[TowerTalk] Cost effectivel Tower height
Steve Hunt
steve at karinya.net
Thu Dec 1 11:16:14 PST 2011
I think we sometimes concentrate too much on looking at antenna heights
that will maximise gain at certain take-off angles, and forget about the
nulls. Those deep elevation nulls can be "killers" if arrival angles
over a wanted path happen to fall in them.
So, before going firm on a height I'd encourage you to look at the ARRL
Angle-of-Arrival statistics for various bands and paths, and make sure
your selected height is not going to put a deep null at a high
probability arrival angle for the bands/paths you are most interested
in. It might be a better trade to be 1dB weak for 80% of the time rather
than 20dB weak for 20% of the time, if you get my point.
73,
Steve G3TXQ
On 01/12/2011 18:47, Andreas Hofmann wrote:
> I have received an overwhelming response to my questions. I should have mentioned a few more points/requirements:
>
> - single multiband beam 40 - 10. No stacks. I am running verticals and wires hanging in trees and can hear ok, but are not being heard well on 40 for example. I want at least a few S units improvement and F/B would be great as well.
> - I like DX and DX contesting, but casually. Focus on Europe.
> - self supporting, no guy wires
> - low profile to appease to wife and neighbors
> - cheap. This is a hobby for me and I am not retired (:-)
> - account for the sloping terrain, so if it can be lower because of it, yes, yes, hence cheaper.
>
> I understand that any multi-band beam is a compromise.
> I understand that any beam might not work to its maximum into all DX directions (different angles needed).
>
> At this point, I want to thank all of you for your input. I will run the suggested software and report back with my findings.
>
> Thanks
> Andreas
> KU7T
>
>
>
> -----Original Message-----
> From: towertalk-bounces at contesting.com [mailto:towertalk-bounces at contesting.com] On Behalf Of Joe Subich, W4TV
> Sent: Thursday, December 01, 2011 9:08 AM
> To: Drax Felton; [TowerTalk]
> Subject: Re: [TowerTalk] Cost effectivel Tower height
>
>
> > Isn't the a half wave high tower the general rule of thumb for a> decent dx angle?
>
> No, 1/2 wave is where a horizontally polarized antenna shows its first null directly overhead.
>
> > After 60ft (1/2 wave on 20m)
>
> 60 ft is 0.86 wave on 20 meters (14 MHz) - one wavelength is 70 feet.
>
> If I had to choose a single tower height *over flat ground* it would be
> 70 feet. That represents 1/2 wave on 40 meters - a point that a dipole or two element Yagi has some decent (but not world beating) performance
> - and a useful height for an 80 meter inverted V or a place to hang inverted L antennas for 160 and 80. In addition, 70 feet in 1 1/5 wave on 15 meters (perhaps the most useful overall height for DX) and 2 waves on 10 (high but not too high except for short skip).
>
> > After 60ft (1/2 wave on 20m) you need more guys with Rohn 25
>
> Two levels of guying is acceptable with Rohn 25 up to 70 feet. Rohn 45 will go to 90 feet with two levels of guying.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 12/1/2011 11:53 AM, Drax Felton wrote:
>> Isn't the a half wave high tower the general rule of thumb for a decent dx angle?
>>
>> After 60ft (1/2 wave on 20m) you need more guys with Rohn 25 and the work difficulty starts increasing rapidly.
