[RFI] DigiKeyer II

Peter Laws plaws at plaws.net
Wed Dec 18 23:18:00 EST 2013

On Tue, Dec 17, 2013 at 8:50 PM, Jim Brown <jim at audiosystemsgroup.com> wrote:
> Hi Peter,
> See comments interspersed.
> First, download and study k9yc.com/RFI-Ham.pdf  I suspect a Pin One Problem
> (see the tutorial) on the 746.

> 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.

As noted previously radio, PS, interface, PC are all tied to a  ground
rod outside the window of the radio room.

> 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.

I thought the interface was powered via the 5 V dc available via the
USB cable but it's not, it uses the 13.8 V dc off ACC1 (not 8 V dc -
that's ACC2).  No wall wart.

>  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.

All bands.  We'll, all I've tried.  I have no toroids large enough to
pass the cable more than twice, sadly.  Made no noticeable difference,
but I have yet to try, as the other fellow said, starting at low power
and working my way up to the pain point.

> I also suggest that you contact Joe, W4TV, who makes it his business to know
> the common cause of issues with his products.  I doubt that the problem is
> in his gear -- I think he got them fixed years ago.

I tried the RigExpert TI5 but it wouldn't do FSK at anything other
than 45.45 baud unless you used certain software.  I missed the
Timewave Navigator, else I'd bought that (it does FSK as well).

I was reluctant to do business with Mr Subich as I am on several lists
where he is active and have observed that as far has he is concerned,
it is *always* the customer's fault regardless of the nature of the
problem.  You posted an example.  He didn't listen to my complaint,
clearly, because he thinks I'm running audio *through* the DK-II when
in fact I just have it connected while operating (you know, so I can
use the CI-V interface that is part of it).

If it turns out that there is no way to operate phone with it
connected at all, which seems unlikely, then it will go on eBay (I'm
surely past whatever return period there was).

I have the tutorial already but have not read it all.  The upcoming
holiday *might* let me rectify that.  I wish there was just a generic
toroid you could buy a 1/2 dozen of just to have on hand for crap like
this.  If there was, I'd order it now.

Again, I'll note that I ran a RigBlaster Plus through the ACC1 port
for years and never had an issue with RF getting in to the audio
chain.  I didn't even ever ground that to the ground bus.

Peter Laws | N5UWY | plaws plaws net | Travel by Train!

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