Re: Topband: TX ANT TO RX ANT COUPLING
> This is not encouraging news for those of us with towers already ground > and are either shunt fed or cage fed. Shunt fed towers can be detuned, or taken out of the picture by phasing a small sample of signals into the RX antenna. > I could try a motor driven inductor or capacitor (small) just to see while > QSX on various RX antennas. Is the required reactance likely to be > inductive or capacitive reacatance? It depends on what is on the tower, the shunt system, and the grounding. It can be anything from open circuit on the drop wire to fairly high reactance. There are too many variables to guess. Outside of measurements, you could model the tower and add a distant vertical 300-500 feet away that is excited as a source. Then find a detuning value for minimum pattern distortion and current in the tower. You'll see considerable pattern distortion on 160 meters from a resonant structure even 500 feet or further away, so obviously there can be considerable interaction to receive antennas even at a fairly large distance. My small vertical reversible Europe array, with each cell 70 foot spacing between two verticals for endfire, and 350 foot broadside spacing, has one endfire cell about 250 feet from my transmitting 4 square. When it looks back into the four square, while watching W1AW, I can change the level of W1AW 20 dB or more by playing with the TX antenna termination in the house. A resistor is never good, but shorts and opens or reactances can be. Some of my RX antenna to TX antenna coupling data is at the bottom of this page: http://www.w8ji.com/antenna_coupling.htm Having two antennas in the nulls of each other is worth a whole lot more than distance. 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: TX ANT TO RX ANT COUPLING
Great idea Pete but I also may run head long into false positive results with so many Beverages (12) and each with a different possible indications. Here with the masking over of any subtle changes by strong ever present boiling tropical QRN yielding a possible infinite number of variables, each by themselves variable may not quickly yield any discernible results. If there was any time day or night when QRN did not run S-9 in almost every direction I would give it a try but I fear that with what i have I may be just peeing up a rope. Herb, KV4FZ On 6/20/2012 4:45 PM, Pete Smith N4ZR wrote: > Doesn't this suggest that there is a role here for cut and try? Take a > set of clip leads to the base of the tower and experiment? > > 73, Pete N4ZR > The World Contest Station Database, at www.conteststations.com > The Reverse Beacon Network at http://reversebeacon.net, blog at > reversebeacon.blogspot.com, > spots at telnet.reversebeacon.net, port 7000 and > arcluster.reversebeacon.net, port 7000 > > On 6/20/2012 3:45 PM, Herb Schoenbohm wrote: >> Tom, >> >> This is not encouraging news for those of us with towers already ground >> and are either shunt fed or cage fed. Even though they are not >> resonate, although top loaded and approaching resonance, it seems that >> even with some elaborate decoupling arrangements, and I hope I am wrong, >> not to much can be gained by even trying to get them "detuned". This is >> crucial for me to know, and I would assume many others that have >> Beverage terminations or feed points 100 feet away, >> >> Thanks for the warning as this summer I was going to install a HV relay >> on the shunt cage to groundbut as you point out it may not help as >> the grounded shunt or cage fed tower is already a noise source for close >> proximity RX antennas. >> >> >> >> >> On 6/20/2012 2:09 PM, Tom W8JI wrote: >>> There are two potential problems with this. As general rules: >>> >>> 1.) Grounding any antenna which is dependent on a ground system to be >>> resonant will maximize reradiation. >>> >>> 2.) Resonant elevated radials, even without an antenna connected, are >>> resonant and re-radiate. >>> >>> 3.) Things that are not resonant can still re-radiate. >>> >>> To minimize coupling from a resonant radial, the radial has to be >>> disconnected from ground and from other radials. >>> >>> Different systems can be different, and in some cases re-radiation can >>> actually cause a null that reduces noise, but the general rule is >>> self-resonant antennas with a ground (Marconi), or nearly self-resonant >>> antennas when grounded, should be floated. Other antennas can be terminated >>> in an inductor, capacitor, or opened, depending on the system. >>> >>> My 220 ft insulated tower, in the center of a four square, is "opened" by >>> shorting a specific length of coax to the "L" matching network. It has much >>> more radiation when open or grounded. radiation is minimal when detuned by a >>> proper impedance. >>> >>> 73 Tom >>> >>> >>> >>> >> ___ >> 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: TX ANT TO RX ANT COUPLING
