http://elecraft.85.s1.nabble.com/AF-1-For-Sale-or-Trade-tp6221588p6223439.html
I did notice the peaking effect, but I didn't think the improvement was all that profound. Also, the effect of the low pass filter is barely noticeable on the K2. I sent an e-mail to tech support at Elecraft and was told to use it with a receiver with a wider audio bandwidth.
I considered that a non-answer, but after thinking more I realized what they were saying was that the K2's audio was already pretty narrow so I shouldn't expect much. They hint at that in their description of the AF-1 on their website. I think the AF-1 would be much more effective overall when used with a "lesser" receiver. For my ear, the K2 doesn't seem to need the help.
> From: Ron D'Eau Claire <
[hidden email]>
> Subject: Re: [Elecraft] AF-1 For Sale or Trade
> To:
[hidden email]
> Date: Tuesday, March 29, 2011, 10:54 PM
> FWIW, among other things it does an
> excellent job of emulating the K3's
> Audio Peaking Filter (APF). The peak has variable gain and
> Q that can
> literally pull signals down in the noise up into the clear.
>
>
> Great addition to the K2 for weak signal enthusiasts.
>
> Ron AC7AC
>
> -----Original Message-----
>
>
> I have a newly built AF-1 audio filter for sale. It
> comes installed in the
> beautiful Lexan cabinet custom made by Dave, W8FGU.
> Photo of the AF-1 in
> cabinet can be viewed on Dave's website at:
>
>
http://w8fgu.home.comcast.net/~w8fgu/af1encl.html>
> I built the AF-1 a few months ago and it works as
> advertised. I just find
> that the filters in my K2 are so good that the additional
> filtering the AF-1
> provides isn't really needed.
>
> U.S. $75.00 includes the AF-1, battery, cabinet, AF-1
> manual and shipping to
> anywhere in North America. I'll ship overseas but
> will have to get back to
> you with the postage rate first. Paypal or money
> order please.
>
> I'm in the market for an Elecraft W-1 wattmeter, so if you
> have one and are
> interested in an AF-1 then maybe we can work out a
> trade. Or if you just
> want to sell your W-1 then please get in touch with me.
>
> 73 and thanks,
>
> Ken Alexander
> VE3HLS
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