[MRCA] Vertical Antenna Relay Project

Sat Nov 15 18:28:43 EST 2014

Thanks, Peter. It was a good project, nothing terribly involved.  Yes, those are power lines. But the picture is deceiving as to their distance. I knew it was far enough away, but I just went out in the cold night to measure to be sure. The power lines are about 75 feet away. 

73 Eugene W2HX

-----Original Message-----
From: MRCA [mailto:mrca-bounces at mailman.qth.net] On Behalf Of Peter Gottlieb
Sent: Saturday, November 15, 2014 6:07 PM
To: mrca at mailman.qth.net
Subject: Re: [MRCA] Vertical Antenna Relay Project

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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