Re: Topband: Top Band Antenna
On Sat,8/8/2015 12:58 PM, john wrote: I have this with interest---lot of "stuff" maybe even at age 74 you can teach an old dog new tricks...bookmarked and will attempt to absorb I'm an old dog too, 74 in the fall, trying to learn new stuff every day. 73, Jim _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Top Band Antenna
I have this with interest---lot of "stuff" maybe even at age 74 you can teach an old dog new tricks...bookmarked and will attempt to absorbthanks 73 john w8wej On 8/8/2015 2:55 PM, Jim Brown wrote: On Sat,8/8/2015 4:05 AM, rodger bryce wrote: Further question: should a ground rod be used as part of a radial system, or should it be treated separately.? I have seen various arguments for and against, wondering what the group thinks on this. A ground rod is NOT an effective part of a radial system, but it IS important for lightning protection. Here are slides for a talk I've done at Pacificon and for several ham clubs. http://k9yc.com/160MPacificon.pdf 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Top Band Antenna
On Sat,8/8/2015 4:05 AM, rodger bryce wrote: Further question: should a ground rod be used as part of a radial system, or should it be treated separately.? I have seen various arguments for and against, wondering what the group thinks on this. A ground rod is NOT an effective part of a radial system, but it IS important for lightning protection. Here are slides for a talk I've done at Pacificon and for several ham clubs. http://k9yc.com/160MPacificon.pdf 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Top Band Antenna
My most recent method of connecting radials at the base of a vertical is to drive in a short copper pipe ground rod and use an all-stainless hose clamp to attach the wires to it. But in some portable operations I have dispensed with any ground rod, and the antenna still seems to work fine. 73/Jon AA1K -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of rodger bryce Sent: Saturday, August 8, 2015 7:06 AM To: topband@contesting.com Subject: Topband: Top Band Antenna Thanks to all who responded to my enquiry...an Inverted 'L' was the most common advice so will give that option some serious thought. Further question: should a ground rod be used as part of a radial system, or should it be treated separately.? I have seen various arguments for and against, wondering what the group thinks on this. Thanks, Rodger/GM3JOB _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Top Band Antenna
Thanks to all who responded to my enquiry...an Inverted 'L' was the most common advice so will give that option some serious thought. Further question: should a ground rod be used as part of a radial system, or should it be treated separately.? I have seen various arguments for and against, wondering what the group thinks on this. Thanks, Rodger/GM3JOB _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Top Band Antenna
Rodger It seems a bit short electrically but with all that top loading you should be able to radiate with a good ground radial system. Just measure the impedance of the slant wire and design a match for that value, I presume the "mast" is grounded at the base well. If you want to make things easier you may wish to try a three of four wire cage around the mast and connect it to the rotor cage and feed the cage at the found level. Don't look for dips just look for a good match. Herb Schoenbohm, KV4FZ On 8/7/2015 10:54 AM, rodger bryce wrote: Gentlemen, I have the following which I would like to turn into a topband antenna if possible. My mast is approximately 40 feet high and there is rotor cage with a 10 foot stub mast, on the stubmast I have an 8 el.log periodic and above that a rotary dipole for 30/40m. I attached a drop wire at approx. 38 feet high, I grounded this wire and tried to grid dip the wire plus mast, all as per ON4UN's book "USING THE BEAM TOWER AS A LOW BAND VERTICAL" the results were zilch, nadda nothing at all, no dip anywhere on any band. I used the MFJ 259B with the GDO accessory. 1. Am I doing this all wrong..highly possible.!! 2. Is the mast not high enough to be used for top band.? I am totally out of my depth here.so any guidance would be much appreciated. Many thanks, Rodger/GM3JOB _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Top Band Antenna
You probably know this Rodger, but just in case... Radials are ESSENTIAL. As many as you can as long as you can make them (up to 1/4 wave) in as many directions as i s possible. I staple mine down with lawn staples (I find them at home improvement stores) and after a year or so they tend to "migrate" underground. Till then, you may have to set your lawn mower to leave a bit higher grass and perhaps mow carefully where they are vulnerable due to one's lawn not being perfectly flat . When I moved QTH after 4 years a while back and decided to remove the radials, I had to rip them up to get them out, so they were essentially invisible by then. Having a radial connection plate, either commercial or home brew (I use the one from DX E ngineering) makes things easier and neater. I have a wire "T" with a 40 ft vertical section and a 90 ft horizontal section and about 35 radials, some as long as 50/60/ft and some as short as 20/30 ft (some even go down my basement access hatch and run in the rafters through my basement, be creative)! I mo deled this in a simple antenna program (that I didn't kn ow much about using, it came with an ARRL Antenna Book) and it spit out values for a matching network that got me into the ballpark. The idea for the "L" is another good one and only requires the ability to have space and an anchor point in one