Re: Topband: Elevated radial number vs efficiency
On N6LF web page you can find the QEX series on ground mounted radials. And there is a ton of discussion of this topic on the reflector as it seems to come up often (may be mixing it with the towertalk reflector). 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com On 1/1/21 11:28 PM, List Mail wrote: Yes, the antenna modelling is helpful, but by no means definitive. Several years ago I put up a top loaded vertical over a very limited buried radial field, 16 x 20 m. It worked, but nothing exciting. It was very hard work burying wire in very hard ground. I then put up an elevated radial system, starting with a pair, tuning them like a dipole. Same with the second pair. After four, the tuning didn't seem at all sensitive. I ended up with 7 x 1/4 wave radials, plus a shorter one where the property boundary was too close. The radials were about 2.5 m high, just high enough to not touch with my outstretched hand. That seemed to work quite ok, compared with a full wavelength doublet antenna up 20 m. I then moved and set up the top loaded now trapped vertical over elevated 4 x 1/4 wave radials for 160 and 4 x 1/4 radials for 80 m. I quickly tired of repairing fallen radials where a horse had rubbed on a post or where I caught the wire on the tractor exhaust pipe! Again, it worked me a decent amount of DX. And I mean "DX" as nearly everything is a very long way from VK3. Last year, I did the work of burying 60 x 33 m radials, clearing away the mess of overhead wires. Does that work any better than the elevated radials? I cannot know, as there was no means of comparative testing. But, it's a whole lot tidier with the wires under the ground than overhead. My conclusion is that elevated radials do work quite decently, and they are probably a little less work than burying a decent radial field. Wires on the ground were never an option, with livestock in the paddock. My suggestion, and the references too, is to put the elevated radials up as high as practicable (higher than I had them). This allows easy access to vehicles to drive under them, without tearing something down. The aim of the radials is to reduce the effect of ground return path losses, and even with 8 radials, I could drive under them, listening to Radio National on 621 kHz, and the signal would be significantly attenuated. All of the above observations were over fairly poor ground, decomposed granite, with granite rocks floating. There is water underlying, however. 73, Luke VK3HJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Elevated radial number vs efficiency
Yes, the antenna modelling is helpful, but by no means definitive. Several years ago I put up a top loaded vertical over a very limited buried radial field, 16 x 20 m. It worked, but nothing exciting. It was very hard work burying wire in very hard ground. I then put up an elevated radial system, starting with a pair, tuning them like a dipole. Same with the second pair. After four, the tuning didn't seem at all sensitive. I ended up with 7 x 1/4 wave radials, plus a shorter one where the property boundary was too close. The radials were about 2.5 m high, just high enough to not touch with my outstretched hand. That seemed to work quite ok, compared with a full wavelength doublet antenna up 20 m. I then moved and set up the top loaded now trapped vertical over elevated 4 x 1/4 wave radials for 160 and 4 x 1/4 radials for 80 m. I quickly tired of repairing fallen radials where a horse had rubbed on a post or where I caught the wire on the tractor exhaust pipe! Again, it worked me a decent amount of DX. And I mean "DX" as nearly everything is a very long way from VK3. Last year, I did the work of burying 60 x 33 m radials, clearing away the mess of overhead wires. Does that work any better than the elevated radials? I cannot know, as there was no means of comparative testing. But, it's a whole lot tidier with the wires under the ground than overhead. My conclusion is that elevated radials do work quite decently, and they are probably a little less work than burying a decent radial field. Wires on the ground were never an option, with livestock in the paddock. My suggestion, and the references too, is to put the elevated radials up as high as practicable (higher than I had them). This allows easy access to vehicles to drive under them, without tearing something down. The aim of the radials is to reduce the effect of ground return path losses, and even with 8 radials, I could drive under them, listening to Radio National on 621 kHz, and the signal would be significantly attenuated. All of the above observations were over fairly poor ground, decomposed granite, with granite rocks floating. There is water underlying, however. 73, Luke VK3HJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Elevated radial number vs efficiency
