Ft. Mott -Ft. Miles Ground Wave Path
          Feasibility   Test October 23, 2011

 

   Misson:  During our Gilbert 2011 meet this year at 0530 in the morning Dave KB3ELD and I discussed the possibility of linking the two W.W.II Coast Artillery reenactment groups via amateur radio between Ft. Mott, NJ and Ft. Miles, Delaware. Since I had all ready operated from Ft. Miles with the 261st in 2009, I offered to set up a 3885 Kcs station at Ft. Miles and conduct low power "ground wave" testing. Lesson learned: stay away from Kormanicki at 0530 in the morning.
       Link to my previous Ops at Ft Miles during a 261st Coast Artillery Reenactment group weekend.

  A special tip of the hat to Dave KB3ELD and Mark KD3ZK for their
efforts in setting up at Ft. Mott . . .

    My set up was easy compared to their setting up of guyed antenna kits and the SCR-543/BC-669 complete with W.W.II motor generator PE-108. I just simply parked the 86 Surburban "War Wagon" , pushed up a pole and hooked up the "borrowed" PRC-70.

 

                           
    The distance between the two areas is 53 NM and probably beyond
any reasonable ground wave coverage using "low power"but due to the fact that the path is mostly overwater I thought that the ground wave would be enhanced.

     Due to the W.W.II equipment frequency restrictions 3885 Kcs* or 75 meters
had to be the frequency/band of operations.


   The actual distance between points and the frequency was probably near the lower limit for NVIS
ops. (Please don't email me about NVIS) so ground wave was our choice.
     

     *The BC-669 upper frequency is approx 4.5 Mcs.

 

                                      

                Dave and Marks Tent at Ft. Mott, not shown is the PE-108 gen set. The gas generator
is remote controlled by buttons on the radio. Transmitter Power output is approximately 45 watts.
Dave is very meticulous and has spent years completing his set.

                                   


                     

                                    
              Remote control of the Generator. Start-Stop and Choke.
 

                                    
  
                  I set up ops on the tail gate of my 86 War wagon.
     Antennas to be tested were the standard halfwave (120 feet) cut for 75 meters fed in the center with RG-58 and a identical length half wave wire fed at the end. A telescoping fiberglass mast was used in the center and near by trees used for the guying the ends. My power output was 4 or 20 watts. Dave could still hear me when I switched to low power of 4 watts.

 

                                   

       Video links with audio for 3885 Kcs ground wave testing, note how steady and strong
Dave is from Ft. Mott via ground wave.

       Initial test with Ft. Mott KB3ELD ON 3885 kCS using a center fed Doublet. Groundwave

       2nd test using a half wave wire end fed with Fuch tuner. Ground Wave.

 

       Note on the next video still on 3885 Kcs the fading of N3FRQ and K2WI but at the end KB3ELD via ground wave is loud.

      3rd test with N3FRQ, K2WI combination waves.


          Just for fun I reeled in my end fed wire to 87 feet, changed to Fuch Tuner over and and switched over to 60 meters on the Mouse and Squirrel frequency 5371.5 Kcs.
   Note that Charlie was loud and clear from Capt Cod.
      4th Just for Fun. 60 meters 5371.5 and Charlie KA1GON from
Cape Cod. Skywave.
      

 

   Conclusion: 2 Way comm between Ft. Mott and Ft. Miles using low power is reliable.
Permanent antenna and a operating position should be established at the two Forts.
       

     
       
       

 

 

                                     
     Speaking of trees my weapon of choice is a tennis ball with a large lead
weight. The tennis ball usually just bounces off of the windshield during any inadvertent collision - - -much better than broken glass caused by that wrench tied to a rope.

                             
                    Tripod for the telescoping fiberglass pole
 

                        
    Half wave center fed double is constructed of two reels of "flexweave" antenna
wire.  Same type that is used on the Gibson Girl kite antenna and available
from any wire dealer. I used a AT-984A/G antenna for the reels in this photo.Wire is marked with a little solder for the different lengths for each band and you only reel out the length that you need. Length reminder placards are labeled on the reels.

                     
        Home brew center insulator made from "lexan".
Two bolts with knurled nuts and two cable ties. Fini.
             Quick disconnect lugs on the end each wire.
   
               
                  Tailgate lunch.
                        
                Small "portable" antenna tuner used for doublets.

                 
 

                              
                      Fuch antenna tuner  (circuit under test and not finished) I have good news and bad news concerning the circuit.
       Link to the Fuch tuner for half wave end fed wires. via DL2FLI

                                      
                       Dual input (SO-239 and BNC) inputs on the left and wire
                  ouput for the end fed half wave on the right. Ground terminal in the rear.
            
                       
           Hong Kong eBay fishing fly (cheep) reel using to store more flexweave
for the half wave "end fed" antenna. Again the different lengths for each
band is marked on the wire, just reel it out and let your fingers find the soldered
on mark. Fast and easy to deploy.
                         
     
                        
                Don't leave home without your ME-61 FS meter.
          Listen on the receiver and peak antenna tuner for max noise in the receiver
and then transmit and peak for max field strength. Nothing else needed.
         
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