[MRCA] Vertical Antenna Relay Project

[Peter Gottlieb]

Well Eugene, that is a substantial project which involves substantial thought, 
design and labor to accomplish.

One thing I just noticed, behind the vertical I see some wires, what are they? 
Are those power lines the vertical could hit if it were blown over?

Peter


On 11/15/2014 4:52 PM, W2HX wrote:
>
> Hello friends,
>
> I’ve been feeling inadequate lately. K4CHE always showing some great homebrew 
> projects and I haven’t done much. So here is a project I’ve been working on. 
> I’ve been working on installing a 43’ vertical antenna and radial system for 
> some DX work. And just to have an alternative antenna to a wire thrown out the 
> window or a non-functioning dipole over the house. In my shack, I have some 
> radios that do 100W, 400W and 1000W. The trick was how to couple various 
> radios to this vertical. So I settled on using two different antenna couplers. 
> One is a Harris RF-382A 500W coupler, the other is a Sunair GCU-1935 1KW 
> coupler. The Harris normally must interface to a Harris radios to receive the 
> correct control signals. However a smart fellow on the Harris list has made a 
> small circuit board to automatically control the coupler with just the 
> presence of RF (and some supply voltage). This allows the coupler to be used 
> with any radio, pretty much. Change frequencies, give a whistle, watch your 
> SWR and you’re good to go. The Sunair is more complex, although I believe I 
> can also make a box in the shack to remotely control this coupler. I have run 
> 12 conductors already to the antenna site to control this coupler.
>
> Even though the Sunair could theoretically handle both high and low power, the 
> Sunair will be a big project in itself whereas the Harris is ready to go. 
> Maybe in the spring I’ll get the Sunair operational for some higher power work 
> (I think our sunspots are on the outs for a while).
>
> So the project is how to switch between these two couplers? In addition, when 
> the system is not in use, I want to ground the 43’ vertical. Here is how I did 
> it. I found a pair of large, HV relays at Fair Radio. These have a 1.5” gap to 
> isolate the positions. Here is a drawing of my idea of how this will work. One 
> relay connects the antenna either to GROUND or to the other relay. The other 
> relay selects between Coupler 1 and Coupler 2. Here is the diagram:
>
> http://www.w2hx.com/x/Antenna-related/Vertical/Antenna-Relay-Box.jpg
>
> The control lines will go into the shack to run the two relays independently. 
> So after planning and an order to McMaster-Carr and finding some time to work 
> on this, here are the results:
>
> The inside. The white wire is 50KV wire and handles the RF connections from 
> the insulators to the relays and out to the vertical: 
> http://www.w2hx.com/x/Antenna-related/Vertical/IMG_5988.JPG
>
> Here is the bottom, you can see a #6 cable on the left for ground and the blue 
> control lines on the right: 
> http://www.w2hx.com/x/Antenna-related/Vertical/IMG_5989.JPG
>
> On the side the insulator on the left goes to the antenna and the insulator on 
> the right goes to coupler 2: 
> http://www.w2hx.com/x/Antenna-related/Vertical/IMG_5990.JPG
>
> On the top the insulator goes to coupler 1 : 
> http://www.w2hx.com/x/Antenna-related/Vertical/IMG_5992.JPG
>
> Here I have outlined the RF path when coupler 1 is in use and the grounding 
> relay is in the “operate” position (see red line): 
> http://www.w2hx.com/x/Antenna-related/Vertical/Coupler%201.jpg
>
> And when coupler 2 is selected: 
> http://www.w2hx.com/x/Antenna-related/Vertical/Coupler%202.jpg
>
> And finally when the antenna is grounded. 
> http://www.w2hx.com/x/Antenna-related/Vertical/Antenna%20Grounded.jpg
>
> Here are some videos of the relays operating:
>
> Coupler select relay: 
> http://www.w2hx.com/x/Antenna-related/Vertical/VID_20141114_184756_594.mp4.mov
>
> Grounding Relay: 
> http://www.w2hx.com/x/Antenna-related/Vertical/VID_20141114_184807_697.mp4.mov
>
> And here is the vertical itself where all this magic will take place.
>
> http://www.w2hx.com/x/Antenna-related/Vertical/final2.jpg
>
> The last thing I need to do on this part of the project is some snubber diodes 
> across the relay coils. And that is phase one of this project. Phase two is 
> another enclosure that will do some other things. Stay tuned (pun intended)!
>
> 73 Eugene W2HX
>
>
>
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