[AK-VHF] Moxon Antennas

[Brandon Clark]

Hi Ed,

I've seen a lot of yagis that use capacitors and inductors for matching, but I've honestly never been fond of doing that. My thinking is that, when an antenna can be as simple as fiberglass and aluminum why go adding electronics? There's certainly a time and place for it, but I try to steer clear of it.

What I want to do is see if I can come up with a new Moxon design that covers the full band without matching. The 2 M and 70 cm yagis I designed for river use do that.

Many older designs (pre-computer modeling) only cover part of a band, but with it being so easy (loosely speaking) to model in the computer I want to see what I can get.

Good idea about posting online. If I come up with something good I'll do a write up and make it available.
Brandon

Sent from ProtonMail mobile

-------- Original Message --------
On Nov 4, 2021, 12:28, Ed Cole wrote:

> Brandon,
>
> OK. I think adding some capacity at ends of the folded element ends
> might shift resonance. To make it controllable from the radio location
> maybe a relay to add the capacitor (probably a silver mica would be best
> for RF power).
>
> Don't know if 4NEC2 can add capacitance in the model, so this might be a
> cut-n-try method and testing with antenna analyzer.
>
> MY converted DB Products 3-element 72-MHz yagi needed some matching help
> even after lengthening the elements for 6m. I used 10pF silver mica's
> to do that. But this was across the driven element so the moxon might
> act differently (though its really a 2-element yagi with element ends
> folded toward each other).
>
> You could publish your results on the KL7VHF website and it might even
> be accepted in QST under hints & stuff.
>
> GL, Ed
> PS: the Tx in my Bridgecom 222 radio has croaked so QRT while its being
> fixed. Been working a few 6m stations on eme. Two of of my 2m yagis
> now installed (snowing today so staying inside).
>
> On 11/4/2021 11:37 AM, Brandon Clark via ak-vhf wrote:
>> Hi Ed,
>>
>> No tuner in the 6 M radio. I'm running a Yaesu 891. I may just spend some time in 4NEC2 and see if I can come up with a design that covers the whole band. I hate to redesign stuff, but sometimes that's how it goes.
>> Brandon
>>
>> Sent from ProtonMail mobile
>>
>> -------- Original Message --------
>> On Nov 3, 2021, 22:49, Ed Cole wrote:
>>
>>> Brandon,
>>>
>>> Maybe using large diameter tubing would extend bw (??), but does your 6m
>>> radio have a antenna tuner? That would allow it to work over wider
>>> frequencies.
>>>
>>> Ed
>>>
>>> On 11/3/2021 11:50 AM, Brandon Clark via ak-vhf wrote:
>>>> Does anyone know of any wideband moxon designs for the 6M band? I'm planning to build one for rover use, but the only designs I've found are SWR limited to either the lower or upper two Mhz of the band.
>>>>
>>>> I'm not a big fan of "partial band" coverage with antennas, especially up here since there is so much mixed use between weak signal modes and FM.
>>>>
>>>> Is anyone familiar with a moxon design that covers the whole band?
>>>> 73,
>>>> Brandon
>>>>
>>>> Sent from ProtonMail mobile
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