[TowerTalk] TowerTalk Digest, Vol 28, Issue 29
K4PI
k4pi at earthlink.net
Fri Apr 8 14:05:40 EDT 2005
I am looking for some of the bolts that are used in the Rohn torque arms.
They are Grade 5, 3 hash marks on head of bolt, galvanized, 2 1/2 X 3/8 and
the oversided nuts that go with them. You have anything like that?
73 Mike K4PI
----- Original Message -----
From: <towertalk-request at contesting.com>
To: <towertalk at contesting.com>
Sent: Friday, April 08, 2005 5:00 PM
Subject: TowerTalk Digest, Vol 28, Issue 29
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> Today's Topics:
>
> 1. Re: 75 meter antenna (Al Williams)
> 2. Re: 75 meter antenna (David Jordan)
> 3. Re: 75 meter antenna (Jim Lux)
> 4. Re: 75 meter antenna (Al Williams)
> 5. FS: Rohn 25 Tower & Accessories (doc)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 7 Apr 2005 09:02:05 -0700
> From: "Al Williams" <alwilliams at olywa.net>
> Subject: Re: [TowerTalk] 75 meter antenna
> To: <towertalk at contesting.com>
> Cc: Rich Patrick <rfpatrick at yahoo.com>
> Message-ID: <000601c53b8b$2c8b5970$25daadd8 at PAPASDELL>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> EZNEC shows that this configuration is a barn burner for straight up
> propagation providing about 4 db gain over a single dipole and much
> attenuation at lower elevation angles. However EZNEC shows that raising
> the
> antennas from 15' to 20/25 adds about 1 db of gain. NVIS articles and 1
> book that I have read say
> that the optimum height is about .2 lambda which agrees with my EZNEC
> modeling. Raising the antennas also makes the input impedance a bit more
> manageable.
> EZNEC doesn't seem to agree with the "...theoretical gain of about 7db"
> as
> it reports about 10 dbi?
>
> It would seem that this configuration would be especially helpful in areas
> with high ham populations--not so good in Wyoming, etc.
>
> k7puc
>
>
> ----- Original Message -----
> From: "David Jordan" <wa3gin at erols.com>
> To: "Jim Miller" <JimMiller at STL-Online.Net>
> Cc: "TOWERTALK" <TOWERTALK at contesting.com>; "Joe Barnes"
> <n4jbk at bellsouth.net>
> Sent: Thursday, April 07, 2005 7:14 AM
> Subject: Re: [TowerTalk] 75 meter antenna
>
>
>> Jim,
>>
>> I run a NVIS on 40m 2 full wave dipoles fed in phase just 15ft above
>> the ground. Within the first 50-75 miles the signals are extremely
>> intense. My station is an Internet remote so I actually operate about
>> 50miles from the xmit antennas. Typically, I pin the "S" meter from 50
>> miles away. The signals on 40m continue to be very strong up to about
>> 350-400 miles, then a dipole at 60ft begins to out perform the NVIS. At
>> around 350-450 miles the two antennas are about the same most of the
>> time but when you get past 500 and well into 900-1000 the dipole at 60ft
>> is about 20db stronger than the NVIS. So, the NVIS does do the job for
>> closer in signals. The same would be true for 80m with the NVIS at about
>> 25-30ft above the ground. The NVIS full wave elements are fed with
>> homebrew 600ohm opern wire (in phase). The two elements are spaced a
>> half wave apart (on 40 that is about 70ft). The theoretical gain is
>> about 7db with a main lob angle of about 80 degree (straight up for all
>> intents and purposes) omin directional.
>>
>> Another nice benefit of the NVIS is that it doesn't hear the foreign
>> broadcast stations nearly as well as the dipole at 60ft.
>>
>> Your inverted V at 95ft would be great for DX but it's really too too
>> high for short distance communications.
>>
>> Having both a NVIS and "V" at 95ft would be a lot of fun.
>>
>> 73,
>> dave
>> wa3gin
>>
>> Jim Miller wrote:
>>
>>>QST June 2002 Page 28 has an article for NVIS for 40 and 80. Should be
>>>just
>>>what you are looking for.