direction. Try to keep the loading wire as parallel to the ground as you can, but don't worry if you can't do that perfectly. Again, antenna modeling software will save you much time matching the antenna. On my "T", one leg e nds up at 50 ft and the other at about 20 feet (due to the supports available ), I would say don't obs ess about it, just do what you can. I live on a small lot and that's what I can do in my context and this works positively, err OK, especially for DX. To put it in context, it is MUCH better than a Butternut vertic al over the same radial "field", so the loading wires can buy you a lot . Think about a RX antenna too. I have a K9AY that is not as optimal as I would like, but it still often makes the difference between copy/no copy for DX (often on bands other than 160, BTW, I have used it up to 15 meters at times!) . Again, be creative and search the internet for ideas. I have not set any new world DX records with this set up, but I did finish my DXCC, so it at least gets you "into the game". Best, Kevin K3OX - Original Message - From: donov...@starpower.net To: topband@contesting.com Cc: "rodger bryce" Sent: Friday, August 7, 2015 12:16:17 PM Subject: Re: Topband: Top Band Antenna Hi Rodger, You will have better success if you add a top loading wire to your mast, which makes it into an inverted-L. Suggest you start with an 80 foot wire in a straight line if possible but otherwise route it any shape necessary . You can increase or decrease the length of the top loading wire to improve the match. As an alternative to shunt feeding your mast, you could simply install an 130 foot inverted-L parallel to your mast and direct feed it from the bottom. You could add a loading coil to the wire if 80 feet is too long. 73 Frank W3LPL - Original Message - From: "rodger bryce" To: topband@contesting.com Sent: Friday, August 7, 2015 2:54:40 PM Subject: Topband: Top Band Antenna Gentlemen, I have the following which I would like to turn into a topband antenna if possible. My mast is approximately 40 feet high and there is rotor cage with a 10 foot stub mast, on the stubmast I have an 8 el.log periodic and above that a rotary dipole for 30/40m. I attached a drop wire at approx. 38 feet high, I grounded this wire and tried to grid dip the wire plus mast, all as per ON4UN's book "USING THE BEAM TOWER AS A LOW BAND VERTICAL" the results were zilch, nadda nothing at all, no dip anywhere on any band. I used the MFJ 259B with the GDO accessory. 1. Am I doing this all wrong..highly possible.!! 2. Is the mast not high enough to be used for top band.? I am totally out of my depth here.so any guidance would be much appreciated. Many thanks, Rodger/GM3JOB _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Top Band Antenna
Hi Rodger, You will have better success if you add a top loading wire to your mast, which makes it into an inverted-L. Suggest you start with an 80 foot wire in a straight line if possible but otherwise route it any shape necessary . You can increase or decrease the length of the top loading wire to improve the match. As an alternative to shunt feeding your mast, you could simply install an 130 foot inverted-L parallel to your mast and direct feed it from the bottom. You could add a loading coil to the wire if 80 feet is too long. 73 Frank W3LPL - Original Message - From: "rodger bryce" To: topband@contesting.com Sent: Friday, August 7, 2015 2:54:40 PM Subject: Topband: Top Band Antenna Gentlemen, I have the following which I would like to turn into a topband antenna if possible. My mast is approximately 40 feet high and there is rotor cage with a 10 foot stub mast, on the stubmast I have an 8 el.log periodic and above that a rotary dipole for 30/40m. I attached a drop wire at approx. 38 feet high, I grounded this wire and tried to grid dip the wire plus mast, all as per ON4UN's book "USING THE BEAM TOWER AS A LOW BAND VERTICAL" the results were zilch, nadda nothing at all, no dip anywhere on any band. I used the MFJ 259B with the GDO accessory. 1. Am I doing this all wrong..highly possible.!! 2. Is the mast not high enough to be used for top band.? I am totally out of my depth here.so any guidance would be much appreciated. Many thanks, Rodger/GM3JOB _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Top Band Antenna
Gentlemen, I have the following which I would like to turn into a topband antenna if possible. My mast is approximately 40 feet high and there is rotor cage with a 10 foot stub mast, on the stubmast I have an 8 el.log periodic and above that a rotary dipole for 30/40m. I attached a drop wire at approx. 38 feet high, I grounded this wire and tried to grid dip the wire plus mast, all as per ON4UN's book "USING THE BEAM TOWER AS A LOW BAND VERTICAL" the results were zilch, nadda nothing at all, no dip anywhere on any band. I used the MFJ 259B with the GDO accessory. 1. Am I doing this all wrong..highly possible.!! 2. Is the mast not high enough to be used for top band.? I am totally out of my depth here.so any guidance would be much appreciated. Many thanks, Rodger/GM3JOB _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Top band antenna in small garden/lot.
Hi Top branders My support for the EI7BA topband antenna ,namely an 80` eucalyptus tree went over in the storms and also demolished my shed with all the radios,and PC`s . I have 2 35` poles and was thinking of of a Marconi T . With 3 top wires abt,2` apart and a tunner at base and use the wire fence abt200` long and some other wires for radials as well,would this be OK,or would you suggest something else. . Regards. Jon G8CCL. _ Topband Reflector Archives - http://www.contesting.com/_topband
