Kiwi hams log record DMR DX contact, prove digital mode’s limits

On September 7, 2014, New Zealand hams John Yaldwyn, ZL4JY and Steve Jepson, ZL2KG, set a new DMR DX record by working DMR simplex over a distance of 191.7 km from the slopes of Mt. Taranaki to Waikanae, New Zealand.

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Cheers!

Don
VA3XFT

 

Congratulations.

I do use 2m FM both on simplex and through repeaters, no matter what the mode on 2m' that is Very Impressive.

Digital Motorola Radio is not something I have, I have heard a few people talk about Digital Motorola, and Yeasu and Icom digital.

Best 73 K2HAT Lee

Essentially, on September 7, 2014 at 12:45pm local time, Steve Jepson, ZL2KG, who was situated at the Stratford Plateau car park on the slopes of Mt. Taranaki, an active stratovolcano located in Egmont National Park, worked John, ZL4JY at his home in Waikanae – a distance of over 191.7 km (119 mi) using the ZL national 70cm DMR simplex frequency on 432.7625 MHz. A Connect Systems CS700 handheld connected to a dual-band 2m/70cm mobile antenna was used at Mt. Taranaki and a Motorola MOTOTRBO XPR 5550 mobile connected to an 8-element Yagi antenna was used in Waikanae for the DMR contact, with perfect signals in both direction

 

So the limit is somewhere between 93 and 132 miles for a particular repeater is New Zealand...And 119 miles from 1 mountain top to another with a decent sized beam antenna. VHF SSB does this all the time and with less altitude and less than ideal conditions. Did I miss something?

 

Same thing I ask on another page that was bragging about this contact.Besides D-STAR can be used on HF & you can make contacts around the world on it & it's Digital as well.It does not sound like very far even an FM signal with a descent antenna system so I also must have missed something?

Clayton
W4KVW

 

The issue that causes the distance limit of DMR on a repeater is the synchronization required to get the data into the correct timeslot. If the distance is too large, the propagation delay becomes significant, and the repeater fails to get the bits of data when expected. See http://forum.motorola-radio-support.co.uk/index.php?action=printpage;topic=1035.0 for some discussion about this.

 

@KB3EHW Thanks.

 

Cool, I wonder if I have the record for D-Star Simplex for my 141Miles, 226.8Km
on 145.670 with a beam on my roof (pre-tower).

In the Great Lakes area, a couple hundred miles on 2m simplex FM is an every morning thing in the summer.