Second-floor station grounding experiences

[KA1ZGC]

Hey guys,

Now that I've got my transmit audio routed through the console, I need to go around and bolster up the ground situation.

The shack is on the second floor of the garage, and that will not change. It is also about 30' away from (and about 15' below) the end of the 200' flat-top. The flat-top runs parallel to the wall my shack is built along. That will not change, either. I'm stuck with what I've got.

"Move your shack" and "move your antenna" are not options.

I've run a 3/8" stranded copper cable (not ideal, I know, but it's all I've got) along the wall and am about to start tying chassis to it.

The more I look at things, the more I think I may cause as many problems as I would solve if I were to tie this cable to a ground rod down on the first floor, at least at 40 meters and above.

I know I'm not the only one to get stuck in this situation, so I'm wondering what kind of experiences you guys have had with second-floor grounds. Were you able to get them to behave on the higher HF bands, were they prone to ground loop issues, etc.

Not looking for advice, just what people have experienced in these situations.

Thanks in advance,

--Thom
Keep Away One Zorched Ground Conductor

[KL7OF]

I had a second floor shack in the 70's...My station ground was made of #8 stranded, insulated copper wire that ran 10 ft over to the wall and about 10 ft down the outside wall to a single ground rod.....I never ran more than 300 watts..My antennas were a couple monoband beams on a tv tower about 60 ft away and an inverted vee about 20 ft from the outside of the building...I never had any problems relating to grounding ..I don't remember having any hot mike problems either...I ran 10 and 15 meters as well as 40 and 75.  I used the #8 stranded wire for my ground because it was what I had and I didn't know any different anyway...my ground rod was a 10 ft pc of 3/4 inch galv water pipe driven into the ground with a (big) hammer....The ground rod/pipe is still there altho I outgrew the shack years ago....Good Luck... Steve

[W2DU]

Perhaps I've been living in blissful ignorance all my 75 years of operating (exclusive of WW2, of course), but I've never used or had a connection to real ground from my equipment, except for the neutral side of the power line.

With the inherent series inductance in such a wire, how do you achieve a 'ground' at a second or third floor at HF with a wire running to real ground? Will someone please educate me on this point and show me what I've been missing? Is there something known as an 'inductance eliminator' that will eliminate the effect of inductance that IMO makes it impossible to achieve a grounding condition at HF at such levels above real ground? Or am I wrong in seeing a Don Quixote effect here?

Walt, W2DU

[Steve - WB3HUZ]

Inductance eliminator? Capacitor.

Perhaps I've been living in blissful ignorance all my 75 years of operating (exclusive of WW2, of course), but I've never used or had a connection to real ground from my equipment, except for the neutral side of the power line.

With the inherent series inductance in such a wire, how do you achieve a 'ground' at a second or third floor at HF with a wire running to real ground? Will someone please educate me on this point and show me what I've been missing? Is there something known as an 'inductance eliminator' that will eliminate the effect of inductance that IMO makes it impossible to achieve a grounding condition at HF at such levels above real ground? Or am I wrong in seeing a Don Quixote effect here?

Walt, W2DU

[W2DU]

Yeah, Steve, I understand that a capacitor can be considered an 'inductance eliminator', but in a wire between a rig on the second floor and real ground? I can understand how a capacitor can tune a ground lead to resonance at one frequency. Is that what you're saying? Doesn't sound practical to me.

Walt, W2DU

[Steve - WB3HUZ]

Works just like an antenna tuner. Is it as good as a "real" ground? Don't know. Never saw any legitimate side-by-side comparisons. But I have used a ground tuner and it worked, at least as far as taming RF in the shack.

[AF9J]

Ditto for me.  I use a ground tuner (I live in a second story apartment), and it has helped with stray RF issues.

73,
Ellen - AF9J

[WU2D]

My original shack was in my childhood home in upstate NY. We had a small house with only three bedrooms, but I was an only child! That means there was a spare bedroom; and not wanting such a space to go unused, we kept a guest bed in there with a dresser and closet BUT I got the rest for a ham shack! This little room was on the second floor.

