<div dir="ltr"><div><div><div>Stephen,<br><br></div>Thanks. I think you answered most of what I was after. That is, there are presently no tiny cameras with direct to digital transmission over RF, but you did remind me that the existing APRN concepts are probably still valid.<br><br></div>That is, the transmission from the mobile robot camera may be SSTV (Greatest availabililty of cameras) , but as soon as it is received, then it is converted to a file and networked onward as needed in digital form.<br><br></div>So I guess then, my call is for a revitalization of a global APRN network that can receive these images from mobile robots (on RF) and seamlessly make them available to viewers (and robot drivers).<br><div><div><div><div><div class="gmail_extra"><br></div><div class="gmail_extra">We're talking about the kind of driving that Mars rovers do. THey get a fixed image, layout the path to be taken within that field of view, then execute the maneuvre and take anotehr picture.<br><br></div><div class="gmail_extra">Of course if you heard the news, dont drive your robot near Philly where vandals might bash it to pieces...<br><br></div><div class="gmail_extra">I envision a mobile robot mission across America driven by (and protected by) Ham Radio Clubs across the county. Driven completely by remote control and handed off from club to club with vision going to the APRM and position to APRS.<br> <br></div><div class="gmail_extra">Bob, WB4APR<br><br></div><div class="gmail_extra"><div class="gmail_quote">On Sat, Aug 8, 2015 at 12:34 PM, Stephen H. Smith <span dir="ltr"><<a href="mailto:wa8lmf2@aol.com" target="_blank">wa8lmf2@aol.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 8/8/2015 6:53 AM, Robert Bruninga via aprssig wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Can we go back and look at the APRN again to see if it is time to upgrade it to digital, so that images can be sent end-to-end instead of posted to web pages?<br>
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Given the same resolution of a simple SSTV (120 by 120 pixels?) how small of a JPEG file can result? Shouldnt take long at 9600 baud.<br>
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120x120 is from a bygone era of 5FP7 radar CRTs being used as display devices.<br>
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The standard minimum SSTV resolution today is a 320x240 pixel (quarter VGA) 3:4 aspect image that will yield about a 50-90K image when saved as a JPG. Over 99% of all SSTV today is generated and received with PC-based soundcard software, rather than dedicated hardware devices, and is sent with modem-like multiple audio tones, not as serial data that would be compatible with a packet-like transmission system.<br>
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What is "upgrade to digital" supposed to mean? Classic SSTV is totally analog. It's almost literally NTSC in (very) slow motion.<br>
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"Digital SSTV" as it exists today, (and is embodied in the recently orphaned EasyPal program whose author died of cancer around the beginning of the year) is essentially just a general-purpose error-corrected file transfer program.<br>
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You shove an existing image file (.JPG, .TIF, .GIF, etc) into the transmit routine that encapsulates it in several layers of error correction before transmission. The actual over-the-air transmission uses multiple (4, 8 or 16) QAM audio subcarriers in the voice passband. At the RX end, EasyPal unpacks the original file from it's layers of FEC and reconstitutes it as the original image file. The typical transmission time is a minute or so and consists of the roaring grinding noise typical of multi-subcarrier data transmisions; i.e. like "56K modems" or digital voice.<br>
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The issue is the easiest way to capture the original live image. N1VG's (Argent Data) single-board SSTV cam will capture 320x240 color images and encode them into your choice of several of the most popular <ANALOG> SSTV formats. However, the output is FMed audio tones, not logic level data. At the receive end, you would use one of the common soundcard SSTV programs such as mmSSTV (Windows freeware) to decode and display.<br>
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I am not aware of ANY standalone hardware that will do EasyPal-style "digital" SSTV. The closest I have come is running EasyPal on one of these dirt-cheap Windows tablets that has built-in cams.<br>
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<<a href="http://WA8LMF.net/Winbook_Tablet" rel="noreferrer" target="_blank">http://WA8LMF.net/Winbook_Tablet</a>><br>
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--<br></blockquote></div><br><div><div><div><div><div><div>Can we go back and look at the <span class="il">APRN</span> again to see if it is time to upgrade it to digital, so that images can be sent end-to-end instead of posted to web pages?<br><br></div>Given
the same resolution of a simple SSTV (120 by 120 pixels?) how small of a
JPEG file can result? Shouldnt take long at 9600 baud.<br><br></div>The
application is remote controlled ROBOTS for the ARRL's STEM outreach.
Students build "mars rovers" and then each school lets the kids then try
to control the other school's robot over APRS.<br><br></div>Mark Spencer at the ARRL has developed the MAREA concepts for the remote control, and I want to revive the <span class="il">APRN</span> concept to give the robots vision.<br><br></div>see: <a href="http://www.arrl.org/marea-ham-radio-robotics" target="_blank">http://www.arrl.org/marea-ham-radio-robotics</a><br></div>and: <a href="http://aprs.org/aprn.html" target="_blank">http://aprs.org/<span class="il">aprn</span>.html</a><br><br></div>Bob, WB4APR</div></div></div></div></div></div>