[MRCA] Vertical Antenna Relay Project

Sat Nov 15 18:31:51 EST 2014

That sounds like a safe distance.

On 11/15/2014 6:28 PM, W2HX wrote:
> 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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