From:  nitespark <nitespark@cox.net>
Date:  24 Sep 2005 21:37:55 Hong Kong Time
Newsgroup:  news.alt119.net/rec.scuba
Subject:  

Re: Underwater Data Link?

NNTP-Posting-Host:  24.254.177.70


Bob Bob wrote:
> Its all intriguing anyway! Not that I have a large enough body of water 
> nearby to try experimenting with it though.
> 
> I did a quick bit of browsing around and even found some experiments 
> done by a VK5 using 160M (http://www.qsl.net/vk5br/UwaterComms.htm) I 
> note he has some attenuation curves that might be worth a look at. 
> Although some kind of packet, PSK or other kind of digital system would 
> work in an SSB bandwidth the problem for the OP is that he probably 
> doesnt want to take a PC with him underwater! Still think a packet TNC 
> at 300BPS might be usable though.
> 
> I am actually here in more ways than one.. Am living in East Texas.
> 
> Cheers Bob W5/VK2YQA
> 
> nitespark wrote:
> ---
> 
>>
>> Nice to see folks from "VK" land here with us.
>>
>> 73 OM
>> Andy
>> WD4KDN

I agree Bob.  Quite interesting.  I was diving last weekend in a quarry 
with two other divers who had wireless comm systems using full face 
masks.  I could hear them talking to each other but couldn't make out 
what they were saying.  They have been trying to talk me into purchasing 
a full face mask with comm but at present, I have other financial 
priorities.  I guess for a very limited distance, 160 meters might work 
but depending on the application, battery size and the associated tx 
power would be limiting factors.  The article mentioned floating an 
antenna to the surface.  If you were to do that, you might as well use 
VHF or UHF depending on distances and power outputs, etc.  For most 
divers, I would think that would not be their first choice because of 
entanglement issues.

If you are in East Texas, depending on where, you are getting pounded by 
"Rita".  Hope all goes well.  Perhaps we can hook up on 20meter?

73
Andy