DMR repeater at the event 2019

[RudolphDiesel]

I know I had this here before but since this gift is new to BM and has the potential of helping a number of people, I am trying to raise a bit more awareness.

We are bringing for the first time a DMR ham repeater to BM 2019. A few technical details to limit the number of questions:

Freq: 441.175/446.175
CC: 1
TG: all

both time slots will be repeated, but there will be no backhaul in order to leave the default world where it belongs. This repeater is open for use by all licensed amateur radio operators. As far as TGs goes: I suggest that if you just want to talk to someone, to use TG 2 slot 1, at least that is where I am going to hang out for most of the time. If you are just want to talk to your buddies in your camp, and since this is a standalone repeater, feel free to invent a TG, that way you have less general chatter.

As far as I know we will be located somewhere around 8:45 and G and if you swing by there, it should not be hard to spot a tall repeater antenna. If not, just give us a shout TG2 TS1 (KA5PLE)

[Token]

Oh, Cmmon, more specs and GeekPorn please!

Tall Antenna!?!?

I’m 6’5” and tall. Is the tower taller???

That’s some lazy PR you got there ...

/s all in good humor with a nudge to get more technical specs...

[RudolphDiesel]

Tall antenna: The antenna alone is 17ft tall and will be mounted either on top of a 10ft RV or on top of a 30ft antenna mast. Is that tall enough?

What else you'd like to know

[Ratty]

Hs, ha. A 27 foot tall pole. We have two 20 foot poles with giant flags and we still ride right past our own camp.

[TT120]

Sounds like a cool idea. I've always wanted to setup my mobile rig for cross band repeat and link in to one of the 2 meter repeaters you can hit out there but I always end up chasing shiny things and never get around to it.

There isn't as much traffic as you'd think but I have talked to several people out there. One time I was chatting with this guy on 2m simplex and it turned out he was in the camp right next door to me.

[Token]

What kind of power are you running on the repeater and what do you expect in terms of coverage and distance?

What kind of antenna, a 70 or a combo 2 meter 3rd harmonic? Ground plane or something more fancy like dipoles, batwings, etc.

You know, geek stuff.

[RudolphDiesel]

> What kind of power are you running on the repeater and what do you expect in terms of coverage and distance?

I have set the radio to 5W transmit power since we are running on solar. Besides 5W 40ft up is plenty of power to cover BRC trash fence to trash fence full quieting. From 40ft up I do expect a coverage are of about 10 miles in radius. With BRC only being 2.5-3 miles in diameter we should have not have a problem. I have tested the setup as is in city environment and have radial throw of more than BRC is in diameter.

> What kind of antenna, a 70 or a combo 2 meter 3rd harmonic? Ground plane or something more fancy like dipoles, batwings, etc.

I have a UVS300 17ft, 8 stacked co-linear 1/2 wave dipoles with a 1/4 waves as a lead in and as a topper.

[RudolphDiesel]

> Sounds like a cool idea. I've always wanted to setup my mobile rig for cross band repeat and link in to one of the 2 meter repeaters you can hit out there but I always end up chasing shiny things and never get around to it.

> There isn't as much traffic as you'd think but I have talked to several people out there. One time I was chatting with this guy on 2m simplex and it turned out he was in the camp right next door to me.

For me one of the problems always was that in order to use a radio out there one has to listen to all the chatter. With DMR that’s not the case. You can select your own TG and then your radio only breaks squelch if the TG you selected and programmed into your radio is active. So basically even of some other folks are going to use the repeater, you are not bothered by it. I know of many people that this is one of the main complaint on FM. I hope the adoption of DMR is better than the one on FM on playa.

[Token]

> What kind of power are you running on the repeater and what do you expect in terms of coverage and distance?

I have set the radio to 5W transmit power since we are running on solar. Besides 5W 40ft up is plenty of power to cover BRC trash fence to trash fence full quieting. From 40ft up I do expect a coverage are of about 10 miles in radius. With BRC only being 2.5-3 miles in diameter we should have not have a problem. I have tested the setup as is in city environment and have radial throw of more than BRC is in diameter.

