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Multiband vertical antenna not working as expected
Vertical antenna on HF?Should I chose a vertical or a horizontal HF antenna?Antenna Tripod for a vertical antennaTheoretical Wifi antenna not working for the expected range2 Meter horizontal or vertical dipole polarization?Why a thousand miles long antenna is not needed to receive LW and MW?What material is best to design a dipole antenna working at VHF frequency?2m Biquad - Why not?Why does not a bigger antenna receive more power?Triband vertical antenna 6/2/70
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;
$begingroup$
I built a vertical out of a 5M aluminium pipe. It tunes fine (and wide!) on 20M.
I decided to add a loading coil to operate it on 40M, and it also worked fine, albeit not so wide.
While I was at it, I extended the coil for operation on 80M as well. It became super narrow! But it worked.
To test this, I used crocodile wires to bite into the coil. I decided make a remote switch out of relays. But it's not working as expected when operating 80M. The SWR jumps around like crazy on my meter, and at some point it just stays inifinite.
This is what I built:
What I suspect is that when both relays are off, there is a very high voltage across the relays and an arc forms, due to the high Q of the coil.
This does not happen when the 40 or 20M relays are activated. The antenna works more or less as expected when the 40 or 20M relays are active.
Could this be the problem? Could it be solved somehow?
I thought of using traps instead of relays to make the antenna "auto switching", but I'm not sure if traps would add more loss than the relays, or if they would whitstand the high voltages appearing on the coil.
antenna vertical
asked Jun 9 at 16:05
hjfhjf
2063 bronze badges
$endgroup$
add a comment |
$begingroup$
I built a vertical out of a 5M aluminium pipe. It tunes fine (and wide!) on 20M.
I decided to add a loading coil to operate it on 40M, and it also worked fine, albeit not so wide.
While I was at it, I extended the coil for operation on 80M as well. It became super narrow! But it worked.
To test this, I used crocodile wires to bite into the coil. I decided make a remote switch out of relays. But it's not working as expected when operating 80M. The SWR jumps around like crazy on my meter, and at some point it just stays inifinite.
This is what I built:
What I suspect is that when both relays are off, there is a very high voltage across the relays and an arc forms, due to the high Q of the coil.
This does not happen when the 40 or 20M relays are activated. The antenna works more or less as expected when the 40 or 20M relays are active.
Could this be the problem? Could it be solved somehow?
I thought of using traps instead of relays to make the antenna "auto switching", but I'm not sure if traps would add more loss than the relays, or if they would whitstand the high voltages appearing on the coil.
antenna vertical
asked Jun 9 at 16:05
hjfhjf
2063 bronze badges
$endgroup$
$begingroup$
What relays are you using?
$endgroup$
– Mike Waters♦
Jun 9 at 17:37
$begingroup$
What do you have for radials. If its just a ground rod you should add 1/4 wave radials equal to the lowest band of operation. This can effect SWR readings and directivity.
$endgroup$
– KB1CHU
Jun 11 at 16:42
$begingroup$
@KB1CHU I'm using the metal roof of my house as a ground plane. I added a random piece (3m) of 9mm aluminium tubing and that seemed to help a bit. The antenna is mounted to one side of the roof, not in the center. The roof is about 6x10m and it's connected to the coax braid.
$endgroup$
– hjf
Jun 12 at 12:59
add a comment |
$begingroup$
I built a vertical out of a 5M aluminium pipe. It tunes fine (and wide!) on 20M.
I decided to add a loading coil to operate it on 40M, and it also worked fine, albeit not so wide.
While I was at it, I extended the coil for operation on 80M as well. It became super narrow! But it worked.
To test this, I used crocodile wires to bite into the coil. I decided make a remote switch out of relays. But it's not working as expected when operating 80M. The SWR jumps around like crazy on my meter, and at some point it just stays inifinite.
This is what I built:
What I suspect is that when both relays are off, there is a very high voltage across the relays and an arc forms, due to the high Q of the coil.
This does not happen when the 40 or 20M relays are activated. The antenna works more or less as expected when the 40 or 20M relays are active.
Could this be the problem? Could it be solved somehow?
I thought of using traps instead of relays to make the antenna "auto switching", but I'm not sure if traps would add more loss than the relays, or if they would whitstand the high voltages appearing on the coil.
antenna vertical
asked Jun 9 at 16:05
hjfhjf
2063 bronze badges
$endgroup$
I built a vertical out of a 5M aluminium pipe. It tunes fine (and wide!) on 20M.