If one's tower does not have radials, is set in concrete, with minimal direct contact with earth (say less than a linear foot, with nothing more than the usual lightning treatment attached to the base, then the base connection is likely rather resistive RF, and strictly by itself the tower is a fairly impeded conductor at 160. The conductors you need to block current on are those going up the tower: coax, control leads, and possibly the lightning ground leads. You can get that done with various applications of #31 ferrite. Toroids, monster clamp-ons, and beads, without getting into specifics. Since house radio garbage stuff frequently comes out coax shields to and then up towers, it is not too hard to get a permanent infusion of junk into just about any RX antenna on a small lot and wind up blaming it on the antenna. If you put a block on **ALL** the coax and control conductors just before they go up the tower, you may solve a lot of problems. For 80 and 160, seven or eight turns of RG400 through a five stack of #31 ferrite FT240 form factor toroids will put a hefty block on stuff off the tower. Simply running eight turns of rotor cable through a five stack will block all the conductors, whether used or not. A good article on how this works is at http://audiosystemsgroup.com/RFI-Ham.pdf Do a search on #31 to go directly to the relevant material. We are developing some special uses of an FCP to substitute for radials where towers on a small lot either are the radiator or support the radiator, as in an inverted L. This allows one to pull all connections to the base of the tower other than lightning protection (through expendable #31 ferrite). These FCP methods will require current blocking treatment of ALL conductors on the tower. This will at one time substantially reduce noise induction, and reduce loss caused by these conductors becoming default lossy radials and significantly decouple all of them from the RX antennas. An FCP, its isolation transformer, and L supported by the tower, is detuned from affecting the RX antenna by breaking the contact between the isolation transformer's radiator connection post and the L. Rather than looking at it all as an unfortunate discovered disadvantage, look at it as there IS a way. It's just to do some stuff on a small lot is going to require a bunch of #31 ferrite. Cheaper than moving :>) 73, Guy. On Wed, Jun 20, 2012 at 3:45 PM, Herb Schoenbohm wrote: > Tom, > > This is not encouraging news for those of us with towers already ground > and are either shunt fed or cage fed. Even though they are not > resonate, although top loaded and approaching resonance, it seems that > even with some elaborate decoupling arrangements, and I hope I am wrong, > not to much can be gained by even trying to get them "detuned". This is > crucial for me to know, and I would assume many others that have > Beverage terminations or feed points 100 feet away, > > Thanks for the warning as this summer I was going to install a HV relay > on the shunt cage to groundbut as you point out it may not help as > the grounded shunt or cage fed tower is already a noise source for close > proximity RX antennas. > > > > > On 6/20/2012 2:09 PM, Tom W8JI wrote: > > There are two potential problems with this. As general rules: > > > > 1.) Grounding any antenna which is dependent on a ground system to be > > resonant will maximize reradiation. > > > > 2.) Resonant elevated radials, even without an antenna connected, are > > resonant and re-radiate. > > > > 3.) Things that are not resonant can still re-radiate. > > > > To minimize coupling from a resonant radial, the radial has to be > > disconnected from ground and from other radials. > > > > Different systems can be different, and in some cases re-radiation can > > actually cause a null that reduces noise, but the general rule is > > self-resonant antennas with a ground (Marconi), or nearly self-resonant > > antennas when grounded, should be floated. Other antennas can be > terminated > > in an inductor, capacitor, or opened, depending on the system. > > > > My 220 ft insulated tower, in the center of a four square, is "opened" by > > shorting a specific length of coax to the "L" matching network. It has > much > > more radiation when open or grounded. radiation is minimal when detuned > by a > > proper impedance. > > > > 73 Tom > > > > > > > > > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: TX ANT TO RX ANT COUPLING
