[TowerTalk] Please Help Me Decide on a Tribander or Monobanders

[Gene Smar]

Gents:

     Here, here for the Skyhawk.  I've had mine up for 12 years, loads on 17 
and 12, broadbanded.


73 de
Gene Smar  AD3F


----- Original Message ----- 
From: "Jerry" <grf at npgcable.com>
To: <towertalk at contesting.com>
Sent: Thursday, April 18, 2013 7:47 PM
Subject: Re: [TowerTalk] Please Help Me Decide on a Tribander or Monobanders


I love my Skyhawk and you can load it with a tuner to work 17 & 12M.
Just finished my DXCC on those bands.
73
Jerry France
K7LY
Lake Havasu City, AZ

On 4/18/2013 4:01 PM, k2qmf at juno.com wrote:
> Go for the SkyHawk tribander.
> Much better than the Force 12 and less expensive too...
> Longer boom etc.
>
> 73,
> Ted  K2QMF
>
>   On Thu, 18 Apr 2013 17:24:31 -0500 Richard Thorne <rthorne at rthorne.net>
> writes:
>> I sure like my C31XR at 79' with a Delta 240 mounted 10' above it. I
>>
>> plan on changing out the 240 with a Delta 230/240  and lower it to
>> about
>> 7' above the C31xr then add a WARC 2/2 at the 10' level.  That will
>> give
>> me a rotatable 10 through 40 solution.
>>
>> I also have a C3 tribander (going on 17 years old) mounted on a
>> rotatable swinging side gate at 40'.
>>
>> I really like the F12 antennas, instant band change and made in
>> America.
>>
>> Rich - N5ZC
>>
>>
>> On 4/18/2013 4:06 PM, Wayne Willenberg wrote:
>>> My 86 or 89 foot crank-up tower project seems to be progressing
>> through my
>>> County review boards.  So now I am getting really excited for my
>> first
>>> tower.
>>>
>>> I am now in ham nirvana because I have to start making up my mind
>> on which
>>> antenna(s) to put on the 15’ mast.  Here is my first dilemma.
>> Should I put
>>> up a tribander (10, 15 and 20M) or 3 monobanders.  My intuition
>> said there
>>> was no way a tribander with the same 20M boom length could beat 3
>>> monobanders having a 20M antenna with the same boom length.
>>>
>>> So, just as an exercise, I looked at Force 12 antennas.  (I am
>> not
>>> endorsing Force 12 antennas, although they do seem to have a good
>>> reputation.  I am also aware that the performance specs of
>> antenna
>>> manufacturers need to be taken with a grain of salt –this is not
>> meant to
>>> be a criticism of Force 12.)
>>>
>>> I started with the Force 12 model C-31XR tribander.  It has 14
>> elements on
>>> a boom length of 31’, a wind load of 10.7 sqft and published
>> figures of:
>>> 20M gain: 14.0dBi, a F/B of 20dB,
>>>
>>> 15M gain: 14.3dBi, a F/B of 22dB, and
>>>
>>> 10M gain: 15.6dBi, a F/B of 21dB.  Published price: $2,970
>>>
>>> Then, I looked for monobanders from Force 12 that had a boom
>> length for the
>>> 20M monobander close to the C-31XR and a gain in the vicinity of
>> the of the
>>> tribander for each of the 3 bands.  Here is what I found:
>>>
>>> EF-420 (20M with 4 elements) has a boom length of 30’, a gain of
>> 14.5Dbi,
>>> a  F/B of 22dB, a wind load of 5.5 sqft, and a cost of $1,300.
>>>
>>> EF-415 (15M with 4 elements) has a boom length of 20’, a gain of
>> 14.6Dbi, a
>>> F/B of 22dB, a wind load of 2.8 sqft, and a cost of $869.
>>>
>>> EF-510 (10M with 5 elements) has a boom length of 18’, a gain of
>> 15.1dBi, a
>>> F/B of 23, a wind load of 2.5 sqft, and a cost of $799.
>>>
>>> The total wind load of the 3 monobanders is 10.8 sqft and a total
>> cost of
>>> $2,968.
>>>
>>> So, at first glance, the price and wind load of the tribander is
>>> practically the same as the sum of the 3 monobanders.  There is no
>> more
>>> than an additional 0.5dB of gain (and 0.5 dB loss of gain on 10M)
>> with
>>> monobanders;  a gain of 2dB F/B (and 2dB more F/B on 10M) for
>> monobanders.
>>> However, I am aware that there will be a degradation of the
>> performance of
>>> at least the middle monobander if I put 3 of them, in a Christmas
>> tree
>>> fashion, on a 15’ mast.  I haven’t been able to find a good
>> discussion of
>>> the amount of degradation—even the 22nd Edition of the Antenna
>> Book has
>>> only a few words to say about this.  Please direct me to a
>> discussion of
>>> this topic if you know one.  I may have to model these antennas on
>> EZNEC to
>>> see the impact of 3 antennas confined to a 15 foot mast.
>>>
>>> On the other hand, there has to be a compromise when 3 antennas
>> are mounted
>>> on a single boom.
>>>
>>> I would really appreciate your help in finding all of the specs I
>> should be
>>> looking at in making this decision.  Any other comments that would
>> push me
>>> one way or the other would also be appreciated.
>>>
>>> Please help me with my first tower!
>>>
>>> 73, Wayne KK6BT
>>> _______________________________________________
>>>
>>>
>>>
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