Remote Antenna Disconnect?

  • 1
  • Question
  • Updated 2 months ago
  • Answered

Prior to the advent of SSDR for iOS, I've always run SSDR from my shack.  My routine has been to connect my antenna, turn on the Astron, and fire-up the 6500.

Now that I have SSDR for iOS I want to play radio all the time, from any room in the house, whenever the mood strikes me.  No problem leaving the Astron fired-up and even leaving the 6500 on.  But I *really* don't want to leave my antenna connected to my station.  Last night we had one heck of a storm with thunder and lightning.

How do folks normally handle this sort of setup?  You folks with remote stations: Do you remotely disconnect and ground your antenna?  If so, what do you use to do this?

Thanks,

Peter
K1PGV


Photo of Peter K1PGV

Peter K1PGV, Elmer

  • 541 Posts
  • 315 Reply Likes
  • curious

Posted 2 years ago

  • 1
Photo of George Molnar, KF2T

George Molnar, KF2T, Elmer

  • 1570 Posts
  • 554 Reply Likes
Hi Peter - I picked up an inexpensive remote relay and use an Ethernet-controlled contact closure to switch or disconnect antennas. Works just fine.
https://www.ebay.com/itm/262352693787
Photo of Carmine Iannace, W1EQX

Carmine Iannace, W1EQX

  • 45 Posts
  • 15 Reply Likes
I use a simple solution as I use my Flex 6500 exclusively remote. I purchased a 12 volt coax relay and placed it in line with my main HF antenna which is a multi-band doublet. When I energize the main 12 volt power supply remotely the relay which is also wired in parallel with the 12 volt supply is automatically energized placing the antenna in line with the Flex 6500. When the power supply is off and the coax relay deenergized the antenna is switched out of line from the Flex. I use a shorted PL-259 connector attached to the coax relay to ensure the antenna feed to Flex is grounded when the relay is deenergized.

Carmine W1EQX
Photo of Bill Barber

Bill Barber

  • 1 Post
  • 0 Reply Likes
I met Dan, N1ZZ, at Dayton and saw his new "disconnect" product.  Here is a description from the EHAM.net/reviews/detail/12819

Note that both the coax center AND coax ground are disconnected from the radio!

"Description: The Paradan Antenna Disconnect actuator protects your radio in two ways.
When your radio is on, it prevents static-discharge, surges, and lightning-
strike effects via a gas discharge tube on the coax line input. When it
senses your radio is turned off, the antenna's signal and ground wires are
shorted together and grounded plus both the coax center and coax ground
are disconnected from the radio. When the radio is powered on, the
actuator reconnects the antenna for normal operation. A great insurance
policy for your radio. The required 12 Volt power for the actuator comes
from the transceiver’s auxiliary power socket. If your radio does not have
an auxiliary power jack, then you can simply connect to your 12 VDC power
supply (presuming you turn the power supply off when not operating). "

I am sure there are less expensive solutions, but this one is ready to plug and play!

Bill, NE1B
Photo of Paul

Paul

  • 448 Posts
  • 129 Reply Likes
I am a little sceptical about the level of protection that relays of the type George shows would offer in the event of a direct or nearby strike. I think the discharge could at least jump the narrow contact gap and/or melt the pcb tracks, if not completely vaporise the whole thing.

I use an Alpha Delta manual switch in line for antenna selection while I am in my shack. This incorporates a replaceable arc protection pill which goes short (permanently) if a significant strike occurs. Although the switch is not remotely controllable, it does give me some peace of mind when out of the shack as it (and the arc pill) is in circuit all the time.

Ultimately this type of "insurance" is subjective, I'm not convinced that some proprietary solutions offer significantly more protection than the simpler approach. I have had this configuration for many years and never disconnect the antenna in a storm - so far so good ;)

Caveat: the antenna is a full wave top band wire loop and so static does not build up
(Edited)
Photo of George Molnar, KF2T

George Molnar, KF2T, Elmer

  • 1570 Posts
  • 554 Reply Likes
Paul - you are absolutely right. My switch provides no meaningful protection against nearby discharges. Grounds and Polyphasers elsewhere provide what they can. Of course, absolute protection is impossible. But I'm comfortable with my level of risk vs reward.
Photo of KM4CQG

KM4CQG

  • 225 Posts
  • 37 Reply Likes
Peter

I had some of the switches mentioned and when you take a direct strike non of these things will save you.

I live in the lighting capital of the world when i leave the house the radio is physically isolated thats the only sure way.

I cant begin to tell you the amount of lost electronic components to lighting.