>>>
>>>73, de Jim KG0KP
>>>
>>>----- Original Message -----
>>>From: "Joe Barnes" <n4jbk at bellsouth.net>
>>>To: <towertalk at contesting.com>
>>>Sent: Wednesday, April 06, 2005 8:33 PM
>>>Subject: [TowerTalk] 75 meter antenna
>>>
>>>
>>>
>>>
>>>>can anyone recomend an antenna for 75 meters that would be optimized for
>>>>zero to about 400 miles? I am currently using an inverted vee with the
>>>>apex at about 95 feet. I have 2 towers here , one is 100 feet the other
>>>>is 125 feet, they are 100 feet apart.
>>>>Thanks , Joe N4JBK
>>>>_______________________________________________
>>>>
>>>>See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>>>>
>>>>
>>>Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
>>>any
>>>questions and ask for Sherman, W2FLA.
>>>
>>>
>>>>_______________________________________________
>>>>TowerTalk mailing list
>>>>TowerTalk at contesting.com
>>>>http://lists.contesting.com/mailman/listinfo/towertalk
>>>>
>>>>
>>>>
>>>
>>>_______________________________________________
>>>
>>>See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>>>Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
>>>any questions and ask for Sherman, W2FLA.
>>>
>>>_______________________________________________
>>>TowerTalk mailing list
>>>TowerTalk at contesting.com
>>>http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>>
>>>
>> _______________________________________________
>>
>> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
>> any questions and ask for Sherman, W2FLA.
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Thu, 07 Apr 2005 12:44:21 -0400
> From: David Jordan <wa3gin at erols.com>
> Subject: Re: [TowerTalk] 75 meter antenna
> To: Al Williams <alwilliams at olywa.net>
> Cc: Rich Patrick <rfpatrick at yahoo.com>, towertalk at contesting.com
> Message-ID: <42556365.8000503 at erols.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Yes, I've not run the measurements myself...a friend provided theidb
> inputs...in my current configuration there are
> reflectors on the ground that are cut 5% long. I doubt they will add
> much but you might try adding them to your EZNEC.
>
> 4 or 7db it does the trick...
>
> 73,
> dave
> wa3gin
>
> Al Williams wrote:
>
>>EZNEC shows that this configuration is a barn burner for straight up
>>propagation providing about 4 db gain over a single dipole and much
>>attenuation at lower elevation angles. However EZNEC shows that raising
>>the
>>antennas from 15' to 20/25 adds about 1 db of gain. NVIS articles and 1
>>book that I have read say
>>that the optimum height is about .2 lambda which agrees with my EZNEC
>>modeling. Raising the antennas also makes the input impedance a bit more
>>manageable.
>>EZNEC doesn't seem to agree with the "...theoretical gain of about 7db"
>>as
>>it reports about 10 dbi?
>>
>>It would seem that this configuration would be especially helpful in areas
>>with high ham populations--not so good in Wyoming, etc.
>>
>>k7puc
>>
>>
>>
>>
>
>
> ------------------------------
>
> Message: 3
> Date: Thu, 07 Apr 2005 12:01:18 -0700
> From: Jim Lux <jimlux at earthlink.net>
> Subject: Re: [TowerTalk] 75 meter antenna
> To: "Al Williams" <alwilliams at olywa.net>, <towertalk at contesting.com>
> Cc: Rich Patrick <rfpatrick at yahoo.com>
> Message-ID: <6.1.1.1.2.20050407094323.02684400 at mail.earthlink.net>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> At 09:02 AM 4/7/2005, Al Williams wrote:
>>EZNEC shows that this configuration is a barn burner for straight up
>>propagation providing about 4 db gain over a single dipole and much
>>attenuation at lower elevation angles. However EZNEC shows that raising
>>the
>>antennas from 15' to 20/25 adds about 1 db of gain. NVIS articles and 1
>>book that I have read say
>>that the optimum height is about .2 lambda which agrees with my EZNEC
>>modeling. Raising the antennas also makes the input impedance a bit more
>>manageable.
