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Author Topic: N2VZ Turbo Tuner - enhancements - manual tuning?  (Read 5177 times)
VA3MW
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« on: May 26, 2011, 07:20:44 AM »

I have an N2VZ Turbo Tuner on my 2005 Nissan Murano, and for the most part it works just fine. 

However, there are times when it does go silly (like RF, etc...) and I would like to be able to manually tune the antenna with my FT857.

After fixing the wire connections from the cables to the board (they are not securely fastened .. so if you have one, you might want to check that) I got looking at the L298N Dual Full Bridge Driver that moves the motor.

I need to do some more testing, but it seems that you can just supply 5V to 1 of 2 pins on the L298N and the antenna will move for you.   There are 4 drivers on the chip and he has them paralleled so that it can drive up to 3amps.

This means you can do a fairly simple mod to manually adjust the antenna and you wouldn't need to build a larger break out box.

Anyone done this yet?

Mike va3mw

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K0BG
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« Reply #1 on: May 26, 2011, 02:04:18 PM »

Don't! The relays ground the antenna leads when they're not energized, which provides dynamic braking. Do the wrong thing, and you'll zap the controller.

The best way is to use two relays, and a simple center off SPDT switch. Go to my web site, and look under Home Brew Things. There is a schematic on how to do it correctly.
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VA3MW
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« Reply #2 on: May 27, 2011, 09:24:28 AM »

Hi Alan

What relays?  All motor control is done via the L298N which is 100% solid state.  Am I missing something?

There is a TTL connection to the input of the L298N.  Supplying TTL logic to the input of the L298N (much like the PIC controller would do), will then command the same device (the L298) to command the antenna.

Of course, I would diode isolate the TTL logic leads (they are already protected by 1 set of diodes and I would have to add another set).

The only other line that controls if the L298 motor controller functions is the enable line and in the TT, that line is tied in a HI state full time.  If Bill wanted to, he could use that line as the input for a pulse modulator and slow down the antenna movements as he approaches a tuned state.  This is what the Hobby guys do when they use this for a motor/drive wheel controller.

I do agree that what you describe is a pretty solid solution (however, I have not tripped over the schematic you speak of.. and I have been through just about every page on your web site.  I am sure I just missed it).

mike va3mw

p.s.  I recently (yesterday) made a very large choke with about 10 loose turns of RG8X through a #2 RED core and I can't believe the difference.  The antenna tunes all the time now.  Most importantly was my ignition noise totally disappeared and my noise floor is about 2 S units less.  I must have missed the memo on the effect the correct choke would have on reception.   

p.p.s  Thanks for all your hard work on your web site.

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K0BG
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« Reply #3 on: May 27, 2011, 05:30:14 PM »

I do not have a current schematic of the Turbo Tuner. Although the circuitry is different, the bottom line is the same. The motor leads are shorted to ground for dynamic braking. This said, perhaps the whole thing has been redesigned, but I can't say.

This said, if you truly need manual control (BetterRF controller on 60 meters for example), then the solution on my web site is the correct methodology.

Using an iron ferrite material (red mix) is not really that effective, as it has a permeability of just 10! Mix 31 on the other hand, with just 7 turns of RG8X, will result in a common mode choke of just under 2,500 ohms at 10 MHz, or about 10 times that of the "red" iron mix with 10 turns.

The reason a common mode choke is needed, has more to do with mounting methodology, and placement, than any other cause. The secondary reason is much more productive, in that common mode is a two way street. If you don't choke it off near the antenna, then the coax transitioning the vehicle's interior, will pick up much more RFI than is picked up by the antenna.



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VA3MW
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« Reply #4 on: May 28, 2011, 12:35:59 PM »

Hi Alan

Thanks for letting me know on the Mix 31.  I will be ordering some this week based on the document authored by the YCCC.  The Red Mix was all I had on hand.

As for the mod I will make to the Turbo Tuner, if you had the schematic, you would understand what I am saying.  I will be injecting switching signals well before the actual DC line to the motor. 