>>
>> Sent from my iPhone
>>
>> On Dec 1, 2011, at 12:31 AM, towertalk-request at contesting.com wrote:
>>
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>>>
>>> Today's Topics:
>>>
>>> 1. Determine cost-effective tower height (Andreas Hofmann)
>>> 2. Re: Determine cost-effective tower height (Jim Lux)
>>> 3. Re: Determine cost-effective tower height (Dick Dievendorff)
>>> 4. Re: Determine cost-effective tower height (Gene Fuller)
>>> 5. Re: Determine cost-effective tower height (Dick Dievendorff)
>>> 6. FW: Determine cost-effective tower height (km5vi)
>>> 7. Re: Determine cost-effective tower height (Jim Lux)
>>> 8. top loaded vertical radial length (LY2KZ)
>>>
>>>
>>> ---------------------------------------------------------------------
>>> -
>>>
>>> Message: 1
>>> Date: Thu, 1 Dec 2011 00:47:46 +0000
>>> From: Andreas Hofmann<Andreas.Hofmann at microsoft.com>
>>> Subject: [TowerTalk] Determine cost-effective tower height
>>> To: "towertalk at contesting.com"<towertalk at contesting.com>
>>> Message-ID:
>>>
>>> <A9B46A478518064C8E335B938C8768840EBE9F66 at TK5EX14MBXC288.redmond.corp
>>> .microsoft.com>
>>>
>>> Content-Type: text/plain; charset="us-ascii"
>>>
>>> Hi,
>>>
>>> I have decided I need a tower to get better antennas up in the air. Thinking about the SteppIR DB 18, 40m 2 el, 20 and up 3el. Now, my property slopes pretty much in every direction by 5 degrees. I need to determine a proper tower height without breaking the bank.
>>>
>>> I was told I should run a computer program to figure a good height of the yagi for my most important directions/DX locations. In fact a friend of mine did the same (on a similarly sloping property) and he found out that a 55 foot tower would be similar to a 120 foot tower on a flat ground. Hence he put up a 55 foot crank up mast and it is rocking. He forgot the program he used.
>>>
>>> So, what tool can I use to find the optimal (not maximal) height of a tower that would work well here?
>>> Also, the tower would be setting on the side of the house with a metal roof (roof about 15 feet high), not sure if this would matter...
>>>
>>> Thanks
>>> Andreas
>>> KU7T
>>>
>>>
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 2
>>> Date: Wed, 30 Nov 2011 16:59:54 -0800
>>> From: Jim Lux<jimlux at earthlink.net>
>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>> To: towertalk at contesting.com
>>> Message-ID:<4ED6D18A.10405 at earthlink.net>
>>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>>
>>> On 11/30/11 4:47 PM, Andreas Hofmann wrote:
>>>> Hi,
>>>>
>>>> I have decided I need a tower to get better antennas up in the air. Thinking about the SteppIR DB 18, 40m 2 el, 20 and up 3el. Now, my property slopes pretty much in every direction by 5 degrees. I need to determine a proper tower height without breaking the bank.
>>>>
>>>> I was told I should run a computer program to figure a good height of the yagi for my most important directions/DX locations. In fact a friend of mine did the same (on a similarly sloping property) and he found out that a 55 foot tower would be similar to a 120 foot tower on a flat ground. Hence he put up a 55 foot crank up mast and it is rocking. He forgot the program he used.
>>>>
>>>> So, what tool can I use to find the optimal (not maximal) height of a tower that would work well here?
>>>> Also, the tower would be setting on the side of the house with a metal roof (roof about 15 feet high), not sure if this would matter...
>>>>
>>>> Thanks
>>>> Andreas
>>>> KU7T
>>>>
>>> HFTA by Ward Silver which comes with the ARRL Antenna Book is what
>>> you want. You enter in the surrounding terrain (or extract it from
>>> DEM files, etc.) and it calculates the pattern.
>>>
>>> Only works for horizontally polarized antennas, by the way.
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 3
>>> Date: Wed, 30 Nov 2011 17:25:50 -0800
>>> From: "Dick Dievendorff"<dieven at comcast.net>
>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>> To: "'Jim Lux'"<jimlux at earthlink.net>,<towertalk at contesting.com>
>>> Message-ID:<001b01ccafc8$29967cf0$7cc376d0$@comcast.net>
>>> Content-Type: text/plain; charset="US-ASCII"
>>>
>>> I think HFTA is by Dean Straw, N6BV. In any case, it's the program
>>> you want for this. Ward edited the new Antenna Book, and included Dean's programs.
>>>
>>> Dick, K6KR
>>>
>>> -----Original Message-----
>>> From: towertalk-bounces at contesting.com
>>> [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim Lux
>>> Sent: Wednesday, November 30, 2011 5:00 PM
>>> To: towertalk at contesting.com
>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>>
>>> On 11/30/11 4:47 PM, Andreas Hofmann wrote:
>>>> Hi,
>>>>
>>>> I have decided I need a tower to get better antennas up in the air.
