Re: Topband: Radials question
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 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
Re: Topband: Radials question
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
Re: Topband: Radials question
Hi Mike, et al, Here are my thoughts interlaced. > 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? ***Using a wire - say 12 gauge - Will probably give you a 100 kHz 2:1 SWR bandwidth. Using a vertical say 2" O.D. at the bottom and 1.25" O.D. at the top will generally triple the bandwidth. Make a model with EZNEC (r) and see what you get. Ground losses also increase band width of these antennas, since "Rg" is in series with the actual antenna impedance. > > 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. ***It does not make a lot of difference. One K1 has a 160 vertical near his house and most of the radials are over 180 degrees. What is important is to get enough radials on/in the ground. > > 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. ###In my opinion, if the ground radials are below "elevated radials" for another antenna there should be no problem. The reverse is also true. I know a ham with 80 meter 4-square around a 160 meter vertical. The 80 meter radials are elevated and the 160 meter radials are in the sod. > > 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 ***Good luck de George, K8GG _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Radials question
Mike, a different question than you asked, but if you have two trees or other supports at 65 feet or greater and more than 130ft apart, I think an 80M dipole strung between them will be a better all around antenna than a vertical. If you can get to 80ft or 100ft the dipole was be markedly better. If you only have a single support an inverted V will be almost as good. This same antenna, you can tie the feed line together at ground level and feed as a Marconi T against ground on 160M. Back to your original questions: As to differing bandwidth claims, they must be using slightly different standards for bandwidth. As long as you have more than a couple radials, I would not worry at all about an asymmetrical radial field. Put down as much copper in whatever directions you got. It's the guys with only 1 or 2 radials that have to worry about tuning. Tim N3QE > On Jun 12, 2017, at 11:29 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
Topband: Radials question
> 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? I don't know the DX Eng. product. Usually "wider bandwidth" means flatter vswr curve at the load. There are right and wrong ways to achieve this. Right: wider driven radiator. Wrong: few radials or no radials at all. There can also be some kind of hocus pocus matching network at the feed point, and that can be okay, or a power wasting circuit depending on how it is done. I'd go with vertical wire to the tree branch and ground system and save money. It will work just as well or better if you use a lot of radials, but because it will be efficient, it will not have a flat vswr curve. You'll need a matching network in the system somewhere. If you can elevate the radials at 10 feet or higher, you may do okay with four of them equidistant and 1/4 wave long. On or below grade you need at least 60 for best performance. > 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 It probably won't be noticeable if you put down a lot of radials. > 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. It won't have any effect on performance. Do you have any metal structures near your vertical antennas? Aluminum siding, metal shedsyou should bond these with brass clamps to copper strap and run that strap back to your ground system common point. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Radials question
I mis-wrote for tired right now. The 160M Gladiator is not top loaded, it has 4 raised radials with traps. Works great tho for me. It helped me get two Hawaii and one Alaska for WAS and 14 DXCC in one night. Not much know about Gladiator tho it is 1.1 antler high. I ment the 40M mono radials it might cross on the 80 meter radials, not the 160M antenna. Sorry, going to bed soon. Should have known my set up. Mike 73 _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Radials question
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