Ian
Photo of Paul

Paul

  • 426 Posts
  • 123 Reply Likes
Sorry to hear about the devastation Peter. As I suspected there's very little that can be done to mitigate a direct strike. Luckily this location is relatively low risk so I'll keep things the way they are. I use my remote set up frequently, so physically isolating the radio from the antenna is not an option here.
Photo of Dan -- KC4GO

Dan -- KC4GO

  • 339 Posts
  • 68 Reply Likes
I agree with Ian, it's very difficult to stop a direct hit. I worked 25 years in the cellular world in central Florida. As they say good luck with that! BellSouth/AT&T spent thousands of $$$$ and still lost equipment all most daily in the summer storm season. I to disconnect the radio(s) 100% the antenna connectors go in to a 5 Gal Glass Jug like water come in. at least 1/2 way down some where in the middle.  (DON'T run remote in the summer in Florida) 
Photo of Kevin Hogg

Kevin Hogg

  • 21 Posts
  • 4 Reply Likes
Putting your cables into a glass jug - are you not just creating a very large capacitor which will store up all that static?  Like you I used to put them in a jam jar, well until I got a unhealthy thump one day :(
(Edited)
Photo of spopiela

spopiela

  • 81 Posts
  • 10 Reply Likes
I just want to comment on usefulness of preventing a charge buildup on the input to a radio. Ben Franklin wouldn't have guaranteed any level of protection to a direct strike. His wisdom was in prevention of the buildup of charge on high structures by bleeding off the charge on the home to ground and allowing any charge buildup in a cloud to pick another point instead of the house. The same is true of preventing charge buildup on the front end of a radio. Will it prevent damage from a direct strike? Nope. However, prior to the strike, things happen to start a a high voltage potential between the cloud and your radio. As a charge builds and you bleed of the electrons to ground by grounding an antenna mast or capping (limiting) the voltage on the front end of your radio , you are making direct strikes less inviting and moving them to somewhere else. It is a preventive measure to a strike. Will it stop a direct strike? Nope. You should do prevention techniques.
Photo of Paul

Paul

  • 442 Posts
  • 129 Reply Likes
Fair comments. Many radios do have sacrificial components at the input. I seem to recall a thread where someone needed the protection diodes in a 6x00 replacing as a result of a nearby strike. Better that than the entire radio.
Photo of Ross - K9COX

Ross - K9COX

  • 336 Posts
  • 102 Reply Likes
Photo of Paul

Paul

  • 448 Posts
  • 129 Reply Likes
Thanks Ross. A spectacular reminder that however hard we mere mortals try, Nature will always win, its just a matter of time ;)
Photo of Kevin LaFata / K0KEV

Kevin LaFata / K0KEV

  • 39 Posts
  • 13 Reply Likes
I promise I'm not trying to sound facetious... But I'm going to throw the "equipment insurance" option out there.  It's not perfect (i.e. it only covers financial losses, you'll still be without a radio for some time if there's damage), but I can say I feel a little more piece of mind. Theoretically I could leave it hooked up to an antenna all the time.  For my flex and laptop, it's about $50/year. It also covers taking the radio to field day, getting it stolen from the car, etc. I'm not advocating leaving the antenna connected if you know there's a storm coming, going on vacation [without the radio]. But in my case, the insurance gives that extra level of protection. 
Photo of Bob G   W1GLV

Bob G W1GLV

  • 659 Posts
  • 109 Reply Likes
Kevin, I agree with you but why go looking for problems.
Photo of Norm - W7CK

Norm - W7CK

  • 747 Posts
  • 151 Reply Likes
I live in Phoenix and during the monsoon season, we can get some pretty severe thunder and lightning storms.

I run everything in the shack on 12v battery power with a couple of 140w solar panels keeping things topped off.  The only gear that runs on AC mains is my 500w amplifier and it goes through an isolation transformer.  This effectively disconnects my entire station from the AC power mains.  Our utilities are underground which limits the likelihood of a strike entering the house via the power lines.

All of my gear in the shack is connected to a switch which also runs off of the batteries.  This switch is connected to another switch via fiber then into my router to the internet.  Everything is isolated including the PC.

My 2m/70cm antenna is the highest antenna I have.  When I travel, I switch to a much lower antenna.

I like using ladder line.  You can take a small plate of steel, drill two holes through to mount a couple spark plugs.  Mount the steel plate to a ground rod and then run each leg of the ladder line across each of the spark plugs.  This isn't a guaranteed way to eliminate lightning from traveling into the shack, but it certainly helps.

Nothing in my shack is grounded.  I have NO ground wires running from any of my equipment to a ground rod.  There should be no reason for lightning to travel past a ground rod at the base of an antenna, across the ground and into the shack.   Crazier things do happen, so I won't say it is a guarantee!   All grounding and lightning protection takes place at the base of each antenna, then coax or ladderline to a disconnect outside the shack.

When I am home and there is a storm approaching, I disconnect the antennas outside the shack.   There are NO live antenna transmission lines entering the shack during a storm, as long as I am home and able to disconnect.

When I travel, I have a fairly inexpensive Icom IC-7100 that I leave connected here in the shack.  Everything else is placed far away from the Icom while I'm traveling.  I use RCFORB from Remote Hams for remote control.   It works really well from my Android phone or from my laptop.  I can't imagine spending that much time on the radio while I'm traveling so I don't feel the need to NEED a panadapter or waterfall.  The Icom is just perfect for my needs. The Icom can also be remotely powered on and off via the app and gives my 80m-6m as well as 2m & 70cm. 

