Hamvention 2012 Road Trip with Mobile Repeater


This is a re-cap of our experience using an IPSC connected XPR-8300 on the road to and from Dayton over the course of the 15 day road trip.

The repeater was a UHF 25 watt XPR-8300, flat-pack mobile duplexer and a 3dB gain NMO roof mounted.  13 watts out of the duplexer, .2 watts reflected.  Nothing exceptional so far.

Internet connections were made via a Verizon LTE dongle (Pantech) plugged into a Cradlepoint MBR-1200 router.  Speeds were up to 13 meg down and 5 meg up on LTE connections.  The router performed well both on Ethernet (repeater & surveillance camera) and WiFi for our various electronics.  We had the WiMax USB device in the side window as well as 2 WiFi antennas.  We would recommend an external WiMax antenna mounted on the roof of the vehicle for serious users or permanent router installations.

When any 2G or GPRS  and up to LTE connection was maintained, the networked repeater worked well.  There is some buffering in the connection as we noticed a longer turn-around time when we chatted with others hams.  It was not objectionable but was apparent.  Audio quality was exactly the same as one would expect from any fixed installation.  Signal reports back to us were consistently good also.  But there was some random junk that mucked up our voice, most noticeable when at or near hand-offs as would be expected.

The biggest problem was hand-offs in that it affected the connection to the IPSC network.  There seemed to be no consistency when handing off or when between coverage areas.  Sometimes the IPSC connection would fix itself, never loose connectivity or only lose it for 30 seconds.  But the bulk of the time, unless there was audio traffic on the network, one could not count on being on the IPSC network.  We used a c-Bridge tool to force the repeater to re-affiliate and all would be fine until possibly the next hand-off.

Part of the trip we locked the connections down to GPRS or 2G speeds in an effort to reduce the tower hand-off issues.  When stationary, the connections were completely stable.  While in motion we could have 4 bars (-73 dBm or better) and still hand-off to another tower.  It did not seem to matter if it was 2,3 or 4G/LTE connections.  But we felt we had the most consistent IPSC connections when we locked the router to 2G presumably because they were the most common across the country.

As much of our travel was off the beaten path, we experienced many service vacuums.  We had 3 other devices on commercial voice or data networks and the router was able to maintain connections most of the time when our hand-helds failed.  Verzion was by far the most reliable, well past AT&T or T-Mobile.  We think that had we been in major metro markets and not traveling between those areas, the hand-offs would have been less of an issue.

So, is this a useable implementation of TRBO?  Nope, not at least the way we did it.  Had we not had someone manning the tablet to confirm IPSC connectivity and if not, forcing network re-affiliations, this would have been a very quiet trip.  This method is not quite ready for prime time.  But it sure was a lot of fun being able to chat on TRBO from Old Faithful, EBR-1, Craters of the Moon and other odd places not known for TRBO activity.

Our thanks to Chris, N3RPV, who loaned us the LTE dongle, router, and data plan to enable this road trip and the Hamvension presence of a DCI repeater.

This is a shot of the repeater, router, batteries and rigrunner as installed on the floor behind the front seats of the Forester, click image for larger view.

Revised: 09/19/2014 05:43

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