Doesn't this suggest that there is a role here for cut and try? Take a set of clip leads to the base of the tower and experiment? 73, Pete N4ZR The World Contest Station Database, at www.conteststations.com The Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com, spots at telnet.reversebeacon.net, port 7000 and arcluster.reversebeacon.net, port 7000 On 6/20/2012 3:45 PM, Herb Schoenbohm wrote: > Tom, > > This is not encouraging news for those of us with towers already ground > and are either shunt fed or cage fed. Even though they are not > resonate, although top loaded and approaching resonance, it seems that > even with some elaborate decoupling arrangements, and I hope I am wrong, > not to much can be gained by even trying to get them "detuned". This is > crucial for me to know, and I would assume many others that have > Beverage terminations or feed points 100 feet away, > > Thanks for the warning as this summer I was going to install a HV relay > on the shunt cage to groundbut as you point out it may not help as > the grounded shunt or cage fed tower is already a noise source for close > proximity RX antennas. > > > > > On 6/20/2012 2:09 PM, Tom W8JI wrote: >> There are two potential problems with this. As general rules: >> >> 1.) Grounding any antenna which is dependent on a ground system to be >> resonant will maximize reradiation. >> >> 2.) Resonant elevated radials, even without an antenna connected, are >> resonant and re-radiate. >> >> 3.) Things that are not resonant can still re-radiate. >> >> To minimize coupling from a resonant radial, the radial has to be >> disconnected from ground and from other radials. >> >> Different systems can be different, and in some cases re-radiation can >> actually cause a null that reduces noise, but the general rule is >> self-resonant antennas with a ground (Marconi), or nearly self-resonant >> antennas when grounded, should be floated. Other antennas can be terminated >> in an inductor, capacitor, or opened, depending on the system. >> >> My 220 ft insulated tower, in the center of a four square, is "opened" by >> shorting a specific length of coax to the "L" matching network. It has much >> more radiation when open or grounded. radiation is minimal when detuned by a >> proper impedance. >> >> 73 Tom >> >> >> >> > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: TX ANT TO RX ANT COUPLING
Tom, This is not encouraging news for those of us with towers already ground and are either shunt fed or cage fed. Even though they are not resonate, although top loaded and approaching resonance, it seems that even with some elaborate decoupling arrangements, and I hope I am wrong, not to much can be gained by even trying to get them "detuned". This is crucial for me to know, and I would assume many others that have Beverage terminations or feed points 100 feet away, Thanks for the warning as this summer I was going to install a HV relay on the shunt cage to groundbut as you point out it may not help as the grounded shunt or cage fed tower is already a noise source for close proximity RX antennas. On 6/20/2012 2:09 PM, Tom W8JI wrote: > There are two potential problems with this. As general rules: > > 1.) Grounding any antenna which is dependent on a ground system to be > resonant will maximize reradiation. > > 2.) Resonant elevated radials, even without an antenna connected, are > resonant and re-radiate. > > 3.) Things that are not resonant can still re-radiate. > > To minimize coupling from a resonant radial, the radial has to be > disconnected from ground and from other radials. > > Different systems can be different, and in some cases re-radiation can > actually cause a null that reduces noise, but the general rule is > self-resonant antennas with a ground (Marconi), or nearly self-resonant > antennas when grounded, should be floated. Other antennas can be terminated > in an inductor, capacitor, or opened, depending on the system. > > My 220 ft insulated tower, in the center of a four square, is "opened" by > shorting a specific length of coax to the "L" matching network. It has much > more radiation when open or grounded. radiation is minimal when detuned by a > proper impedance. > > 73 Tom > > > > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: TX ANT TO RX ANT COUPLING
There are two potential problems with this. As general rules:
1.) Grounding any antenna which is dependent on a ground system to be
resonant will maximize reradiation.
2.) Resonant elevated radials, even without an antenna connected, are
resonant and re-radiate.