I have taken the liberty to move Jim's most recent reply on the Common mode thread over here where it is more on topic Jim: True enough There is a work around however Dick Weber k5UI ( SK ..I think) published an article in Communications Quarterly in 1999 on an approach using non resonant ( i.e not .25 wavelength ) radials which significantly reduces the impact of unbalanced radial currents. I cant find a link to a copy on the WEB, I have a copy of the article (contact me off list) if you cant find one . Running four 100 foot radials ( ~.2 wavelengths) I am able to have (measured)� radial currents that vary less than 2% over all four radials installed in a heavily wooded environment where some attempt was made to try and keep all of them "around " 7' above ground At .2 wavelengths N6LF's work suggests that I am giving up around .2db ...which suggests I might want to look at going from 100' radials to 150 /160' ? Will have to look at that, it would require I redo all my matching networks not sure I want to go through that for .3db ...8^( NR1DX manu...@artekmanuals.com On 1/1/2021 4:28 PM, Jim Brown wrote: On 1/1/2021 12:09 PM, Mike Waters wrote: I am ONE of the people who claim that four elevated radials can have approximately the same efficiency as 120 buried quarter wavelength radials. N6LF's work on this showed that imbalance of the current in elevated radials can significantly reduce field strength. Imbalance can be caused by differences in heights, lengths, and soil underneath them. Depending on our real estate, hams may find it difficult or impractical to install elevated radials having the symmetry of a broadcast station. Rudy has published work showing that 8 elevated radials are better than 4 for this reason. 73, Jim K9YC On 1/1/2021 4:55 PM, Mike Waters wrote: Thanks for catching that, Dave! I certanly can't argue with Rudy N6LF, but those two λ/4 10' high elevated radials in my old 160m page made that inverted-L a "killer"* in an ARRL 160 contest about 10 years ago. That was using only 100 watts. Broke a number of DX pileups, to my utter amazement. *Having said that, I had nothing else to compare it to in an A/B test! 73, Mike W0BTU On Fri, Jan 1, 2021, 3:37 PM Artek Manuals wrote: Correction that should be N6LF (not N6FL) NR1DX On 1/1/2021 4:26 PM, Artek Manuals wrote: N6FL was quoted earlier ... https://www.antennasbyn6lf.com/design_of_radial_ground_systems/ However N6FL states "The article is primarily intended to show why I (he, N6FL) _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector -- Dave manu...@artekmanuals.com www.ArtekManuals.com -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Elevated radial number vs efficiency
My experience was not on top band BUT on a 80 meter 4 sq. initially I installed 4 gullwing elevated tuned radials for each of the 4 elements. The array played will but over time it became quit clear on wet rain or even dew conditions the array played much better in transmit and not as much obvious in recive. This prompted me to strip and install 112 ¼ wave radials per element. Wayne ,W3EA Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10 From: Mike Waters<mailto:mikew...@gmail.com> Sent: Friday, January 1, 2021 4:55 PM To: topband@contesting.com<mailto:topband@contesting.com> Subject: Re: Topband: Elevated radial number vs efficiency Thanks for catching that, Dave! I certanly can't argue with Rudy N6LF, but those two λ/4 10' high elevated radials in my old 160m page made that inverted-L a "killer"* in an ARRL 160 contest about 10 years ago. That was using only 100 watts. Broke a number of DX pileups, to my utter amazement. *Having said that, I had nothing else to compare it to in an A/B test! 73, Mike W0BTU On Fri, Jan 1, 2021, 3:37 PM Artek Manuals wrote: > Correction that should be N6LF (not N6FL) > > NR1DX > > On 1/1/2021 4:26 PM, Artek Manuals wrote: > > N6FL was quoted earlier ... > > https://www.antennasbyn6lf.com/design_of_radial_ground_systems/ > > > > However N6FL states "The article is primarily intended to show why I > > (he, N6FL) > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Elevated radial number vs efficiency
