[1000mp] Observations After Roofing Filter Install and OtherUpgrades

[4x1ad]

You can also perform the W8JI Noise Blanker simple mod in order to correct 
the stupid NB design of entire 1000(xx) line. It works.

73 Morel,
4X1AD

----- Original Message ----- 
From: "Dean Fewkes" <kg7mz at mytargets.com>
To: <1000mp at mailman.qth.net>
Sent: Friday, January 14, 2005 4:55 PM
Subject: [1000mp] Observations After Roofing Filter Install and 
OtherUpgrades


> Well I did some major upgrades to my Mark V field this last weekend. These 
> upgrades
> included:
>
> The Inrad roofing filter.
> 2.8 HTZ Inrad filters for the 2nd and 3rd IF.
> Inrad key click mod.
> Changed out the old K9AN bonus mod for a .022 capacitor instead of .047.
>
> Here are some initial observations that really stood out:
>
> The roofing filter greatly improved my AM reception and short wave 
> listening. This is
> because the puny ceramic AM filter used in the 3rd IF let way too much 
> stuff blow by
> including hi-pitched whines etc. The roofing filter STOPPED this with only 
> a slight
> reduction in observed fidelity. It is now what I would call the perfect 
> filter width for AM.
> If you want hi-fi, you can use the synchronous receive feature because it 
> needs only one
> sideband and the carrier of the AM signal and is not restricted at all by 
> the roofing filter.
>
> The noise blanker causes much less distortion and works just as well, 
> thanks to the
> roofing filter.
>
> The clicks that are normally heard in the headphones of the Field model 
> while working
> QSK are gone, and the S meter pinning that is often associated with QSK is 
> gone. I am
> not sure if these improvements are due to the roofing filter or the key 
> click mod.
>
> As advertised, the roofing filter does reduce or eliminate interference 
> from strong signals
> that are near your operating frequency.  For those of us that must use the 
> noise blanker at
> times, this improvement is very significant. Without the noise blanker the 
> improvement is
> more subtle but still definitely makes a difference.
>
> The change in the old K9AN bonus mod made the CW audio quality a little 
> less
> restrictive and smoother when using the wide filters. I thought the .047 
> blocked too much
> hi-pitched reception when wanting to listen to a wide pass-band. This is 
> really a personal
> preference.
>
> I hope this information is helpful and I will probably add more after 
> further use.
>
> Dean Fewkes
> KG7MZ
> Kalama, WA
>
>
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