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Re: [TenTec] SSB and CW filters wanted

To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Subject: Re: [TenTec] SSB and CW filters wanted
From: "Mark van Wijk, PA5MW" <pa5mw@home.nl>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 10 Oct 2015 12:55:14 +0200
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
Since no RX366 turns up anywhere, I will do the INRAD #902 46Mhz 6-pole upgrade to my Orion or Orion II (cannot decide yetwhich is best on 160m) original 2nd receiver

That renders my spare original TT 300Hz filter useless
inscription says:
Ten Tec
48296
300 Hz BW
MA06504

Anyone interested?

73 Mark, PA5MW





-----Original Message----- From: Rick - DJ0IP / NJ0IP
Sent: Saturday, October 10, 2015 11:46 AM
To: 'Discussion of Ten-Tec Equipment'
Subject: Re: [TenTec] SSB and CW filters wanted

I agree with Barry on the Orion 1.
Due to a quirk in the design, installing smaller filters in the 2nd bank was
of no help.
The only solution there was the INRAD 600 Hz filter.

My point (in general) is that you don't need to have the sharpest-skirt
8-pole filter as the roofing filter.  A 4-pole filter of suitable bandwidth
is fine.

With the Orion II, there was no need to look for steeper 3rd party filters.

73 - Rick, DJ0IP
(Nr. Frankfurt am Main)


-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Barry N1EU
Sent: Saturday, October 10, 2015 10:46 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] SSB and CW filters wanted

Although I would agree that the narrow xtal filters are generally
unnecessary for general Orion 565 use, I wouldn't agree that they are never
needed if you're a semi-serious cw contester or low band dx'er.

The xtal filters have one main purpose - prevent the hardware AGC from
kicking in to prevent ADC overload on strong s9+ signals in the passband.
It's not the end of the world if the hardware AGC kicks in, but you'll
suffer gain compression and possible audible artifacts.

So if you operate cw in a crowded contest or chase dx on a crowded band,
there's a reasonable chance that you'll encounter an adjacent s9+ signal
inside the 1000hz filter passband that could be tamed with a narrow cw
roofing filter.

And for reasons explained here, http://users.vnet.net/btippett/inrad_.htm ,
go with the Inrad 600hz filter NOT the Ten-Tec narrow filters on the Orion
565.

Due to the inherent broadness of ssb signals, I don't think there's an
advantage to installing the 1.8KHz roofing filter.

Barry N1EU


On Sat, Oct 10, 2015 at 6:52 AM, Rick - DJ0IP / NJ0IP <Rick@dj0ip.de> wrote:

Allen, Carl is correct.

You don't need really steep skirts and deep attenuation with the
roofing filter.
The roofing filter's job is to add just enough selectivity to prevent
overloading of the down-stream circuits.  The DSP filters on their own
do the job of providing the main selectivity and they do it quite well
- far better than the XTAL filters we were previously using for this
job; assuming their circuitry is not overloaded

In the old designs, the roofing filter had to assist with the overall
selectivity because the single XTAL filter in the downstream IF did
not have steep enough skirts nor enough ultimate attenuation.

Although good XTAL filters measured in the lab can show attenuation of
up to 100dB, when inserted into a radio their ultimate attenuation
typically falls off to just 80 dB, due to blow-by.  Cascading XTAL
filters (i.e., roofing +
IF) raises the ultimate attenuation to about 100 dB.

When the Orion came out, I discussed this with Jack Burchfield and he
assured me that adding more XTALS to the roofing filter did not bring
any additional benefit.  It just brings additional size, cost,
attenuation and points of possible failure.

73 - Rick, DJ0IP
(Nr. Frankfurt am Main)


-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of A R
Sent: Saturday, October 10, 2015 6:26 AM
To: n4py3@earthlink.net; Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] SSB and CW filters wanted


Carl,



Is that really true? Aren't the 218 and 219 employed as roofing
filters in the 1st IF, and isn't the DSP BW control in the 3rd IF? If
strong adjacent (and/or dirty) signal conditions warrant
tighter/narrower BW roofing filters than the narrowest 2.4KHz and
1.0KHz roofing filters supplied as "standard"
in the ORION, then wouldn't the option roofing filters at the 1st IF
be more effective in dealing with the consequences of strong
adjacent/dirty signal conditions than at the 3rd IF?



Allen--W7GIF


----- Original Message -----

From: Carl Moreschi<mailto:n4py3@earthlink.net>

To: Discussion of Ten-Tec Equipment<mailto:tentec@contesting.com>

Sent: Friday, October 09, 2015 7:33 PM

Subject: Re: [TenTec] SSB and CW filters wanted



You don't need them.  The skirts on the Orion DSP filters are very
sharp making those filters not really needed.

Carl Moreschi N4PY
58 Hogwood Rd
Louisburg, NC 27549
www.n4py.com<http://www.n4py.com/>

On 10/9/2015 9:14 PM, Tim Wininger wrote:
> Looking for # 218 (1.8Khz) and #219 (250Hz) filters for a newly
> acquired Orion.
>
> Anyone got these filter excess to their needs?
>
> Thanks for the response,
>
> Tim, AB4B
> Rogersville,AL
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