Thanks to everyone that has written to me on the reflector and via email. I've read everything you've written and hopefully your efforts have helped me or guided me towards getting this antenna working better.
I've made some changes, bought some equipment/parts and built some stuff per all of your advise. So I have some new observations and data and a few more questions. I'd really just like to get this playing better for the 160m CW contest in a couple of weeks. First, so I could use my antenna analyzer (by knocking down the 27.5KW AM station just down the road) I bought a DLW Associates BCB brickwall filter customized to have a strong dip at 1210kHz. It works great all across the BC band and my transciever is happier and I can use it out at the antenna to help the Comet CAA-500 analyzer actually make measurements. I also ordered the 2.4" #31 toroids and some RG400 as suggested at the often referenced K9YC website. I will build the choke as directed but for now I am using a DX Engineering Maxi-Core feedline choke that is supposedy effective to 160m but they provide no data sheet. I'll get the parts for the K9YC designed choke this week and will substitute that right away. The antenna (freshly measured and rehung) has a near-ground mounted feed point. The insulated 14g THHN wire is a total of 135' in length. It goes straight vertical for 90', makes a 90 degree bend and runs horizontally for 45'. It is well insulated at the end and it does not touch any trees at any point. I have attached 30 insulated wire radials each 42' in length (as suggested in a K9YC presentation referencing a K3LC study in the NCJ) laying on the ground roughly evenly distributed. The paper said that 12 radials would be "adequate" but I had room and materials for 30 so that's what I laid out. Here are some measurements I made and I can take others you may wish to see. My analyzer does not sign the reactance value. R=50 X=27 SWR=1.7 @ 1813 MHz then also R=50 and X=21 SWR=1.5 @ 1890 MHz The lowest X value I could obtain is X=5 with R=35 SWR=1.4 @ 1845 MHz This is with a 15' piece of coax from the feedpoint to the choke then a very short jumper to the BCB filter then a short jumper to the analyzer. I'll be able to put the choke right at the feedpoint (if that will make a difference) when the toroid/RG400 arrives. I measured the SWR curve and it starts at 2.0 @ 1800 and bottoms around 1.4 @ 1840 but it doesn't rise above 2.0 again until 1940. That is far too broad, right? Lots of loss somewhere still? So, that's where I am. It has worked US coast to coast, easily to Alaska and Hawaii and to N. Cook. It is being heard in VK and I worked half a dozen JAs all with 100 watts but I still think it has many problems. This is definitely an improvement thanks to all of your tips and advise but what can I reasonably do to make it better or am I at diminishing returns? I'm willing to put some more time and energy into it and also take more measurements if that would help. Any ideas? 73, Todd - NR7RR _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
