DX-B Quarter Wave Single Wire Sloper

[A71AN]

I have installed and tested the DX-B Quarter Wave Single Wire Sloper dipole antenna and tested it this evening but result are not satisfactory at all.

SWR on 160 couldn't even be tuned using the MFJ-989C tunner.

30M is ok, other wise all of the 80 and 40 meters, do get tuned with the MFJ tunner but when the antenna is connected direct the SWR is more than 5.

Again the noise level on this antenna is more than 40db, there for there is no signal heard again exept the 30 meters.

I installed it 18 meter high.

A friend of asked me to cut slightly from the end of the antenna and test the SWR, I did the cutting before the testing, around 8 inches from the end of the wire.

Again the SWR is not just the problem but the noise is very much beyound and repairs.

That why I like to disconnect and bring down the DX-B, I thought this evening that it is also effecting my others antennas.

Still struggling with getting things done here.

Afriend also told me that as long as the noise level is over the 40db, it means the antenna do have a strong receiptions.

All this I am not an expert with, that why I will approciate it if there is some thing I can do before I dismantel this antenna.

Thank you all, 73

[n8yx]

Discuss the grounding of the shield side of the feedline at the antenna - how is this accomplished? Is the antenna supported by a conductive mast which is itself grounded?

How about the station grounds themselves?

[AG3Y]

Good day to you, Rashed,

I hate to tell you this, but your antennas are doing exactly what they should be doing, bringing RF from the ionosphere, into your radio ! Unfortunately, they are also doing something else, which is bringing man-made noise from power lines, telephone lines, and so forth, into your radio too!

I believe the only way you are going to eliminate your problem is NOT to change your antennas, but to eliminate or minimise the signal from the SOURCE! Have you determined where the greatest amount of noise is coming from ? Did you take a portable radio around and find loud static and other crashes coming from power wires, and so forth ? Can you get the local electrical or power company involved in your search for the noise source? All this static and so forth, must be wasting a significant amount of the power company's electricity. I would contact them and see what kind of help they can offer you.

Best wishes and good luck in finding that noise source. You will not have good results until you get the devices producing the noise, quieted down.

73, Jim

[A71AN]

Quote[/b] (AG3Y @ Dec. 04 2007,13:12)]Good day to you, Rashed,

I hate to tell you this, but your antennas are doing exactly what they should be doing, bringing RF from the ionosphere, into your radio ! #Unfortunately, they are also doing something else, which is bringing man-made noise from power lines, telephone lines, and so forth, into your radio too! #

I believe the only way you are going to eliminate your problem is NOT to change your antennas, but to eliminate or minimise the signal from the SOURCE! # Have you determined where the greatest amount of noise is coming from ? #Did you take a portable radio around and find loud static and other crashes coming from power wires, and so forth ? # Can you get the local electrical or power company involved in your search for the noise source? # All this static and so forth, must be wasting a significant amount of the power company's electricity. # I would contact them and see what kind of help they can offer you.

Best wishes and good luck in finding that noise source. #You will not have good results until you get the devices producing the noise, quieted down.

73, Jim
My friend Jim, good evening to you, since 2 days back I have not seen a mint sleep, trying to get things in order.

Sure for the previous problem with the noise I have sorted out compeletly, I been the last 4 days, working on all bands, USB and CW, after having all of the dimmers removed from the third floar of the house.

Also the key problem elemented as I have re routed the satellite cabels away from my place and removed the sterio amplifir of the sorround system.

Using the CP-6, had no sign of noise on 17,40 and 80 meters, using the A3S yagi, had no more noise on 20,10 and 25 meters.

I like to learn and work CW more and more, I thought the DX-B will open the 30 meters for me, it didn't.

Now I have all of the set up on the roof, I will jst remove the DX-B and like to install a singel element alaminum pipe for the 30 meters, half wave will be 15 meters, is it possible to have a digram how to do this, please my friend.

I worked 30 meters with the CP-6 tunned ok with me, and managed to do numbers of contacts but some one told me that this will damage the traps of my antenna as it is not designed for this band, I only work 100Q per foot.

My friend also the DX-B looks not tidy at all and the familly here are not happy with it and not with me thins evening, the hose is new and looks real missy:))))

I can cover up to 80 meters so far using the CP-6 and A3S, no need for more.

If I mange the 30 meters , thats all I need my friend.