The handbook said I needed a ground  and at 16 I kept to the book so I went down to the hardware store and bought a very long ground rod and pounded it in right below the window. (It is still there by the way and does not look like it will be going anywhere soon). I think I used #8 solid up to the shack, about a 25 ft run.

Of all of the great antenna ideas found in the 1972 handbook, the bamboo fishing pole wrapped with # 14 wire helically wound looked like the answer for 80 Meter Novice operation. I got about 50 feet of wire wrapped around this pole. This unresonated thing could be mounted up on the Chimney where an old TV mast once was attached, which had to be an advantage. I found 35 feet of old 75 ohm TV coax and attached the hot to the helical whip and left the ground braid floating. Back at the trusty ARC-5, I grounded the braid to the chassis and my monster ground and attached the hot to the antenna post.

Now an ARC-5 will load almost anything and it obliged, pegging my Field Strength Meter (which was my only tuning aid).

Suddenly I hear a yell downstairs. My father said that the TV had blacked out and lamps were coming on by themselves and such.

Mike WU2D

[W2DU]

I dunno, I can't believe that I was just lucky, but I never had any 'RF in the shack' problems over those years, and most of the time I was running a kw on either AM or CW. As I said earlier, I've never made a connection to ground, and never considered it necessary.

Walt, W2DU

[Steve - WB3HUZ]

You're right. Other than meeting NEC, there isn't necessarily a good reason for a ground, especially when running a balanced antenna system.

I dunno, I can't believe that I was just lucky, but I never had any 'RF in the shack' problems over those years, and most of the time I was running a kw on either AM or CW. As I said earlier, I've never made a connection to ground, and never considered it necessary.

Walt, W2DU

[k4kyv]

Perhaps a set of ground radials running along the garage ceiling/shack floor, and extending outside down the walls.

I had a severe 40m rfi problem in my shack.  Rf  got into all the audio equipment, and I could get an rf burn by touching some of the cables.  Finally I ran five or six quarter-wave radials from right under the transmitter to the far end of the shack.  The  distance is about right, 32 ft, for λ/4.  The radials are under the floor,  stapled to the floor joists.  I can light a neon lamp off the far end of each radial, but they established a good enough common ground point at the transmitter to eliminate the problem.  The shack floor is only about 3 feet above the ground, but a direct wire to an 8' ground rod didn't do the trick.

I use 3" copper strap as my main grounding conductor.  To get through the floor, I drilled a series of small holes in a straight line about 3" long, each just large enough to pass #14 wire.  I terminated the ground strap above the floor over the line of holes, and silver-soldered copper wires to the end, poked them down through the holes, and silver-soldered them to the end of more copper strap and continued the run.  I must have used 8 or 10 wires.  Much easier and less damaging to the structure of the building than sawing a 3" slot in the floor to accommodate the copper strap, but electrically equivalent to a continuous run.

[N3DRB The Derb]

I had always treated station ground as a afterthought. this time I wanted to persue it as a main concern  just to see if here was a difference. I plan on adding RF strap in the future. What I have installed will make this job easy.         

[steve_qix]

My shack is located in a room over an attached garage, and as the house it built into the side of a hill, the shack is on the 2nd floor, even though it is on the first floor of the house (confusing!) - suffice to say the shack is about 12 feet above the ground.

I don't even bother trying to provide an "earth" ground of any consequence.  It is too far away, and trying to get a good ground is pointless around here with all the ledge and all.

Anyway, what I do is tie everything together with copper braid.  Every rack is connected to every other rack with this stuff.  All of this is connected to the ground of the room wiring (and ultimately house wiring).  This is also connected to the heat and cold water pipes.

The idea is to make sure there is no RF potential between any units in the shack, and hopefully, no RF potential within the house itself.  All antennas are fed with coax.

It appears to work out very well.  I don't generally have RF problems unless I'm running a total unshielded tank coil, sitting on the bench, clip-leaded to a powerful RF amplifier (which I do all the time!) - and then ONLY if there is some poorly designed piece of equipment around - one with insufficient RF bypassing at the inputs, etc.

