grounding the shack - Page 1
Forum section: electronics / rf-microwave

author: A.Z.
author_rank: Super Contributor
timestamp: August 09, 2020, 10:02:34 am
content: just stumbled upon this interesting documenthttp://kc.flexradio.com/knowledgebasearticle50426.aspxdiscussing the correct way of grounding a radio shack and showing, near the bottom of page, what I think is a really SMART way of grounding the shack when it is far away from the ground stake, that is, using this approachThe idea of using a run of coax as the ground wire and a capacitor to adjust the potential is really smart, in my opinion

author: fordem
author_rank: Regular Contributor
timestamp: August 15, 2020, 01:33:39 am
content: Forty odd years ago we used something conceptually similar when installing NCR Century systems - it was referred to as an "insulated, isolated" ground.The AC power to the equipment had to be run in metallic conduit, with an insulated isolated ground wire internal to the conduit and the conduit could only be grounded at the supply end, the idea being that the grounded conduit "shielded" the AC supply lines from electrical noise without acting as an antenna - getting the electrician running the circuit to comply with requirements was usually a challenging task, I cannot recall how many times I've heard the phrase "ground is ground"

author: bob91343
author_rank: Super Contributor
timestamp: August 15, 2020, 04:23:34 am
content: A long transmission line will have a very wide range of impedance over the frequency span. If it's a quarter wave shorted at the far end it will have essentially an infinite impedance at that frequency.I am unsure why you want to ground your equipment. For lightning protection perhaps, then don't worry about resonance effects. For general good practice, I have tried grounding and not grounding and see negligible difference. That's because I use resonant antennas with good matching. For safety, the green grounding wire in the power conduit will usually suffice.

author: radiolistener
author_rank: Super Contributor
timestamp: August 22, 2020, 02:30:21 pm
content: Quote from: A.Z. on August 09, 2020, 10:02:34 amfor what reason you're doing it? Do you planning to use grounding as a part of antenna? But it will be very noisy and leads to interference for home electronics in TX mode.

author: A.Z.
author_rank: Super Contributor
timestamp: August 24, 2020, 10:14:08 am
content: Quote from: radiolistener on August 22, 2020, 02:30:21 pmNo, as an RF ground for the shack in case it's far from ground (say an upper floor), not at the antenna

author: radiolistener
author_rank: Super Contributor
timestamp: August 24, 2020, 10:38:08 am
content: Quote from: A.Z. on August 24, 2020, 10:14:08 am"RF ground" is a part of antenna. Counterpoise for the vibrator.If you're using unbalanced antenna, you will have noise and interference problems with such "RF ground".For balanced antenna and good RF choke, there is no need for such "RF ground", except for the electric safety purposes.

author: A.Z.
author_rank: Super Contributor
timestamp: August 24, 2020, 01:04:21 pm
content: Quote from: radiolistener on August 24, 2020, 10:38:08 amI disagree, a balanced antenna like a dipole or an unbalanced antenna like a longwire or random wire with a proper counterpoise system will have their own RF ground, and then, assuming they're fed with coax, it's usual to add CMC chokes to the feedline, this since we don't want the feedline to be part of the antenna system; the problem is at the shack, you have a bunch of rigs which need RF grounding too, and that "trick" helps obtaining a decent one even if the nearest ground stake is some tenth of meters away; there are even "artificial ground" (sic) like the MFJ-931, and those work pretty much the same, but the "coax and capacitor" can be built at a fraction of the cost

author: jh15
author_rank: Frequent Contributor
timestamp: August 25, 2020, 12:41:06 pm
content: Until Sept 9, you can attend the virtual "Dayton" hamfest starting on Aug. 8.https://qsotoday.vfairs.com/After you register, you can access all presentations and exhibits until Sept 9. I haven't seen much if any spam even though going to exhibit booths.Grounding And Bonding: The Essentials - Ward Silver, N0AXThis is the presentation given live with chat back then. (live chat is turned off now). He wrote the recent ARRL book "Grounding and Bonding for the Radio Amateur".He mentions problems with RF grounding.I think I saw your coax and capacitor method in my "The Wireman" catalog by Press Jones, SK.