[aprssig] APRN Now! (cell phone uploads too)
Stephen H. Smith
wa8lmf2 at aol.com
Mon Aug 10 10:06:09 CDT 2015
On 8/9/2015 9:55 PM, Robert Bruninga via aprssig wrote:
> Shucks, while we wait for the SSTV camera to integrate into the APRN network,
> with an OBJECT identifying HT remember there is also no restriction on using
> a cell phone camera NOW to upload an image into the APRN site.
Actually, sending pics with a cell cam, without APRN involved, is already fully
integrated. Nearly all cell cams already automatically embed data from the
phone's GPS into the EXIF (EXtended INformation) header of the JPG file. Send
the pic to an email address with the normal"MMS" (Multimedia Messaging Service
- i.e. a text message with attached picture)- a feature present on nearly all
phones. (Even my ancient Moto E-815 clamshell "dumb phone" can do this.)
Since this IS a text message, you can include any comments in the text part
When the received JPG is viewed in apps like the freeware IrfanView, clicking
"Image, Information" will reveal the EXIF data including GPS coordinates. One
more click will open Google Maps with the exact location pinpointed, usually
within 20-30 feet.
> just remember, because it is easy to do with a cellphone, the APRN site
> structure should be designed from the ground up to be compatible with the
> APRS radio as the field entry device, and with the APRS object data as the
> image identifier and cataloging system.
This is inherently going to be much more kludgy, due to the need to deal with
both the analog SSTV transmission and the digital packet transmissions
separately. I DO run mmSSTV (for the analog pic) and the UZ7HO Soundmodem
(for the packet data) simultaneously on the same sound card at the same time
Transmit, however, will be much more complex (unless you have an APRS radio
that can do built-in Mic-E burst on unkey such as a D700, TH-D72, D-710, etc),
since you will have two separate sound sources that need to go into the mic
jack or mini-DIN "data" port. I.e. the N1VG SSTV board and something like an
OpenTracker or TinyTrack to generate the packet burst. Not to mention the
sensing of PTT by the SSTV source to trigger the packet burst afterwards.
This is relatively easy to do with a full-sized radio, but will be a hopeless
mess on a handheld. Since the mic and ext speaker are normally on the same
jack, plugging in a cable to send the APRN image cuts off the internal mic AND
speaker. This leads to having to constantly plug and unplug the external
device in order to hear and make voice transmissions. Realistically, no one is
going to walk around with a tangle of Y-cables and multiple external boxes
dangling from their hand-held.
I assume you would be doing this on a channel other than 144.390, since the
picture transmission will take from 36 seconds (for the low quality Robot 36
mode) to 110 seconds (for the far sharper Scottie 1 mode), which would be VERY
disruptive to the normal 144.39 APRS channel. This implies, at the receive
location, a radio and antenna separate from the one doing normal APRS igate
duty. I do this, but i doubt that this will gain very much uptake by the ham
population at large to create a wide-spread network.
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