I decided to add a loading coil to operate it on 40M, and it also worked fine, albeit not so wide.
While I was at it, I extended the coil for operation on 80M as well. It became super narrow! But it worked.
To test this, I used crocodile wires to bite into the coil. I decided make a remote switch out of relays. But it's not working as expected when operating 80M. The SWR jumps around like crazy on my meter, and at some point it just stays inifinite.
This is what I built:
What I suspect is that when both relays are off, there is a very high voltage across the relays and an arc forms, due to the high Q of the coil.
This does not happen when the 40 or 20M relays are activated. The antenna works more or less as expected when the 40 or 20M relays are active.
Could this be the problem? Could it be solved somehow?
I thought of using traps instead of relays to make the antenna "auto switching", but I'm not sure if traps would add more loss than the relays, or if they would whitstand the high voltages appearing on the coil.
antenna vertical
antenna vertical
asked Jun 9 at 16:05
hjfhjf
2063 bronze badges
asked Jun 9 at 16:05
hjfhjf
2063 bronze badges
asked Jun 9 at 16:05
hjfhjf
2063 bronze badges
asked Jun 9 at 16:05
hjfhjf
2063 bronze badges
asked Jun 9 at 16:05
hjfhjf
2063 bronze badges
2063 bronze badges
$begingroup$
What relays are you using?
$endgroup$
– Mike Waters♦
Jun 9 at 17:37
$begingroup$
What do you have for radials. If its just a ground rod you should add 1/4 wave radials equal to the lowest band of operation. This can effect SWR readings and directivity.
$endgroup$
– KB1CHU
Jun 11 at 16:42
$begingroup$
@KB1CHU I'm using the metal roof of my house as a ground plane. I added a random piece (3m) of 9mm aluminium tubing and that seemed to help a bit. The antenna is mounted to one side of the roof, not in the center. The roof is about 6x10m and it's connected to the coax braid.
$endgroup$
– hjf
Jun 12 at 12:59
add a comment |
$begingroup$
What relays are you using?
$endgroup$
– Mike Waters♦
Jun 9 at 17:37
$begingroup$
What do you have for radials. If its just a ground rod you should add 1/4 wave radials equal to the lowest band of operation. This can effect SWR readings and directivity.
$endgroup$
– KB1CHU
Jun 11 at 16:42
$begingroup$
@KB1CHU I'm using the metal roof of my house as a ground plane. I added a random piece (3m) of 9mm aluminium tubing and that seemed to help a bit. The antenna is mounted to one side of the roof, not in the center. The roof is about 6x10m and it's connected to the coax braid.
$endgroup$
– hjf
Jun 12 at 12:59
$begingroup$
What relays are you using?
$endgroup$
– Mike Waters♦
Jun 9 at 17:37
$begingroup$
What relays are you using?
$endgroup$
– Mike Waters♦
Jun 9 at 17:37
$begingroup$
What do you have for radials. If its just a ground rod you should add 1/4 wave radials equal to the lowest band of operation. This can effect SWR readings and directivity.
$endgroup$
– KB1CHU
Jun 11 at 16:42
$begingroup$
What do you have for radials. If its just a ground rod you should add 1/4 wave radials equal to the lowest band of operation. This can effect SWR readings and directivity.
$endgroup$
– KB1CHU
Jun 11 at 16:42
$begingroup$
@KB1CHU I'm using the metal roof of my house as a ground plane. I added a random piece (3m) of 9mm aluminium tubing and that seemed to help a bit. The antenna is mounted to one side of the roof, not in the center. The roof is about 6x10m and it's connected to the coax braid.
$endgroup$
– hjf
Jun 12 at 12:59
$begingroup$
@KB1CHU I'm using the metal roof of my house as a ground plane. I added a random piece (3m) of 9mm aluminium tubing and that seemed to help a bit. The antenna is mounted to one side of the roof, not in the center. The roof is about 6x10m and it's connected to the coax braid.
$endgroup$
– hjf
Jun 12 at 12:59
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
It may very well be that the open contacts are arcing, and I'm betting that's what is happening.
Here are some possible solutions. How about using different relays that have less tendency to arc:
- Open-frame relays with much wider contact spacing
- Vacuum relays
- Multiple relays in series
Another possibility might be that RF on the control lines may be activating the relays. Suitable RF chokes and bypass capacitors might help that.