Thanks for catching that, Dave! I certanly can't argue with Rudy N6LF, but those two λ/4 10' high elevated radials in my old 160m page made that inverted-L a "killer"* in an ARRL 160 contest about 10 years ago. That was using only 100 watts. Broke a number of DX pileups, to my utter amazement. *Having said that, I had nothing else to compare it to in an A/B test! 73, Mike W0BTU On Fri, Jan 1, 2021, 3:37 PM Artek Manuals wrote: > Correction that should be N6LF (not N6FL) > > NR1DX > > On 1/1/2021 4:26 PM, Artek Manuals wrote: > > N6FL was quoted earlier ... > > https://www.antennasbyn6lf.com/design_of_radial_ground_systems/ > > > > However N6FL states "The article is primarily intended to show why I > > (he, N6FL) > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Elevated radial number vs efficiency
Correction that should be N6LF (not N6FL)
NR1DX
On 1/1/2021 4:26 PM, Artek Manuals wrote:
Mike & Bill
Thank you!!! I sometimes think there is too much emphasis on NEC
modelling and never enough real world verification with actual field
measurements
{I have hijacked the original thread and changed the subject. to be
more on point }
N6FL� was quoted earlier in the previous thread, for his work on
studying the effects of elevated radials and he in fact states on his
web page which IS by all means� worthy of reading and close study.� I
am reposting the link here
https://www.antennasbyn6lf.com/design_of_radial_ground_systems/
However N6FL� states "The article is primarily intended to show why I
(he, N6FL)� suggest that 10-12 elevated radials should be used if
possible. " . His own data however is a bit contradictory and his
comment lacks� the context of radial length. Radials of .25
wavelengths (Page 37 figure 12, QEX, March 2012) produces a gain
identical to 16 radials of the same length. His data suggests that if
you lengthen the elevated radials to .6 wavelengths then 16 elevated
radials do indeed produce ~.6db improvement over four radials of that�
same length. Most of us are unlikely to want to invest in the almost a
mile of additional wire on 160M to get that .6db improvement, let
alone the labor involved in stringing it up and keeping it up.
What I also stumbled on in reading that same article is that only two
elevated radials is only down by .4db compared to four radials, which
would suggest that even only two (elevated) radials would perform as
good or better than ground mounted radial fields of a couple of dozen
radial range. A quick google search did not produce a similar study to
N6LF's work for ground mounted radials though I am sure it is out
there and the readers of this thread will find it for everyone's
reading enjoyment !
Cheers and HNY
Dave
NR1DX
On 1/1/2021 3:09 PM, Mike Waters wrote:
This link at to top of that page is a must-read, too.
https://web.archive.org/web/20180923221943/http://lists.contesting.com/_topband/2007-11/msg00248.html.
Guess I might as well include the text...
I am ONE of the people who claim that four elevated radials can have
approximately the same efficiency as 120 buried quarter wavelength
radials.
I have installed such systems at three Standard Broadcast stations in
the
United States, and made field strength measurements that, when
analyzed in
accordance with FCC procedure, showed that the unattenuated field
strength
at one kilometer was essentially the same as the FCC criteria for
broadcast
antennas with 120 buried 90 degree radials (Figure 8 of Part 73 of
the FCC
Rules).
The first station was in 1990 and it was WPCI, 1490 kilohertz,
Greenville,
SC where the height of the tower steel was 93 degrees above the base
insulator and 87.2 degrees above the point of attachment of the four
elevated radials. The radials were horizontal all the way to the tower
where they were attached with an insulator and connected to the outer
conductor of a coax cable. The coax center conductor was connected
to the
tower at that point. The license application containing the field
strength
measurements, measurement analysis and explanations can be found in
the FCC
Public Reference Room under file number 900615AE.
Measurements were made on eight equally spaced azimuths out to three
kilometers using a Nems Clark model 120E field strength meter. 146
measurements were made for an average of over 18 per azimuth. Power
was set
at one kilowatt using a General Radio model 916A RF impedance bridge
for the
radiation resistance and a Delta Electronics precision RF ammeter for
the
antenna current. The measurement data was analyzed with EDX Engineering
program AMDAT which is described in IEEE Transactions on
Broadcasting, Vol.
