Topband: intersecting ground radials

[Tom W8JI]

> Hi I would like to place monopoles for 160 and 80m bands 30m apart causing 
> their ground radials to intersect. The radials are #20 bare copperweld 
> (since I happen to have 4000m) that would be laid out on top of the soil 
> before turf was placed on top. These antennas would be used for 
> transmitting only and never at the same time. Is it necessary to solder 
> the intersecting wires together where they cross for any reason like they 
> recommend for phased arrays? Naturally I hope not...>>>>

They either should be soldered together, or well separated. The last thing 
any of us want is a poor connection. A poor connection can make RF noise or 
rectify and mix signals, and a close spaced connection can arc and make a 
heat source that literally can cause wires to blow apart in lightning hits.

I hope you are not in an area of severe lightning if you are going to use 
#20. While I get away with #16 without any issues at all in repeated direct 
lighting hits, I would not risk  #20. Maybe if you had many radials #20 
would work, but otherwise there is some danger you could reach the  fusing 
current limit.

Fusing current of #20 is 58 amperes, which is half of #16 and one quarter of 
#12 AWG copper. I use a minimum of 30 long radials of number 16 and have no 
problems with lighning melting wires **IF** they are not laying on other 
conductors with poor connections.

I left a piece of guy strand laying on the ground below a tower, where it 
crossed both a large heliax cable and a wide copper flashing. After a strike 
or two I found it had melted the wide flashing and blown a hole through the 
heliax jacket. I sure learened a lesson on "close but not bonded" 
conductors!

My arc welders don't melt the very thin welding wire except at the arc 
point. :-) My experience is this carries over to unintentional arcs.

73 Tom