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@ix.netcom.com>
To: "Discussion of Ten-Tec Equipment" <tentec@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@Blomand.net>
Sent: Jan 29, 2013 12:06 PM
To: Discussion of Ten-Tec Equipment <tentec@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@bellsouth.net>
To: "'Discussion of Ten-Tec Equipment'" <tentec@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@contesting.com] On Behalf Of
k4elo@fastmail.fm
Sent: Sunday, January 27, 2013 6:47 PM
To: tentec@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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