[Elecraft] KX3 Roofing Filter Question

[Brian “VE3BWP” Pietrzyk]

Hi Stan,
 
I ordered mine with the roofing filter and no regrets. When its on its like the radio is a horse with blinders on. Any nearby flailing distractions are removed from view so the horses brain doesn’t have to process it. 

Its not that often I need it but when some other strong signal is close enough to your frequency and shows up on your pan adaptor the front end of the KX3 is negatively influenced and it will compromise the receivers s/n ratio and ability to receive the content to want even though you can hear it. The roofing filter will save the day and you can hold your ground and not have vacate the frequency. I use it on SSB and digimodes as well. 

I was recently doing QRP on the beach in the bahamas and after I got all settled in on a frequency and started a few pile ups some commercial shortwave station came on the air. It must have been very close because i

Message: 22
Date: Mon, 29 Jan 2018 16:20:06 -0500 (EST)
From: stan levandowski <sjl219 at optonline.net>
To: Elecraft at mailman.qth.net
Subject: [Elecraft] KX3 Roofing Filter Question
Message-ID: <765520bb.1faf0.16143ca985b.Webtop.39 at optonline.net>
Content-Type: text/plain; charset=UTF-8; format=flowed

I am going to order another KX3 this week. Probably tomorrow.? The last 
one I ordered in 2012 did not have the roofing filter option and I do 
not THINK I missed it.

I use ONLY CW and I do NOT contest.? I like to CASUALLY chase DX and I 
play in low stress sprints like NAQCC but mostly I just like to RAG 
CHEW.

My antenna is an EFHW installed as a "half square" in trees at 30 feet 
(MyAntennas 4010).

I have reviewed the Elecraft site notes, and done a fair amount of 
Googling and I now am more confused than ever.? It seems that the real 
value lies in dealing with strong signals, crowded bands and ferocious 
contesting conditions.

My bottom line question is this:? If I DO NOT get the roofing filter 
option will my KX3 receiver be LESS SENSITIVE?? The Sherwood report 
shows a pre-amp off sensitivity of .9 uv which improves to a very 
impressive .09 with the preamp on.? Is this somehow related to the 
roofing filter?

I am especially concerned because I remember doing an A/B comparison on 
a weak signal between my previous KX3 and my 55 year old Drake 2B and 
the 2B beat the crap out of the factory built KX3.? I can't help 
wondering if the roofing filter I didn't buy in 2012 had something to do 
with this.

I sure could use a real simple answer:? buy it or don't buy it?? CW 
sensitivity is my ultimate goal because if I can't hear 'em I can't work 
'em.

Thanks and 73,
Stan WB2LQF