>>> Thinking about the SteppIR DB 18, 40m 2 el, 20 and up 3el. Now, my
>>> property slopes pretty much in every direction by 5 degrees. I need
>>> to determine a proper tower height without breaking the bank.
>>>> I was told I should run a computer program to figure a good height
>>>> of the
>>> yagi for my most important directions/DX locations. In fact a friend
>>> of mine did the same (on a similarly sloping property) and he found out that a
>>> 55 foot tower would be similar to a 120 foot tower on a flat ground. Hence
>>> he put up a 55 foot crank up mast and it is rocking. He forgot the
>>> program he used.
>>>> So, what tool can I use to find the optimal (not maximal) height of
>>>> a
>>> tower that would work well here?
>>>> Also, the tower would be setting on the side of the house with a
>>>> metal
>>> roof (roof about 15 feet high), not sure if this would matter...
>>>> Thanks
>>>> Andreas
>>>> KU7T
>>>>
>>> HFTA by Ward Silver which comes with the ARRL Antenna Book is what you want.
>>> You enter in the surrounding terrain (or extract it from DEM files,
>>> etc.) and it calculates the pattern.
>>>
>>> Only works for horizontally polarized antennas, by the way.
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 4
>>> Date: Wed, 30 Nov 2011 21:09:30 -0500
>>> From: "Gene Fuller"<w2lu at rochester.rr.com>
>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>> To: "Dick Dievendorff"<dieven at comcast.net>, "'Jim Lux'"
>>> <jimlux at earthlink.net>,<towertalk at contesting.com>
>>> Message-ID:<E2520ACDBCEE43858C2FEB22186E5240 at FamilyRoom>
>>> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>>> reply-type=original
>>>
>>> Agreed, HFTA is the way to go. ARRL Antenna Handbook ed 21 includes
>>> the software and instrustrutions you will need. A little hand held
>>> GPS will give you your tower location, and a fair bit of
>>> determination for the novice, will give you a great picture of what you have to work with.
>>> Gene / W2LU
>>>
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From: "Dick Dievendorff"<dieven at comcast.net>
>>> To: "'Jim Lux'"<jimlux at earthlink.net>;<towertalk at contesting.com>
>>> Sent: Wednesday, November 30, 2011 8:25 PM
>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>>
>>>
>>>> I think HFTA is by Dean Straw, N6BV. In any case, it's the program
>>>> you want for this. Ward edited the new Antenna Book, and included
>>>> Dean's programs.
>>>>
>>>> Dick, K6KR
>>>>
>>>> -----Original Message-----
>>>> From: towertalk-bounces at contesting.com
>>>> [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim Lux
>>>> Sent: Wednesday, November 30, 2011 5:00 PM
>>>> To: towertalk at contesting.com
>>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>>>
>>>> On 11/30/11 4:47 PM, Andreas Hofmann wrote:
>>>>> Hi,
>>>>>
>>>>> I have decided I need a tower to get better antennas up in the air.
>>>> Thinking about the SteppIR DB 18, 40m 2 el, 20 and up 3el. Now, my
>>>> property slopes pretty much in every direction by 5 degrees. I need
>>>> to determine a proper tower height without breaking the bank.
>>>>> I was told I should run a computer program to figure a good height
>>>>> of the
>>>> yagi for my most important directions/DX locations. In fact a
>>>> friend of mine did the same (on a similarly sloping property) and he
>>>> found out that a
>>>> 55 foot tower would be similar to a 120 foot tower on a flat ground.
>>>> Hence
>>>> he put up a 55 foot crank up mast and it is rocking. He forgot the
>>>> program he used.
>>>>> So, what tool can I use to find the optimal (not maximal) height of
>>>>> a
>>>> tower that would work well here?
>>>>> Also, the tower would be setting on the side of the house with a
>>>>> metal
>>>> roof (roof about 15 feet high), not sure if this would matter...
