The Sainsonic AP510 APRS tracker can work well

As long as you recognise that the stock antenna is truly dire. And you’re prepared to fiddle a lot to get the AP510 and software going. This is not something that works out of the box. As supplied from Ebay in April 2016 the firmware of this didn’t match the software, in fact the firmware was too old. Cue much frustration and turning off and on to try and get it to talk. No dice.

Sainsonic AP510 description

Do what this guy says he has a treasure trove of the files in the links to the youtube post. It worked for me. I had to flash the firmware before my box would talk to the Sainsonic config software, and without doing that this device is no use at all.

Now if you can get an integrated GPS, APRS tracker, 2m rig for £78 it’s a great deal, if you can’t configure it it’s a rotten deal. But it worked for me in the end. There’s much to like, it’s small, it has its own battery, the price is right etc. There are things not to like – the male SMA on the board. SMAs are fragile, that pin is gonna break after about 500 cycles, which is why it’s nice to have the plug on the cable or the rubber duck aerial so you get to change that rather than the rig. Oh and the USB connector is a 3.3V RS232 connector, not a USB connector, though it can use a mini USB connector to a normal USB outlet to charge.

So I configured it and fired it up and it sort of works, well, out to about 200m for a J-pole vertical in my loft. Now I admit a J-pole with its somewhat live coax even after a CM coax choke doesn’t belong in the cluttered environment of the loft and I’ll change it for a Diamond X-30 or the like outside at some point, but I have a receive igate on it and it serves other mobile APRS stations okay enough, and serves me up to about 500m in the town with a Kenwood THD7.

The Sainsonic is only good for 1W, but then the Kenwood TH-D7 has a 7.2V battery pack which is probably only good for about 3W and that works well, So I decided to swap the stock Sainsonic antenna for the one from the Kenwood – so still a rubber duck, of about mid 1990s vintage. I need a SMA female barrel, which I made up from adapters.

All of a sudden, instant improvement in range to about 500m from my igate, after which the tracker is handed over to one of the wide area digipeaters on a tall building about 5 miles away. Win. It’s not clear to me why that wide area digipeater G4MRS-2 didn’t penetrate further into the town, but that’s RF for you. Perhaps I will turn off my igate and see if the Sainsmart can reach g4MRS-2 on its own.

From which I conclude that the stock antenna on the Sainsmart AP510 truly sucks and is not fit for purpose, but the box itself is okay. The stock antenna is 18cm long, the Kenwood one 20cm so the difference in length alone doesn’t seem enough. The SWR of the Kenwood was about 2 at 145MHz and the Sainsmart stock antenna about 3, but it’s hard to know what you are measuring without a controlled counterpoise

Using a regular f-f SMA barrel and a normal SMA fit rubber duck like the Kenwood one  should make this thing a whole heap more useful as a pedestrian or bike tracker 🙂