[600MRG] Approved 2x

[patrick hamel]

Jeremy,
I have never been in your part of the country and don't know the geology, but here on the gulf coast we had an AM broadcast tower over the water on piers which covered the entire gulf coast with 1 KW.
After the storm "Camille" in 69 the company moved inland about a mile in wet sand. At That point, the signal strength was drastically reduced just 15 miles away.
Whether your dirt would act like the wet sand in a microwave radar dummy load, or whatever I can't guess, but you can find out  by measuring the "R" component of "R +/- X). Your radiator will have a known radiation Resistance calculated based on electrical effective height. If your Vector analyst shows a resistance several times greater than that predicted "R" then start adding the radials. Remember your instrument measures all the losses plus radiation resistance. Anything near the radiator will soak up power. A 70 foot tall vertical base-loaded will have several thousand volts across the base insulator and coil. Get the biggest insulator you can find - Power company surplus but NOT hollow PVC!

Also for a vertical, the top loading is considered loading only at these frequencies and not part of the radiation producing antenna for the EIRP math.
Look at www dot antennas by n6lf dot com and spend some cost-free time reading -- before spending money on hardware.
www.500kc.com, aa1a's site, and w5jgv's site all have good information.
73,
Pat W5THT & WD2XSH/6

 

----- Original Message -----
From: "Jeremy w7eme" <w7eme at yahoo.com>
To: "600MRG Reflector" <600mrg at w7ekb.com>
Sent: Friday, November 17, 2017 2:03:36 PM
Subject: [600MRG] Approved 2x

Aloha,
I have received approval for both 2k2m and 600m at two of our properties, denied a third. The latter, BPA main lines are clearly quite close. 
Anyhow, I wish to try something ops on 600m from CN85. We have a beach front property that is secluded, on the 45th parallel. My thoughts for the ease of getting some bit of signal out, I will operate a 70 vertical, irrigation tubing on insulated ground mounted base. Guyed and incorporate a cap hat as the top guys.
I am looking for some advice on my ground system. The earth at this location is eternally damp to wet at less than three feet deep. High salinity due to the Pacific. Conductivity is very high when poking around with a megger, even in just damp sand. Sometines just a few ohms over a dozen feet. Will I even require much effort in a raidial system or counterpoise? I am thinking environmental influence on tuning the antenna may be significantly less with a substantial ground plane versus just conductive earth?
Mahalo in advance for any thoughts...
73 Jeremy  w7eme




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