attenuator needed
From: Vic K2VCO <vic@rakefet.com>
Date: Mon, 15 Nov 2010 13:45:01 -0800
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I need about 10w drive for my 813's, so the 6 db attenuator will bump this up 
to 40w, 
dissipating 30w. That should be fine, especially since it will be used for CW.

On 11/15/2010 1:33 PM, Larry Benko wrote:
>    Vic,
>
> Be careful as the attenuators are rated for dissipation and not power
> input. Therefore a 50W 3dB attenuator is usable with a 100W input where
> a 50W 6dB attenuator is only usable with a 66.7W input.  Hopefully that
> works fine for you.  Also you might have duty cycle on your side
> depending on the mode of transmission you use.
>
> 73,
> Larry, W0QE
>
> On 11/15/2010 2:06 PM, Vic K2VCO wrote:
>> Thanks! I just ordered the 6 db version. Lots of interesting stuff there.
>>
>> On 11/15/2010 12:54 PM, Jim Barber wrote:
>>> Henry radio has been selling some Florida RF attenuators on fleaBay for
>>> reasonable prices.
>>>
>>> http://cgi.ebay.com/New-50-Watt-Hybrid-30-dB-50-ohm-Attenuator-/390115387682?pt=LH_DefaultDomain_0&hash=item5ad4b06922
>>>
>>> If that URL doesn't work, find Henry Radio's eBay store and use the
>>> search term attenuator in the in-store search box.
>>>
>>> I've bought several Florida RF parts from them recently and have been
>>> happy with the transactions.
>>>
>>> 73,
>>> Jim N7CXI
>>>
>>> On 11/15/2010 12:38 PM, Vic K2VCO wrote:
>>>> I made a 6 db attenuator for the input of my grid-driven amplifier in 
>>>> order to bring the
>>>> drive requirement up a bit and to provide a better SWR for the exciter 
>>>> during tuning. I
>>>> used some film resistors from Mouser. I suspect that these have a low 
>>>> voltage rating,
>>>> because one of them shorted after a few minutes of 10-meter operation. 
>>>> They didn't show
>>>> any sign of heating, so I think it was a voltage/frequency issue and not 
>>>> simply overheating.
>>>>
>>>> Anyway, I need a 50-ohm attenuator that can dissipate about 40 watts and 
>>>> can be used at
>>>> HF. Anything from 3 to 6 db will work. I had a Henry solid-state amp that 
>>>> had a couple of
>>>> these, which bolted to the heat sink. Does anyone know where I can buy 
>>>> such a thing, or
>>>> how to make one from reasonably priced parts?
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-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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