Actually, I never suggested a Q for the coil. Al must have been
thinking about somebody else when he said that part, although the rest
of what he attributed to me is accurate. I usually use a Q of 200 for
an air core coil if I'm trying to be conservative, but a Q of 400 is
reasonable if yo
The Drake tuners used a Pi-L circuit topology in which the circulating
current in the inductor is independent of the load impedance. Assuming
almost all the loss is in the inductor, that means that the loss is
independent of the load impedance.
(Another advantage of that topology is you get g
na
> > Sent: Tuesday, July 13, 2021 9:32 AM
> > To: elecraft@mailman.qth.net
> > Subject: Re: [Elecraft] Question about antenna matching
> >
> > Thanks to Al N1AL, Jack W6FB, and Dave AB7E for great information that
> > helped me a lot.
> >
> >
orona
> Sent: Tuesday, July 13, 2021 9:32 AM
> To: elecraft@mailman.qth.net
> Subject: Re: [Elecraft] Question about antenna matching
>
> Thanks to Al N1AL, Jack W6FB, and Dave AB7E for great information that
> helped me a lot.
>
> I'm in the circuit simulation
13, 2021 9:32 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Question about antenna matching
Thanks to Al N1AL, Jack W6FB, and Dave AB7E for great information that helped
me a lot.
I'm in the circuit simulation business, after all, and I confess that I was
just being lazy
Thanks to Al N1AL, Jack W6FB, and Dave AB7E for great information that helped
me a lot.
I'm in the circuit simulation business, after all, and I confess that I was
just being lazy, so I ran some simulations that confirmed what Dave, in
particular, had said.
As suggested by Dave, I chose typica
It's probably worth noting that KAT500 stores the bypass SWR (VSWRB) for every
tuning solution (every bin and every antenna in that bin). The bypass SWR is
used to limit the power that can be applied to the tuner without it faulting.
e.g.
DM BN00;BIN 31;FR 1810-1819;ADDR 10612;
AN3;BYPN;SIDET;
out of the box.
73
Bob, K4TAX
Message: 2
Date: Sun, 11 Jul 2021 16:17:43 -0500
From: Jack Brindle
To: Elecraft Reflector
Subject: Re: [Elecraft] Question about antenna matching
Message-ID:<7cc60665-e824-4132-bc62-014d695d7...@me.com>
Content-Type: text/plain; charset=utf-8
There is
Hi, Al.
Yes, some mismatches are much more problematic than others, even for the
same SWR.
One way to see this is to use TLW, the transmission line calculator that
comes free with the ARRL Antenna Book. Choose whatever load impedance
you want in any combination of real and reactive values.
There is another big consideration in modern ATUs which use toroid cores for
the inductors. The cores will heat up during transmission, especially for bad
mismatches. Remember, the ATU still has to deal with the high reflected power
as it provides a good match for the radio. If the heating reach
I can't speak directly about Elecraft tuners, but I did design an
antenna tuner when I was at Drake many years ago.
We specified the Drake MN-2700 at 5:1 SWR. I made sure it would match
that SWR at all phase angles on all specified bands.
Typically the low-impedance end tends to be the harde
I take it to mean, the tuner will "probably" match any halfway well
designed antenna...
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 7/11/21 11:58 AM, Al Lorona wrote:
This quest
This question is about how manufacturers spec the matching range of their
antenna tuners.
If an antenna system presents an impedance of 5 + j0 ohms to the antenna tuner,
that's an SWR = 10 to 1.
But, an antenna impedance of 50 - j143 ohms is also SWR = 10. So is 110 - j200
ohms.
When a manufa
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