Topband: Mixed RF grounds

Mike Waters mikewate at gmail.com
Fri Oct 19 18:45:21 EDT 2018


Iain,

The FCP is a *great* design by Guy, K2AV. It's for Topbanders on a small
lot, but it sounds like yours is not as small as some. From what I've read
here, whether an FCP will improve your signal over two λ/4 elevated radials
at least 10' high is kind of doubtful.

One of my 10' high λ/4 elevated radials was almost straight N, and the
other one was bent at crazy angles to the S because the neighbor's fence
was too close.

73, Mike
www.w0btu.com

On Fri, Oct 19, 2018 at 5:01 PM <g4sgx at justfans.co.uk> wrote:

> Hi Mike,
>
> Yes that seems to agree with most writings.
>
> I hope soon to swap the two radials for an FCP to see what all the fuss is
> about. See if its so much better as been told.
>
> I fell in love with TB after a recent trip to V31 when I worked some very
> marginal QSO’s with JA, VK and Russia. Quite a sense of achievement as I
> watched the greyline sweep across Europe.
>
> CW only I’m afraid.
>
> I did have an inverted-L over seawater so my TX was good, my Rx antenna
> wasn’t usable. (Local aircon/floodlights)
>
> 73 Iain
>
>
>
>
>
>
>
> *From:* Mike Waters <mikewate at gmail.com>
> *Sent:* 19 October 2018 22:21
> *To:* g4sgx at justfans.co.uk
> *Cc:* topband <topband at contesting.com>
> *Subject:* Re: Topband: Mixed RF grounds
>
>
>
> Hello Iain,
>
>
>
> You heard correctly! My inverted-L with 2 elevated radial had no ground
> rods except on one terminal of a spark-gap lightning arrester. Description
> and photos at
>
> www.w0btu.com/160_meters.html (scroll down). You *must* also have an
> effective common-mode feedline choke near the feedpoint.
>
>
>
> 73, Mike
>
> www.w0btu.com
>
>
>
> On Fri, Oct 19, 2018, 4:02 PM <g4sgx at justfans.co.uk> wrote:
>
> Hi,
>
> In my limited garden I can get away with an 17 high inverted-L with 2 very
> bent elevated radials and very odd angles. One of them in the farmers
> field.
>
> It has certainly got me out but I have been told if I sick some copper rods
> down at the base and connect to the radials (coax shield and radials) this
> is not going to be beneficial.
>
> This seems counter-intuitive.
>
> Before I get digging (cos I got to try it anyway and take some analyser
> readings) can anyone comment on this?
>
> Iain G4SGX
>
>


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