28506 GPS questions

MSDTech

1. Is there a way to shorten the cable on the antenna? I will be using this on a small robot (15" footprint) and don't need the long cable. If not, is there a good antenna with a short cable that will work with this unit.
2. I noticed the schematic in the Parallax documents does not match the schematic on the Simplytronics website do not match. Which is correct for the module?

Chris Savage

The only way to shorten the cable would be if you have a new connector (and the required tool) to attach to the shortened cable.

As for the schematic, since SimplyTronics designed this module I would say they would have the latest schematic, however I will check with them.

Chris Savage

It was also pointed out that you may not have meant schematic, but rather the wiring diagram. Can you confirm please?

MSDTech

I was talking the schematic. For example, the RX TX pins on the VPN 1513 on the SimplyTronicx diagram are connected to pins 26 and 27 on the propeller. While the Parallax diagram only shows the TX pin connected to pin 18 on the propeller. If I want to write my own firmware, I would need to be aware of this.

Chris Savage

Can you link the documents you're referring to? I am aware of the schematic on the SimplyTronics site, but the other document you're referring to I cannot find.

MSDTech

OOPS, I was looking at the documentation for the 58506, while the unit I bought was the ST-00059, which is Parallax P/N 58510. I guess I need a better magnifier/reading glasses working with these small parts.

Chris Savage

Okay, so you're set then or do you still have questions on the product you have? I can still help you if I have the details.

MSDTech

Just one other question, when mounting the antenna, is there a preferred orientation?

Publison

MSDTech wrote: »

Just one other question, when mounting the antenna, is there a preferred orientation?

Up

The curved part should be pointing up. Flat part parallel to the ground.

WBA Consulting

You can shorten the cable and solder directly to the PCBA. I have a module with this modification half done. I can complete this weekend and post pictures and results of the performance. I am also looking at replacing the connector on the end because I have the means to do so. If an antenna with a 10" cable was available, these modules would be much more useful (in my opinion).

MikeDYur

WBA Consulting wrote: »

You can shorten the cable and solder directly to the PCBA. I have a module with this modification half done. I can complete this weekend and post pictures and results of the performance. I am also looking at replacing the connector on the end because I have the means to do so. If an antenna with a 10" cable was available, these modules would be much more useful (in my opinion).

I just wondered how the shortened cable worked out for you, going to do the same to mine, wanted to make sure it don't effect reception. Also, sounds like you went with opening the weather resistant patch antenna enclosure, I was hoping to re-use the conector end, or just cut and splice the extra cable out.

MikeDYur

To late for a responce, past the point of no return.

MikeDYur

Don't Do It!

The cable length must be an active part of the antenna, no acquisition indoor or out, another experiment in futility.