[Elecraft] AX1 dipole

[Fred Jensen]

Indeed, that's why I put "insensitive" in quotes [and "ground" too].  
Zero return current loss can be a large factor in improving vertical 
antenna performance however.  Field loss is inevitable, and is what 
makes Beverages work, so I guess it's not all bad.  I fed my Franklin 
kludge with the coax up the inside of the lower element which also 
served as the support.  The usable BW was a big improvement over the 
Alexloop which exhibits little BW on 20 and almost none at all on 30.

Contrary to a somewhat popular belief [and sometimes advertising in the 
magazines too], there are no magic antennas, they are all subject to the 
same physical laws.  You also don't need it to be "perfect" in all 
respects.  If you get current to flow in a conductor that isn't buried 
or under salt water, it will radiate.  Some configurations radiate 
better than others but appearances can be deceiving.  Most hams viewing 
my HOA-friendly WOOF{1} would assume it almost doesn't work.  They'd be 
surprised.

When the thread got around to co-linear vertical dipoles, I got to 
thinking about the Franklin.  I can envision an Elecraft AX1-F.  With 
Cycle 25 climbing, 12 and 10 are showing welcome life and size becomes 
acceptable at those bands.

Trivial factoids for the day:  KFBK is quasi-famous not only for its 
Franklin in a rice paddy. The engineering crew built an out-phasing 
transmitter which was used for quite awhile until it became their 
back-up.  McClatchy, which owned KFBK at the time, sold the rights to 
RCA who renamed it "Ampliphase" and dominated the AM broadcast market 
for a number of years.  The station was also the radio birthplace of 
Rush Limbaugh, way back when he didn't actually believe what he was 
broadcasting.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

{1} Wire On Organic Fence

David Gilbert wrote on 9/29/2022 12:52 PM:
>
> The two half waves in phase gain their improved performance by being 
> spacially separate.  The more you load it to shorten the two dipoles, 
> and the closer you arrange them, the less they provide any benefit.  
> It would have no benefit at all as a short portable antenna.
>
> By the way, any vertical antenna is not insensitive to ground.  A 
> vertical dipole merely doesn't need anything extra for a return 
> current path, but it will still have all of the normal ground loss for 
> the radiated field that is a function of the ground conductivity.
>
> Dave   AB7E
>
>
> On 9/29/2022 12:30 PM, Fred Jensen wrote:
>> The Franklin is two vertical, co-linear half-waves fed in-phase. 
>> Google will offer way more than you want to read.  Obviously a large 
>> structural challenge for a full-size one at MF.  The one I built as a 
>> test was heavily loaded and worked about like EZNEC-4 predicted.  I 
>> think it's insensitivity to "ground" may be one reason it works well, 
>> but that's just a guess.
>>
>>
>> 73,
>>
>> Fred ["Skip"] K6DGW
>> Sparks NV DM09dn
>> Washoe County
>>
>> Dan Presley wrote on 9/29/2022 12:20 PM:
>>> Fred-can you share details on this antenna? Not familiar with it. 
>>> Thanks.
>>>
>>> Dan Presley 503-701-3871
>>> danpresley at me. com
>>> N7CQR at arrl.net
>>>
>>>
>>>> On Sep 29, 2022, at 12:08, Fred Jensen<k6dgwnv at gmail.com> wrote:
>>>>
>>>> I've long wondered why hams haven't done more with Franklin 
>>>> verticals?  KFBK [1530 kHz in Sacramento] uses one located in the 
>>>> southern end of the Sacramento Valley, and it's known as a Flame 
>>>> Thrower.  I think KNBC [680 kHz?] in SF had one back in the 50's 
>>>> sometime too.  They're big at MF, but much more tractable at HF, 
>>>> and they are amenable to loading techniques. I built one [fairly 
>>>> heavily loaded] out of Buddipole parts I had, and its performance, 
>>>> particularly when I was still activating summits, was surprising. 
>>>> Like a small loop, the Franklin pretty much ignores ground ... 
>>>> although KFBK's probably likes being located in rice fields filled 
>>>> with water. 😉
>>>>
>>>> 73,
>>>>
>>>> Fred ["Skip"] K6DGW
>>>> Sparks NV DM09dn
>>>> Washoe County
>
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