Topband: bottom fed antenna causing broad band signal?

[Terry Conboy]

On 2011-10-24 4:10 PM, BRYON PAUL n0ah VEAL wrote:
> I have a good friend who has a 1/4 wave 80 foot vertical (63 feet) who decided to put a 100 foot coil to bottom feed the antenna for 160M.  Using a tuner, (no UnUN) he is resonant at 1.830 but the signal is very broad banded at 4 miles away. Originally, he started with a coil made of 50 feet of copper and was resonant at 1.890Mhz.  Any red flags with this design to warrant this problem of hearing him 30KHz wide, (10 up, 20 down) ?? On the scope, the signal looks very clean, and I only see it 3-5 Khz wide, as I would expect. Hut he is transmitting CW on LSB using CW software.  The coil is only around 2 1/2 inches wide- I am thinking larger turns would be less of a coil-  Any suggestions appreciated- this is not an antenna I understand very well but would like to get some input- The station is very clean for issues but is the coil suspect-  I think I would just gone with an Inv L....... hihi
> Please feel free to respond to n0ah at arrl.net.
>
> Paul  N0AH
>
>
Base loading coils for short verticals can have a very high RF voltage 
across them (and also the base insulator).  If he's running high power, 
there's a chance there is some arcing going on.

Maybe he's inadvertently running "spark gap" instead of CW.

73, Terry N6RY