[TowerTalk] antennas in water

[Richard Hill]

Conductivity:
metals (copper etc)          30-70 * 1 000 000 Siemans per square meter
Sea water                    5 Siemans per square meter
Saline water                 0.4 Siemans per square meter
Drinking water               0.05-0.000 5 Siemans per square meter
Deionized water in air       0.000 005 Siemans per square meter

Dry salt crystals do not conduct well between crystals. I've wondered how well a desert playa lake bed might do for RF transfer.  The surface may be quite dry, but soils may be saturated just an inch below.  There is a progression of ions in playa lake beds.  The lighter alkaline elements blow off in the summer and lakes go from being alkaline towards becoming sodium chloride dominated.

Rich
NU6T

-----Original Message-----
>From: Michael Tope <W4EF at dellroy.com>
>Sent: Mar 18, 2009 1:17 PM
>To: CRAIG CLARK <jcclark at wildblue.net>
>Cc: towertalk at contesting.com
>Subject: Re: [TowerTalk] antennas in water
>
>CRAIG CLARK wrote:
>
>>My 160 vertical is located in a fresh water swamp. The key to it's success
>>has been the thousands of feet of radial wire I have laid down.....not on
>>the water. I located it there as it was away from the house and out of sight
>>from the wife and the road, not for any perceived benefit from location.
>>
>>Fresh water is not a good conductor. 
>>
>
>I don't think anyone is disputing that, Craig, but neither is dry rocky 
>soil a good conductor (trust me, I have first hand experience with lousy 
>soil). Seawater is clearly superior to either of these two by several 
>orders of magnitude (about 3 in the case of average soil). The relavent 
>questions are whether rain soaked soil or fresh water lakes are 
>significantly better than average or poor soil. I suspect the answer is, 
>yes, but I don't have hard data to back that up.
>
>I think I remember reading that W8JI had some data for a fresh water 
>proximate BC sight that suggested the lake was somewhere between 15 and 
>30 mS/m, but I may be misremembering. I would be real happy with 15 to 
>30 mS/m compared to what I have now. I recall that the KS8S/AD8P contest 
>station in Deshler Ohio (Northwest region of state) was right in the 
>middle of a 15mS/m zone on the FCC conductivity map. From what I 
>understand you could dig down a few feet into Dean's yard and hit water. 
>It seemed like you could shunt feed a piece of spaghetti there and do 
>well on 160.
>
>BTW, even if the muck in your fresh water marsh has improved 
>conductivity over dry soil, I wouldn't expect that to obviate the need 
>for a good radial system. Copper is still a many many orders of 
>magnitude better conductor than even saltwater. I would expect the main 
>benefit of the mucky soil to be a positive impact on the psuedo Brewster 
>angle.
>
>73, Mike W4EF.............
>
>>With all due respect to other posters,
>>most of the comments have been anecdotal in nature and do not reflect any
>>scientific measurements of performance.
>>
>>I have done any number of searches from Terman to Laport and Google and can
>>find nothing that touts locating an antenna in fresh water to enhance
>>performance.
>>
>>73 Craig
>>
>>
>>Craig Clark K1QX
>>Radioware
>>PO Box 209
>>Rindge NH 03461
>>603 899 6957
>>  
>>
>
>
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