BC-32, No. 2, June 1986.
The result was an RMS value of the eight radials of 302.7 mV/m/kW at one
kilometer. This compares with the FCC Figure 8 value of 307.8
mV/m/kW for a
93 degree tower with 120 ninety degree buried radials, however, a
tower 87.2
degrees (the height of the WPCI tower above the four horizontal
radials) has
an FCC rated efficiency of 303.7 mV/m/kW, one mV/m more than our
measured
value.
The WPCI radials were number 10 copper wire 90 degrees long and 8.7
degrees
(16 feet) above ground. A coax cable was fed through the inside of the
tower from the T network at the tower base to the point of radial
attachment. The top of the base insulator was approximately five
feet above
ground. The impedance was measured at the input to the coax which
was the
point of current measurement for determination of power. The bridge
measurement was R 78 +j56.4.
The FCC personnel in the Broadcast Bureau were initially reluctant to
entertain the notion of an AM broadcast ground system which was so
radically
different from what had been used from the beginning of vertical
broadcast
antennas in the
Topband: Elevated radial number vs efficiency
Mike & Bill
Thank you!!! I sometimes think there is too much emphasis on NEC
modelling and never enough real world verification with actual field
measurements
{I have hijacked the original thread and changed the subject. to be more
on point }
N6FL was quoted earlier in the previous thread, for his work on
studying the effects of elevated radials and he in fact states on his
web page which IS by all means worthy of reading and close study. I am
reposting the link here
https://www.antennasbyn6lf.com/design_of_radial_ground_systems/
However N6FL states "The article is primarily intended to show why I
(he, N6FL) suggest that 10-12 elevated radials should be used if
possible. " . His own data however is a bit contradictory and his
comment lacks the context of radial length. Radials of .25 wavelengths
(Page 37 figure 12, QEX, March 2012) produces a gain identical to 16
radials of the same length. His data suggests that if you lengthen the
elevated radials to .6 wavelengths then 16 elevated radials do indeed
produce ~.6db improvement over four radials of that same length. Most
of us are unlikely to want to invest in the almost a mile of additional
wire on 160M to get that .6db improvement, let alone the labor involved
in stringing it up and keeping it up.
What I also stumbled on in reading that same article is that only two
elevated radials is only down by .4db compared to four radials, which
would suggest that even only two (elevated) radials would perform as
good or better than ground mounted radial fields of a couple of dozen
radial range. A quick google search did not produce a similar study to
N6LF's work for ground mounted radials though I am sure it is out there
and the readers of this thread will find it for everyone's reading
enjoyment !
Cheers and HNY
Dave
NR1DX
On 1/1/2021 3:09 PM, Mike Waters wrote:
This link at to top of that page is a must-read, too.
https://web.archive.org/web/20180923221943/http://lists.contesting.com/_topband/2007-11/msg00248.html.
Guess I might as well include the text...
I am ONE of the people who claim that four elevated radials can have
approximately the same efficiency as 120 buried quarter wavelength radials.
I have installed such systems at three Standard Broadcast stations in the
United States, and made field strength measurements that, when analyzed in
accordance with FCC procedure, showed that the unattenuated field strength
at one kilometer was essentially the same as the FCC criteria for broadcast
antennas with 120 buried 90 degree radials (Figure 8 of Part 73 of the FCC
Rules).
The first station was in 1990 and it was WPCI, 1490 kilohertz, Greenville,
SC where the height of the tower steel was 93 degrees above the base
insulator and 87.2 degrees above the point of attachment of the four
elevated radials. The radials were horizontal all the way to the tower
where they were attached with an insulator and connected to the outer
conductor of a coax cable. The coax center conductor was connected to the
tower at that point. The license application containing the field strength
measurements, measurement analysis and explanations can be found in the FCC
Public Reference Room under file number 900615AE.