During the winter, when there are far fewer storms, I often leave my amp and tuner inline with the IC-7100.

My shack is a very simple setup.  I don't have a bunch of extra switches, relays, cables and powered do dads here.  I primarily use my 6700 when I'm home and can really enjoy all it has to offer.  I like the KISS principle.....

Last year I had a nearby strike which came down one of the security camera's ethernet cables.  This took out the POE switch that the cameras were plugged into.  It did not travel any further.
(Edited)
Photo of HCampbell  WB4IVF

HCampbell WB4IVF

  • 181 Posts
  • 39 Reply Likes

Even a high quality switch that grounds unused ports is not good insurance against a lightning-induced surge.  I learned that expensive lesson the hard way years ago when my radio, autotuner, and connected PC were damaged by a surge (caused by a nearby but not direct strike).  Now I keep antenna cables physically disconnected (and separated by several feet) outside the house when not in use during lightning season. Also the station AC power cables!

I think when it comes to lightning surge protection, proper station grounding is far more important than the selection of a switch:

http://www.w8ji.com/house_ground_layouts.htm

http://www.w8ji.com/lightning.htm

Since my station grounding is not up to that standard, I’ll keep connecting/disconnecting cables and power cords like some of the other folks who have commented ......  until lightning season is over in a couple months or so. 

Howard
(Edited)
Photo of KM4CQG

KM4CQG

  • 225 Posts
  • 37 Reply Likes
Howard

Your spot on when it comes to lighting.

Ian
Photo of HCampbell  WB4IVF

HCampbell WB4IVF

  • 169 Posts
  • 38 Reply Likes

Thanks Ian.  I had spent a small fortune on ground rods,  AC main panel surge protector, grounding remote antenna switches, 12v surge arresters for the remote switch power cables, point of use high-joule AC surge arresters, etc.  All to no avail when that strike hit nearby.  I’ve improved my ground system somewhat since then, but it will never be ideal since my shack is far from the power entrance.  So like you and some of the others I’ll keep connecting/disconnecting cables, the best protection I can think of short of packing it back into the boxes and into the closet!  (-: 

Howard
Photo of Mark WS7M

Mark WS7M

  • 396 Posts
  • 113 Reply Likes
I am in the process of building something like this:

https://vimeo.com/133917999

Mine however will ground the centers of the incoming feedlines when pulled back.  Like Ian says there is little that will protect you from a direct strike.  I mean we are talking hundreds of thousands of volts and amps!   For most of the small relay disconnecters that is like providing fuel for the fire which is exactly what I think would happen with a direct or even a very near by strike.  That relay/board is just gonna melt.

Even a device like in the video is gonna suffer severe damage with a direct strike.  My hope is that if I can pull the coax far enough away and ground them, that portion of the disconnector would likely become a melted slag but hopefully the radio might still survive especially if hit has a static discharge system on it.

I cannot confirm this, I could be very wrong.  But I seem to feel this would be far better than any relay.  Perhaps less effective than a manual disconnect and float of the radio.

I just like building things and I have at my disposal right now 6-8 mechanical engineers, a full CNC, lathe, water jet, press brake and other equipment.  For a few hundred bucks, some beer and company I can get something pretty cool built.
Photo of K1UO - Larry

K1UO - Larry

  • 781 Posts
  • 126 Reply Likes
If you want to "commercialize" that, I'll take one Mark :)
Photo of Mark WS7M

Mark WS7M

  • 396 Posts
  • 113 Reply Likes
I will consider it for sure Larry, but it won't be a money making thing, it will be a cover the costs thing I think.

Anyway I will build one, take pix and let people know how it is going.
Photo of K1UO - Larry

K1UO - Larry

  • 781 Posts
  • 126 Reply Likes
Appreciate those efforts Mark..  Good Luck.  We will look forward to seeing your progress.
Photo of Kari Gustafsson SM0HRP

Kari Gustafsson SM0HRP, Elmer

  • 232 Posts
  • 20 Reply Likes
Mark your mechanical antenna disconnect is the way to go. Provided you have done the "golden standard" of grounding and bonding of antennas, towers and shack. Like published on many places. Ward Silvers N0AX latest book and speach on the contest university covers it all up very well.
I would like to do what you are pursuing. Tell me how do you plan to ground the centers of the connectors?
73s Kari SM0HRP
Photo of Mark WS7M

Mark WS7M

  • 396 Posts
  • 113 Reply Likes
Karl,

It will be a mechanical rocker type assembly that when pulled back rocks up to contact the centers.  Not designed yet but will share the idea when close.

Mark
Photo of Staffan Lindberg

Staffan Lindberg

  • 1 Post
  • 0 Reply Likes
I made this mechanical solution 2011, and it had works just fine during this years.
Today it is a little modified (new electric cylinder, instad of the bult and not solution from 2011)

Some pictures and building information can be found here    https://sites.google.com/site/sm3jggwebcac/

73s Staffan SM3JGG