Thank you my friend and best regards to you and yours

[A71AN]

Quote[/b] (n8yx @ Dec. 04 2007,12:42)]Discuss the grounding of the shield side of the feedline at the antenna - how is this accomplished? Is the antenna supported by a conductive mast which is itself grounded?

How about the station grounds themselves?
Yes my friend, the masst is effectively grounded as well as the sheild side of the cox cabel is also grounded, the ground is very effective and deep into a wet ground of at least 5 meters, the road is also proper ground rod.

There is no telephones cabels in the whole area, all of our telephones system tv cabels and internet are of under ground system, this is designed and installed during the build up of the house.

No more abstracts I can find so far, I tried to elemenate everthing possible could cause a problem for my system.

Thank you my friend

73

[K3UD]

I am not an antenna expert like some of the others here but I
do use half slopers for 160, 80, 40, and 30 meters. In my installation the slopers run from the top of a 38 foot tower at various angles to convenient tie down points. The end of the slopers are all over 7 feet above the ground. The tower has a large tribander on it as well as an 11 element two meter antenna. The coax shield is grounded to the tower itself.

I have always heard that the antennas on top of the tower act as
elevated radials or top loading in a half sloper setup. The SWR as measured in the shack will vary from 1.5 / 1 (30 and 40 meters) to almost 4 /1 (80 meters) bandwidth on 160 at 3/1 points is about 20khz. I use a tuner and get what I consider pretty good results with the system, meaning I can work everything I can hear.
(maybe hearing is another story http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

Half Slopers seem to act more like verticals than anything else and like Verticals they tend to pick up more noise than a loop or dipole.

I do know that running slopers off of trees or wood, fiberglass or metal poles and having a wire dropped down the pole to a ground rod does not elicit good performance, at least in my installations on various field day operations.

Although I have not made any field strength measurements, I did put in a ground radial system in the yard and connected it to the tower and found that performance on the slopers seemed to improve. I then put the radial system on a relay that could connect or dis-connect the radials from the shack. When I disconnected them I noticed that the SWR varied a bit and I had to touch up the antenna tuner I use.

I also asked stations on the air to compare signals with and without the radial system attached to the tower. Many said I sounded louder with the system connected and some even told me they could see it on the S meter. Some said there was no difference, and a few told me that I did not sound as good with the radials attached.

I have also used the Alpha Delta DX-B and it worked well for me. The bandwidth on 160 was a about 10KHz up and down from resonance before I needed the use the transmatch. I have come to the conclusion that the more aluminum you have on top of your tower the better the system works.

On the other hand, I had taken all the antennas off the tower for some work and dropped the DX-B off the tower. Since I had no other antenna I clamped the DX-B to my continuous steel fencing that served as the counterpoise and ran to DX-B to a low branch in a convenient tree. At no time was the antenna more than 8 feet off the ground at its highest point. I made quite a few contacts with it using my tuner.

Best Of Luck

73
George
K3UD

[A71AN]

Quote[/b] (K3UD @ Dec. 04 2007,14:14)]I am not an antenna expert like some of the others here but I
do use half slopers for 160, 80, 40, and 30 meters. In my installation the slopers run from the top of a 38 foot tower at various angles to convenient tie down points. #The end of the slopers are all over 7 feet above the ground. The tower has a large tribander on it as well as an 11 element two meter antenna. #The coax shield is grounded to the tower itself.

I have always heard that the antennas on top of the tower act as
elevated radials or top loading in a half sloper setup. #The SWR as measured in the shack will vary from 1.5 / 1 #(30 and 40 meters) to almost 4 /1 (80 meters) bandwidth on 160 at 3/1 points is about 20khz. I use a tuner and get what I consider pretty good results with the system, meaning I can work everything I can hear.
(maybe hearing is another story http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif #

Half Slopers seem to act more like verticals than anything else and like Verticals they tend to pick up more noise than a loop or dipole.

I do know that running slopers off of trees or wood, fiberglass or metal poles and having a wire dropped down the pole to a ground rod does not elicit good performance, at least in my installations on various field day operations.

Although I have not made any field strength measurements, I did put in a ground radial system in the yard and connected it to the tower and found that performance on the slopers seemed to improve. I then put the radial system on a relay that could connect or dis-connect the radials from the shack. When I disconnected them I noticed that the SWR varied a bit and I had to touch up the antenna tuner I use.

I also asked stations on the air to compare signals with and without the radial system attached to the tower. Many said I sounded louder with the system connected and some even told me they could see it on the S meter. Some said there was no difference, and a few told me that I did not sound as good with the radials attached.