Measurements were made on eight equally spaced azimuths out to three
kilometers using a Nems Clark model 120E field strength meter. 146
measurements were made for an average of over 18 per azimuth. Power was set
at one kilowatt using a General Radio model 916A RF impedance bridge for the
radiation resistance and a Delta Electronics precision RF ammeter for the
antenna current. The measurement data was analyzed with EDX Engineering
program AMDAT which is described in IEEE Transactions on Broadcasting, Vol.
BC-32, No. 2, June 1986.
The result was an RMS value of the eight radials of 302.7 mV/m/kW at one
kilometer. This compares with the FCC Figure 8 value of 307.8 mV/m/kW for a
93 degree tower with 120 ninety degree buried radials, however, a tower 87.2
degrees (the height of the WPCI tower above the four horizontal radials) has
an FCC rated efficiency of 303.7 mV/m/kW, one mV/m more than our measured
value.
The WPCI radials were number 10 copper wire 90 degrees long and 8.7 degrees
(16 feet) above ground. A coax cable was fed through the inside of the
tower from the T network at the tower base to the point of radial
attachment. The top of the base insulator was approximately five feet above
ground. The impedance was measured at the input to the coax which was the
point of current measurement for determination of power. The bridge
measurement was R 78 +j56.4.
The FCC personnel in the Broadcast Bureau were initially reluctant to
entertain the notion of an AM broadcast ground system which was so radically
different from what had been used from the beginning of vertical broadcast
antennas in the 1920s, and as refined by the classic article on broadcast
ground systems in the thirties (Ground Systems as a Factor in Anten
Topband: Elevated Radial Question
Gentlemen: I’ve recently installed my first 160M antenna - a 90 foot linearly loaded sloping vertical with a single 126ft elevated ( 10-15ft off the ground ) vertical. I’m feeding this with a dual core current choke balun and to my surprise it presents a 1.2 SWR at 1.83Mhz at the balun. 2:1 SWR bandwidth is ~ 50KHz. The shack connection to the balun is through about 125ft of RG213 coax on the ground. It seems to be working OK but my question is: I can add one more 126ft elevated vertical but it would be almost at a right angle to the first radial and would come within 15ft of the house with aluminum siding - Will this additional elevated vertical provide some improvement or just create the potential for additional noise pick-up due to it’s location near the house? Thanks in advance for your thoughts and suggestions. 73 Bob W3RW _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: elevated radial
Hello You want the elevated radials as high as possible. 3 meters is probably as low as you would want. 5 meters would probably be optimum. To be effective, the radials would need to be resonant, and you would need at least two, preferably four. The current on each radial should be equal. Any vegetation under the radials may have some effect. Hopefully the corn is down and harvested before the 160 meter DX season starts. As was suggested, the K2AV folded counterpoise, when installed as Guy suggests, is a good compromise that has enabled many hams to get on 160 Meters when they are in locations that are not radial friendly Peter K1ZJH _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: elevated radial
Hello Anton I thoroughly recommend the K2AV folded counterpoise that I use (248 countries wkd on 160 in 6 years). Read k2av.com. He suggests that it might be equivalent to 4 elevated radials. The counterpoise is easy to construct yourself. The balun is available from balundesigns.com or easy to construct yourself too. It would be very useful if you have an antenna analyser for final matching. Contact me off reflector if you want help with. 73 John G3XHZ Sent from my iPhone > On 16 Jan 2019, at 03:12, donov...@starpower.net wrote: > > Hello Anton, > > > One elevated wire will work, more than one will work much better. > > > Elevated wires must be near resonant length, a good starting point > is to make your wire about 125 feet (38 meters) long > > > Good luck! > > > 73 > Frank > W3LPL > > > > > > > - Original Message - > > From: "Anton Moehammad via Topband" > To: topband@contesting.com > Sent: Wednesday, January 16, 2019 3:07:07 AM > Subject: Topband: elevated radial > > Hello All,I wondering if You can give me advice about some unclear thing for > my second attempt 160m antenna. I can put a vertical antenna but > unfortunately there is no way I can lay down my ground in or on the ground > the best I can is put the ground wire at least 3m above average ground > because its an corn field, is there anything I need to worry or pay attention > about it ?with my 80m inverted V antenna my S meter go as high as S9 for > 160m. any advice. I live in YB land and this is my second attempt to be on > air on 160 any advice will appreciate. > thank You. > Anton > _ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: elevated radial