Anyway, I've had a bunch of "shacks" on the 2nd floor (some on the 4th and 6th floor, when I was in college), and RF in the shack was of little consequence.  Audio rectification in nearby stereos, etc. was entirely another matter, but unrelated to earth grounding.  This was direct pickup from the antenna connected to a big AM transmitter on 75 meters, and the fact that every student in the dorm had a stereo with nice, long speaker leads to provide plenty of pickup!   The WAS award was for Worked All Stereos !  Thank goodness I don't have do deal with THAT problem anymore  

Regards,

Steve

[w4bfs]

aw Steve ... the WAS award was unconfirmed ... dose guys wit the stereos had a buzz on and thot you were part of Pink Floyyd's music, enyhoo ... beefus

[k4kyv]

The stereos, with several feet of cable to each speaker, and each speaker providing plenty of end-loading, makes a perfect dipole for picking up 75m rf and transmitting it back to the amplifier where every active device inside becomes a diode rectifier.

Probably would be less a problem to-day, since full-size stereos with a speaker in each corner of the room is so old hat.  Now most of the residents of the dorms would be listening to the tin-can audio from iPods and other subminiature MP3 devices.

[WQ9E]

A lot of the "TVI era" Johnson manuals (Viking 2, Valiant, etc.) have a pretty good section on RF grounding through the use of resonant sections of wire so downloading one of these manuals from BAMA will provide some useful info.  My first novice shack was a second floor bedroom and besides a little interference to an FM tuner from my Valiant there were no problems.  Fast forward a few months to a general ticket and an SB-102 and stray RF became an issue when my mic started to bite back so I used the Johnson routine of multiple resonant grounds.

The little MFJ ground tuner works pretty well and I have held onto mine for awhile even though I no longer use it since two of my operating positions are in the ground floor of the house and the barn and the third is in the basement so grounding is no longer a problem.  The MFJ is just a small tuner device with a meter to indicate "flow" into the ground line and it would be pretty easy to homebrew a version from junkbox parts.  I bought mine when I was in the doctoral program but I had very little time to use it.

[KA1ZGC]

Okay, now I've got historic testimonials, I'll give you some more info.

RF in the shack is not something I'm afraid will become a problem. RF in the shack is already a problem.

RF getting into my audio console was a serious problem until I ran a flimsy wire from the transmitter to the console. Then it became a minor problem.

Changing the speakers from a set I built when I was 14 to a pair of AR TSW-410s made the problem rear its head a bit higher.

I have since removed this flimsy jumper and tied both units to the "ground" conductor run along the wall using much manlier (albeit longer) conductors. This made things worse instead of better, but I haven't got the exciter or monitor amp tied to it yet, so that's no shock (no pun intended).

So many things have been added and/or changed in the shack that RF problems coming and going are no suprise to me at all. After all, I'm on step 12 of a list of about 200 things that need doing to this shack.

It sounds as though even attempting to tie this conductor directly to actual Earth ground may be an excercise in futility, as I suspected. My primary concern is to eliminate two or more different pieces of the puzzle having different ideas of what "ground" is.

From the on-air discussions I've been having on the topic, coupled with what I've read here, it sounds like I'm heading in a reasonable direction.

[KF9CM]

I've used this set-up for years with good results. You can use RG 8 with the Legal limit.

73 de Gary, KF9CM

[k3zrf]

Nice, had not thought of a coaxial 'ground'.

Not so long ago I had a second floor shack, balanced feeders but #2 welding cable to three 8' ground rods down below. Used compression connects and could work 40 & 15 metros.

[steve_qix]

Okay, now I've got historic testimonials, I'll give you some more info.

RF in the shack is not something I'm afraid will become a problem. RF in the shack is already a problem.

RF getting into my audio console was a serious problem until I ran a flimsy wire from the transmitter to the console. Then it became a minor problem.

Changing the speakers from a set I built when I was 14 to a pair of AR TSW-410s made the problem rear its head a bit higher.

I have since removed this flimsy jumper and tied both units to the "ground" conductor run along the wall using much manlier (albeit longer) conductors. This made things worse instead of better, but I haven't got the exciter or monitor amp tied to it yet, so that's no shock (no pun intended).

