Signal Strength surveys

[VK6NCB]

Hi everybody.
I am wondering what everyone uses to produce heatmaps of signal strength for their clients ?
I think the answer is going to be fieldfox or anritsu, but I am looking for a more affordable option.

I work on mine sites, a couple of hours flight from our office, and often require signal surveys to be done as the pits get deeper, to ensure reliable comms.
the company wont buy a fieldfox, and if they did its highly unlikely the boss would want it out in the hot dusty environment of the mines.

does anybody have a cheaper option that will produce either a heatmap as an end product, or GPS location and RSSI as a CSV ? something affordable for a technician to buy on their own, that doesn't cost more than a new car ?
I have been looking at the new RF Explorer pro and signalhounds.

I do have a TinySA, so even if theres some software that can do the job, that would be great.

I am aware Motorola have their survey software, which would be perfect if I were on a Motorola site, but the sites I look after are running Hytera XPT, and I am unaware of any similar software for Hytera

Thank you in advance

 

[TampaTyron]

If trbo, you can try th Mototrbo Site Survey tool. We do RSSI checks on conventional, IPSC, cap plus, connect plus and cap max. Alternatively, an anritsu or keysight with channel mapper or coverage analyzer tool would be decent. Paper map and pen with radio in rssi works too. I feel the best option is to jump to a shop that properly supports its techs (in the last 3 years, I have gone from 5 techs to 35 and from 2 decent pieces of test gear to 2 dozen)..... TT.

 

[Ubbe]

If the pit goes deeper, what happens to the GPS data when the view angle of the sky gets more narrow?

At one time we used self made programs done in Basic. Use any reliable receiver that can output signal strength, either numbers or a DC voltage that can be converted to a number, then log time, GPS coordinates, signal levels at the sample rate you'll need. The Basic program handle the logging and compiled the results.

We always did coverage logging from roads that a customer would use and created kmz trails for Google Earth with different colors to represent different signal strengths, so the track will follow how you moved around in the pit and show its signal levels.

It will take time to do your selfmade solution but also to try out and learn any bought system, so for just one measure, or several a couple of years apart, it will be more wise to hire that service from experienced professionals as it will always result in data you can trust.

/Ubbe

 

[VK6NCB]

If trbo, you can try th Mototrbo Site Survey tool. We do RSSI checks on conventional, IPSC, cap plus, connect plus and cap max. Alternatively, an anritsu or keysight with channel mapper or coverage analyzer tool would be decent. Paper map and pen with radio in rssi works too. I feel the best option is to jump to a shop that properly supports its techs (in the last 3 years, I have gone from 5 techs to 35 and from 2 decent pieces of test gear to 2 dozen)..... TT.

Jumping ship is not an option at the moment, though it might be possible in 6-12 months.
I will take a closer look at the anritsu we have at the office, it might have a mapping/logging option available. if not, looks like paper and pen are my best options
thank you for the advice.

I just had a thought, its a conventional DMR site, I wonder if I can set my Moto handheld to work with the hytera repeaters and the moto survey tool.

If the pit goes deeper, what happens to the GPS data when the view angle of the sky gets more narrow?

At one time we used self made programs done in Basic. Use any reliable receiver that can output signal strength, either numbers or a DC voltage that can be converted to a number, then log time, GPS coordinates, signal levels at the sample rate you'll need. The Basic program handle the logging and compiled the results.

We always did coverage logging from roads that a customer would use and created kmz trails for Google Earth with different colors to represent different signal strengths, so the track will follow how you moved around in the pit and show its signal levels.

It will take time to do your selfmade solution but also to try out and learn any bought system, so for just one measure, or several a couple of years apart, it will be more wise to hire that service from experienced professionals as it will always result in data you can trust.

/Ubbe

We are supposed to be the "experienced professionals" but in the past we have been dealing with small sites, and one or two channels, which makes a manual "pen and paper" method with a radio that reads RSSI quite an easy task.
as the company has grown we are dealing with bigger and bigger sites, which is why i am trying to automate the process.
hiring a fieldfox might be the best option, if I cannot get the moto site survey tool to work (which thinking about it now it should - when I originally posted, I was at a Hytera XPT trunked site, but I have moved to a conventional DMR site using Hytera gear)





Thank you both for the help I will let you know how it all goes in the coming weeks

 

[RFI-EMI-GUY]

Whatever method you use, consider a read of TIA TSB-88D or latest and keep in mind that the uplink from the portable is important as it is USUALLY, the weakest link due to portable antenna and power levels.

 

[Ubbe]

When you look at the coverage situation in both outbound and inbound it is usually a static interference situation at the basestations receiver that can be fixed with filters and other actions, but a portables receiver are exposed to a more demanding RF situation that are more dynamic and can change wildly at different locations within the coverage area, and the receiver in a portable are usually of a lesser quality that the one used at the basestation.

If you have something like a 25W output at the basestation and the portable use 5W it will usually have equal coverage in both directions and a bit of headroom at the portables receiver coverage. When doing surveys you can use a much better receiver and plan for any interference in the weaker ones in the receivers that the customer are using, or use the radio model that the customer use, if that are possible, to the get the true coverage at the moment when the survey are done, but that could change at any point so always better to add some extra dB at the basestation TX, especially if it is working as a repeater.

/Ubbe

 

[TampaTyron]

Mototrbo site survey tool will work in your scenario as it send commands to the radio to key up and gathers RSSI and GPS from the radio itself. I recommend taking an RSSI reading from a portable, then comparing that to the MOTOTRBO mobile RSSI with a 1/4 wave ant on the roof. Then, apply that correction (difference between portable RX RSSI and mobile RX RSSI) to the Site Survey Tool. Strongly recommend basing your entire readings/testing methodology around portables if your customer has any portable in the entire system that they reply on. The thought there is if the system runs for a portable, then a mobile will be great. If it is an on site system and is near the tower sites, turn the power down on the mobiles to keep from making the site deaf. Also, consider using low gain antennas if you are digging into pits or up mountains and such (take advantage of the large vertical beamwidth........). Good luck. TT

 

[stevehn787]

Some time ago there was an option board for the DP3000 and DP4000 series Mototrbo radios.
This allowed you to select a poling rate and it sampled RSSI and stored it on the option board to be downloaded later.
It wasnt a full heat map as such, but gave dots on google earth maps to indicate outbound coverage.

It could automatically key the radio and sample the RSSI.
Dont know if it is still available, or any use, but seemed like a simple idea.

 

[aliby19]

I too was looking to do some simple/basic coverage analysis. I stumbled across this SDRangel forum post, showing that the free/open source SDRAngel coupled with a Software Defined Radio (SDR) usb stick connected to a laptop or an Android phone can plot RSSI values on a map.

It doesn't build a full blown heatmap per se, but it does give some idea of signal strength at points along a route.

(Image from the forum post noted above)

Note - During my testing, I kept having issues with both the Windows and Android versions of the app not being able to save the heatmap, so I ended up shelving my project for the time being. Looks like a bunch of releases/updates have happened since my testing, so hopefully my issues have been resolved.

SDRAngel Main Website: SDRangel – Open-source TX & RX Software Defined Radio
SDRAngel GitHub: GitHub - f4exb/sdrangel: SDR Rx/Tx software for Airspy, Airspy HF+, BladeRF, HackRF, LimeSDR, PlutoSDR, RTL-SDR, SDRplay and FunCube
SDRAngel Getting Started Wiki: Quick start

 

[Ubbe]

the free/open source SDRAngel coupled with a Software Defined Radio (SDR) usb stick connected to a laptop or an Android phone can plot RSSI values on a map.

Be careful doing RSSI plotting using a USB dongle if you want the values to be useful to you. You could be plotting interference and overload issues from the dongle itself. Always use the best possible reference standard receiver, and preferable with external bandpass filters, for this kind of work or the result will be more or less useless.

/Ubbe

 

[DisasterGuy]

Artisu LMR Master or Freedom service monitor with the site survey software

 

[speedway_navigator]

Hytera has an RSSI program.