> What kind of antenna, a 70 or a combo 2 meter 3rd harmonic? Ground plane or something more fancy like dipoles, batwings, etc.

I have a UVS300 17ft, 8 stacked co-linear 1/2 wave dipoles with a 1/4 waves as a lead in and as a topper.

Super Slick!

So coverage to gate road, maybe, with a handheld ... but too short to reach Gerlach.

Really grand for you to bring this out. Every year it seems people look for a comms solution for art and big mutant vehicles and come up short. MURS was cool for a while but that too is getting sketchy.

Ground the heck out of that antenna.
Maybe share your grounding so others can learn about the depth reached and technique used.

[TT120]

RE: Grounding. As I understand it, the water table is around 15' below the surface of the Playa. If you can get a ground rod down that far, you'd have a very efficient antenna system.

[Token]

RE: Grounding. As I understand it, the water table is around 15' below the surface of the Playa. If you can get a ground rod down that far, you'd have a very efficient antenna system.

I’ve heard from reputable sources over the years, folks that have augered deep, drove in truck drive shafts and axles as anchors for big stuff ...

The water table is highly variable and can be as shallow as a few feet, or down 15 and below.

Moisture levels needed for good grounding are very likely reachable past 4-6 feet.

Would be fun to get measured resistance data to confirm.

[Zubeneschamali]

Awesome, thanks for the setup. KM6MYC @ C&915. Close enough to walk over and check it out. I'll bring the beer!

[RudolphDiesel]

I don't know if we can throw to Gerlach. I just measured the distance and at 12 miles we are certainly at the outer edges of the reach, but it might just be possible, since Gerlach is a few feet higher than the Black Rock desert, and with a perfectly flat horizon even two feet make a world of a difference.

Tell you what, if one of you is coming in later than Thursday (which is when I will be setting up the whole shebang) just start calling from wherever you think there might be LOS.

I will be hanging out on TG 2 TS 1 (KA5PLE)

I'd really be interested in the results just how far we can be heard with the setup and with 5W.

Of course that depends if I can get the tall mast up or if I have to go with the shorter height. If I have to mount the antenna just on top of the camper chances are we will not be heard in Gerlach, with the 30ft master and then the 17ft antenna we might.

Also I don't think we will need a lot of grounding for RF reasons. The UVS300 is a ground plane antenna and thus far has not needed grounding. Maybe I'd get one mile more throw, but even the current setup is overkill to support BRC

[TT120]

I don't know much about DMR as I'm an old school analog HF guy but it sounds like something fun to experiment with. Would you be able to backhaul to an analog repeater or could you assign a talk group to analog operations?

[RudolphDiesel]

In order to create a back haul we would need a RELIABLE IP(internet) connection of at least 38k. So, it’s not really high bandwidth but a cell connection on the playa as unreliable as they are during the week is not going to cut it.

No, I cannot put anything onto a FM channel since the whole protocol end to end is digital.

Really the only way to create a backhaul ( which, to be honest I not enthused about) would be to set up some form of a satellite up connection that runs on 12V and does not chew through too much power since everything has to run on solar.

[Token]

There is reliable internet on the Playa, been there for a long time, you just need to know the right people at the BORG.

They run a fat link back to the Gerlach office on licensed spectrum using wireless backhaul for infrastructure services, the box office, etc.

I’d argue it’s not a technical problem so much as a philosophical one. BRC should remain remote and less-than accessible from the outside is my emotive viewpoint.

[TT120]

I guess what I was asking was is it possible to link in to an analog repeater so that us old skool guys with analog equipment could use it.

I agree on keeping the default world out of it. I quite enjoy being off the grid.

[RudolphDiesel]

Sorry, no, we cannot link a good old FM to a TG. At least not with the equipment I have.

At the same time a cheap DMR HT is less than or around $70, or a really good one with active APRS beacon in is around $220.

OR, you swing by at our camp, ask for me and get a loaner for the event. I will bring two extra radios that I can loan out to folks. I will bring one extra GD77 and one extra CS700 (first come first serve)