>>EZNEC doesn't seem to agree with the "...theoretical gain of about 7db"
>>as
>>it reports about 10 dbi?
>>
>>It would seem that this configuration would be especially helpful in areas
>>with high ham populations--not so good in Wyoming, etc.
>>
>>k7puc
>
> A lot of the details are going to depend on what the soil properties are,
> and I'd venture that most hams don't have a real good handle on exactly
> what they are for their particular site.
>
> When you ran your EZNEC models did you use the sommerfield ground or the
> reflection coefficient? (makes a big difference on feed point impedances,
> and the corresponding gains)
>
>
>
>
> ------------------------------
>
> Message: 4
> Date: Thu, 7 Apr 2005 12:19:21 -0700
> From: "Al Williams" <alwilliams at olywa.net>
> Subject: Re: [TowerTalk] 75 meter antenna
> To: <towertalk at contesting.com>, "Jim Lux" <jimlux at earthlink.net>
> Cc: Rich Patrick <rfpatrick at yahoo.com>
> Message-ID: <000401c53ba6$bb120f20$25daadd8 at PAPASDELL>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=response
>
>
> ----- Original Message -----
> From: "Jim Lux" <jimlux at earthlink.net>
>
>
>>
>> A lot of the details are going to depend on what the soil properties are,
>> and I'd venture that most hams don't have a real good handle on exactly
>> what they are for their particular site.
>>
>> When you ran your EZNEC models did you use the sommerfield ground or the
>> reflection coefficient? (makes a big difference on feed point impedances,
>> and the corresponding gains)
> Although I have ran hundreds of wire antennas with EZNEC, I am still a
> novice--usually variations of wire configurations rather than exploring
> the
> effects of various ground properties.
>
> I used the "real/hi accuracy and 1 medium 0.005,13). Also used only #16
> copper wire.
>
> We will appreciate advice.
>
> k7puc
>
>
>
> ------------------------------
>
> Message: 5
> Date: Thu, 07 Apr 2005 21:22:48 -0400
> From: doc <kd4e at verizon.net>
> Subject: [TowerTalk] FS: Rohn 25 Tower & Accessories
> To: "For Sale - Swap List (For Sale - Swap List)"
> <forsale-swap at mailman.qth.net>
> Cc: FLBOATANCHORS at yahoogroups.com, towertalk at contesting.com
> Message-ID: <4255DCE8.3060706 at verizon.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> I need a 50' tiltover or 5 or 6 Rohn 45 or 55 sections.
>
> Need to sell my Rohn 25 stuff. Asking prices are picked
> up. Small items may be shipped and are plus actual cost.
> Pictures available upon request.
>
> (Items are located in Florida a little north of Tampa.)
>
> 11 Rohn 25G Mid-Sections $30. each
> 1 Rohn 25AG Top Section $30.
> 1 Rohn 25AG Top Section $25.
> 2 Rohn 25G cut-off mid-sections $10. each
> 1 Rohn BPH25G HINGED BASE PLATE $75.
> 3 Rohn AS25G Accessory Shelves $30. each
> ? Rohn various turnbuckles $10. each
> 2 Rohn side-arms $20. each
> 2 Rohn RP25GCM SPECIAL ROTOR POST $15.
> 1 Rohn HB25AG ADJUSTABLE HOUSE BRACKET $35.
> 3 Rohn WM-series Wall Brackets $10. each
> 2 Rohn Gable End Mounts $10. each
> ? Rohn 25 Misc Hardware $??
>
> --
> Thanks! & 73, doc kd4e
>
> |_|___|_|
> | | & | |
> {|
> /\ {|
> / \ {|
> / \ {|
> / @ \ {|
> | |~_|~~~~|
> | -| | |
> ============\ # West Central Florida
> KD4E ==============================
> http://bibleseven.com
> Ham PC = 100% Linux Novell-Suse 9.2
> Halli, Heathkit, Homebrew, MFJ, TenTec, Yaesu
> Radio Life: http://www.gospelcom.net/twr/
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>
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> End of TowerTalk Digest, Vol 28, Issue 29
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