Seen these Auto ATU's


ronald keller
 






On Monday, May 25, 2020, 2:04 PM, montanaaardvark <boblombardi@...> wrote:

(I think I just hit a wrong button and got dumped - sorry if this is a dupe)

Do those "ATU-100 mini tuners by N7DDC" have a claimed impedance range?  You know, like the Icoms that have them have always claimed 3:1 VSWR.

I looked at a couple of eBay auctions and didn't see one.


Tnx,

Bob
--
W4ATM - 35 Miles south of the Kennedy Space Center
Retired RF Design Engineer
Now able to play with all the hobbies I never had enough time for


montanaaardvark
 

On Mon, May 25, 2020 at 09:09 PM, Charles & Sandra Cohen wrote:
FWIW --

There's an extensive write-up of this N7DDC auto-tuner here:

http://radioaficion.com/news/automatic-antenna-tuner-kit/

But it doesn't give an impedance range.

Neat unit . . .  I'm not giving up my LDG Z-11 Pro.
Thanks Charles - at least I'm feeling more like it's not my Search Engine ability that got no results.  I looked in several places.  They'll tell you the component size range, but that's all I've found.

I know what you mean about your Z-11 Pro.  My IC-7000 sits on the AT-7000 that LDG made specifically for the radio. 
 

Bob
--
W4ATM - 35 Miles south of the Kennedy Space Center
Retired RF Design Engineer
Now able to play with all the hobbies I never had enough time for


Charles & Sandra Cohen
 

FWIW --

There's an extensive write-up of this N7DDC auto-tuner here:

http://radioaficion.com/news/automatic-antenna-tuner-kit/

But it doesn't give an impedance range.

Neat unit . . .  I'm not giving up my LDG Z-11 Pro.

.   Charles / VA7CPC


montanaaardvark
 

(I think I just hit a wrong button and got dumped - sorry if this is a dupe)

Do those "ATU-100 mini tuners by N7DDC" have a claimed impedance range?  You know, like the Icoms that have them have always claimed 3:1 VSWR.

I looked at a couple of eBay auctions and didn't see one.


Tnx,

Bob
--
W4ATM - 35 Miles south of the Kennedy Space Center
Retired RF Design Engineer
Now able to play with all the hobbies I never had enough time for


Steve Sawicki
 

Interesting size and I like the power cell,can you provide the link as to the site.
Regards.
Steve
AB2ET


 

By the way with an 8:1 SWr using RG8X at 7 mhz the losses would be 2.24dB or about 40%%.
100 watts in 53 watts at the antenna.
About 34% at 4 mhz, and 50% at 14 mhz, 60% at 28 mhz.
By the way I could measure this and the losses occur on receive as well.
Best not to give up that much when already handicapped in emergency and portable operations.
For that matter losses are losses at home as well.
A tuner at the antenna is more efficient in many ways due to mismatched currents in the shield as well with noise pickup etc.

On Mon, May 25, 2020 at 10:42 AM J.D. Barron via groups.io <jeter.d.barron=gmail.com@groups.io> wrote:
You are correct, but if you need the tuner anyway might as well put it where it will do the most good, especially if it is small and low power. In the camper I use for my emergency go box there is not a lot of excess space anyway,
I know that with the AS2259 the mast is actually a very low loss foam filled coaxial feedline that plugs together to get the height. This low loss mast plugs directly into the tuner in this case.


On Mon, May 25, 2020 at 10:24 AM Helmut Wabnig <hwabnig@...> wrote:


Have you ever measured "feed losses"?

This is like something from hell or evil devils.

In normal circumstances, that is, not extremely off VSWR,
the so called "feed losses" cannot even be measured with standard
cheap amateur radio equipment, so small they are.

If you have not tried it, you don't know.


OE8UWW





--
J.D. Barron



--
J.D. Barron


 

You are correct, but if you need the tuner anyway might as well put it where it will do the most good, especially if it is small and low power. In the camper I use for my emergency go box there is not a lot of excess space anyway,
I know that with the AS2259 the mast is actually a very low loss foam filled coaxial feedline that plugs together to get the height. This low loss mast plugs directly into the tuner in this case.


On Mon, May 25, 2020 at 10:24 AM Helmut Wabnig <hwabnig@...> wrote:


Have you ever measured "feed losses"?

This is like something from hell or evil devils.

In normal circumstances, that is, not extremely off VSWR,
the so called "feed losses" cannot even be measured with standard
cheap amateur radio equipment, so small they are.

If you have not tried it, you don't know.


OE8UWW





--
J.D. Barron


Helmut Wabnig
 

Have you ever measured "feed losses"?

This is like something from hell or evil devils.

In normal circumstances, that is, not extremely off VSWR,
the so called "feed losses" cannot even be measured with standard
cheap amateur radio equipment, so small they are.

If you have not tried it, you don't know.


OE8UWW


 

Here is my thought about this ATU and it's size.
I have been using either an MFJ 939 or LDG - 100 when portable and installing it at the base of the 30' telescoping fidhing pole with a set of radials spread out on the ground.
I have also used a crossed dipole NVIS antenna to good effect (a copy of the AS2259). Either requires a tuner. What I am thinking about is building one of these with some NIMH batteries and mounting it as a balun at the feed point so that the feed losses would be minimal. It would be possible to incorporate a "TEE" power inserter to get 12 volts to the unit and eliminate the batteries as well. 
Darn it, just when I thought I had finished with my project list.


 

NOW YOU HAVE DONE IT!!!
Posted something that I am interested in with no link or directions on how to find them.
NOW I am forced to GOOGLE!!!!!
Power? SWR range?? Just when I was getting  past project lust!