So many things have been added and/or changed in the shack that RF problems coming and going are no suprise to me at all. After all, I'm on step 12 of a list of about 200 things that need doing to this shack.

It sounds as though even attempting to tie this conductor directly to actual Earth ground may be an excercise in futility, as I suspected. My primary concern is to eliminate two or more different pieces of the puzzle having different ideas of what "ground" is.

From the on-air discussions I've been having on the topic, coupled with what I've read here, it sounds like I'm heading in a reasonable direction.

Oh, you have *RF PICKUP* in your equipment.  This is solvable, albiet it may be some work.  I used to have the problem too!  It took work, but all is solved!  How I did it (and you're probably doing this as I type!):

1) ALL AC, DC and control connections and wires entering or exiting ALL equipment are filtered and bypassed to the chassis.  This includes the AC line (both sides - RF chokes and caps to ground - the caps on the equipment side - I'm assuming RF is trying to get IN not OUT).  If a control or power wire goes to an RF amplifier, the bypassing assumes RF trying to get OUT.  THIS IS VERY IMPORTANT - in fact, doing this one thing solved almost all of the problems I had.  A lot of RF finds its way into the equipment through the AC line.  RF ground loops make this even more of a problem.  Filter/Bypass the AC power inputs to everything !

2). All outputs (speaker outputs, headphones, etc. are filtered and bypassed to keep RF from getting IN).  Sounds counter-intuitive, but RF getting back into output connections, particularly when there is negative feedback involved is a major problem.  RF coming in from an output connection will find its way to an input somehow - coupling, radiation, etc.

3). All inputs are filtered with RF chokes and bypassed with .001uF caps to keep RF from getting IN.

4). Every rack, cabinet, case, etc. is connected together with wide braid (about 1 inch wide).  This is connected to the heat pipes, AC ground and anything else that's part of the house that conducts electricity, and is connected eventually to ground.  Even the microphone boom is connected to this grounded structure, but the mic is NOT connected electrically to the boom (stops ground loops).

The only way to get RF into something is for there to exist an RF *potential* at the offending piece of equipment.  By bypassing all RF to the neutral, and putting chokes in series with the lines going in and out - thereby RAISING the RF impedance (and subsequently lowering the current), you both shut away the RF with the caps to ground, and reduce the current with the inductances in series.

Anyway, that's how I did it.  My shack is probably what one would describe as RF hostile.  I run completely unshielded equipment within feet of microphones and preamps, receiver audio amplifiers and inputs... and there is no problem if everything that could pick up RF is properly filtered.

You'll definitely get it corrected!

Regards,

Steve

[KA1ZGC]

Well, Steve... I was trying to avoid turning this into a "how to get rid of the RF in your shack" thread. That's why I deliberately left out the RF pickup problems I was having. I knew the ground situation was something I was going to have to tackle no matter what, and was looking for insight on second-floor grounding, which I got. Thanks to all who contributed.

As your heard on Monday night, I finally got the RF situation straightened out. Grounding the monitor amp and changing the mike from unbalanced audio coax to balanced shielded audio cable (with the console end of the braid soldered to the console chassis ground rail and the mike rewired in a balanced configuration) has eliminated the RF in the transmit audio no matter what I'm touching or not touching. This is light-years better than it has ever been.

That's not to say there isn't more work to do, or that there's no RF bypassing in my future. I will likely do that anyway as a matter of prevention.

Mind you, this success is on 75 meters. We'll find out soon how this flies on 40 and 20, where the antenna radiates much more towards the shack.

This is where the question of bonding the station ground to earth ground becomes more important. 16 feet is a much larger portion of a wavelength at those frequencies than it is at 75 or 160, and I fear actually making everything hot relative to the earth by tying to it, especially with the stranded copper cable I'm using.

At any rate, the RF issue has been dealt with, so it comes back to "to float or not to float".

Thanks everyone for the insights and suggestions. I'm far better informed about remote grounding than I was a couple of days ago, for which I'm grateful.

--Thom
Killer Agony One Zipper Got Caught

[N0BST]

On that coax grounding lead- why couldn't you just tie the center conductor and shield together at the ground rod and use only the center conductor as a central tie point at the shack?

Scott Todd