Sainsonic AP510 APRS tracker experiments

I bought an AP510 some time ago, at the time results were disappointing, but the firmware has improved over the years. Using 20141215 I was getting signals out to about 8 miles from the typical white stick omnis like Diamond X50, and up to 20 miles from near Chagford on Dartmoor when it was mounted in a backpack. As you can see from the header picture, I had a great RF takeoff and not much vegetation in the way from pedestrian height 😉

Thank you G6SQX and G0MAS for running high performance APRS IGates! The difference in performance with the antenna taped to the fibreglass shell at the back of my campervan is visible in the paucity of reports near G0MAS around Uffculme, range was only a quarter of that as a pedestrian. Despite having steady power and a USB lead as a counterpoise to the aerial. Maybe taping the aerial to the fibreglass detuned it, this thing is marginal enough at 1W output.

Some of the idea of getting this was to play with radio on the hills so it’s good that it performs better in pedestrian mode. I’d like to have a better feel of why exactly that was.

Improving the aerial – or not

The usual principles apply with radio, the best performance win is getting a better aerial. The original aerial supplied was absolute garbage¹, and I improved it by substituting this fine ebay product of dubious provenance

and throwing away the original aerial so that it didn’t waste any more of my time. The original was about the same length as the Baofeng rubber duck aerial in this pic

That’s about as far as I want to go, not so long that toting this in the field is an absolute pain in the backside but long enough to get an improvement.

My Nagoya 771 is clearly a ripoff of the original when you look at this pic from

Nagoya’s website. Reading Julian’s website where he had a very similar antenna which he deemed crap, so I was inspired to test mine for SWR, and I confess that Julian was right on the money

So I decided to test the Baofeng antenna

Maybe I should go with the Baofeng. I tested a Watson WSMA-7000 that I had bought when I thought I had lost the antenna for the THD7E,

I should throw away my fake chinese antenna and either buy a real Nagoya, or stick with the shorter length. Getting a real 771 seems to be a tough game. Looking at the (a dodgy?) Diamond version of this from radioworld the reviewer on Feb 3 observed a SWR of 1:5.5 so maybe these are only good for 70cms.

In the meantime, I’ll run with the Baofeng, or get an SMA barrel and use the Watson. A SWR of 2 and a bit isn’t inspiring, but is a damn sight better than 5! Perhaps a good honest 50cm telescopic aerial with a 0.5m tail as a counterpoise is the way to go here if I want a longer aerial, you can’t beat the honesty of a λ/2 dipole…

Like many bits of Chinese radio gear, the AP510 instructions are in Chinglish and the process of getting the thing working is tortuous and grief-stricken, though the AP510 Yahoo Group has all the information you need to know, and this video is a good place to start. The Yahoo group is vastly improved by having the Chinese developer on it for the last couple of years, the documentation is almost competent now. I do feel for him at times, it is amazing how many people can’t follow the instructions on how to configure the unit – start off with the radio OFF and set the config software to start trying to read the config before you even THINK of turning the radio on. Yes, it’s barmy and doesn’t seem kosher in any way, but it really works better if you do what the man says.

Just say no to Prolific USB adapters and their clones

I have flashed the firmware to 20170403² and will see how I get on. One piece of total pain that you can get right out of your life is the original USB to serial interface, which is tastelessly taken in on a mini USB connector that isn’t a real USB socket, but really a serial port. Sainsonic supply it with a knockoff Prolific USB to serial chip, and a knockoff driver. The company Prolific should be destroyed and run out of town  for their response to clones, which was to end of life the chips that were cloned so the Windows 10 driver doesn’t see them. Never use a Prolific part for anything – no good will ever come of a company with that sort of bad character.

For some products which have an internal Prolific clone USB to serial converter you are SOL and have to do the driver shenanigans described in this thread. For this one, all you need is to use a FTDI USB to 3.3V serial cable – I use these guys who are on Ebay as USBtoTTL, and I use their clear USB housing because it is good to see the RS232 activity on the blinkenlights, life is too short to putz about with anything made or purporting to be made by Prolific.

Then it’s simply a case of cutting off a Mini USB cable end and connecting ³ white from the USB to yellow on the FTDI cable (RX), green on the USB to orange on the FTDI cable (TX). Use a 3.3V FTDI cable. Nice if you can get one with 5V power, in which case wire that to the red USB lead, but if not you can config and flash the AP510 with internal power. Obviously if you flash the rig on battery and brick it, then that’s your tough luck, you have been warned 😉 But I chanced it and got away with it. Take it slow and read the sequence instructions carefully. This is another start with the unit off and set the firmware uploader searching and only then press the red button to start the unit, but this time keep the button pressed until you get the upload successful result from the uploader.

Pay a little more for the FTDI cables, and throw away anything with a Prolific chip in it. Prolific trashed my old Belkin USB to serial adapter. I’d be surprised in Belkin used knockoffs, but for Prolific to protect their interests and IP I got stuffed. Bastards…

Alternatively you can use Linux and Chirp to config this unit, for some reason the Linux prolific drivers work fine. That way you get to spend the time you save on making Windows Prolific drivers work, on making linux work instead, TANSTAAFL 😉