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Author Topic: RF Ground & reception: a question...  (Read 2912 times)

Posts: 52


« on: March 08, 2003, 12:30:29 AM »

As life involves compromise, I'm currently installing my shack in a room built into the roof-space of my new house, 5.5m (18') above ground.

I have a 1m x 1m copper plate on an internal wall onto which all equipment will ground for both DC and RF. That plate is connected to ground via a 250mm (about 1') wide copper strip of length 7.2m (23.5') which at the ground end is connected to both deep ground rods for DC earth and a network of 20 short rods connected together with braid just below the surface over a wide area for RF ground.

Obviously I'm ok for DC ground but the rf ground is another matter. Given the length I have, I expect to have poor rf ground on the 30m and 10m bands and ok but not great rf ground on the 20m and 12m bands. This prediction is based on the high impedence rf path I expect on bands where the path to ground length is odd multiples of 1/4 wavelength.

Whether I'll have problems in reality remains to be seen - it'll be a few weeks before I can put my theory to the test...

What I want to ask is:

Does a poor rf ground in any way affect reception? i.e. even if I don't lend up with a 'hot shack' on transmit, is my rf ground as described likely to compromise my reception capability on certain bands?

Posts: 21837

« Reply #1 on: March 11, 2003, 12:40:28 PM »

Why would it?

Unless you are using an antenna which requires an earth "return" to function, such as an end-fed long wire, an RF ground does absolutely nothing with regard to reception (or transmission) of radio signals.

If you use balanced antennas (dipoles, loops, quads, yagis, etc) or ground-independent unbalanced antennas (base-fed vertical with radials, etc), the RF ground performs no function.  Your "return" is provided by the antenna design, and connecting or disconnecting to the earth makes no difference whatever.

I'm active, running high power, on 12 amateur bands from 160m through 70cm, and have never had an RF ground of any sort. I do very, very well on the air and have a QSL card collection that's so large (more than 75,000 cards from 321 DX entities) that I stopped collecting any -- out of room.

An RF ground can be helpful in some cases, but if you use current-fed antennas providing their own current return for the RF signal, as most of us do, improving station performance -- or reception -- is not a factor.

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