Jim:
No problem on your questions, and welcome to the list.
First, as far as I know, my equipment is reasonably well grounded, as
evidenced by the fact that I don't seem to get much RFI in the shack when
transmitting on various bands.
Secondly, I have tried several different types of ferrite cores as RF
chokes, on both the power cord and audio cable for the speaker, but they did
not eliminate the RFI. I even got RFI when the speaker was not connected to
anything and running on batteries. This leads me to believe that this
particular speaker is especially susceptible to RFI, which a few others have
suggested as well.
73 from Tom Behler: KB8TYJ
----- Original Message -----
From: "Jim Gammon" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, May 10, 2012 12:42 AM
Subject: Re: One Other Thought about the RFI in the Speaker
> Hi, just a couple of thoughts from a new guy on the list. Is
> your equipment thoroughly and properly grounded? Second, have you
> ever tried those little snap-on iron loops that you rap your
> power cord in) I know your speakers don't have wires, but if you
> put the power cord of your rig into the loop it may help. I use
> those things here and they cut down SSB RFI significantly into my
> computer speakers which are notorious for picking up stuff. Jim
> WA6EKS
>
> ----- Original Message -----
> From: Steve Dresser <[log in to unmask]
> To: [log in to unmask]
> Date sent: Wed, 9 May 2012 22:53:05 -0400
> Subject: Re: One Other Thought about the RFI in the Speaker
>
> Tom,
>
> Do you get RFI if you run barefoot? If not, you may have some
> amplifier-specific issues.
>
> Steve
>
> ----- Original Message -----
> From: "Tom Behler" <[log in to unmask]
> To: <[log in to unmask]
> Sent: Wednesday, May 09, 2012 20:31
> Subject: Re: One Other Thought about the RFI in the Speaker
>
>
> Mike:
>
> I just tried the speaker with batteries, and no speaker cable
> connected at
> all, and still got RFI through the unit when using my amp on 20
> meters at
> about 600 watts.
>
> So, obviously, the speaker itself is not very RF resistant.
>
> It's too bad, since it is such a nice-sounding speaker.
>
> 73 from Tom Behler: KB8TYJ
>
> ----- Original Message -----
> From: "Mike Duke, K5XU" <[log in to unmask]
> To: "Tom Behler" <[log in to unmask]
> Sent: Tuesday, May 08, 2012 8:02 PM
> Subject: One Other Thought about the RFI in the Speaker
>
>
> Tom,
>
> Those were great speakers. I had one for a number of years
> before
> something in the amplifier died. I never tried it with any of
> my
> transceivers, so I can't say whether or not mine had a problem
> with
> RFI.
>
> Have you tried seeing if the RF gets into it with the speaker
> turned
> on, running on battery power, but with no audio cable connected
> to it?
>
> By removing all external cables, including the audio input, you
> can
> determine whether the RF is coming in on the audio cable or not.
>
> I suspect it is getting in through the internal wiring of the
> amplifier itself. In that case, fixing it may be a real trick.
> You may
> need to begin with ferrite beads on the leads between the
> speaker and
> circuit board, and on the leads between the circuit board and
> battery
> holder.
>
> Just 2 more cents for your knowledge bank.
>
>
>
>
>
>
>
>
> Mike Duke, K5XU
> American Council of Blind Radio Amateurs
>
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