[Amps] RF parts and parasitics!!

[Carl]

I fail to see the phrase "very high" anywhere in that article.

Perhaps you can assist these tired old eyes.

Carl
KM1H



----- Original Message ----- 
From: "Bill, W6WRT" <dezrat1242 at yahoo.com>
To: <amps at contesting.com>
Sent: Wednesday, August 26, 2009 2:29 PM
Subject: Re: [Amps] RF parts and parasitics!!


> ORIGINAL MESSAGE:
>
> On Wed, 26 Aug 2009 12:54:06 -0500, "Gary Schafer" 
> <garyschafer at comcast.net>
> wrote:
>
>>
>>If drawing a conclusion from a test you must first have the proper test
>>setup with the proper equipment. Using an SWR bridge to determine if the
>>input impedance of the tube is constant is not the right equipment.
>
> REPLY:
>
> I disagree. An SWR bridge will indeed show the AVERAGE impedance over the 
> RF
> cycle, whether drawing grid current or not.
>
> W8JI's statement was that when grid current is NOT drawn, the cathode-grid
> impedance is very high. Since without grid current, the cathode-grid 
> impedance
> is essentially the SAME over the RF cycle, an SWR bridge will indeed show 
> that
> the input impedance is still low even with no grid current. That was my 
> point.
>
> 73, Bill W6WRT
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps