Packet Loss

Hotspot Fixing Packet Loss with AutoCal

Ben16 Comments

The thing with digital communications, it can be extremely complicated. It only takes one tick box to be ticked incorrectly to take your station off the air.  Just as easily one tick box will get you on the air and sounding great.

With Analogue, it was all about antenna gain, SWA, power and height.  Digital is vastly different, especially via a hotspot, as it is all about lack of power, mic gain and packet loss.  Packet loss can be tricky and is often put down to a bad internet connection.  However, that is not always the reason, and if your internet is good, and your packet loss is above 1%, then it can get tricky to know why.

Assuming you have a good connection, you have your hotspot close to your modem if it is via wifi and your radio is also close to your hotspot, then here is something you may want to try.  I will explain how to do it using an OpenSpot, as that is what I am using, however, most hotspots may have the same or similar features.

After many years of using the same hotspot, I noticed more and more the hotspot didn’t seem to recognise my signal from my radio.  I could hear fine, and my hotspot even said it was receiving my signal, but my call didn’t come up on the dashboard and the other person couldn’t receive my signal unless it did come up on the dashboard.

It started 3 in 1 times I would trigger the hotspot like normal, then it changed to 1 in 3.  It got worse before it made the hotspot almost unusable.

My hotspot, an OpenSpot2, has a AutoCal option and will analyse an incoming signal and tries to find out the frequency difference between the OpenSpot and the transmitter. They suggest that you only run AutoCal feature if the openSPOT2 shows BER above 1% for your radio’s transmission, as errors in the voice stream usually won’t be noticeable if the BER is below 1%.

You can see this on the OpenSpot by going to the Status screen and open the BER graph and transmit. A quicker way is to look when you transmit on the dashboard of your OpenSpot, you can see below the BER is next to the B, and this example has a loss of 1.3%.

Dashboard showing BER loss.

With the Openspot, press the quick setup button, select the type of radio you are using (I am using a DMR radio), and then you can see the AutoCal button.

All you need to do is press that AutoCal button.  Then scroll down and you will see it doing the three phases. Make sure the correct modem mode is selected. Hold the PTT button on your radio until all 3 phases are completed. Once complete, you can try the echo test to check you are working well.

Then you can return to normal use and the BER should have reduced to well below 1%.

OpenSpot have more information here in their user manual.

I hope this helped you, and if you enjoyed it, here are some other posts I have done. Please don’t forget to put your email address in to make sure you get the latest posts.

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