Hello Anton, One elevated wire will work, more than one will work much better. Elevated wires must be near resonant length, a good starting point is to make your wire about 125 feet (38 meters) long Good luck! 73 Frank W3LPL - Original Message - From: "Anton Moehammad via Topband" To: topband@contesting.com Sent: Wednesday, January 16, 2019 3:07:07 AM Subject: Topband: elevated radial Hello All,I wondering if You can give me advice about some unclear thing for my second attempt 160m antenna. I can put a vertical antenna but unfortunately there is no way I can lay down my ground in or on the ground the best I can is put the ground wire at least 3m above average ground because its an corn field, is there anything I need to worry or pay attention about it ?with my 80m inverted V antenna my S meter go as high as S9 for 160m. any advice. I live in YB land and this is my second attempt to be on air on 160 any advice will appreciate. thank You. Anton _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: elevated radial
Hello All,I wondering if You can give me advice about some unclear thing for my second attempt 160m antenna. I can put a vertical antenna but unfortunately there is no way I can lay down my ground in or on the ground the best I can is put the ground wire at least 3m above average ground because its an corn field, is there anything I need to worry or pay attention about it ?with my 80m inverted V antenna my S meter go as high as S9 for 160m. any advice. I live in YB land and this is my second attempt to be on air on 160 any advice will appreciate. thank You. Anton _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Elevated Radial Lengths
On 80 meters, my vertical uses four elevated radials, each are 48 feet in length and about 11 feet high. They are tied together at the center and loaded with a small Air Dux coil of approximately 3.4 uh. The other end of the coil is tied to the coax shield. This antenna works better than the antenna did when it had full sized radials. A bonus is that the antenna can be resonated to a desired frequency by simply changing the tap on the coil. The wire radiator is cut for a 1/4 around 3650. To achieve 1:1 SWR, I have a shunt matching coil across the vertical wire and coax shield. I believe that Dave, W5UN used 96 foot long radials on his 160M 4 square and a similar coil loading setup. The above shortened radial designs follow recommendations made by Dick Weber, K5IU, who empirically demonstrated that 1/4 wave radials are inferior to properly shortened sixty degree (or lengthened 120 degree radials), 73, Dennis W0JX _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Elevated radial Question
Tom - Did you receive my last email describing my NEW elevated radial system? I think all is well but would like your thoughts and confirmation of what I found. I highly respect your opinion so I'll send it again if necessary. Thanks, Terry W7KW All good topband ops know fine whiskey is a daylight beverage. _ Topband Reflector
Re: Topband: elevated radial question
Hi, Grant! Well, sometimes we have to just "flower where we're planted" and what is IS! I actually think that an 85' high TEE with elevated radials will be an excellent 160 antenna for you!! Actually, I don't expect that you really need 7 radials. Four should do fine! Of course, you could add more later. If you wish! I don't think you'll have much interaction between your radials and the 4 square receive array since it is vertical, but if the 4 square array has radials you might try to keep them separated from your 160 transmit radials. I used to have m y 160 inverted-L radials on my small lot, along with my 80m GP radials and both worked great! I surely would avoid contact between the 160 radials and that metal building. Any contact would substantially alter the current distribution, electrical length and resonance of the radials. All that can be checked with some imaginative work with an antenn analyzer or dip meter.Note that if you connect any two reasonable opposing radials together near the feedpoint, of your TEE, the pair should be 1/2 wave resonant. I absolutely would NOT connect to the building NOR would I run the radias over the metal roof! Just use FEWER radials! High conductivity is GOOD! Just don't connec to it! BTW, you could also hang and 80m quarter wave wire off the flat topof your tee and attach I to the same feed point as the 160 antenna. Of course you would also need to add