It's a myth that all traps are lossy. If they don't get hot to the touch at sustained 100W or higher, then their loss is insignificant. Scroll to the bottom of https://www.w8ji.com/traps.htm:
3.) Do traps create noticeable loss, perhaps one dB per trap typically?
NO! Even the worst traps (coaxial traps) in the worse possible condition of operation are only 1.6dB loss for BOTH traps!
answered Jun 9 at 17:29
Mike Waters♦Mike Waters
4,1952 gold badges6 silver badges35 bronze badges
$endgroup$
$begingroup$
What about these? tme.com/ar/es/details/li05-1a85/reles-electromagn-de-lengueta/… they are inexpensive reed relays, rated for 4KV
$endgroup$
– hjf
Jun 9 at 17:47
$begingroup$
@hjf What voltage are your present relay contacts rated at?
$endgroup$
– Mike Waters♦
Jun 9 at 17:50
1
$begingroup$
Just regular "ice cube" no-name chinese relays with generic specs. probably 250V.
$endgroup$
– hjf
Jun 9 at 18:03
add a comment |
$begingroup$
Your suspicion is justified. Voltage increases (and current decreases) as you move toward the open-circuited end of the antenna. The most common solution is to situate the loading coil - and, perhaps, a resonating capacitor - at the base of the antenna. A base-loaded vertical only 5m tall will not be very efficient on 80m, but a center-loaded antenna will probably not be great either, as it's only about 1/4 the length of a resonant monopole.
The voltage along the 5m radiator can be reduced and efficiency can be improved by effectively lengthening the radiator with "top hat" conductors. This will increase the current at the top of your 5m aluminum pipe and, depending on the size of the top hat, reduce the amount of inductive loading you need to add.
answered Jun 9 at 16:26
Brian K1LIBrian K1LI
3,3104 silver badges19 bronze badges
$endgroup$
1
$begingroup$
But a hatted 5M vertical won't tune in 20M, correct?
$endgroup$
– hjf
Jun 9 at 16:30
$begingroup$
@hjf If it won't, disconnect it with a HV relay as suggested in my answer here.
$endgroup$
– Mike Waters♦
Jun 9 at 17:31
$begingroup$
@hjf Since you have to add compensating reactance, you might decide to make the system resonant on 40m and "tune" it on 20m and 80m. The permutations of lengths and loading are endless!
$endgroup$
– Brian K1LI
Jun 9 at 18:37
$begingroup$
@BrianK1LI Added that link you your comment. ;-)
$endgroup$
– Mike Waters♦
Jun 9 at 21:18
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
It may very well be that the open contacts are arcing, and I'm betting that's what is happening.
Here are some possible solutions. How about using different relays that have less tendency to arc:
- Open-frame relays with much wider contact spacing
- Vacuum relays
- Multiple relays in series
Another possibility might be that RF on the control lines may be activating the relays. Suitable RF chokes and bypass capacitors might help that.
It's a myth that all traps are lossy. If they don't get hot to the touch at sustained 100W or higher, then their loss is insignificant. Scroll to the bottom of https://www.w8ji.com/traps.htm:
3.) Do traps create noticeable loss, perhaps one dB per trap typically?
NO! Even the worst traps (coaxial traps) in the worse possible condition of operation are only 1.6dB loss for BOTH traps!
answered Jun 9 at 17:29
Mike Waters♦Mike Waters
4,1952 gold badges6 silver badges35 bronze badges
$endgroup$
$begingroup$
What about these? tme.com/ar/es/details/li05-1a85/reles-electromagn-de-lengueta/… they are inexpensive reed relays, rated for 4KV
$endgroup$
– hjf
Jun 9 at 17:47
$begingroup$
@hjf What voltage are your present relay contacts rated at?
$endgroup$
– Mike Waters♦
Jun 9 at 17:50
1
$begingroup$
Just regular "ice cube" no-name chinese relays with generic specs. probably 250V.
$endgroup$
– hjf
Jun 9 at 18:03
add a comment |
$begingroup$
It may very well be that the open contacts are arcing, and I'm betting that's what is happening.
Here are some possible solutions. How about using different relays that have less tendency to arc:
- Open-frame relays with much wider contact spacing
- Vacuum relays
- Multiple relays in series
Another possibility might be that RF on the control lines may be activating the relays. Suitable RF chokes and bypass capacitors might help that.
It's a myth that all traps are lossy. If they don't get hot to the touch at sustained 100W or higher, then their loss is insignificant. Scroll to the bottom of https://www.w8ji.com/traps.htm:
3.) Do traps create noticeable loss, perhaps one dB per trap typically?
