[ARC5] ER ARC-2 & Antenna Matching

[Dennis Monticelli]

Harmonic suppression will be less, though the degree of it will depend upon
how much inductance is cranked in.

I use a shunt scheme, although a different one from putting the cap right
across the antenna.  I did not measure the "before" harmonic suppression
but did measure it on an HP spectrum analyzer afterwards.  It met ARRL
guidelines.

I should also note that the leads going in and out (power, keying) are rich
sources of harmonics if you do nothing about it.  Unlike antenna launched
harmonics they don't radiate very far but they can affect your house and
perhaps close-by neighbors.  You can suppress these any number of
conventional ways.  If the cover isn't on all bets are off.  Tried that for
grins once and she's a potent radiator :-)

Dennis AE6C

On Tue, May 8, 2018 at 10:39 AM, AKLDGUY <neilb0627 at gmail.com> wrote:

> An important consideration is harmonic suppression. Does a series cap
> provide that? A parallel one certainly should. Why not both, with a small
> fixed cap in series to a large broadcast type variable in shunt from coax
> inner to braid.
>
> Neil ZL1ANM
>
>
> On Wednesday, May 9, 2018, David Stinson <arc5 at ix.netcom.com> wrote:
>
>> Saw ER's latest issue with that cool ARC-2/ARC-5
>> combination.  The author (our very own Jeep Platt)
>> speaks of using 1000 pFd ( I assume between the
>> ANT post and ground) to match a 50-Ohm load on 80
>> Mtrs.  I use 100 pFd in series with the 50-Ohm
>> load and get full output.  I'm not trying to
>> criticize someone else's solution, and I know
>> we've talked about this before; just want to
>> understand- would think that 1000 pFd to ground
>> would eat a lot of power in circulating currents,
>> just like matching an electrically short vertical
>> by putting a big cap at the bottom.  It will tune
>> it, but since the majority of the RF currents are
>> down near the ground, they contribute nearly
>> nothing to the radiation resistance of the overall
>> system.  A series cap doesn't divide the RF
>> currents this way.  Some folks- and I assume with
>> good, sound reasons- prefer the cap to ground
>> method.  What am I missing here?
>> Thanks,
>> Dave S.
>>
>>
>>
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