Grounding the Ham Shack

[VK3DCA]

Hello,
I'm a new HAM operator setting up my shack.
Can I please get some advice from the more experienced operators.

I understand how important it is to have proper grounding for the ham shack. However, I need to be clear about where to place my 'Copper Grounding Bar' which connects to my ground rod and is also my central point to which all HAM equipment requiring a ground are also connected.
(1) Should my 'Copper Grounding Bar' be located closer to my outside Ham Earthing Rod (which goes deep into the ground), or
(2) Should my 'Copper Grounding Bar' be located closer to my Ham equipment within the Ham Shack?

I think the correct answer is (1) but I need to be clear about this.
Thank you.
Dean

[VK5PJ]

Hello Dean,
the answer all revolve around what gives you the path of the least resistance so distance between items in the chain are the key points here to be considered.

To have the earthing bar nearer the equipment, you need to have a single (or multiple in paralell) larger diameter multi-strand cable connecting the bar to the rod (do not scrimp on this cost as it is a key point in making it work). Cables from the equipment to the bar can now be shorter and of a lesser diameter but again do not scrimp on this part of the deal as it is the overall resistance that gets you over the line here.

You can have the earthing bar closer to the earth rod but now you must have each of the connections from each device to the earth bar considerably larger than in the option above.

Earthing is sometimes a forgotten part of the shack and in the end the ham pays the cost with hum loops and stray RF causing problems with radios, I am glad you are taking this seriously. Please also consider bonding your radio antenna structure (tower, pole etc) to you main earth stake as this will help when you have lightning in the area as it will force all items to be at the same static voltage level and in many cases avoid damage from local area strikes.

if you are interested, there is a very detailed guide by the Motorola communications company in the USA on how they approach construction of their remote mountain top sites (does not get much more savage than this) https://www.k3emd.com/downloads/Motorola_R56.pdf and in there are two or more chapters on earthing, maybe not riveting bed time reading but a handy reference none the less from people who have been doing this sort of stuff for more years than most.

Regards,
Peter vk5pj

[VK3DCA]

Peter,
Thank you kindly for your reply. I will read through Motorola document this weekend, with great interest.

Just a few more facts about my setup.
(a) The shack is actually on the second level of a double story house so I have some distance from the Ham radio to the ground rod.
(b) I have a separate (second) ground rod which is underneath the antenna tower which is dedicated to the antenna only.
(c) For the Ham Shack I already have all of the separate ham shack earthing wires going down to the earthing bar which is located very very close to the earthing rod. So I guess I can attempt to run with this current setup (but it could easily be changed to re-locate to the shack if I needed to).

Note my thinking in regards to (b) of having a second ground rod dedicated to the antenna and mast is that this would be a safer setup than also connecting the antenna and tower to my common Ham Shack earth. By separating the two I only need to disconnect the antenna connection to my radio and I am safe in a thunderstorm in the event where I get a direct hit to the antenna and/or tower. Otherwise if everything were connected to one earthing rod (e.g. my Ham Shack earthing rod) then if there was a lightning strike and even if my antenna connection was disconnected from my radio then conceivably I figure the high voltages from a lighting strike could still go up the earthing wire and cause significant damage to equipment via the earth connection before it's discipitated completely on the other end via the earthing rod. Please let me know if this does not sound correct.

Note that I am not up and running yet because I'm trying to put in place proper foundations in my setup before I power-up; so as to minimise any problems. One of the frustrations with dealing with any possible RFI problems is that from my reading you can't easily measure RFI in any direct way ....you can only look out for the symptoms of RFI and this is less likely to occur in a low power setup where in my instance I can only currently run 10 watts.

Based on the above additional information on my setup any further comments are welcome. Thank you!

Dean.
VK3FDCA

[VK5PJ]

Hi Dean,
if you can find a way, please run a copper connection between tower earth rod and shack earth rod, this will stop the two earths getting to different potential when the ground is poor (most soils in VK). If you have a near by (not direct) lightening strike, the two locations will have different voltage levels and then all of a sudden your feedlines start to have serious voltage differences and some radio gear may go pop. While nearby strikes are not common for most people, if the dice do roll and come up with your number at least your given a fighting chance.

I know it may sound a bit daunting but hope the Motorola guide gives you some clues.

Regards,
Peter. vk5pj

[VK3DCA]

Peter,
Thanks for this additional information.
I note your recommendation to "...run a copper connection between tower earth rod and shack earth rod...". Thank you for confirming this requirement! So, my next task will require me to dig an 11 metre long trench to electrically link the two earthing rods together.

