Navigator Interface works well, but has some issues

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Earlier this year I purchased the Navigator from US Interface. It has done a very nice job mopping up various connections between my computer and the Icom IC-746 transceiver.

I used this fine interface with great success, however, last week it blew its fuse.

The many months of great service include the following:

CAT Interface
I worked the Virginia QSO Party and made good use of the CAT connection with my N3FJP software; It is so nice watching the contest software automatically update the band and frequency information as I operate the transceiver.

Digital
PSK31 was also an easy thing for the Navigator during the QSO Party. Later my first Olivia contacts were a breeze.

CW Reception
I am not very good with CW yet so rely on CW Skimmer to help. It connects to the sound card interface of the Navigator with ease and works great so long as you remember to Calibrate your sound card settings with your software (like MixW).

CW Sending via Winkey
The Winkey IC is my favorite Morse keying solution for computer sending of CW and the Navigator kindly has one. It totally relieves the computer from any real-time timing requirements and handles the keying of the radio straight off. It also accepts the paddle inputs allowing either the computer or the paddles to operate the radio with no switching. I used it with success during the QSO Party and the CQWW CW contest the following week. Perfect.

RTTY
I worked a RTTY contest using the Navigator. This was my first RTTY contact ever. Worked great.

Essentially, every thing the Navigator promises it delivers.

The only problems I have with this assembly include:

  • When initially plugged into a USB port, the unit screeches and squeals its internal speaker for several seconds before the PWR light turns on. After a few moments, the PWR light turns yellow then green and all is well for as long as the unit remains attached to an active USB port.
  • During the above “squeal event” the Navigator keys up the transceiver via the PTT line. You must remember to have the radio off while you power up the Navigator.
  • During the above “squeal event” the Navigator pulls well over 800 mA of current – 300 more mA than the USB 500 mA maximum allows. The unit settles into well under 10 mA after this starting issue.
  • Last week the Navigator refused to power on at all. I tried it on different USB ports, but no go. An email sent to the tech support of US Interface suggests the power input fuse near the USB jack has blown. Sure enough, the fuse is rated for 1/2 amp and is open circuited; It is no surprise it blew because of the squeal current noted above.

I discussed the possibility of replacing the fuse myself with tech support, but he encouraged me to send it in for warranty repair suggesting the high current is certainly an issue and the squeal issue has a work around. The three year warranty is quite remarkable and, as told to me by tech support, is valid for all except surge/lightning issues where damage to the board is obvious. My board is clear of any such damage so my unit is off to tech support.

The Navigator is one of the few interfaces completely powered by the USB port current. The USB specs suggest a maximum of 500 mA. However, laptops and some desktops don’t provide the full amount of current. I have long wondered about the practicality of powering a unit with this much circuitry off of the USB, but the folks at US Interface seem to think it will work fine. I would be delighted to provide an external source of power for this interface as I have seen far too many issues with USB ports in regards to meeting the 500 mA current. By the way, I have used this interface with a laptop, laptop + powered USB hub, and a desktop. All three solutions squealed, but always worked just fine in ten seconds or so.

Anyway, the unit is off to the factory for warranty repair.

I will report the results.

UPDATE 2009:
The unit is back from factory repair, the problem is gone and works great.

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