[aprssig] Mobile Off-Air Display

Fred Hillhouse Jr fmhillhouse at comcast.net
Wed Aug 12 09:27:24 EDT 2015

That is an interesting idea Greg! I wish my car stereo had that option.
Actually it does if I use NTSC and drive backwards everywhere. ;)


I used to think I wanted more resolution but there are trade-offs. If tiles
are used, they are 256x256. On the typical low resolution monitor, they
would occupy about a 2” square are and the info was readable. Now the tile
occupies about ½” square (7” HD) and the information is not readable without
getting close to it.




Best regards,

Fred N7FMH




From: aprssig [mailto:aprssig-bounces at tapr.org] On Behalf Of Greg D via
Sent: Wednesday, August 12, 2015 12:38 AM
To: Andrew P.; TAPR APRS Mailing List
Subject: Re: [aprssig] Mobile Off-Air Display


Hi Andrew,

SD cards have a speed rating, which I presume would affect the read and/or
write performance you saw.  What sort of pedigree did the SD cards you used

I'm still thinking of connecting a Pi to the Video-in on my car's audio/nav
unit (at a whopping 640x480 resolution) and doing an Rx APRS display that
way.  Could also connect a USB web-cam to the Pi for a back-up camera, etc.,
etc.  Once you have a computer on board, the sky is the limit.

Greg  KO6TH

Andrew P. via aprssig wrote:

I hate to bad-mouth my own product, but the Pi's disk storage (on an SD
card) is just too slow for map rendering in YAAC on a mobile station (it is
up to barely tolerable on a Pi B 2). I've accelerated the rendering code in
YAAC about as far as I can, and on a Pi the load is now mostly reading the
disk files of mapping data, rather than the actual rendering. I need to
conduct some experiments with USB memory sticks to see if they are any
faster than SD cards on the Pi as a storage device for YAAC map data. And
I've looked at those 7" LCD screens they have for the Pi; nice idea, but how
do you scotch-tape and chewing-gum the Pi to one of those screens so it will
hold together in the mobile environment?

Andrew, KA2DDO
author of YAAC ("Yet Another APRS Client")


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