3.) Things that are not resonant can still re-radiate.
To minimize coupling from a resonant radial, the radial has to be
disconnected from ground and from other radials.
Different systems can be different, and in some cases re-radiation can
actually cause a null that reduces noise, but the general rule is
self-resonant antennas with a ground (Marconi), or nearly self-resonant
antennas when grounded, should be floated. Other antennas can be terminated
in an inductor, capacitor, or opened, depending on the system.
My 220 ft insulated tower, in the center of a four square, is "opened" by
shorting a specific length of coax to the "L" matching network. It has much
more radiation when open or grounded. radiation is minimal when detuned by a
proper impedance.
73 Tom
- Original Message -
From:
To: "Jim Koshmider" ;
Sent: Wednesday, June 20, 2012 1:06 PM
Subject: Re: Topband: TX ANT TO RX ANT COUPLING
> Hi Jim,
>
> I just use a simple SPST open frame relay to ground the vertical section
> of the antenna and no I do not use QSK ... yet ... (need to add it to the
> old amp) The vertical section is about 60’ and the rest is horizontal at
> about 80’ up. Yes, I have been very pleased with this for this lot. I have
> thought about the flag antennas (Waller) and the Hi-Z antennas for rx and
> will experiment with that in the future. Oh yes, I have a relay that
> grounds the feed on the K9AY loop during transmit as to not get too much
> signal into the front end of the rig (K3).
>
> Just let the DX know you are in NM and they will come calling :) I grew
> up in Hobbs, NM and it worked.
>
> 73, Mike
>
> From: Jim Koshmider
> Sent: Monday, June 18, 2012 12:09 PM
> To: mikefur...@att.net
> Subject: Re: Topband: TX ANT TO RX ANT COUPLING
>
> Outstanding job, Mike...!
>
> It's encouraging to hear about your successes. Your results are
> amazing.
>
> I have a similar situation here, in Albuquerque, and am in the
> process of setting up my Inverted L - essentially the same way as yours.
> I tried a different configuration, using a shorter vertical component of
> the "L" (only about 33 feet tall), but I am convinced that having a taller
> vertical component (about 44 feet tall) will give me a better low-angle
> signal. Since I don't have the benefit of having tall pines in my yard,
> the horizontal part of my "L" will droop down to about 25 feet at the end.
> Still that's not too much of a handicap.
>
> About your relay for grounding your transmit antenna... do you use a
> vacuum relay? { If you don't use QSK, I suppose a typical latching relay
> would work just as well. }
>
> I'm sure glad you commented on this issue. I was beginning to wonder
> if I would ever be able to work outside the continental US on 160! (Ha!)
>
> 73, and best DX,
>
> Jim, K8OZ
>
>
> --- On Mon, 6/18/12, mikefur...@att.net wrote:
>
>
>From: mikefur...@att.net
>Subject: Re: Topband: TX ANT TO RX ANT COUPLING
>To: topband@contesting.com
>Date: Monday, June 18, 2012, 8:34 AM
>
>
>I perhaps have maybe a worst case scenario ... I live on a 60' by
> 90' lot in
>Houston. Fortunately I have some very nice tall pine trees that
> support my
>inverted L. It has one elevated radial in the shape of an L about
> 20' above
>the ground and the antenna is fed through a current balun. One leg
> of my
>K9AY loop is within 6' of the elevated radial and 40' from the
> antenna. Yes,
>I get significant noise transferred from the transmit antenna to
> the K9AY
>loop on receive. As per ON4UN's book, he suggests to ground the TX
> antenna
>during receive and I set up a relay to do such and as a result,
> there is a
>significant decrease in the received noise from the loop. The power
> line in
>my area is underground, underneath and parallel for some distance
> with that
>radial.
>
>Just what I have managed to do here and have worked 155 countries
> with 600
>W.