NO! Even the worst traps (coaxial traps) in the worse possible condition of operation are only 1.6dB loss for BOTH traps!
answered Jun 9 at 17:29
Mike Waters♦Mike Waters
4,1952 gold badges6 silver badges35 bronze badges
$endgroup$
$begingroup$
What about these? tme.com/ar/es/details/li05-1a85/reles-electromagn-de-lengueta/… they are inexpensive reed relays, rated for 4KV
$endgroup$
– hjf
Jun 9 at 17:47
$begingroup$
@hjf What voltage are your present relay contacts rated at?
$endgroup$
– Mike Waters♦
Jun 9 at 17:50
1
$begingroup$
Just regular "ice cube" no-name chinese relays with generic specs. probably 250V.
$endgroup$
– hjf
Jun 9 at 18:03
add a comment |
$begingroup$
It may very well be that the open contacts are arcing, and I'm betting that's what is happening.
Here are some possible solutions. How about using different relays that have less tendency to arc:
- Open-frame relays with much wider contact spacing
- Vacuum relays
- Multiple relays in series
Another possibility might be that RF on the control lines may be activating the relays. Suitable RF chokes and bypass capacitors might help that.
It's a myth that all traps are lossy. If they don't get hot to the touch at sustained 100W or higher, then their loss is insignificant. Scroll to the bottom of https://www.w8ji.com/traps.htm:
3.) Do traps create noticeable loss, perhaps one dB per trap typically?
NO! Even the worst traps (coaxial traps) in the worse possible condition of operation are only 1.6dB loss for BOTH traps!
answered Jun 9 at 17:29
Mike Waters♦Mike Waters
4,1952 gold badges6 silver badges35 bronze badges
$endgroup$
It may very well be that the open contacts are arcing, and I'm betting that's what is happening.
Here are some possible solutions. How about using different relays that have less tendency to arc:
- Open-frame relays with much wider contact spacing
- Vacuum relays
- Multiple relays in series
Another possibility might be that RF on the control lines may be activating the relays. Suitable RF chokes and bypass capacitors might help that.
It's a myth that all traps are lossy. If they don't get hot to the touch at sustained 100W or higher, then their loss is insignificant. Scroll to the bottom of https://www.w8ji.com/traps.htm:
3.) Do traps create noticeable loss, perhaps one dB per trap typically?
NO! Even the worst traps (coaxial traps) in the worse possible condition of operation are only 1.6dB loss for BOTH traps!
answered Jun 9 at 17:29
Mike Waters♦Mike Waters
4,1952 gold badges6 silver badges35 bronze badges
edited Jun 9 at 17:52
answered Jun 9 at 17:29
Mike Waters♦Mike Waters
4,1952 gold badges6 silver badges35 bronze badges
answered Jun 9 at 17:29
Mike Waters♦Mike Waters
4,1952 gold badges6 silver badges35 bronze badges
answered Jun 9 at 17:29
Mike Waters♦Mike Waters
4,1952 gold badges6 silver badges35 bronze badges
4,1952 gold badges6 silver badges35 bronze badges
$begingroup$
What about these? tme.com/ar/es/details/li05-1a85/reles-electromagn-de-lengueta/… they are inexpensive reed relays, rated for 4KV
$endgroup$
– hjf
Jun 9 at 17:47
$begingroup$
@hjf What voltage are your present relay contacts rated at?
$endgroup$
– Mike Waters♦
Jun 9 at 17:50
1
$begingroup$
Just regular "ice cube" no-name chinese relays with generic specs. probably 250V.
$endgroup$
– hjf
Jun 9 at 18:03
add a comment |
$begingroup$
What about these? tme.com/ar/es/details/li05-1a85/reles-electromagn-de-lengueta/… they are inexpensive reed relays, rated for 4KV
$endgroup$
– hjf
Jun 9 at 17:47
$begingroup$
@hjf What voltage are your present relay contacts rated at?
$endgroup$
– Mike Waters♦
Jun 9 at 17:50
1
$begingroup$
Just regular "ice cube" no-name chinese relays with generic specs. probably 250V.
$endgroup$
– hjf
Jun 9 at 18:03
$begingroup$
What about these? tme.com/ar/es/details/li05-1a85/reles-electromagn-de-lengueta/… they are inexpensive reed relays, rated for 4KV
$endgroup$
– hjf
Jun 9 at 17:47
$begingroup$
What about these? tme.com/ar/es/details/li05-1a85/reles-electromagn-de-lengueta/… they are inexpensive reed relays, rated for 4KV
$endgroup$
– hjf
Jun 9 at 17:47
$begingroup$
@hjf What voltage are your present relay contacts rated at?
