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Author Topic: Z11 autotuner acting strange...  (Read 1960 times)
SV1ENS
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« on: October 09, 2010, 08:51:05 PM »

Hi all,

For sometime now I've been using my FT718 and Z11 autotuner with a balcony mounted horizontal dipole (two 40m mobile whips) in all HF bands (all but 180m) with relatively good tuning results. Earlier today the tuner tuned normally on 40m.

Later in the afternoon the tuner somehow lost it's ability to tune anything lower than 20m. The FT817 SWR meter reports the dipole to be an acceptable 2.5-3 tune when the tuner is offline, but when the tuner is used, it refuses to tune and I get a "high SWR" alert from the radio...

What could be the problem ??
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WX7G
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« Reply #1 on: October 10, 2010, 06:06:46 AM »

Have you tried changing the batteries?
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SV1ENS
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« Reply #2 on: October 10, 2010, 07:05:37 AM »


The Z11 has the option to work with a power supply...
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SV1ENS
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« Reply #3 on: October 10, 2010, 08:51:22 AM »


A bit of new info...

Tuning has become a little harder for the rest of the bands also, I see the "high SWR" warning more often than before, I tapped on all the relays to release any stuck ones, but nothing...

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AD6KA
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« Reply #4 on: October 10, 2010, 10:30:44 AM »

Quote
What could be the problem ??
Since it worked OK before, something has changed.
Double check all of your coax connections, and physical connections
in the antenna itself. (Loosened screws, loose hamtick element).
Have you had any really wet weather? Make sure water hasn't gotten into
anywhere it's not supposed to be.

RF could be getting into the tuner? But why now...who knows?
Quote
Have you tried changing the batteries?
Depends if he has the older discontinued metal enclosure
Z-11 QRP tuner (which does not take batteries) or the newer Z11ProII.
Like the man said, if you're using batteries, change them.
If you power it externally throw some chokes on the
DC power cable close to the tuner.

Check all the simple stuff first OM.
Good luck.  73, Ken  AD6KA
NB: I have the Z-11 QRP Tuner (no longer made)
http://www.ldgelectronics.com/c/252/products/7/30/3
Great tuner made SUPER by getting rid of the stock disc capacitors
and replacing them with Cornell Dubilier Silver Mica caps
of greater range in the tuning circuit. Also make a better
enclosure-to-PC Board ground for that tuner and
add a brass Ground screw at the back. There's a darn
hole already drilled there for one, LDG was just too lazy to add it.
If you have this version, Z-11 QRP, dont let them
try to sell you the $40 CPU upgrade,(Trade, really, they
want their $40 chip back,hihi. It's a waste of money.
Nice tuner once ya get the buga out. Runs to 30 watts they say, I've
run it past 50 watts.
« Last Edit: October 10, 2010, 10:46:03 AM by Ken Pendarvis » Logged
SV1ENS
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« Reply #5 on: October 11, 2010, 08:52:14 AM »

The Z11 is the original first version in the metal box. My feelings about this tuner are mixed, I never really felt confident with the SWR results, and for some reason the "memory" tuning never really worked for me.

I checked coax and connectors and all are ok, antenna elements and coax are dry as Toronto has been in a middle of a dry Indian summer, grounded the rig to condos ground source (only one available as I'm 21 levels above ground) and antenna to the safety metal structure of the balcony.

The tuner simply refuses to even start the tuning process in the bands below 20 meters, mind you that the dipole tunes on 40 without the tuner. I also get the "high SWR" warning more often while tuning in the 20- bands.

I'm inclined to think that something went wrong with the tuner, a stuck relay maybe ? I had the same problem with a AH-4 outdoor tuner that reset itself with a "gentle" broomstick tap when it got stuck :-) I visually checked the tuner, no parts look damaged, however there is a slight smell of burned part but I can't "smell" it's origin or visually see it. Unfortunately the relay tapping proved unsaccesfull and the plastic casing of the relays can't be removed to reveal the contacts.

My resources are somewhat limited as my "regular" hamshack is in a different continent and debugging is not as easy...

73
Demetre - VE3/SV1ENS
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KJ6EAD
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« Reply #6 on: October 11, 2010, 10:24:49 AM »

I'd be inclined to remove the socketed chips then function test each relay coil with a small power supply or battery pack of the appropriate voltage.
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W3LK
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« Reply #7 on: October 11, 2010, 04:13:26 PM »

It's quite possible the Z11 does from trying to match high SWR situations with the mobile whips. It puts a real strain on any tuner, especially a small one like the Z11, trying to make those whips work on other bands.

I seen it happen before with bigger units than the Z11.
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
AD6KA
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Posts: 2238




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« Reply #8 on: October 11, 2010, 10:12:15 PM »

Just for an experiment....borrow a 25 foot (or longer) piece
of coax and put that in the line. The two 40m hamsticks
present such a very low resistance, it may have fallen below
the range of the tuner.
(Yeah, I know....you said it was working OK before.)
Like I said....it's an experiment.

I really like my older Z-11 QRP tuner.
It'll match a 25 foot wire INSIDE THE SHACK
on 80 meters!
But I built it from a kit and modified it.
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SV1ENS
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« Reply #9 on: October 16, 2010, 07:44:26 AM »

Hi all,

The Z11 simply does not "click" it's relays any more, I suppose if it was an unmatchable antenna
it would lock itself into an endless relay clicking before it gave up the tuning process.

In any case, I purchased a Z817 which works like a charm, tunes the hamstick dipole well and
actually remembers old tunes unlike my Z11 did...

The Z11 will have to wait for my return to my regular shack where it will undergo a diagnose and
repair.

TNX to all who replied
73
VE3/SV1ENS
 
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