Re: Topband: Radials question Hey Gang,
Thank you for the comments and I been re-reading them and learning. This will be a fun late summer or early fall project. Thanks! Mike n0 odk 73 On Tue, Jun 13, 2017 at 9:54 AM, Grant Saviers <[email protected]> wrote: > The larger the diameter of the antenna, the broader the bandwidth. So an > aluminum self supporting vertical that starts with 3" diameter tubing (the > HD DXE starts with 4") can have twice the intrinsic bandwidth of 16ga > wire. It also gets a bit shorter for same resonance frequency. I had a > guyed 80m vertical of 3" irrigation tubing which had about double the > bandwidth of a wire one. > > Another choice is a simple fixed series capacitor with a shorting relay to > move the resonance up the band. I use 3 series caps and paralleled relays > on my 160m T to cover all of 160 in 50KHz steps, <2:1. It worked out that > the short, C, C/2, C/3 series values were right on to cover the band in > even steps. The untuned resonance is 1810KHz. Others use series variable > capacitors, but a vacuum variable is probably needed at the smallest value > of C. That costs a lot more than fixed 1KV caps and takes longer to QSY. > > Grant KZ1W > > > On 6/12/2017 20:29 PM, Mike Paskeuric wrote: > >> Hey Topbanders, >> >> I was looking to buy or make a mono type 80 meter antenna for DXing. >> >> I was wondering couple things. If I make a full quarter wave vertical WIRE >> in tree 65 feet tall and see DX Engineering verticals claim 65 foot tall >> but wider bandwidth. What is their secret or just advertisement? >> >> Second question, I understand more radials make vertical better, but >> what >> happens if one side half or one third the length radials due to space in >> yard are shorter by 20 to 30 foot? Is it noticeable enough to buy a >> vertical in middle of yard instead of wire in tree towards side of yard? >> Dollars verses radial lengths. >> >> Third and last question, can some of the radials, quarter of them, >> overlap with radials of another antenna (160M mono vertical Gladiator >> antenna)? Would it affect the performance noticeable. >> >> I don't need long answers, just something to help out a bit. >> Not sure what antenna to buy or make yet. I am in 2 and half acres and can >> maybe stretch in field next to me some with no one knowing. Not many 80M >> momo antennas to choose from. >> It is a late Summer or Fall project so time to think. >> >> Mike >> n0 odk >> 73 >> thanks for suggestions gang. >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband >> >> > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