$endgroup$
– Mike Waters♦
Jun 9 at 17:50
$begingroup$
@hjf What voltage are your present relay contacts rated at?
$endgroup$
– Mike Waters♦
Jun 9 at 17:50
1
1
$begingroup$
Just regular "ice cube" no-name chinese relays with generic specs. probably 250V.
$endgroup$
– hjf
Jun 9 at 18:03
$begingroup$
Just regular "ice cube" no-name chinese relays with generic specs. probably 250V.
$endgroup$
– hjf
Jun 9 at 18:03
add a comment |
$begingroup$
Your suspicion is justified. Voltage increases (and current decreases) as you move toward the open-circuited end of the antenna. The most common solution is to situate the loading coil - and, perhaps, a resonating capacitor - at the base of the antenna. A base-loaded vertical only 5m tall will not be very efficient on 80m, but a center-loaded antenna will probably not be great either, as it's only about 1/4 the length of a resonant monopole.
The voltage along the 5m radiator can be reduced and efficiency can be improved by effectively lengthening the radiator with "top hat" conductors. This will increase the current at the top of your 5m aluminum pipe and, depending on the size of the top hat, reduce the amount of inductive loading you need to add.
answered Jun 9 at 16:26
Brian K1LIBrian K1LI
3,3104 silver badges19 bronze badges
$endgroup$
1
$begingroup$
But a hatted 5M vertical won't tune in 20M, correct?
$endgroup$
– hjf
Jun 9 at 16:30
$begingroup$
@hjf If it won't, disconnect it with a HV relay as suggested in my answer here.
$endgroup$
– Mike Waters♦
Jun 9 at 17:31
$begingroup$
@hjf Since you have to add compensating reactance, you might decide to make the system resonant on 40m and "tune" it on 20m and 80m. The permutations of lengths and loading are endless!
$endgroup$
– Brian K1LI
Jun 9 at 18:37
$begingroup$
@BrianK1LI Added that link you your comment. ;-)
$endgroup$
– Mike Waters♦
Jun 9 at 21:18
add a comment |
$begingroup$
Your suspicion is justified. Voltage increases (and current decreases) as you move toward the open-circuited end of the antenna. The most common solution is to situate the loading coil - and, perhaps, a resonating capacitor - at the base of the antenna. A base-loaded vertical only 5m tall will not be very efficient on 80m, but a center-loaded antenna will probably not be great either, as it's only about 1/4 the length of a resonant monopole.
The voltage along the 5m radiator can be reduced and efficiency can be improved by effectively lengthening the radiator with "top hat" conductors. This will increase the current at the top of your 5m aluminum pipe and, depending on the size of the top hat, reduce the amount of inductive loading you need to add.
answered Jun 9 at 16:26
Brian K1LIBrian K1LI
3,3104 silver badges19 bronze badges
$endgroup$
1
$begingroup$
But a hatted 5M vertical won't tune in 20M, correct?
$endgroup$
– hjf
Jun 9 at 16:30
$begingroup$
@hjf If it won't, disconnect it with a HV relay as suggested in my answer here.
$endgroup$
– Mike Waters♦
Jun 9 at 17:31
$begingroup$
@hjf Since you have to add compensating reactance, you might decide to make the system resonant on 40m and "tune" it on 20m and 80m. The permutations of lengths and loading are endless!
$endgroup$
– Brian K1LI
Jun 9 at 18:37
$begingroup$
@BrianK1LI Added that link you your comment. ;-)
$endgroup$
– Mike Waters♦
Jun 9 at 21:18
add a comment |
$begingroup$
Your suspicion is justified. Voltage increases (and current decreases) as you move toward the open-circuited end of the antenna. The most common solution is to situate the loading coil - and, perhaps, a resonating capacitor - at the base of the antenna. A base-loaded vertical only 5m tall will not be very efficient on 80m, but a center-loaded antenna will probably not be great either, as it's only about 1/4 the length of a resonant monopole.