NOTE: Also, due to the distance of the Ham Shack to the ground rod another alternative if I have any problems when all of this is up and running; will be to create an artificial ground with an MFJ-931, Using this device I can still connect my existing ground wire from my 'Copper Grounding Bar' to the MFJ-931 instead of using a counterpoise wire.

Dean
VK3FDCA

[VK5PJ]

Hey Dean,
it is force of habit to say copper, these days there are a selection of conductor types but copper while expensive is still good bang per buck... my advice if to shop around the big electrical places (where the contractors go) for part rolls of cable that they do not want, the proverbial stock take misfits that they would prefer to be rid of and not count or measure, you may be surprised what may come up in the conversation.... many times they get left with special orders and just want it gone for a song. I can say I have exploited that a few times and ended up with cables that I would not have normally been able to afford... BUT be prepared to get a re-buff or two as some shops may think you trying to pull a swift one.

Stock take is approaching again so its always worth a try.

Oh, if you can afford it, put the cable in some orange conduit and include a pull string, the conduit will protect the cable from the stray shovel that may be digging a hole..

Peter.

[VK3DCA]

Peter,
Really appreciate the expert advise here.
I have done further research and you are 100% correct about the need to electrically connect the two earth rods together. This raises two issues for me one of which you have already touched on:

(1) How to do this cost effectively.
So, another alternative I was thinking about was; instead of using expensive copper cable in a PVC conduit pipe in the ground is to instead use copper pipe similar to the type used by plumbers for hot water! I can get "SOFT DRAWN 5/16" 8MM OD, 15 METRE ROLL (30M) of COPPER TUBE" from eBay for about $55. This might be a better alternative keeping cost down, it';s pliable and is an excellent conductor in the ground further enhancing my grounding system and I have what I need to physically connect it end to end to each of the two grounding rods. What do you reckon about this?

(2) Electrically connecting the Antenna and Mast Earthing rod to my Ham Shack earth will expose me to greater risk of a lightning strike (if I am really un-lucky) so I now need to look at installing two lightning arrestors for each of the two antenna's (for HF antenna and VHF/UHF Antenna).
NOTE my earthing Bar is within 3-feet of the first Earthing Rod so I will now extend the Earthing bar to incorporate all of the separate long run Earthing cables from the Ham Shack equipment plus the two lightning arrestors. Let me know if this config sounds O.K. to you or not.

The whole thing is getting bigger and bigger ...but this just normal with Ham Radio isn't it!
Dean
VK3FDCA

[VK3DCA]

Peter,
Really appreciate the expert advise here.
I have done further research and you are 100% correct about the need to electrically connect the two earth rods together. This raises two issues for me one of which you have already touched on:

(1) How to do this cost effectively.
So, another alternative I was thinking about was; instead of using expensive copper cable in a PVC conduit pipe in the ground is to instead use copper pipe similar to the type used by plumbers for hot water! I can get "SOFT DRAWN 5/16" 8MM OD, 15 METRE ROLL (30M) of COPPER TUBE" from eBay for about $55. This might be a better alternative keeping cost down, it';s pliable and is an excellent conductor in the ground further enhancing my grounding system and I have what I need to physically connect it end to end to each of the two grounding rods. What do you reckon about this?

(2) Electrically connecting the Antenna and Mast Earthing rod to my Ham Shack earth will expose me to greater risk of a lightning strike (if I am really un-lucky) so I now need to look at installing two lightning arrestors for each of the two antenna's (for HF antenna and VHF/UHF Antenna).
NOTE my earthing Bar is within 3-feet of the first Earthing Rod so I will now extend the Earthing bar to incorporate all of the separate long run Earthing cables from the Ham Shack equipment plus the two lightning arrestors. Let me know if this config sounds O.K. to you or not.

The whole thing is getting bigger and bigger ...but this is just normal with Ham Radio isn't it!
Dean
VK3FDCA

[VK5PJ]

Hi Dean,
the copper tube method should work I think, can not think why not, had not really thought out of the box for my setups although I did use car battery leads from the 3 tower legs to the three earth rods at my place. They were relatively cheap from a national car parts place and gave me a huge strand count for each connection.

Yes it all can spiral out of control so try to keep a focus on your end goal before you end up spending more time earthing that you do enjoying the hobby.

Regard,
Peter, vk5pj