[TenTec] Yaesu comparison

[Bob McGraw - K4TAX]

The operative description was "SSB selectivity".  The roofing filter has 
little to do with that aspect in as much as it only protects the IF portion 
which is outside of the DSP BW value.  Therefore the roofing filter 
bandwidth value is always equal to or greater than the DSP BW value.

Yes the roofing filter does keep strong signals which are outside of the DSP 
BW from captureing the AGC and thus reducing the gain within the DSP BW but 
I don't view the roofing filter as having direct impact on SSB selectivity.

73
Bob, K4TAX


----- Original Message ----- 
From: "Billy Cox" <aa4nu at ix.netcom.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Wednesday, January 30, 2013 11:49 AM
Subject: Re: [TenTec] Yaesu comparison


> Bob,
>
> I believe you are discounting how well the "roofing
> filter" really protects the actual "IF" chain?
>
> Given today's platforms, the line is rather blurred
> as many would consider the "roofing filter" as being
> part of the IF chain too.
>
> Not nearly as easy to define as in years past as to
> either the DSP or the "roofing filters".
>
> Not so long ago, DSP was still primarily audio, not IF.
>
> The DSP systems we have today are excellent, but tend
> to still need an additional filter placed ahead in the
> system to prevent overload and other challenges.
>
> Rather interesting to see how Yaesu copied the K3,
> which followed the Orion platform, after the failure
> of their FT2000 platform with it's RX weaknesses.
>
> Of course Rob Sherwood needs to be remembered for his
> work with the Drake platforms that started all of this!
>
> 73 de Billy, AA4NU
>
>
> -----Original Message-----
>>From: Bob McGraw - K4TAX <RMcGraw at Blomand.net>
>>Sent: Jan 29, 2013 12:06 PM
>>To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
>>Subject: Re: [TenTec] Yaesu comparison
>>
>>First I'd say that a roofing filter has little to do with actual receiver 
>>IF
>>selectivity.  In other words, the roofing filter is pre the DSP 
>>selectivity
>>which would typically be less than the BW of the roofing filter.   Today's
>>receivers develop their selectivity in the DSP system.
>>
>>In the referenced video, I could not discern the DSP selectivity of the K3
>>or the FT-5000.   The Orion II BW is 520 Hz.
>>
>>
>>73
>>Bob, K4TAX
>>
>>
>>DISCLOSURE:
>>This is to inform all persons, I am a Tentec Ambassador and I receive
>>compensation according to the Tentec Ambassador program.  In addition, I
>>serve as a volunteer beta test person to Tentec for the Omni VII, Eagle 
>>and
>>Argonaut VI radios.  I hold no employment relationship, no financial
>>interests nor do I conduct any commercial business, direct or indirect, 
>>with
>>Tentec.
>>
>>
>>
>>
>>
>>
>>
>>
>>----- Original Message ----- 
>>From: "Dan Thompson" <w4uh at bellsouth.net>
>>To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>
>>Sent: Monday, January 28, 2013 3:05 PM
>>Subject: Re: [TenTec] Yaesu comparison
>>
>>
>>> Here is a You Tube comparing the K3, Orion II, & FT5000.
>>> http://www.youtube.com/watch?v=8SqVBkA535o
>>>
>>> 73, Dan W4UH
>>>
>>> -----Original Message-----
>>> From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of
>>> k4elo at fastmail.fm
>>> Sent: Sunday, January 27, 2013 6:47 PM
>>> To: tentec at contesting.com
>>> Subject: [TenTec] Yaesu comparison
>>>
>>> Has anyone on the list had the chance to do an A/B comparison between
>>> the Orion II and the Yaesu FTdx5000?  Particularly in terms of ssb
>>> selectivity.
>>>
>>> I used to have an Orion II and sold it (bad move!), but now much later,
>>> have a Yaesu FTdx5000, but I am not satisfied with it's selectivity,
>>> maybe due to only a 3 kHz roofing filter.  So I am seriously thinking of
>>> going back to the Orion with a 1.8 roofing filter.
>>>
>>> Any comments?
>>>
>>> Thanks and 73
>>> Wayne
>>> K4ELO
>>>
>>>
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>>
>>
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