The voltage along the 5m radiator can be reduced and efficiency can be improved by effectively lengthening the radiator with "top hat" conductors. This will increase the current at the top of your 5m aluminum pipe and, depending on the size of the top hat, reduce the amount of inductive loading you need to add.
answered Jun 9 at 16:26
Brian K1LIBrian K1LI
3,3104 silver badges19 bronze badges
$endgroup$
Your suspicion is justified. Voltage increases (and current decreases) as you move toward the open-circuited end of the antenna. The most common solution is to situate the loading coil - and, perhaps, a resonating capacitor - at the base of the antenna. A base-loaded vertical only 5m tall will not be very efficient on 80m, but a center-loaded antenna will probably not be great either, as it's only about 1/4 the length of a resonant monopole.
The voltage along the 5m radiator can be reduced and efficiency can be improved by effectively lengthening the radiator with "top hat" conductors. This will increase the current at the top of your 5m aluminum pipe and, depending on the size of the top hat, reduce the amount of inductive loading you need to add.
answered Jun 9 at 16:26
Brian K1LIBrian K1LI
3,3104 silver badges19 bronze badges
answered Jun 9 at 16:26
Brian K1LIBrian K1LI
3,3104 silver badges19 bronze badges
answered Jun 9 at 16:26
Brian K1LIBrian K1LI
3,3104 silver badges19 bronze badges
answered Jun 9 at 16:26
Brian K1LIBrian K1LI
3,3104 silver badges19 bronze badges
3,3104 silver badges19 bronze badges
1
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But a hatted 5M vertical won't tune in 20M, correct?
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– hjf
Jun 9 at 16:30
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@hjf If it won't, disconnect it with a HV relay as suggested in my answer here.
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– Mike Waters♦
Jun 9 at 17:31
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@hjf Since you have to add compensating reactance, you might decide to make the system resonant on 40m and "tune" it on 20m and 80m. The permutations of lengths and loading are endless!
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– Brian K1LI
Jun 9 at 18:37
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@BrianK1LI Added that link you your comment. ;-)
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– Mike Waters♦
Jun 9 at 21:18
add a comment |
1
$begingroup$
But a hatted 5M vertical won't tune in 20M, correct?
$endgroup$
– hjf
Jun 9 at 16:30
$begingroup$
@hjf If it won't, disconnect it with a HV relay as suggested in my answer here.
$endgroup$
– Mike Waters♦
Jun 9 at 17:31
$begingroup$
@hjf Since you have to add compensating reactance, you might decide to make the system resonant on 40m and "tune" it on 20m and 80m. The permutations of lengths and loading are endless!
$endgroup$
– Brian K1LI
Jun 9 at 18:37
$begingroup$
@BrianK1LI Added that link you your comment. ;-)
$endgroup$
– Mike Waters♦
Jun 9 at 21:18
1
1
$begingroup$
But a hatted 5M vertical won't tune in 20M, correct?
$endgroup$
– hjf
Jun 9 at 16:30
$begingroup$
But a hatted 5M vertical won't tune in 20M, correct?
$endgroup$
– hjf
Jun 9 at 16:30
$begingroup$
@hjf If it won't, disconnect it with a HV relay as suggested in my answer here.
$endgroup$
– Mike Waters♦
Jun 9 at 17:31
$begingroup$
@hjf If it won't, disconnect it with a HV relay as suggested in my answer here.
$endgroup$
– Mike Waters♦
Jun 9 at 17:31
$begingroup$
@hjf Since you have to add compensating reactance, you might decide to make the system resonant on 40m and "tune" it on 20m and 80m. The permutations of lengths and loading are endless!
$endgroup$
– Brian K1LI
Jun 9 at 18:37
$begingroup$
@hjf Since you have to add compensating reactance, you might decide to make the system resonant on 40m and "tune" it on 20m and 80m. The permutations of lengths and loading are endless!
$endgroup$
– Brian K1LI
Jun 9 at 18:37
$begingroup$
@BrianK1LI Added that link you your comment. ;-)
$endgroup$
– Mike Waters♦
Jun 9 at 21:18
$begingroup$
@BrianK1LI Added that link you your comment. ;-)
$endgroup$
– Mike Waters♦
Jun 9 at 21:18
add a comment |
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What relays are you using?
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– Mike Waters♦
Jun 9 at 17:37
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What do you have for radials. If its just a ground rod you should add 1/4 wave radials equal to the lowest band of operation. This can effect SWR readings and directivity.
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– KB1CHU
Jun 11 at 16:42
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@KB1CHU I'm using the metal roof of my house as a ground plane. I added a random piece (3m) of 9mm aluminium tubing and that seemed to help a bit. The antenna is mounted to one side of the roof, not in the center. The roof is about 6x10m and it's connected to the coax braid.
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– hjf
Jun 12 at 12:59