http://elecraft.85.s1.nabble.com/Elecraft-CW-Net-Announcement-tp7663535p7663570.html
choke at the feedpoint to kill the common mode current. Almost in any
CWops no. 5
> It's a fairly simple antenna. Yes, one radial is all you really "need,"
> a couple more help improve efficiency and increase the BW. In the olden
> daze [50's], we'd use 3 or 4 and cut them just a little different. Also
> increased the BW, especially on 10, and in the later 50's, 10 was open
> 28000 - 29700, 24/7. It's really a very forgiving antenna. The
> radials, with rope extensions are often used as guys as well. The droop
> angle will affect the main lobe elevation somewhat, but I'll bet I could
> do a blind "taste" test with you and you'd never really know the
> difference. That angle is more often used to adjust the impedance at
> the feed point.
>
> Make that angle 90 deg and you have a vertical half-wave dipole
> center-fed out of phase. Make the elements 1/2 wave each, mechanically
> easy on 10 and even 15, and cophase feed them in the center, and you
> have a Franklin vertical [see KFBK, one of the last ones I know of].
> Very versatile basic design, works great, lasts a long time.
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 7/26/2020 3:38 PM, Rick NK7I wrote:
>> The reading I've done says only one radial is required; that the
>> 'favoring' in the direction of the radial is not enough to be worried
>> about; that there is no cancellation from opposing (or just more)
>> radials. I have used a single radial ground plane and found this to
>> be true (at 6' over dirt on 80M). It favors a morning net 800 miles
>> away, yet worked DX in any other direction easily (then I moved to a
>> rotating dipole at 60' which beats it out). That ground plane easily
>> beat out a horizontal dipole I used before them all (fixed, in the
>> 'wrong' angle because of tree location).
>>
>> Both the radiator and radial are tuned (equally), but the angle of
>> difference from dipole to the traditional 90 deg ground plane will
>> cause the resistance to vary (roughly 72 ohms as a dipole, dropping to
>> ~50 ohms when at 90 degrees), So if another angle is chosen (inverted
>> Y), to match a 50 ohm feedline (to have a 1:1 SWR), the element
>> lengths are adjusted equally until that match is made; altering the
>> resonance of the wires (maximum transfer of energy). And inverted Y
>> antenna would be between that 50-72 ohm range, still acceptably low
>> SWR to not mess with.
>>
>> Which again, is not a significant variance, so put it up, try it out
>> and compare to other antennas. Wire is cheap enough to play with and
>> try things out.
>>
>> Modeling will demonstrate the pattern and 'take off' angles quite
>> clearly; reality is often different because of local objects, ground
>> resistance, height...
>>
>> Don't forget to add a common mode current choke at the feed.
>>
>> 73,
>> Rick NK7I
>>
>>
>>
>> On 7/26/2020 11:57 AM, Don Wilhelm wrote:
>>> Fred,
>>>
>>> That would be correct if they are oriented at 180 degrees from each
>>> other so as to cancel the horizontal radiation. Elevated radials
>>> must be tuned to be effective, but only 2 are needed. How much tuning
>>> will depend on the height above ground.
>>>
>>> 73,
>>> Don W3FPR
>>>
>
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