>
>73, Mike WA5POK
>
>-Original Message-
>From: W2PM
>Sent: Monday, June 18, 2012 5:50 AM
>To: Bill and Liz
>Cc:
>Subject: Re: Topband: TX ANT TO RX ANT COUPLING
>
>
Re: Topband: TX ANT TO RX ANT COUPLING
Hi Jim,
I just use a simple SPST open frame relay to ground the vertical section of the
antenna and no I do not use QSK ... yet ... (need to add it to the old amp)
The vertical section is about 60’ and the rest is horizontal at about 80’ up.
Yes, I have been very pleased with this for this lot. I have thought about the
flag antennas (Waller) and the Hi-Z antennas for rx and will experiment with
that in the future. Oh yes, I have a relay that grounds the feed on the K9AY
loop during transmit as to not get too much signal into the front end of the
rig (K3).
Just let the DX know you are in NM and they will come calling :) I grew up in
Hobbs, NM and it worked.
73, Mike
From: Jim Koshmider
Sent: Monday, June 18, 2012 12:09 PM
To: mikefur...@att.net
Subject: Re: Topband: TX ANT TO RX ANT COUPLING
Outstanding job, Mike...!
It's encouraging to hear about your successes. Your results are amazing.
I have a similar situation here, in Albuquerque, and am in the process of
setting up my Inverted L - essentially the same way as yours. I tried a
different configuration, using a shorter vertical component of the "L" (only
about 33 feet tall), but I am convinced that having a taller vertical component
(about 44 feet tall) will give me a better low-angle signal. Since I don't
have the benefit of having tall pines in my yard, the horizontal part of my "L"
will droop down to about 25 feet at the end. Still that's not too much of a
handicap.
About your relay for grounding your transmit antenna... do you use a
vacuum relay? { If you don't use QSK, I suppose a typical latching relay would
work just as well. }
I'm sure glad you commented on this issue. I was beginning to wonder if
I would ever be able to work outside the continental US on 160! (Ha!)
73, and best DX,
Jim, K8OZ
--- On Mon, 6/18/12, mikefur...@att.net wrote:
From: mikefur...@att.net
Subject: Re: Topband: TX ANT TO RX ANT COUPLING
To: topband@contesting.com
Date: Monday, June 18, 2012, 8:34 AM
I perhaps have maybe a worst case scenario ... I live on a 60' by 90'
lot in
Houston. Fortunately I have some very nice tall pine trees that support
my
inverted L. It has one elevated radial in the shape of an L about 20'
above
the ground and the antenna is fed through a current balun. One leg of
my
K9AY loop is within 6' of the elevated radial and 40' from the antenna.
Yes,
I get significant noise transferred from the transmit antenna to the
K9AY
loop on receive. As per ON4UN's book, he suggests to ground the TX
antenna
during receive and I set up a relay to do such and as a result, there
is a
significant decrease in the received noise from the loop. The power
line in
my area is underground, underneath and parallel for some distance with
that
radial.
Just what I have managed to do here and have worked 155 countries with
600
W.
73, Mike WA5POK
-Original Message-
From: W2PM
Sent: Monday, June 18, 2012 5:50 AM
To: Bill and Liz
Cc:
Subject: Re: Topband: TX ANT TO RX ANT COUPLING
Do you have much noise in the first place to reradiate? Line noise also
is
very spotty along a power line - along the same line of wires any nasty
arcing noise can be very strong or very weak at certain spots so the
noise
level - if you have noise - may not be strong enough to reradiate with
any
affect.
Sent from my iPad
On Jun 17, 2012, at 17:34, "Bill and Liz"
wrote:
> I have been following the thread with interest. I have a K9AY and a
DO
> loop
> located within 60 to 75 ft of the TX vertical at our summer home.
> Interestingly, I find both these antennas very quiet with no sign of
noise
> being coupled to them via the TX antenna. I work a lot of DX from
this
> location on topband using these loops as well as a pair of Beverages,
both
> of which also pass fairly close to my TX vertical and both of which
are
> very
> quiet.