some 80m radials! Good luck!! Sounds lie it's likely to be a really good 160 transmit antenna! -MUCH better than a delta loop~ Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Grant Saviers Sent: Wednesday, December 12, 2012 7:06 PM To: topband@contesting.com Subject: Topband: elevated radial question I'm finalizing the layout for a tree hung T loaded vertical for TB, about 85' to the top, two x 45' mostly horizontal loading wires, and radials elevated 10' above (much?) better than average soil, at least this time of year when I have standing water among the trees. (Redmond, WA) I'm taking W8JI's advice and going with the top loaded vertical rather than a delta loop, particularly after I determined I can squeeze seven fairly symmetrical 130' radials in (with a cooperative neighbor). I plan a switched series capacitor feed for bandwidth, with the antenna resonant at 1815KHz or so. Now two questions before stringing wire - 1. My new DXE 4 square receive array is outside the radial field, with the center of the square 82' from the radials perimeter. Does it matter if the end of one radial is about 30' from a corner 4sq antenna, or should I pitch the radials to maximize the separation? Even as much as a 90 degree (or more) segment with no radials? At 90 degree pitch the nearest radial ends would be about 80' from their nearest 4sq antenna. 2. Now the unusual circumstance - there is a 56' x 70' steel building entirely inside the radial circle, but at the perimeter. Steel roof, walls, and Ufer grounded to the perimeter footing. My thinking, not sure I'm correct, is to NOT attach any radials to the building (12' to eves, 14' to peak), but nestle it between 2 radials with about 15' feet of minimum clearance. OTOH, I can connect one or more radials to the steel, or run one or more insulated radials over the roof to a support off the perimeter end of the building. And then OTOH, the steel sure makes this part of the radial field pretty high conductivity. This one is definitely not in the handbooks or in ON4UN or in the N6LF QEX articles. btw I have a SteppIR BigIR vertical going on the center of this roof as a secondary/backup HF antenna. Inputs appreciated, Grant KZ1W ___ Topband reflector - topband@contesting.com ___ Topband reflector - topband@contesting.com
Topband: elevated radial question
I'm finalizing the layout for a tree hung T loaded vertical for TB, about 85' to the top, two x 45' mostly horizontal loading wires, and radials elevated 10' above (much?) better than average soil, at least this time of year when I have standing water among the trees. (Redmond, WA) I'm taking W8JI's advice and going with the top loaded vertical rather than a delta loop, particularly after I determined I can squeeze seven fairly symmetrical 130' radials in (with a cooperative neighbor). I plan a switched series capacitor feed for bandwidth, with the antenna resonant at 1815KHz or so. Now two questions before stringing wire - 1. My new DXE 4 square receive array is outside the radial field, with the center of the square 82' from the radials perimeter. Does it matter if the end of one radial is about 30' from a corner 4sq antenna, or should I pitch the radials to maximize the separation? Even as much as a 90 degree (or more) segment with no radials? At 90 degree pitch the nearest radial ends would be about 80' from their nearest 4sq antenna. 2. Now the unusual circumstance - there is a 56' x 70' steel building entirely inside the radial circle, but at the perimeter. Steel roof, walls, and Ufer grounded to the perimeter footing. My thinking, not sure I'm correct, is to NOT attach any radials to the building (12' to eves, 14' to peak), but nestle it between 2 radials with about 15' feet of minimum clearance. OTOH, I can connect one or more radials to the steel, or run one or more insulated radials over the roof to a support off the perimeter end of the building. And then OTOH, the steel sure makes this part of the radial field pretty high conductivity. This one is definitely not in the handbooks or in ON4UN or in the N6LF QEX articles. btw I have a SteppIR BigIR vertical going on the center of this roof as a secondary/backup HF antenna. Inputs appreciated, Grant KZ1W ___ Topband reflector - topband@contesting.com
Re: Topband: elevated radial symetry and layout
