Topband: water saturated ground effect

[n2kw at juno.com]

Byron,
How has the 3db bandwidth been affected?
Have you noticed any difference in antenna performance?
Going from an inefficient ground system, to a more-efficient ground/radial one, raises SWR, and also narrows bandwidth.  This is because you're going from a resistive load, to a tuned (reactive) one.  You say that you have observed a change in feedpoint impedance/matching, but nothing else.
Herb pointed out that FRESH water can act as an insulator, which I had never considered.  If your radial system is insulated from earth, you have a lesser ground, I guess.   I have seen articles advising use of INSULATED wire, to reduce corrosion.  They used to dump bags of Copper Sulphate at the ground stakes in the past, but I don't think that is PC these days.  Did you plan on planting a garden there? Personally, I am an advocate of elevated radial systems, but realize this is often simply not an option.  (Even "turkey-wing" radials are more efficient than buried ones, unless you do a lot of burying.)  How about adding some chickenwire?  That's the secret of an efficient buried radial system ...."adding."

Allen - N2KW
---------- Original Message ----------
From: BRYON PAUL n0ah VEAL <bryonveal at msn.com>
To: "topband at contesting.com" <topband at contesting.com>
Subject: Topband: water saturated ground effect
Date: Mon, 18 Jul 2011 18:31:55 -0600



On my Cushcraft MA160V, the resonant SWR point has lowered from almost 5:1  to 1:1 without the Amidon unUn in line.  All 26 of the buried radials are attached.  The main difference is that the normally dry ground is saturated from 6 inches of rain in the past two weeks.  Can the water saturated soil really make this much of a difference?  The last time this antenna showed this good of an SWR, was when I had no radials attached, in dry dirt, as expected-  Of course attaching radials only began to show the true impedance mismatch, thus the need for the Amidon UnUn to match the coax to the antenna- Bottom line, the antenna is acting like I disconnected the radials, which are very much intact- My guess is that as the soil drys out, my SWR at sresonance will once again rise, and i will need the UnUn again for matching reasons- does this sound right>?

73  Paul  N0AH



      
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK

____________________________________________________________
57 Year Old Mom Looks 27!
Mom Reveals $5 Wrinkle Trick That Has Angered Doctors!
http://thirdpartyoffers.juno.com/TGL3131/4e283398d6efa11b06est04duc