>
> So, why am I not hearing this noise many are experiencing? The TX
> vertical
> is a 60 ft toploaded affair and I do not de-tune it on receive. All
I
> have
> done is to run all the feedlines for both RX antennas and the TX
vertical
> underground in different conduits to a remote switching location.
Someone
> please tell me why I am missing out on all the fun of having noise on
my
> RX
> antennas.
>
> Bill, VE3CSK
>
>
>
Re: Topband: TX ANT TO RX ANT COUPLING
I perhaps have maybe a worst case scenario ... I live on a 60' by 90' lot in Houston. Fortunately I have some very nice tall pine trees that support my inverted L. It has one elevated radial in the shape of an L about 20' above the ground and the antenna is fed through a current balun. One leg of my K9AY loop is within 6' of the elevated radial and 40' from the antenna. Yes, I get significant noise transferred from the transmit antenna to the K9AY loop on receive. As per ON4UN's book, he suggests to ground the TX antenna during receive and I set up a relay to do such and as a result, there is a significant decrease in the received noise from the loop. The power line in my area is underground, underneath and parallel for some distance with that radial. Just what I have managed to do here and have worked 155 countries with 600 W. 73, Mike WA5POK -Original Message- From: W2PM Sent: Monday, June 18, 2012 5:50 AM To: Bill and Liz Cc: Subject: Re: Topband: TX ANT TO RX ANT COUPLING Do you have much noise in the first place to reradiate? Line noise also is very spotty along a power line - along the same line of wires any nasty arcing noise can be very strong or very weak at certain spots so the noise level - if you have noise - may not be strong enough to reradiate with any affect. Sent from my iPad On Jun 17, 2012, at 17:34, "Bill and Liz" wrote: > I have been following the thread with interest. I have a K9AY and a DO > loop > located within 60 to 75 ft of the TX vertical at our summer home. > Interestingly, I find both these antennas very quiet with no sign of noise > being coupled to them via the TX antenna. I work a lot of DX from this > location on topband using these loops as well as a pair of Beverages, both > of which also pass fairly close to my TX vertical and both of which are > very > quiet. > > So, why am I not hearing this noise many are experiencing? The TX > vertical > is a 60 ft toploaded affair and I do not de-tune it on receive. All I > have > done is to run all the feedlines for both RX antennas and the TX vertical > underground in different conduits to a remote switching location. Someone > please tell me why I am missing out on all the fun of having noise on my > RX > antennas. > > Bill, VE3CSK > > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2180 / Virus Database: 2433/5075 - Release Date: 06/17/12 > > ___ > 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: TX ANT TO RX ANT COUPLING
Do you have much noise in the first place to reradiate? Line noise also is very spotty along a power line - along the same line of wires any nasty arcing noise can be very strong or very weak at certain spots so the noise level - if you have noise - may not be strong enough to reradiate with any affect. Sent from my iPad On Jun 17, 2012, at 17:34, "Bill and Liz" wrote: > I have been following the thread with interest. I have a K9AY and a DO loop > located within 60 to 75 ft of the TX vertical at our summer home. > Interestingly, I find both these antennas very quiet with no sign of noise > being coupled to them via the TX antenna. I work a lot of DX from this > location on topband using these loops as well as a pair of Beverages, both > of which also pass fairly close to my TX vertical and both of which are very > quiet. > > So, why am I not hearing this noise many are experiencing? The TX vertical > is a 60 ft toploaded affair and I do not de-tune it on receive. All I have > done is to run all the feedlines for both RX antennas and the TX vertical > underground in different conduits to a remote switching location. Someone > please tell me why I am missing out on all the fun of having noise on my RX > antennas. > > Bill, VE3CSK > > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2180 / Virus Database: 2433/5075 - Release Date: 06/17/12 > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: TX ANT TO RX ANT COUPLING
