Garmin 396/496, GXM30 extension cord

Does anyone know of a source for a long (like 15') extension cord for the GXM30?

I have a 396 in my RV-8, with the GPS antenna on the turtledeck (under the aft canopy). The GPS antenna is trivial to extend with coax and connectors)

Right now, I'm flying with the GXM30 (XM receiver/antenna) on the front seatback, but I'd rather have it on the turtledeck or in the wingtip. I really like keeping the glareshield uncluttered.

The cable between the 396 and the GXM30 is a mini-USB, which is often used with digital cameras. Garmin has an extension which is 5 or 6 feet, but not long enough to reach the turtledeck.

I'm looking for a 15' or so mini-USB cable which is male on one end, and mini-USB female on the other.

TIA

flyeyes said:

Does anyone know of a source for a long (like 15') extension cord for the GXM30?

Click to expand...

Check the garmin site, under accessories for the 396/496.... I'm sure I saw one there at one time. I don't know what the max length can be tho, there is a limit depending on which USB chipset they used.

aadamson said:

Check the garmin site, under accessories for the 396/496.... I'm sure I saw one there at one time. I don't know what the max length can be tho, there is a limit depending on which USB chipset they used.

Click to expand...

I've got one of Garmin's, and it's 5 or 6 feet. I could daisy chain three together, but would prefer a neater (and presumably less lossy) solution.

This may or may not work... If I recall correctly, there is a max cable length limit of something like 3m (~10ft) for the GXM30. Much more cable than that and I think the voltage drop at the antenna exceeds some maximum threshold and things start to get all pear-shaped. Your mileage may vary.

mcb

Extending USB cables by simply daisy-chaining cables can lead to unpredictable results...

On the market there are "active USB extension cables" that use the 5V provided on the USB connector to power some chip that regenerates and amplifies the signal. On the market I found a few 16' active USB extension cables, check out this page:

http://www.usbgear.com/USB-Extension.html

Two notes on this exercise:

1- Garmin never said that the GXM30 is a USB device, but there should be no reason why extending the cable with an active cable wouldn't work, IMHO

2- all of the cables I've seen have the big "A" type USB connector, and not the mini-USB used on the Garmin unit, so some tweaking with adapters and such is needed. And this adds possible points of failure in the chain.

Is it worth it? Wouldn't it be easier to put the hockey puck somewhere else close by the Garmin unit?

Ciao, Luca

USB extension cables are usually designed as hubs with only one port. This means the host system needs to know how to talk through a hub. I doubt the 396 knows how to deal with a hub.

By no means an expert on the Garmin stuff, but I wouldn't be surprised if the USB extension cables don't work even if the signal is USB. If it isn't USB, then there's almost no way it will work, since the cable assumes a differential USB signal.

Unfortunately, I can tell from first hand experience that an off-the-shelf Mini USB extension cable WILL NOT work with a 396/496.


So far, only the Garmin supplied extension with the "L" shaped connector will work. Due to panel space, I'm in need of a cable that will run straight out the back of my 496, not in an elbow like the Garmin supplied cable. Has anyone else run into this and come up with a solution?