I have also used the Alpha Delta DX-B and it worked well for me. The bandwidth on 160 was a about 10KHz up and down from resonance before I needed the use the transmatch. I have come to the conclusion that the more aluminum you have on top of your tower the better the system works.

On the other hand, I had taken all the antennas off the tower for some work and dropped the DX-B off the tower. Since I had no other antenna I clamped the DX-B to my continuous steel fencing #that served as the counterpoise and ran to DX-B to a low branch in a convenient tree. At no time was the antenna more than 8 feet off the ground at its highest point. I made quite a few contacts with it using my tuner.

Best Of Luck

73
George
K3UD
Thank you very much, I also do have 1.4 SWR on 30 meters, go up to 4 or 5 on 40M, and so on 80 and 160, this also baring in mind that I did cut around 8 inches from the antenna, I thought this will help the swr, a mistake:((

I was in first place planning to hung this on my tower but then the DX-B is 60 feet in length, and I have no space for it on the roof, that why I decided to install at the another corner where I can gain more space, the mast is galvanized steal, guide wires used at to side of the mast and 2X earthing, one for the mast and one with the coax shield side.

I test it this evening, the noise level is tremendously high and no way can I hear anything out of it.

Later during the test, I used my CP-6 vertical and managed straight away to build a pile which I request permissions of the other stations to go qrt to continue working on this matter.

Still I could not find an answer for the 30 meter band, if the A3S tuned with a tuner and I worked on this ban with this antenna will I damage the traps or not and is it possible to build my own signal element 30M aluminum antenna, and what would I need for this.

I am trying now to search the net for any possibility.

Thank you my friend and 73

[kq9j]

Quote[/b] (K3UD @ Dec. 04 2007,14:14)]Half Slopers seem to act more like verticals than anything else and like Verticals they tend to pick up more noise than a loop or dipole.

I have also used the Alpha Delta DX-B and it worked well for me. The bandwidth on 160 was a about 10KHz up and down from resonance before I needed the use the transmatch. I have come to the conclusion that the more aluminum you have on top of your tower the better the system works.

Best Of Luck

73
George
K3UD
I bought the Alpha Delta twin sloper about ten years ago. It worked OK on 40 and 160 but never could get the thing below 5:1 on 75.

The 75 meter half broke off right at the top that winter.

Since then, I have been using it exclusively for 160. Believe it or not, I have just under 100 khz bandwidth under 2:1 and I have never had a tuner. And I get out and hear very well from about 1830 to 1920.

I am afraid to ever move the thing. I never heard of anybody having that kind of bandwidth on 160, sans tuner. I think I just got lucky. http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

[A71AN]

Quote[/b] (kq9j @ Dec. 04 2007,17:24)]Quote[/b] (K3UD @ Dec. 04 2007,14:14)]Half Slopers seem to act more like verticals than anything else and like Verticals they tend to pick up more noise than a loop or dipole.

I have also used the Alpha Delta DX-B and it worked well for me. The bandwidth on 160 was a about 10KHz up and down from resonance before I needed the use the transmatch. I have come to the conclusion that the more aluminum you have on top of your tower the better the system works.

Best Of Luck

73
George
K3UD
I bought the Alpha Delta twin sloper about ten years ago. It worked OK on 40 and 160 but never could get the thing below 5:1 on 75.

The 75 meter half broke off right at the top that winter.

Since then, I have been using it exclusively for 160. Believe it or not, I have just under 100 khz bandwidth under 2:1 and I have never had a tuner. And I get out and hear very well from about 1830 to 1920.

I am afraid to ever move the thing. I never heard of anybody having that kind of bandwidth on 160, sans tuner. #I think I just got lucky. # #http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif
I am scared to operate at 2:1SWR, the best I got on DX-B yestrday on 160M is 1.5:1 and this is with the MFJ tuner, but the noise level is very much high, would this sort of SWR be safe to operate on with 100W of power ?

Thank you

73 my friend

[kq9j]

Generally a 1.5:1 SWR is acceptable. Certain radios may not like it and cut back power a bit. All my transmitters have tube finals and will operate into 2:1 or greater, but of course the lower the SWR the better the match and the more efficient transmission. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

Too many people make too much of SWR and go insane trying to get that perfect 1:1 reading.

