[TowerTalk] Cost effectivel Tower height
Joe Subich, W4TV
lists at subich.com
Thu Dec 1 09:08:28 PST 2011
> 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
>>>
>>> _______________________________________________
>>>
>>>
>>>
>>> ___________
>>
> _______________________________________________
>
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>
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