Update on this project. The guy doing my brush cutting has an auger attachment so putting down holes will be easy. That opens the door to sticking another 4 poles out on the corners. That would allow 8 radials per vertical in some combination. I'm going to have him drill the holes and I'll stick in the posts. But not sure if I will use them at the moment. In EZNEC, the currents for the 8 radial variation are not even as in the case of the 4-per variation. I need to dig into it more but I do think the ideal distribution is to have even currents across radials and in the 4-square you won't get that. The result was confirmed using the NEC4 engine as well. Which means going from the 4 to the 8 case is not straight forward (as one of the guys already suggested). It could also be that my assumption of even currents as an ideal - or my model - or something else is wrong. With the poles I can play with it down the road. I do have the W8WWV RVM system so measuring the radial current/phase is something that would be interesting to look into. 73/jeff/ac0c www.ac0c.com alpha-charlie-zero-charlie -Original Message- From: Jeff Blaine Sent: Wednesday, September 12, 2012 1:02 PM To: David Novoa, W4DN ; topband@contesting.com Subject: Re: Topband: elevated radial symetry and layout Gentlemen, thanks for the offline comments. And yes, I do understand and agree that more radials leads to less individual radial dependence. NL's QEX articles show that in the graphs which is very interesting. And also that a ground mounted screen is less sensitive yet. The current install is a temporary setup just to carry through this contest season and into next year when I can get the tree work done to clear the final resting place. So 4 is the magic number. And the question is how to lay out those few to get the best overall symmetrical pattern among the 4 verticals in the array. Sorry for the confusion. 73/jeff/ac0c www.ac0c.com alpha-charlie-zero-charlie -Original Message- From: David Novoa, W4DN Sent: Wednesday, September 12, 2012 12:16 PM To: topband@contesting.com Subject: Re: Topband: elevated radial symetry and layout Fellows, I think that's an interesting question. Please reply to Jeff's inquiry on the reflector, so all of us who are interested in the subject can benefit from your advice. TU es 73, Dave, W4DN (Ex-KP4AM) ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: elevated radial symetry and layout
Gentlemen, thanks for the offline comments. And yes, I do understand and agree that more radials leads to less individual radial dependence. NL's QEX articles show that in the graphs which is very interesting. And also that a ground mounted screen is less sensitive yet. The current install is a temporary setup just to carry through this contest season and into next year when I can get the tree work done to clear the final resting place. So 4 is the magic number. And the question is how to lay out those few to get the best overall symmetrical pattern among the 4 verticals in the array. Sorry for the confusion. 73/jeff/ac0c www.ac0c.com alpha-charlie-zero-charlie -Original Message- From: David Novoa, W4DN Sent: Wednesday, September 12, 2012 12:16 PM To: topband@contesting.com Subject: Re: Topband: elevated radial symetry and layout Fellows, I think that's an interesting question. Please reply to Jeff's inquiry on the reflector, so all of us who are interested in the subject can benefit from your advice. TU es 73, Dave, W4DN (Ex-KP4AM) ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: elevated radial symetry and layout
Fellows, I think that's an interesting question. Please reply to Jeff's inquiry on the reflector, so all of us who are interested in the subject can benefit from your advice. TU es 73, Dave, W4DN (Ex-KP4AM) ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: elevated radial symetry and layout
I’m cooking up my first 4-square using a set of elevated radials. Is there a consensus on what the optimal way of laying out the radial pattern is? If the radials are spread out on the 0/90/180/270 points, we have overlap between each of the radial center points (the 180 degree radial on the top vertical overlaps with the 0 degree radial on the bottom, for example). In the ON4UN book, a good diagram of the bonded and trimmed variety is shown for the ground mounted. But for elevated, he suggests alternating the radials on each vertical with a 45 degree rotation. Unfortunately his drawing is only for 2 verticals. If you expand his layout, all of the vertical radials are clear except for the pair which bisect the diagonal centerline and thus overlap. In addition, the center is where the control box is going to have to be as well - so that puts the radials with their attendant significant currents in close proximity to the phasing lines and box. In Rudy’s QEX he goes into the reduced sensitivity to symmetry associated of using 8-12 elevated radials per vertical. But for the more simple 4 per vertical case, I am looking for what the proper routing method should be to optimize the symmetry of the 4 square. Thanks! 73/jeff/ac0c www.ac0c.com alpha-charlie-zero-charlie ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
