[Top] [All Lists]

Re: [RFI] DigiKeyer II

To: "rfi@contesting.com" <rfi@contesting.com>
Subject: Re: [RFI] DigiKeyer II
From: Peter Laws <plaws@plaws.net>
Date: Wed, 1 Jan 2014 20:38:19 -0600
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
Went on the local 10 m net tonight.  RF hash audible as I lowered the
power down to the "1/3" point (I have to dig out the watt meter to
find out what that was).

Crystal clear as soon as I disconnected ACC1 (with 4 turns of the
cable through a #31 toroid.

On Wed, Jan 1, 2014 at 1:51 PM, Peter Laws <plaws@plaws.net> wrote:
> On Tue, Dec 17, 2013 at 8:50 PM, Jim Brown <jim@audiosystemsgroup.com> wrote:
>> Hi Peter,
>> See comments interspersed.
> Likewise.  FINALLY got time to do something about this.  Meantime, I
> bought some ferrite.
>> A connection to earth is NOT part of a solution to RFI.  Proper bonding of
>> equipment IS.  That includes short fat copper (#10, or copper braid stripped
>> from transmitting coax) from every chassis to every other chassis that is
>> interconnected. In your case, that means from the computer to the microHAM
>> to the 746. The rig must also be bonded to the power system ground, and to
>> all other grounds in your home.
> All items mentioned have thick braids to a copper bar at the back of
> the desk.  DK-II, IC746Pro, Power supply, PC.
> Bar is connected to ground rod outside window, though the braid is
> suspect, of course.  I picked up 25' of  6 ga at the local bigbox but
> balked at the price of ring terminals (over a buck a piece?), so
> that's not installed quite yet.  There are TransiTraps on each of the
> feedlines that are also connected to the ground rod you say isn't
> important for RFI.
>> Maybe a Pin One Problem, but also a possible power problem.  How are you
>> powering your microHAM?  The wall wart that came with it, or from the 12V
>> bus?  Use the wall wart, not 12V.
> No wallwart.  USB, but not powered that way.  Pulls 13.8 V dc from the
> ACC1 on the radio.
>>  Is this problem present on all bands, or only on 17M?  Take one of your
>> ferrite cores and wind 4-5 turns of the ACC1 cable through it. Do the same
>> with the USB cable.
> Bought 2.5" OD Fair Rite toroids, 4 ea mix 31 and mix 43.  Bought some
> snap-ons, too, just for fun.
> Got 4 passes through a #31 toroid.  Not sure if a 5th is possible.
> No change, though, I still hear it through the headphones.  I'll find
> someone to give me a report after I run some errands, but I already
> know the answer - it will go away the instant I unplug ACC1.
> As I noted a while back.  Same PC, same radio, same antennas, same
> ground using a RigBlaster Plus had no audio problems ever.  The RB+
> has no audio device in it, or USB, and is powered off shack power
> supply ... but all audio, coming and going, passes though it.  Never a
> problem.
> Swap in the DK-II and I boom - RF on the audio.

Peter Laws | N5UWY | plaws plaws net | Travel by Train!
RFI mailing list

<Prev in Thread] Current Thread [Next in Thread>