Hi Bill The resonance element reradiate noise and also the signal. If you think about why a yagi works, all elements reradiate the signal from the driven elements, but what about on reception, . It is the same. All resonate elements reradiate. Any resonant structure does the same. Here detuning the TX antenna droops the noise by 2 S units on the RX noise. >> So, why am I not hearing this noise many are experiencing? << Noise does no add because it is incoherent, so when you remove one layer you hear start hearing the second layer, there is always noise. But you can hear only to predominant noise the strong one. Detuning a tower is no easy, NX4D 90 FT vertical with top hat is insulated from the ground, Doug was using one vacuum relay to disconnect the tower from the feed line, Doug did it in 2007 however last year he decided to tune a wire tapped 30 FT on the tower, the wire was there because he used to shunt feed the tower. Doug used a capacitor to tune the wire like W8JI explain on his website, guess what, 2 S units down on the noise floor. Now is WF has a really deep null on the sides and RX is much better. On Doug's case some capacitance or something was not right, end even using a detuning relay and floating the tower was not enough to detune the structure, How far the tower can detune your RX antenna,? Well it is easy to see it using EZNEC, one wave far is not enough and on 160m it is over 500ft away. Regards Jose Carlos N4IS - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2180 / Virus Database: 2433/5075 - Release Date: 06/17/12 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: TX ANT TO RX ANT COUPLING
Sounds like a 1/4 wave vertical to me if its toploaded enough to resonate. Do the radials pass over or under the Beverage? Carl KM1H Carl KM1H - Original Message - From: "W2XJ" To: Sent: Sunday, June 17, 2012 5:53 PM Subject: Re: Topband: TX ANT TO RX ANT COUPLING > Probably part has to do with the fact that your vertical is 1/8 > wavelength and rule of thumb is 1/8 wavelength or less do no have a > significant influence unless extremely close. > > On 6/17/12 5:34 PM, Bill and Liz wrote: >> I have been following the thread with interest. I have a K9AY and a DO >> loop >> located within 60 to 75 ft of the TX vertical at our summer home. >> Interestingly, I find both these antennas very quiet with no sign of >> noise >> being coupled to them via the TX antenna. I work a lot of DX from this >> location on topband using these loops as well as a pair of Beverages, >> both >> of which also pass fairly close to my TX vertical and both of which are >> very >> quiet. >> >> So, why am I not hearing this noise many are experiencing? The TX >> vertical >> is a 60 ft toploaded affair and I do not de-tune it on receive. All I >> have >> done is to run all the feedlines for both RX antennas and the TX vertical >> underground in different conduits to a remote switching location. >> Someone >> please tell me why I am missing out on all the fun of having noise on my >> RX >> antennas. >> >> Bill, VE3CSK >> >> >> >> - >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2012.0.2180 / Virus Database: 2433/5075 - Release Date: 06/17/12 >> >> ___ >> UR RST IS ... ... ..9 QSB QSB - hw? BK >> > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1424 / Virus Database: 2433/5075 - Release Date: 06/17/12 > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: TX ANT TO RX ANT COUPLING
Probably part has to do with the fact that your vertical is 1/8 wavelength and rule of thumb is 1/8 wavelength or less do no have a significant influence unless extremely close. On 6/17/12 5:34 PM, Bill and Liz wrote: > I have been following the thread with interest. I have a K9AY and a DO loop > located within 60 to 75 ft of the TX vertical at our summer home. > Interestingly, I find both these antennas very quiet with no sign of noise > being coupled to them via the TX antenna. I work a lot of DX from this > location on topband using these loops as well as a pair of Beverages, both > of which also pass fairly close to my TX vertical and both of which are very > quiet. > > So, why am I not hearing this noise many are experiencing? The TX vertical > is a 60 ft toploaded affair and I do not de-tune it on receive. All I have > done is to run all the feedlines for both RX antennas and the TX vertical > underground in different conduits to a remote switching location. Someone > please tell me why I am missing out on all the fun of having noise on my RX > antennas. > > Bill, VE3CSK > > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2180 / Virus Database: 2433/5075 - Release Date: 06/17/12 > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
