[1000mp] Roofing filter and weak sigs

[w2nra at optonline.net]

Mike,

I have heard that due to an improvement in design the menu 9-1 adjustment is no longer necessary.  BTW I have one of the early roofing filters and I concer with everything you say.  My receiver is so quiet now that when I first installed the roofing filter I thought I did it wrong and broke the rig.  I've had this installed for quite some time now and I still think it's great.  Before I always had a background S-1 to S-2 noise level.  After S-0 is the norm.

73,
Art
W2NRA

Mike Schatzberg wrote:

>Hello Vidi:
>
>There has been quite a bit written here about the roofing filter.  The
>archives will be worth a review on this subject.
>
>To summarize my experience, the noise floor is reduced by perhaps as much as
>8 to 10 db from my stock Mark V, making it far easier to copy weak signals.
>In fact, after reducing the IF gain in menu 9-1 by two numbers, I am able to
>read S0 signals Q5.  Following the installation of the mod, my S meter
>readings were 15 db higher.  A reduction of 3 number reduced the readings to
>parity with before the mod readings.  I settled with a reduction of 2
>numbers, which I felt gave the best signal to noise results for reading very
>weak signals.
>
>The improvement comes about for two reasons.  The first you have already
>stated, the 6 pole 4 khz crystal 1st IF filter in series with the stock 12
>khz filter, lets in less noise.  Secondly, the latest production Inrad
>filters have lower insertion loss, and the two stage low noise amplifier has
>a net gain of several db.
>
>You will find that the roofing filter mod will accomplish the same noise
>reduction that your IF amplifier mod does, but has all the advantages of the
>narrower 1st IF filter as well.
>
>It is well worth the investment, you will discover a new receiver when it is
>installed.  Don't forget to do the Noise Blanker Mod as well.
>
>Regards and Happy DXing,
>
>Mike Schatzberg
>WB2AJI
>----- Original Message ----- 
>From: "Vidi & Hester" <zs6al at cis.co.za>
>To: <1000mp at mailman.qth.net>
>Sent: Monday, March 14, 2005 8:02 AM
>Subject: [1000mp] Roofing filter and weak sigs
>
>
>>Hello everyone
>>
>>I took part in the BERU contest using a FT-1000MP with the Inrad original
>>front end mod installed.  I had to deal with a lot of VERY weak signals
>
>more
>
>>so than with  overpowering nearby  stations.  I have read a lot about the
>>advantages of the roofing filter in strong near signal situations.
>
>However
>
>>I was wondering if the restricted front end bandwidth brought about by the
>>roofing filter will limit the band of total background noise entering the
>>rig and thereby making it easier to pick out signals from in the normal
>
>low
>
>>level of background  noise.
>>
>>Bottom line:  Will a roofing filter improve weak signal reception?
>>
>>Comments based on experience will be appreciated
>>
>>Regards,
>>
>>Vidi, ZS1EL