>>>>> Thanks
>>>>> Andreas
>>>>> KU7T
>>>>>
>>>> HFTA by Ward Silver which comes with the ARRL Antenna Book is what
>>>> you want.
>>>> You enter in the surrounding terrain (or extract it from DEM files,
>>>> etc.) and it calculates the pattern.
>>>>
>>>> Only works for horizontally polarized antennas, by the way.
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 5
>>> Date: Wed, 30 Nov 2011 18:19:50 -0800
>>> From: "Dick Dievendorff"<dieven at comcast.net>
>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>> To: "'Gene Fuller'"<w2lu at rochester.rr.com>, "'Jim Lux'"
>>> <jimlux at earthlink.net>,<towertalk at contesting.com>
>>> Message-ID:<001801ccafcf$b4a4c4d0$1dee4e70$@comcast.net>
>>> Content-Type: text/plain; charset="us-ascii"
>>>
>>> Google Earth is another (free) tool that you can use to determine the
>>> latitude and longitude of your specific antenna location.
>>>
>>> Dick
>>>
>>>
>>> -----Original Message-----
>>> From: Gene Fuller [mailto:w2lu at rochester.rr.com]
>>> Sent: Wednesday, November 30, 2011 6:10 PM
>>> To: Dick Dievendorff; 'Jim Lux'; towertalk at contesting.com
>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>>
>>> Agreed, HFTA is the way to go. ARRL Antenna Handbook ed 21 includes
>>> the software and instrustrutions you will need. A little hand held
>>> GPS will give you your tower location, and a fair bit of
>>> determination for the novice, will give you a great picture of what you have to work with.
>>> Gene / W2LU
>>>
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From: "Dick Dievendorff"<dieven at comcast.net>
>>> To: "'Jim Lux'"<jimlux at earthlink.net>;<towertalk at contesting.com>
>>> Sent: Wednesday, November 30, 2011 8:25 PM
>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>>
>>>
>>>> I think HFTA is by Dean Straw, N6BV. In any case, it's the program
>>>> you want for this. Ward edited the new Antenna Book, and included
>>>> Dean's programs.
>>>>
>>>> Dick, K6KR
>>>>
>>>> -----Original Message-----
>>>> From: towertalk-bounces at contesting.com
>>>> [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim Lux
>>>> Sent: Wednesday, November 30, 2011 5:00 PM
>>>> To: towertalk at contesting.com
>>>> Subject: Re: [TowerTalk] Determine cost-effective tower height
>>>>
>>>> On 11/30/11 4:47 PM, Andreas Hofmann wrote:
>>>>> Hi,
>>>>>
>>>>> I have decided I need a tower to get better antennas up in the air.
>>>> Thinking about the SteppIR DB 18, 40m 2 el, 20 and up 3el. Now, my
>>>> property slopes pretty much in every direction by 5 degrees. I need
>>>> to determine a proper tower height without breaking the bank.
>>>>> I was told I should run a computer program to figure a good height
>>>>> of the
>>>> yagi for my most important directions/DX locations. In fact a
>>>> friend of mine did the same (on a similarly sloping property) and he
>>>> found out that a
>>>> 55 foot tower would be similar to a 120 foot tower on a flat ground.
>>>> Hence
>>>> he put up a 55 foot crank up mast and it is rocking. He forgot the
>>>> program he used.
>>>>> So, what tool can I use to find the optimal (not maximal) height of
>>>>> a
>>>> tower that would work well here?
>>>>> Also, the tower would be setting on the side of the house with a
>>>>> metal
>>>> roof (roof about 15 feet high), not sure if this would matter...
>>>>> Thanks
>>>>> Andreas
>>>>> KU7T
>>>>>
>>>> HFTA by Ward Silver which comes with the ARRL Antenna Book is what
>>>> you want.
>>>> You enter in the surrounding terrain (or extract it from DEM files,
>>>> etc.) and it calculates the pattern.
>>>>
>>>> Only works for horizontally polarized antennas, by the way.
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> ___________
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
> _______________________________________________
>
>
>
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>
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> _______________________________________________
>
>
>
> _______________________________________________
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