[Ham-Mac] CI-V interface noise

[Lee (WW2DX)]

Chris,

I had the same issue with my CI-V box (blackcat) and as soon as i  
checked the Radio VFO button my noise level jumped.
I ended up wrapping the USB cable around a few ferrite cores and the  
noise went away.
I hope it works for you.

73 de Lee
WW2DX

On Apr 15, 2007, at 9:44 PM, EZ Rhino wrote:

> Chris and Don, thanks for the quick replies.  First, I didn't mean  
> to imply that there is something wrong with either of your  
> products; the fact that the noise recurs with two different  
> interfaces is probably a good sign that there is nothing wrong with  
> the interface itself.
>
> IT hadn't occurred to me that it could be radiated through the  
> antenna.  For fun, I disconnected the coax from the radio and tried  
> to duplicate the noise in the normal manner.  No noise.  I  
> reconnected the coax and wound it into a choke balun outside, just  
> before it comes into the house (my wire antenna is fed with ladder  
> line to ground level.)  It seems to help some (in conjunction with  
> the two toroids on the USB cable.)
>
> Without changing out the power supply, I can't say whether or not  
> that would help.  I guess I can check on cost and see if it is  
> worth trying.
>
> Thanks!
>
> Chris
>
>
>
>
>
>
>
> On Apr 15, 2007, at 2:24 PM, Don Agro wrote:
>
>> Hi Chris,
>>
>> On 15-Apr-07, at 4:03 PM, EZ Rhino wrote:
>>
>>> This is driving me bonkers.  There has got to be someone else on  
>>> this list with this problem besides me.
>>>
>>> Problem:  When I connect my iMac to my Icom 746pro (USB from  
>>> computer to "data" port on radio), I get a LOT of noise appear in  
>>> the radio.
>>>
>>> Equipment:  PowerPC iMac, running Tiger.  MicroHam USB interface  
>>> II.  Icom 746pro.  I use MacLoggerDX and CocoaModem.
>>>
>>> Specifics:  Click the "Radio VFO" box on MLDX, and the noise  
>>> appears. Click it again and the noise goes away.  It is worst  
>>> (unacceptable) on 15 meters;  also present on 20m and 17m.    
>>> Before I went to my current interface (MicroHam) I was using a  
>>> Black Cat USB Ci-V interface with the same problem, but it wasn't  
>>> as noisy as my current interface.  I mostly solved the problem  
>>> before by wrapping the USB cable from the computer through a  
>>> large toroid.  (transformer E core, to be precise.)  When I put  
>>> the MicroHam interface on, I put an additional E core on the  
>>> cable, and still can't reduce the noise to what I consider  
>>> acceptable levels.  I've tried grounding the iMac, grounding the  
>>> interface, etc. to no avail. (Where the heck are you supposed to  
>>> ground an iMac anyways? I pulled the back cover off and attached  
>>> a braid to a case screw.)   I am annoyed that using interfaces  
>>> with supposed "isolation" still doesn't eliminate the noise.   
>>> Anyone have any suggestions for something I haven't already tried?
>>>
>>> Thanks in advance,
>>>
>>> Chris
>>> KF7P
>>
>> I know this probably isn't going to be of much help to you - but  
>> the only two times I have had noise problems on HF they have been  
>> due to a terminally ill power supply in my older MDD PPC desktop Mac.
>>
>> I have replaced the power supply twice and will probably have to  
>> do it again (design flaw). The HF noise serves as an 'early  
>> warning' system for me that the power supply is going.
>>
>> What I am suggesting is the possibility that the noise may be  
>> originating in the iMac switching power supply and the USB/CI-V is  
>> just acting as an electrical conduit ?
>>
>>
>> 73 Don Agro VE3VRW
>>
>> D o g   P a r k   S o f t w a r e   L t d .
>>
>> email: dagro at dogparksoftware.com
>>   www: http://www.dogparksoftware.com
>>     iChat AV:dogpark at mac.com
>>
>> _______________________________________________
>> Ham-Mac mailing list
>> Ham-Mac at mailman.qth.net
>> http://mailman.qth.net/mailman/listinfo/ham-mac
>
> _______________________________________________
> Ham-Mac mailing list
> Ham-Mac at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/ham-mac