CPU clock speed

[deniska]

Nylon32, thanks for your report...
I am still waiting for my mini-USB extention cables to arrive... If the cable proves to be effective in improving psp-290's reception, I may try to talk the manufacturer in to producing a special PSP version so no extra wires a nesessary...

If you have time and courage, it would be interesting to find out if raising the incoming voltage (to power the psp-290 unit) to 4-5 volts would increase the sencitivity even further...

Some people reported that psp-290 exibits worse sensitivity then PSP's battery is low... so perhaps raising the voltage (by powering it from outside sourse (3 aaa batteries) may do the oposite....

Of course, there is a chance of bricking the gps, unit, so I'll understand if you don't want to mess with it...

[Nylon32]

I might be able to get a hold of a fairly accurate variable DC output power-pack, so i'll give this a try.

::edit well the DC power pack didn't work at all. I checked all the connections for any short circuits or loose connections and still the unit refused to activate. but I'll try and find a few AAA batteries and see it they give me anything.

[deniska]

What was your exact connection diagram?

What you probably want to do is to conect the (-) of the battery to the USB ground wire (4) (see these diagrams: http://pinouts.ru/Slots/USB_pinout.shtml)
It should go to both PSP and GPS device.

Then the (+) of the battery goes to (+) port of GPS only! (this should be one of those side wires)

[Nylon32]

Well I wired up the power pack similarly to the way you suggested, but it had a ground terminal so I used that and connected the GPS and PSP to that terminal and the variable V+ terminal to just the GPS and it didn't give me any results.

After that I tried wiring it exactly as you said, but I could only get my hands on 4 fully charged, but quite old 1.2v Rated Rechargeable batteries, these too didn't work but this could have been due to them not having enough voltage left in them. If I can find some new 1.5v AAA's then I'll give it another try

Also I tried just connecting the GPS using my extension cable and just using the PSP output and again I was consistently getting a lock on 6 satellites and at one point while driving was getting a lock on 8 satellites, and I never noticed it drop the connection, By how much do you think a higher voltage could improve the signal by?

[deniska]

it's hard to say...

[Nylon32]

I managed to get the GPS to work using a separate power supply, I used 2 AAA batteries that were giving 1.8v each the pic shows it all wired up but the wire came loose from the top of the PSP as I took the picture.

it also does seem to activate quicker, taking less than a minute to get a lock on 4 satellites

Link to the picture:
http://img382.imageshack.us/img382/404/dsc00387hp3.jpg

I'll give it a try with 3 AAA batteries and see if it gives better results

btw I'm doing all this at 111mhz as it still seems to be best for getting a lock on satellites quickly

Edit::

I've just tried it with 3 1.5v AAA batteries (In total giving 5.3-5.4v as they're new batteries) and it got 2 satellites in view instantly a few more within a few seconds and a lock soon after that. Seeing as there don't seem to be any immediate adverse affects I'll try seeing how it behaves while on the move

[deniska]

cool, let me know if you find anything else..
thanks for your research....

[An0nJ0hn]

I may give the extension cable idea a try, I'll report back on how it went

:Edit
Well after dome very difficult soldering I managed to adapt a mini usb plug from an old mp3 player, and attach that to the end of an existing cable which allowed me to extend the usb part then all I had to do is secure a couple of wires to the DC jacks either side, and I'm pleased to say that it worked in less than a minute getting a fix on 4-5 satellites, as you can see from the picture this sort of set-up isn't ideal but the the improvement in signal strength (from 2-3 bars to 4-5 indoors) and accuracy is amazing.

http://img136.imageshack.us/img136/9829/dsc00367vx3.jpg

I got my cable today and I second Nylon32's results. I filed down the sides of the cable so that the power rods would fit into the sides of the mini usb female plug's casing. Then I took some spare cable I had and used it to connect the positive power. Nylon32 is correct about it working fine without the ground line although I will likely add it when I figure out how I'm going to make my cable permanent. I used no soldering and basically did a poor job of it but it works which is what I wanted to find out. I managed to get three bars reception indoors and under some pretty heavy rain today using the cable. It would be pretty sweet if we could get some proper cables made although I'm not giving up on making my own.

[Nylon32]

heh, I got my cable a couple of days ago and I modified it in exactly the same way

[An0nJ0hn]

heh, I got my cable a couple of days ago and I modified it in exactly the same way

Nice! That's pretty funny. What are you gonna use for connectors to the PSP and GPS receiver? I'll have to hit the local stores and see what they have as far as parts that I could cap the cable with. Let me know if you have any ideas.