02-07-2023, 03:35 PM
I had a similar idea nearly 10 years ago, copper pipe with lugs added, heavy gauge wire as flyleads. I agree that it is the RF impedance to earth that becomes a concern, more-so if you are running any unbalanced antennas such as a longwire or a vertical.
I opted for a different approach with a similar overall concept. I have used 30x30x1.5mm aluminium angle along the back of the shack bench with a Vee cut in one face to allow it to be bent to 90 degrees and thus also allow it to go along just one side of the table top as well as the back. It is screwed into the back edge after all of the interconnection points (for flyleads) have been made and tightened.
A series of 6.5mm countersunk holes plus a swag of 1/4" screws were fed through the angle material and a star washer and 1/4" nut applied on the top side to tighten it up. My flyleads to the radio gear were simply lengths of RG-213 stripped of the outer sheath after the inner was removed. A Philips #2 screwdriver used to make a hole when flattened, then the last 40-50mm soldered. That provided a hole that fit over the 1/4" screws, and a wingnut and flat washer was added to the top of each, some screws had multiple flyleads too. The earthing fly-cables were made as short as possible and the 'far' end was treated similarly, a hole plus flatten plus solder. I did NOT flatten the coax braid as I wanted the lowest possible inductance. The 'semi-flexible lead' clamped to yet-another earth rod/spike from Bunnings and fed into the shack and up to the aluminium angle was a piece of LDF4-50 solid (but bendable) coax outer, clamped not soldered.
I think the aluminium angle came from Bunnings, along with the 1.4M earth rod/spike, the LDF4-50 was about 1.2 metres long initially and was cut to size (a junkbox item for me). The RG-213 was all pre-loved cable and essentially junkbox. I used 1/4" screw hardware simply because I had an excess supply (Bunnings was selling off imperial size screw stuff cheaply at the time ! ). The only soldering involved was the flattened braid where the screw hole was created, easy to do with either a gas or electric iron.
I typically do not have RF feedback or "hot chassis" syndrome, except if I have removed the earthing lead to do something and have forgotten to re-attach it at the back of the radio (etc..). I have the radios, power supplies, rotator controllers, and even the computer gear all attached via flyleads to the earth bus. There is still some need to utilise clip-on toroids in some places to minimise RF into audio and computer cabling but that is now a standard process for most operators.
My approach probably cost less than 5PJ's, easier to construct and is probably as effective, the most critical detail being the 'cable' length between the earth rod and the common angle 'earth bus' has to be as short as is absolutely possible.
I opted for a different approach with a similar overall concept. I have used 30x30x1.5mm aluminium angle along the back of the shack bench with a Vee cut in one face to allow it to be bent to 90 degrees and thus also allow it to go along just one side of the table top as well as the back. It is screwed into the back edge after all of the interconnection points (for flyleads) have been made and tightened.
A series of 6.5mm countersunk holes plus a swag of 1/4" screws were fed through the angle material and a star washer and 1/4" nut applied on the top side to tighten it up. My flyleads to the radio gear were simply lengths of RG-213 stripped of the outer sheath after the inner was removed. A Philips #2 screwdriver used to make a hole when flattened, then the last 40-50mm soldered. That provided a hole that fit over the 1/4" screws, and a wingnut and flat washer was added to the top of each, some screws had multiple flyleads too. The earthing fly-cables were made as short as possible and the 'far' end was treated similarly, a hole plus flatten plus solder. I did NOT flatten the coax braid as I wanted the lowest possible inductance. The 'semi-flexible lead' clamped to yet-another earth rod/spike from Bunnings and fed into the shack and up to the aluminium angle was a piece of LDF4-50 solid (but bendable) coax outer, clamped not soldered.
I think the aluminium angle came from Bunnings, along with the 1.4M earth rod/spike, the LDF4-50 was about 1.2 metres long initially and was cut to size (a junkbox item for me). The RG-213 was all pre-loved cable and essentially junkbox. I used 1/4" screw hardware simply because I had an excess supply (Bunnings was selling off imperial size screw stuff cheaply at the time ! ). The only soldering involved was the flattened braid where the screw hole was created, easy to do with either a gas or electric iron.
I typically do not have RF feedback or "hot chassis" syndrome, except if I have removed the earthing lead to do something and have forgotten to re-attach it at the back of the radio (etc..). I have the radios, power supplies, rotator controllers, and even the computer gear all attached via flyleads to the earth bus. There is still some need to utilise clip-on toroids in some places to minimise RF into audio and computer cabling but that is now a standard process for most operators.
My approach probably cost less than 5PJ's, easier to construct and is probably as effective, the most critical detail being the 'cable' length between the earth rod and the common angle 'earth bus' has to be as short as is absolutely possible.
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.