[A71AN]

Quote[/b] (kq9j @ Dec. 05 2007,05:54)]Generally a 1.5:1 SWR is acceptable. Certain radios may not like it and cut back power a bit. All my transmitters have tube finals and will operate into 2:1 or greater, but of course the lower the SWR the better the match and the more efficient transmission. # http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

Too many people make too much of SWR and go insane trying to get that perfect 1:1 reading.
Thank you my friend, the DX-B already down now, A71EM will help me in getting the antenna for the 30M, that’s all I need along with what I have.

Thank u again and 73

[AG3Y]

The more I think about this subject, the more I believe your answer is to use a separate antenna for receiving. You need a small magnetic loop style antenna that you can rotate to null out the noise.

The signals you receive may be weaker than they would be with a full sized antenna, but the signal over the noise ratio should be better, if you can isolate the direction the noise is coming from, and orient the antenna so that noise source is in a null or direction of weakest reception of the noise.

There are several plans for such antennas in handbooks and on the net. Use "magnetic loop receiving antenna" for a search phrase, and let us know what you find!

Best luck, Good DX and 73, Jim

[A71AN]

Quote[/b] (AG3Y @ Dec. 05 2007,06:45)]The more I think about this subject, the more I believe your answer is to use a separate antenna for receiving. #You need a small magnetic loop style antenna that you can rotate to null out the noise. #

The signals you receive may be weaker than they would be with a full sized antenna, but the signal over the noise ratio should be better, if you can isolate the direction the noise is coming from, and orient the antenna so that noise source is in a null or direction of weakest reception of the noise.

There are several plans for such antennas in handbooks and on the net. # Use "magnetic loop receiving antenna" for a search phrase, and let us know what you find!

Best luck, Good DX and 73, #Jim
Ok my frind, Jim, I will, search for this, in the net, but again this noise on the CP-6 and my A3S is very stisfactory now, this morning I manged to make cw contacts with the state and, this afternoon again with the state on 20 meter, both are different antenna.


Thank you my friend, best regards to you and yours

73

[WB2WIK]

I've installed and used the DX-B several times at different locations. It is not a good antenna, and actually is a pretty bad antenna: And I'm a big Alpha-Delta fan. I use Alpha-Delta coax switches, and their DX-CC parallel dipoles, and their DX-LB 40-80-160 trapped dipole, etc. with great success. I just never liked the DX-B because it was ineffective everywhere I used it.

However, despite all that, an "ineffective" antenna shouldn't be receiving a ton of noise unless you have some local noise source. I note you mention you have a new home and have already eliminated light dimmers and such, but chances are there are other "modern" noise sources in your home. I live in the City (Los Angeles) and my noise level is low enough that I can hear and work DX easily on 30 meters, using a vertical with 24 radials. Typical noise level is about S3, not S0 as I would like, but still low enough for success.

Huge noise sources I've noted from within my own homes over the years include low voltage lighting under kitchen cabinets and such (horrible!), aquarium heaters, electronic alarm systems (mostly from the power supplies), fluoroescent lighting fixtures (including the ballasts), of course light dimmers (already discussed), and any appliance that has a "remote control" operation, including televisions, stereo systems, TiVo digital video recorders and so forth. With some of these appliances the only way to "quiet them down" is to completely unplug them -- because simply "shutting them off" does not eliminate the noise they generate. Remote-control devices are "always on," to some extent, otherwise you couldn't turn them "on" using a remote control.

Ditto goes for computers. Modern PCs are never completely "off," although the mother board might be -- but the power supply remains "on," providing standby voltage (+5v) all the time, as long as the PC is plugged in. As such, some of these systems generate noise continuously until they are literally unplugged.

A really high noise level received by an antenna as small and gainless as the DX-B would almost have to be locally generated.

WB2WIK/6

[A71AN]

Quote[/b] (WB2WIK @ Dec. 05 2007,09:21)]I've installed and used the DX-B several times at different locations. #It is not a good antenna, and actually is a pretty bad antenna: And I'm a big Alpha-Delta fan. #I use Alpha-Delta coax switches, and their DX-CC parallel dipoles, and their DX-LB 40-80-160 trapped dipole, etc. with great success. #I just never liked the DX-B because it was ineffective everywhere I used it.

