Alinco: Alinco DJ-MD5TGP weak GPS reception

[bozata]

I have two of those and both of them have very weak GPS reception. It takes about a min for them to acquire signal when I am out in the open (not a problem), on the field. Impossible to get a signal in the city (even with wide streets). I live in a high-rise, relatively away from other buildings and still cannot get a signal, even on the balcony.

Since I do not have any issues with other GPS devices, even smartphones with internal antennae, I am wondering if something is wrong with the chip they used or the antenna design. I looked at the teardown article and it is hard to see exactly what is the antenna and if there is a way to improve the reception. Also, I am not sure how many satellites they track in the firmware.

Has anyone experienced similar issues with the GPS? Any suggestions?

 

[ladn]

Are you current on the latest firmware?

 

[bozata]

Are you current on the latest firmware?

I thought it was assumed Yes, 1.13c

 

[bozata]

The chip seems pretty good http://www.icofchina.com/d/file/xiazai/2016-12-05/b5c57074f4b1fcc62ba8c7868548d18a.pdf

 

[jonwienke]

The Reyax modules are better, and don't generate RFI. They are the ones I use when installing internal GPS in scanners for those reasons.

Amazon.com: REYAX RY8253F 10Hz GPS Glonass BeiDou Uart 3.3V Flash antenna module battery I2C: GPS & Navigation

Amazon.com: REYAX RY8253F 10Hz GPS Glonass BeiDou Uart 3.3V Flash antenna module battery I2C: GPS & Navigation

www.amazon.com

 

[bozata]

The Reyax modules are better, and don't generate RFI. They are the ones I use when installing internal GPS in scanners for those reasons.

Amazon.com: REYAX RY8253F 10Hz GPS Glonass BeiDou Uart 3.3V Flash antenna module battery I2C: GPS & Navigation

Amazon.com: REYAX RY8253F 10Hz GPS Glonass BeiDou Uart 3.3V Flash antenna module battery I2C: GPS & Navigation

www.amazon.com

What do you think about the Alinco antenna? I am a bit concerned that is right above the screen.

 

[jonwienke]

I haven't evaluated the Alinco module, so I have no opinion on it. The other one mentioned is one of many I tested and rejected for RFI issues. If you're considering changing modules, the Reyax one is very good about getting a satellite lock in comically adverse conditions, such as under the driver's seat in a vehicle, in the basement of a house, etc. and it will calculate a fix from multiple GNSS systems simultaneously (GPS, GLONASS, etc.). The Reyax module also has a pretty effective feature for filtering out RFI from other devices, although you have to enable it manually.

 

[bozata]

I haven't evaluated the Alinco module, so I have no opinion on it. The other one mentioned is one of many I tested and rejected for RFI issues. If you're considering changing modules, the Reyax one is very good about getting a satellite lock in comically adverse conditions, such as under the driver's seat in a vehicle, in the basement of a house, etc. and it will calculate a fix from multiple GNSS systems simultaneously (GPS, GLONASS, etc.). The Reyax module also has a pretty effective feature for filtering out RFI from other devices, although you have to enable it manually.

Not sure if they would be simple swapout, even if I rewire the pins. The comm protocol seems different.

I am afraid I have to work with what Alinco put in, with minimum mods....

 

[jonwienke]

If the Alinco module outputs NMEA, you still need to figure out if it uses 1.8V TTL, 3.3V TTL, or RS232 to communicate with the radio. An oscilloscope may be handy for that--will at least tell you polarity and voltage of the signal lines.

 

[bozata]

If the Alinco module outputs NMEA, you still need to figure out if it uses 1.8V TTL, 3.3V TTL, or RS232 to communicate with the radio. An oscilloscope may be handy for that--will at least tell you polarity and voltage of the signal lines.

I can certainly do a lot to improve it but was wondering if there is a simpler approach.

Frankly, I bought it based on rave reviews online and I am disappointed overall - hence, my reluctance to invest too much.