Upsampling

[Adam]

This is apparently another significant benefit of upsampling. As you probably recall, one of the only drawbacks to broadcasting at 5 Hz is decreased radio range/penetration. To achieve the bandwidth necessary to transmit the corrections from our base at 5 Hz we were required to modify the modulation to D16QAM.

We now have the option of transmitting from our base at 1 Hz, upsampling at the rover and running the corrections through the Beast mode processor at 5 Hz with no loss in fidelity. Upsampling effectively neutralizes the only drawback in processing at 5 Hz.

By running the base at 1 Hz with a modulation of D8PSK, upsampling at the rover and processing at 5 Hz, we regain the loss in UHF radio range. I use the 1 watt radio so heat has not been a problem. For those of you transmitting 35 watts at 5 Hz, you may have experienced additional heat management issues. I suspect the battery run time may increase as well.

Has anyone tried this configuration?

I use Upsampling with the 35 watt radio. The radio doesnt seem to generate as much heat using upsampling as it does with 5 hz broadcast. I didn't buy a fan until a couple weeks ago, so upsampling helped a lot this summer to reduce heat.

 

[Darren Clemons]

I use Upsampling with the 35 watt radio. The radio doesnt seem to generate as much heat using upsampling as it does with 5 hz broadcast. I didn't buy a fan until a couple weeks ago, so upsampling helped a lot this summer to reduce heat.

This is just not something I'm up on or completely understand. When you say you "use" upsampling with the 35w radio, where/how is that selected to be used? What is the main benefit for how we've been running with our T1M and the LS? Jim mentioned earlier in this thread that 5hz from the base "reduces" radio range, I don't remember that being discussed or being told that might be an issue when everything first went to 5hz. We've been struggling and wondering why this 35w radio will not go nearly the distances that we expected for over a year, could this be the reason why?

So, in what I'm reading, IS the base going to go back to 1hz and then be upsampled to 5hz at the rover?

 

[Adam]

Darren, the setting will be under Setup - Advanced - Rtk - set update rate to .2 and check use upsampling. It will help with range some, It's not gonna help if the range is limited by a lot of vegetation or terrain. It's really not that big of a deal for me, I rarely need to be a mile or more away, but from talking to some of you PLSS guys you need all you can get, so it helps.

 

[Matt Johnson]

This is just not something I'm up on or completely understand. When you say you "use" upsampling with the 35w radio, where/how is that selected to be used? What is the main benefit for how we've been running with our T1M and the LS? Jim mentioned earlier in this thread that 5hz from the base "reduces" radio range, I don't remember that being discussed or being told that might be an issue when everything first went to 5hz. We've been struggling and wondering why this 35w radio will not go nearly the distances that we expected for over a year, could this be the reason why?

So, in what I'm reading, IS the base going to go back to 1hz and then be upsampled to 5hz at the rover?

The updated version (October 6, 2016) of the Triumph LS Quick Start Guide has this information:

 

[Darren Clemons]

Thanks Matt, somehow I've missed any discussion or talks about this. So when I click on "use data upsampling" does that automatically put the base back into 1hz transmissions?
Also, if I use data upsampling I need to switch modulation to D8PSK?
The main question though is, IF we are getting good performance like we've been using it with both base/rover at 5hz is there any benefit to using up sampling? Yes, we have had a few spots where radio range has been a bit of an issue but not many. We've had a fan on our 35w from day one so heat hasn't been an issue either.

 

[Darren Clemons]

Darren, the setting will be under Setup - Advanced - Rtk - set update rate to .2 and check use upsampling. It will help with range some, It's not gonna help if the range is limited by a lot of vegetation or terrain. It's really not that big of a deal for me, I rarely need to be a mile or more away, but from talking to some of you PLSS guys you need all you can get, so it helps.

Sorry, I missed this post Adam when I saw Matt's. This answers pretty much everything I asked above. Doesn't sound like anything I'll try much. However, I was on a job two weeks ago that the edges were 4000-5500' away from my base and we stayed in that "danger" zone. Radio % hovering between 45-70%. When that happens you're pretty much dead in tough spots. The signal just won't hold strong enough for long enough to acquire good RTK solutions so on that site I would've tried this for sure. An "extra" 1000' of possible radio range would've been golden.

 

[Matt Johnson]

The base transmission rate is configured in Base Rover Setup. Any modulation with work with 1 Hz transmission but DQPSK would be the preferred option for 1 Hz transmissions. Only D16QAM works with 5 Hz transmissions.

 

[Nate The Surveyor]

OK, I have the fan kit. Is the fan kit recommended any more? I'm thinking of removing my fan kit... because it would tend to restrict air flow to the fins. I spoke with Shawn a bit ago, and he seemed to THINK so, but Thought I should be sure.
Another thing I m working on is a TUBE for the radio... Think of one of the old Flumes, or very tall smoke stacks... with a little heat, they generate a vacuum. Natural air flow. It's called the "Chimney Effect". https://en.wikipedia.org/wiki/Chimney So, If I made a little chimney for the radio, out of some light PVC, and it was set up vertical, with an opening at the bottom then it potentially could increase air flow, over the radio.
Any thoughts?
Thanks
Nate

 

[Matt Johnson]

It would have to be very hot outside for the radio to overheat at 1 Hz and 10 watts of power (the max allowed by FCC with the 5 dBd antenna). The simplest way to tell if you need the fan is to use the radio without it. If it gets too hot to touch, then you need the fan.

 

[Jim Frame]

It would have to be very hot outside for the radio to overheat at 1 Hz and 10 watts of power (the max allowed by FCC with the 5 dBd antenna). The simplest way to tell if you need the fan is to use the radio without it. If it gets too hot to touch, then you need the fan.

My license allows 70w ERP.

 

[Matt Johnson]

My license allows 70w ERP.

Yeah, there are a few people that have 70 watt ERP licenses, most of us are limited to 35 watts ERP.

 

[Nate The Surveyor]

Ok, nate reporting.
Don't need fan any more.
Often, I use my old 1/2 wave antenna, not the 5/8 one. It seems to penetrate woods better. Many of my jobs, 10 watts is PLENTY.
Long range is back! (clap, clap, clap)
N

 

[Nate The Surveyor]

T-2, with 35 watt radio:

On frequency modulation, which will yield better range, and penetration, in the trees?

DBPSK
DQPSK
D8PSK
D16QAM

And, is any one of the above PREFERRED, for 25KHZ bandwidth?
As I read it, DQPSK is preferred for 12.5 KHZ bandwidth... Is this still true?

I found mine was set at D16QAM, (don't know how that happened...) But, my range was suffering... So, I went checking.

Also, is RTCM3.0 the best for the Receive Format?

Thanks!

N

 

[Matt Johnson]

I wrote about modulation selection in the Quick Start Guide:

So you have the modulations listed in order from best range to worst and also from most power consumption to least. 25 kHz bandwidth is illegal in the US and there is no reason to use it.

"RTCM 3.0 Min" format transmits all the data that is needed.