However, despite all that, an "ineffective" antenna shouldn't be receiving a ton of noise unless you have some local noise source. #I note you mention you have a new home and have already eliminated light dimmers and such, but chances are there are other "modern" noise sources in your home. #I live in the City (Los Angeles) and my noise level is low enough that I can hear and work DX easily on 30 meters, using a vertical with 24 radials. #Typical noise level is about S3, not S0 as I would like, but still low enough for success.

Huge noise sources I've noted from within my own homes over the years include low voltage lighting under kitchen cabinets and such (horrible!), aquarium heaters, electronic alarm systems (mostly from the power supplies), fluoroescent lighting fixtures (including the ballasts), of course light dimmers (already discussed), and any appliance that has a "remote control" operation, including televisions, stereo systems, TiVo digital video recorders and so forth. #With some of these appliances the only way to "quiet them down" is to completely unplug them -- because simply "shutting them off" does not eliminate the noise they generate. #Remote-control devices are "always on," to some extent, otherwise you couldn't turn them "on" using a remote control.

Ditto goes for computers. #Modern PCs are never completely "off," although the mother board might be -- but the power supply remains "on," providing standby voltage (+5v) all the time, as long as the PC is plugged in. #As such, some of these systems generate noise continuously until they are literally unplugged.

A really high noise level received by an antenna as small and gainless as the DX-B would almost have to be locally generated.

WB2WIK/6
Thank you my friend, for all of this usuaful informations.

I have elemenated most of the noise sources so far and I have very much exceptable noise level comparing it to one week ago, using both the A3S yagi and the CP-6 vertical.

Specially since yestrday where I have compeletly removed all of the satellite cabels and the sorround system next room.

The DX-B was totally a different matter, with all what I have done here, the SWR ratio was so high infact on 160 meter even the manual tuner falied to bring to 1:1 ratio.
It was all ok on 30 meter but thats the only band tuned to 1.5swr. The rest within 4 or 5.

I have this afternoon removed the DX-B, and I expect another antenna arranged by my friend A71EM very soon , main while, I can at least now have a little rest in mind and phisical also.

I can wait for the 30 meter antenna, and also rebuild my TH-11, I do have another 2 pieces of the tower left, that will carry over the TH-11 for me.

Thank you my friend and best regards from qatar to you and yours

73

[KD0BQM]

Additional sources of Noise:

Ceiling fans (especially those with variable speed controls)
Range hoods
Furnace Motors (especially those with variable speed dc motors)
Electric Blankets and controls for same
"Cordless" telephones (both base units AND remotes)
Weather Alert Radios
Battery Powered toys (The larger the batteries, the more noise. I'm talking here about the battery powered Cars, SUV's etc.) and their chargers.
All NiMH battery chargers
Wall mounted thermostats with mercury switches
Service entrance panels with aluminum busses. Also entrance panels fed with incoming aluminum wire where no "anti-oxidant" has been applied to the line lugs.
Cordless Keyboards and Mice along with LED mice.
Computer Speakers and Printers that remain on when the power is off.
And the list goes on..
and on
and on.

Hugh - KDØBQM

[WB2WIK]

Quote[/b] (KD0BQM @ Dec. 05 2007,19:08)]Additional sources of Noise:

Ceiling fans (especially those with variable speed controls)
Range hoods
Furnace Motors (especially those with variable speed dc motors)
Electric Blankets and controls for same
"Cordless" telephones (both base units AND remotes)
Weather Alert Radios
Battery Powered toys (The larger the batteries, the more noise. #I'm talking here about the battery powered Cars, SUV's etc.) and their chargers.
All NiMH battery chargers
Wall mounted thermostats with mercury switches
Service entrance panels with aluminum busses. #Also entrance panels fed with incoming aluminum wire where no "anti-oxidant" has been applied to the line lugs.
Cordless Keyboards and Mice along with LED mice.
Computer Speakers and Printers that remain on when the power is off.
And the list goes on..
and on
and on.

Hugh - KDØBQM
I'd reply to that but my keyboard radiates a lot of noise every time I touch a key.

I've heard the transient radiated by this old computer and keyboard is probably enough to launch the Shuttle.

http://todayinspacehistory.wordpress.com/2007....-6-2007 (http://todayinspacehistory.wordpress.com/2007/12/05/most-important-things-to-know-about-the-sts-122-shuttle-launch-december-6-2007/)

Oh crap, what's that noise? http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

[kl7aj]

http://www.cebik.com/wire/sloper.html

w4rnl (http://www.cebik.com/wire/sloper.html)

Pretty comprehensive sloper material. L.B. does his homework.

eric