[TowerTalk] coax stubs /bandpass filter

[W0MU Mike Fatchett]

I don't recall seeing anything where the braid was not connected. 


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-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Jim Brown
Sent: Monday, May 24, 2010 9:59 AM
To: Tower Talk List
Subject: Re: [TowerTalk] coax stubs /bandpass filter

Hi Rag, 

What page and photo or schematic are you looking at?  Its been a few months
since I looked through his book, but I dont recall any circuits where stubs
were not somehow connected in parallel with the line. 

73,

Jim K9YC

On Mon, 24 May 2010 15:57:05 +0200, Stein Roar Brobakken wrote:

>Hi Jim

>I got his book from W2JVN now, but there is two schematic I think looks 
>like the shield of the stubs is just connected shield to shield and NOT 
>further to a BOX f.ex. to empty can with SO-239 on top...

>Am I right what I see ??? that the shield of the coaxstubs is not mixed 
>to the shield of the coax from PA ? its not look that on pictures I 
>seen from others...

>This is late into the book when you have 2nd Harmonic stubs in 
>inverted-V shape, and the shield is just connected into the top of 
>where the coax meets ....???



>73 LA6FJA Rag



>-----Opprinnelig melding-----
>Fra: towertalk-bounces at contesting.com
>[mailto:towertalk-bounces at contesting.com] P vegne av Jim Brown
>Sendt: 29. mars 2010 09:37
>Til: towertalk at contesting.com
>Emne: Re: [TowerTalk] coax stubs /bandpass filter

>On Mon, 29 Mar 2010 08:58:24 +0200 (MEST), Stein Roar  LA6FJA-K3RAG wrote:

>>Hi

>>I have made a set of coaxstubs for bandpass filter, but it is not 
>>enough
>attunation..
>>Is it normal with 20-30 db attunation ??

>Yes. See http://audiosystemsgroup.com/Coax-Stubs.pdf  This is a first 
>draft tutorial that I'm still working on.

>>We had big problems during WPX SSB as LN5O we experienced that the 
>>stubs
>didnt
>attunate enough between 20 40 & 15m...

>You need to buy W2VJN's excellent book on this topic. You can order it 
>for $20 from Inrad (the filter people). Also, there are several very 
>useful articles by N0AX in QST. They are referenced in the tutorial 
>(link above).

>73,

>Jim K9YC


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