[Amps] Alpha Input SWR

[Hardy Landskov]

My K3 has a real problem driving the 8410. Even with the matching network it 
has a problem I can't seem to understand.
The SWR on 12 m is over 3:1.
Hardy N7RT

----- Original Message ----- 
From: "Peter Voelpel" <dj7ww at t-online.de>
To: <amps at contesting.com>
Sent: Friday, January 09, 2015 7:26 PM
Subject: Re: [Amps] Alpha Input SWR


> What is bad about SWR <2?
>
> 73
> Peter
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Hardy 
> Landskov
> Sent: Samstag, 10. Januar 2015 03:09
> To: Charles Henry; ed at w0yk.com; amps at contesting.com
> Subject: Re: [Amps] Alpha Input SWR
>
> Charly,
> Changing the length of coax to the input will not change the SWR. Look at 
> a
> Smith Chart.  Only dealing with the tube's capacitance along with the 50 
> ohm
>
> resistor to ground with a suitable matching network will lower the input
> SWR. I wish Alpha and whoever is the designer of amps now would  match the
> input to every band but they don't. It's not that much more money to do it
> right.
> I am going to sell this 8410 because of that reason. What a piece of junk.
> 73 HNY to all....  Hardy N7RT
>
> ----- Original Message ----- 
> From: "Charles Henry" <k4vud at hotmail.com>
> To: <ed at w0yk.com>; <amps at contesting.com>
> Sent: Friday, January 09, 2015 3:15 PM
> Subject: Re: [Amps] Alpha Input SWR
>
>
>> All I have been able to do is to cut and try the length of the drive coax
>> from the radio RF output to the amplifier input.
>> Sri forgot the lengths and never got 1:1 anyway.   Charly
>>
>>> From: ed at w0yk.com
>>> To: amps at contesting.com
>>> Date: Fri, 9 Jan 2015 08:44:18 -0800
>>> Subject: [Amps] Alpha Input SWR
>>>
>>> What experience can anyone share for reducing the input SWR on Alpha
>>> amps?
>>> On some bands the input SWR is 1.6:1 or higher on our 86A, 87A and 91B
>>> amps.
>>>
>>> Thanks,
>>> Ed W0YK
>>>
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>>
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