of the dipoles is only fourteen feet high. With this antenna, my K3, or
since erecting it in early July. Since these photos were made, I've
. See:
> If you are mainly interested in working DX and especially if you are
> limited in height, you can also install the parallel dipoles
> vertically, more of less.
>
>
> Eric Tichansky wrote:
>> In a space limited situation, a parallel dipole (or inverted-V) does
>> well. Just calculate your 1/2 wave lengths for each band connect them
>> to a common feedpoint. Use small diameter PVC for spreaders. Even on a
>> small lot, you could get away with an 80-10 parallel (fan) inverted-V.
>> The ends of the 80m elements can be bent towards the ground, sideways,
>> etc. Trimming each band's elements can be tedious, but you could just
>> live with the cut-by-formula mismatch and use the tuner, you'll be in
>> the general ballpark.
>>
>> As far as position/bearing, unless you are erecting nearly flat-top
>> dipoles and at decent heights (ie. 60ft on 40M), you're not going to see
>> any significant directivity or pronounced broadside pattern. An
>> inverted-V approaches a more omni-directional pattern and low heights
>> produce higher angle (ie. cloud burner) radiation. Add in objects
>> around the antenna and all kinds of weird things start to happen (ie
>> rain gutters, metal roof ridges, etc.) Check this out for relative
>> patterns vs. height, referenced to 40M:
http://www.qsl.net/aa3rl/ant2.html>>
>> Reflectors/directors can be added to an inverted-V setup, and do work
>> well for directivity, but again, the resulting radiation angles will
>> depend on height.
>>
>> For diversity on a small lot, I would try a loop or a vertical to
>> compliment the dipole(s)/inverted-V.
>>
>> GL es 73 - no3m
>>
>> Clint wrote:
>>
>>> Fellow Elecrafters,
>>>
>>> I have a feeling this may open the flood gates but here goes.
>>>
>>> I am a newbie Ham but a long time SWL going back to my Knight Kit Star Roamer. I am fixin' to set-up my antenna farm. OK, it will be more like an antenna garden as I have a small house and lot. My K3/100 has a KAT3 and KRX3. I plan on using 3 Dipoles and maybe an inverted V for diversity receive (what a great feature). I got on Google Earth and plotted out the areas I am interested in. I live just up the street from Elecrafts new HQ (talk about fast service) on the central coast of California (CM96CX).
>>>
>>> A bearing of 118 deg (antenna runs from 28 to 208 deg) cuts across Central America and South America on one side and across Manila and Singapore, skirting Japan, on the other (298 deg). This is a great coverage for me as I used to live in Singapore and spent lots of time in Asia (work) and Central America (not work).
>>>
>>> The next one is 32 deg (antenna runs from 122 to 302 deg) which cuts through London and Rome on to the Middle East. The other side is not too much, Tahiti and the South Pacific. I am thinking of a reflector on this one as there is not allot at 212 deg that interests me and that should help with Europe, I think.
>>>
>>> The next one is 78 deg (antenna runs from 122 to 302 deg) which cuts across the US through North Carolina, Bermuda and on to South Africa. The other side, 258 deg, runs through the Solomon Islands and right down the middle of Australia to Perth.
>>>
>>> I know the lobes will spread way out from these bearings over these long distances but these numbers are a starting point. The antennas will also cross forming a pattern similar to an asterisk on my roof/lot, a good thing I am guessing.
>>>
>>> I was thinking about Inverted V's for most of these until I checked what the side lobes would pick-up. On the 118 deg antenna it would be the South Pacific (no problem) and Europe (big interference problem while shooting for C/S America and SE Asia).
>>>
>>> The 32 deg would pick-up Japan, SE Asia on one side lobe and Mexico, Central America on the other. Too many unwanted signals if I am trying for Europe.
>>>
>>> The 78 deg side lobes would pick-up Alaska, central Russia and west India on one side and the South Pacific, places like Pitcairn, and on to Antarctica. Maybe an inverted V would be OK on this one.
>>>
>>> The Diversity may be a big inverted V or just an L shape long wire. I laid out a spread sheet with the lengths for a Dipole plus 15 deg, 22 deg, 30 deg, 37 deg, 45 deg, 60 deg and 75 deg inverted V's from 160 to 2 meters using the center of the Extra class bands (my next conquest) looking for some magic number. Nothing jumps out at me but of course a ¼ wave 80 is close to a ½ wave 40, a ½ 60, ¼ 30 and so on. I think I can squeeze in a ¼ wave 80 meter dipole (~31.2 feet/side) in most directions and maybe a shorter one above this (easiest for me but technically wrong?). The longer one higher may be possible but won't be easy. 160 meters will be another project for another day.
>>>
>>>
>>>
>>> So my questions are:
>>>
>>> 1) What length would be best and give me the use of the most bands? Remember, I have a limited space.
>>>
>>> 2) How far from the dipole should a reflector be. It should be about 5% longer and grounded, right?
>>>
>>> 3) The auto-tuner on the K3 is amazing. Is it easier for it to tune an antenna that is to long or to short? I'm guessing long but I am not certain.
>>>
>>> 4) Any suggestions on which band/antenna length is best for these targets? I am mostly active late afternoon and evening (till about 10 PST) and mornings after 6.
>>>
>>> Thanks,
>>>
>>> Clint KI6SSN
>>>
>>>
>>>
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>>
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