[Elecraft] Filters for K3

[Duncan Carter]

One of my neighbor hams had a 75A4 when I was in high school - no later 
than 1957.

Dunc, W5DC

Joe Subich, W4TV wrote:
>   
>> Drake??   What about Collins and the 75A4 that had a fine shift 
>> control on the front panel,  done mechanically/electrically 
>> but was well before Drake had a radio.. Width was controlled 
>> by filters. 
>>     
>
> I don't know when the 75A4 was introduced but the shift control 
> was present on the Drake 2B, probably the 2A and maybe even 
> the 1A.  In any case, independent shift and width controls 
> certainly go back into the 60's if not earlier ... long before 
> high cut and low cut were mis-identified as shift and width. 
>
> 73, 
>
>    ... Joe, W4TV 
>  
>
>
>
>
>   
>> -----Original Message-----
>> From: Merv Schweigert [mailto:k9fd at flex.com] 
>> Sent: Tuesday, December 29, 2009 8:22 PM
>> To: lists at subich.com
>> Cc: 'Elecraft Reflector'
>> Subject: Re: [Elecraft] Filters for K3
>>
>>
>> Drake??   What about Collins and the 75A4 that had a fine shift 
>> control on the front panel,  done mechanically/electrically 
>> but was well before Drake had a radio.. Width was controlled 
>> by filters. 
>> Merv KH7C
>>
>>
>> Originally, IF shift was defined as moving one IF passband 
>> within another IF passband, making the resulting passband the 
>> intersection (not the union) of the two passbands.
>>     
>>
>> Again, you are incorrect.  Drake implemented a shift control long 
>> before any of the Japanese imports and its shift moved the entire 
>> passband without changing the width.  Width was controlled 
>> separately, in discrete steps.  
>>
>> Many of Yaesu's transceivers ... going back to the 1970's ... 
>> also had independent shift and width controls.  Even today 
>> the FT-1000D, FT-1000MP, Mark V, FT-2000, FT-9000, etc. have 
>> width and shift controls that are independent and behave 
>> exactly like the K3 in Width/shift mode.  
>>
>> It was only when Kenwood eliminated the third filter and 
>> failed to link the mixers that shift/width became effectively 
>> a high cut or low cut filter.  
>>
>> Like so many other features of the radio, what you prefer 
>> depends on what you first used.  For me, the current Elecraft 
>> design is the right way to do shift and width.  Even better, 
>> I can select independent shift and width for CW and digital 
>> operation or high/low cut for SSB operation at the press of 
>> the encoder (or if I select 10 Hz steps for shift the behavior  
>> can change automatically as I change between voice and CW/data 
>> modes). 
>>
>> 73, 
>>
>>    ... Joe, W4TV 
>>   
>>
>>
>>
>>   
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net 
>> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Al Lorona
>> Sent: Tuesday, December 29, 2009 6:18 PM
>> To: Elecraft Reflector
>> Subject: Re: [Elecraft] Filters for K3
>>
>>
>>     
>> It depends entirely on which brand of radio you were using
>> and how the manufacturer implemented IF shift and/or width. 
>>       
>> Originally, IF shift was defined as moving one IF passband 
>> within another IF passband, making the resulting passband the 
>> intersection (not the union) of the two passbands.
>>
>> When  you do that, you effectively reduce the width *and* the 
>> center frequency of the IF passband... it has nothing to do 
>> with manufacturers failing to make it work correctly.
>>
>> Take two pieces of paper and cut a square in each. Hold them 
>> up to a window, and slide one square horizontally across the 
>> other one, and note how the width *and* center of the opening 
>> shifts left or right. This is what I mean when I say, "IF 
>> shift". We might be talking about two different things.
>>
>> Regards,
>>
>> Al W6LX ______________________________________________________________
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>>     
>
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