[TenTec] INRAD Omni VI roofing filter kit - success

[Ken Brown]

Hi Rick,

Yes I understand where that Inrad mod puts the new roofing filter. I 
guess what I did not understand is that with only one NAR button on the 
Omni VI (non version 3 or Plus) you sort of have to leave out the 
"regular" narrow 9 MHz optional filter. ... Now I get it. I still wonder 
whether Jason ever had a narrow filter in the normal 9 MHz IF optional 
narrow filter position, and how the performance amongst 40 meter SWBC 
stations and strong amatuer signals compared with the new mod and the 
filter earlier on in the IF. His post sounded to me like he had never 
had a filter in the regular narrow slot, and went straight to the Inrad 
mod. I guess I may have read somthing into his post that wasn't really 
there.

DE N6KB

>Ken I think that you may have misunderstood where the roofing filter is in
>the "food chain".  The "stock" Omni V and VI have 2-pole filters at the very
>front end of the 9 MHz IF board.  These filters are 12 to 15 kHz (yes that's
>kHz) wide and hard wired.  Their purpose is a first line of defence for
>nearby signals. 
>
>The InRad mod goes in front of this filter and gives the operator the option
>to significantly narrow the front end of the 9 MHz board.  It's location is
>between the RF board and the 9 MHz board.  The mod contains a 4-pole filter
>(either 600 Hz or 2400 Hz).  The NAR switch(s) are used to (a) control the
>roofing filter and/or (b) the NAR filter.  The roofing filter is not located
>at the end of the 9 MHz "food chain" like the NAR filters.  It is actually
>at the opposite end of the 9 MHz schematic.
>
>The roofing filter can be switched in or out so that the operator does not
>lose any functions (e.g. FM or a wider 2,800 Hz IF filter) by installing the
>mod.
>
>I have installed the 2400 Hz version in my Omni V.9 and, other than a small
>glitch with the cabling, found the process relatively painless.  
>
>73, 
>
>Rick 
>VE7TK
>
>Website:  http://www3.telus.net/ve7tk  
>
>---------------------------------------------
>  
>
>>Date: Thu, 13 Jan 2005 21:35:59 -1000
>>From: Ken Brown <ken.d.brown at verizon.net>
>>Subject: Re: [TenTec] INRAD Omni VI roofing filter kit - success
>>To: tentec at contesting.com
>>Message-ID: <41E7765F.7050306 at verizon.net>
>>Content-Type: text/plain; charset=us-ascii; format=flowed
>>
>>Hi Jason,
>>
>>I understand why someone with a non plus or version 3 upgraded Omni VI 
>>would want the Inrad modification, in order to get another 
>>narrow 1st IF 
>>filter option. And I can also understand that even if you already had 
>>two narrow filter options in a version 3 or Omni VI +, there 
>>might still 
>>be some improvement in BDR by adding the Inrad modification. What I 
>>don't understand is why don't you have a filter in your Omni VI NAR 
>>slot? It seems like it would have been much easier just to 
>>plug a filter 
>>in there. That would have also been a big improvement, even if 
>>not quite 
>>as good as the Inrad mod, and cheaper and easier to do.
>>
>>DE N6KB
>>
>>    
>>
>>>I don't have a filter in my Omni VI NAR slot - it used to be 
>>>      
>>>
>>my "Mute"
>>    
>>
>>>button but now it becomes the enable/disable switch for the INRAD 
>>>roofing filter. 
>>>      
>>>
>>    
>>
>
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