Michael Coslo wrote in
:

Lostgallifreyan wrote:
Jeff wrote in
:

Apparently no-one knows the impedance of a Sangean ATS-909 radio, I've
asked several people, at least one of whom specialises in modifying
that radio.

Perhaps there is a reason. It isn't terribly important at all.


Which is why I think no-one stated it too. One person here said it wasn't
stated perhaps because no-one I suggested was adept was actually adept enough
to do it. These are the contradictions I keep seeing. They tend to gravitate
around a poster's ideas as pecived by a reader, rather than by science. I
think you're right in this case, so I'm not arguing.

Looks like 1K is best guess based on schematic. Loss won't bother me so
much as SNR. Several people advised that a 15 foot vertical whip is
likely to overload the input so loss is not my main concern.

Not to be overly precise, but the whip won't overload your radio, strong
signals might. Those little radios are pretty sensitive.


Yes. Which is why I'm looking at getting signals from outside rather than
inside. I don't mind losses so much.

So what are you trying to do here, aside from get an external signal
into a radio? If you want to have an audiophile grade antenna system,
you need to go out and get some good hardline coax*. You can also make
some measurements to determine the exact input impedance of your radio,
then construct a balun to match it to the rest of the system. If
measurement isn't your thing, you can probably get by with a 9:1 balun,
as a back of the envelope calculation.


Going to try that. Winding enamelled wire onto a few bought ferrite torroids
isn't exactly hard work. There will be one at the antenna end too.

Then if you can put them in, you need around 120 radials that you use
for the ground on your antenna. You can either elevate them, lay them on
the ground, or shallow bury them. If you have a wife the third option is
probably what you want to do.

There are other little tweaks, such as silver contacts, a good quality
tuner, and probably some I haven't thought about yet. Some still hold
out for low oxygen copper.

Do all that, and you can still do pretty close to the results with a
long wire hanging out of your window.


Radials, yes, where I have room for them. I don't have any need for 'OFC'
wire, in anything. Or silver, come to that.. Maybe if I met a warewolf? Or is
it vampires? Silver was supposed to be good against one or the other..

Now if you get a communications grade radio, some of my less tongue in
cheek suggestions might help more. But make no mistake, you are deep
into the world of diminishing returns.


Apart from a few bits of ferrite and a coax, and a whip to get upwards reach
in a space where sidewards reach can't do much good, I'm not after much. I'm
pretty sure it will beat hanging the wire out the window of a house full of
modems and computers and other RFI generators.

note 1.

Coolest hardline I ever saw was at a TV station. It was about a foot in
diameter on the jacket, and I didn't see the center conductor, but my
best guess is that it was around 2 inches in diameter.


Curious. If they were that worried about resistive losses, they'll be high on
the buyer list for room temperature superconductors if they think they'll
help.

note 2.

I'm not trying to be rude, but you've been getting some good info in
here, you're just not taking it. Reminds me of some of the students
coming out of college these days with a nice fresh bachelor's degree.
They don't accept input, and think they should be promoted for showing
up on time.


I'm not complaining about the info. Already said I came here because I
thought the SNR was better. But there's also enough contradiction in advice
I've seen to suggest a considerable mismatch. So taking all of it is not only
unwise, but perhaps impossible.