Re: [IC-7000] Re: USB to IC-7000 interface and N1MM+

Steve W3AHL


It is possible that the Radio Shack converter has a lower output high voltage on the CIV line than most others.  Comparing the IC-706 versu IC-7000 CIV circuits, the 706 has a 6.8K pullup to 5 VDC on the CIV receive transistor's base, while the 7K has 10K to 3.3 VDC.  I tried several USB to CIV adapters with two different laptops and didn't have any problems with N1MM, event after adding a 6' extension cable to both the USB and CIV cables.

So I think the 7K's CIV circuit is OK, but maybe not quite as much noise margin as the 706.

The other minor difference between the two is how the CIV jack's ground signal (CIVE) is routed.  On the 706, CIVE is routed to the CIV circuit on a signal trace.  On the 7K the CIVE signal is just connected to the Main PCB ground foil at the CIV receptacle.  So if your station/system/house RF grounding is marginal, that may introduce more noise onto the CIV signal, which the 7K may be more sensitive to.  I disconnected my radio chassis ground wire from the station single-point ground buss and didn't have a problem.  But I also have modified my power supply to float DC- from the AC earth ground to eliminate ground loops.

Have you tried disconnecting everything that isn't absolutely necessary from the radio and computer to see if the problem still remains.  If that corrects the problem, then you may have a grounding issue.  If it doesn't correct it, you could still have a grounding issue of course.  Running the radio on a 12 VDC battery or verifying your DC- isn't connected to AC ground inside the power supply (or other equipment connected to the power supply) would probably eliminate a ground loop as being the issue.

Without seeing your setup it is hard to guess all possible causes, but it only takes one seemingly minor problem to create these kinds of problems.  I still suggest replacing the Radio Shack converter if all else fails.  I haven't found the 7K's CIV circuit to be a problem for the owners that I have had direct experience with over the years, although I certainly have seen many flaky USB-CIV & serial converters, especially with RFI sensitivity on the USB interface cable.

Steve, W3AHL

---In ic7000@..., <k3ydx@...> wrote :

Steve et all-

The use of an external USB "powered" hub might be worth trying.
So far I suspect I'm dealing with a communications level issue between the 7000 and the Lenovo laptop.

Here's what I have found so far.  Radio=IC-7000, Lenovo T510 and RS USB to serial interface (20-047) results in the intermittent operation with N1MM+ software.  The radio frequency does not track as the dial is changed but will often be close to correct as the dial change is stopped but off by several hundred Hz.  Then of course the radio times out on the N1MM+ software bandmap and the LEDs on the interface quit blinking.

Same set up with an original IC-706 in play and everything works apparently as it should.  Dial rotation and then stop and the frequency displayed in the software is correct.  Mode change is tracked correctly as is the band change operation.  This would lead me to think the issue is within the IC-7000 and something to do with the CI-V circuit.

However, if I take the same setup as in the second paragraph above except plug the USB RS interface into my dual core Dell desktop, everything works as it should and as it has in the past.  

Apparently some issue exists between the communications levels of the Lenovo USB ports and the CI-V IC-7000 port which is well beyond my level of ineptitude to figure out at this time!

If I can dig up a powered USB hub I'll give that a try.

Thanks for the suggestions and input from all.


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