If you have a look at the L298N data sheet (that is what the motor is directly connected to), you will understand what I mean.  With this mod, you do NOT actually connect to the motor leads at all. 

The basic Turbo Tuners circuit is pretty straight forward. 

This is how my current common mode choke looks like.

http://www.walkerphotography.ca/Hobbies/Dayton-Hamvention-2011/i-gntbXP3/0/M/DSC00609-M.jpg


73, Mike
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K0BG
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« Reply #5 on: May 29, 2011, 12:56:40 PM »

I'm a bit familiar with the L298N. I guess my feelings toward it may be biased, but the full isolation relays give you is sometimes worth the price of admission. That, and the limited current capability of the chip. Sure wouldn't run a Larry's antenna!
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VA3MW
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« Reply #6 on: May 29, 2011, 01:09:10 PM »

Larry?  Is that the Scorpion? 

That is the Chip that Bill N2VZ uses for his Turbo Tuner (at least in  my 3 year old Yaesu one).  The motors are directly connected to the output of that chip.  There are 4 drivers on the chip http://www.sparkfun.com/products/9479 and  he runs them in parallel complete with the current sense configured to talk back to the PIC controller.  It is good up to 4 amps.

There are no relays in the Turbo Tuner at all.  It is 100% solid state. 

Many 73 ... Mike
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K0BG
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« Reply #7 on: May 30, 2011, 11:36:54 AM »

No it is not. The Scorpion is made by Ron Douglass. It uses a Pittman gearmotor like almost everyone else. (Oddly enough, some screwdrivers are exact copies of the DK3, replete with B&D battery screwdriver motor. Ugh!)

Larry's Antennas (http://www.kj7u.com/) uses a modified, 18 volt, screwdriver motor. The run current is about 2.5 amps, but can be much more depending on the tightness of the contact collar. Stall can be as high as 12 amps for the same reason. That would long since pop the L298.
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VA3MW
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« Reply #8 on: June 04, 2011, 08:35:10 AM »

Alan

I am confused by your last comment.  I was talking about the Turbo Tuner and the HiQ 4" configuration. 

Where are you referencing the relays?

73
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K0BG
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« Reply #9 on: June 04, 2011, 08:55:47 AM »

The HiQ uses a German made gearmotor. Regardless of the coil size, they all draw about 250 to 300 mils when running, and about 650 to 850 when stalled. They are compatible with the Turbo Tuner, and the BetterRF TCSC. The latter uses 10 amp relays, the former the L298 ≈2.5 amps max.
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WB6KIO
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« Reply #10 on: September 26, 2011, 10:31:21 AM »

Bought my Turbo Tuner during this past year and didn't have a very warm experiance . It wouldn't operate in my installation the way it was advertised. Called Mr.KantzN2VZ about it and was advised to adjust dip switches inside tuner. I adjusted but it still didn't work right. Called again and was asked to send unit back for a refund so I did this past July and here it is almost October and still no comunication by phone or Email ! Looked on the internet and found at least 13 other hams on QRZ and Eham and Yahoo/ic-7000groups that have been treated the same way. I reccomend not doing business with N2VZ Enterprises but if you already have, "GOOD LUCK"!!! 73 de WB6KIO/Steve
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VA3MW
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« Reply #11 on: September 26, 2011, 02:49:09 PM »

All

I had lots of problems with my TT at first. 

The 2 things that fixed it. 

Very good RF grounds on the antenna.

You absolutely have to add chokes at the feed point, radio and the control leads.  You can't just breeze over that part and say that isn't my problem. 

If the tuner won't tune and never stops, then RF on your feedlines and control lines IS the problem. 

Alan talks about it here:  http://www.k0bg.com/common.html

I know, it is hard to measure and debug RF common currents, but until you add some chokes (mix 31 or mix 43), I wouldn't complain about any automatic tuner.

Once I did that, my TT has worked 100% of the time and that was 6 months ago. 

CHOKES CHOKES CHOKES CHOKES

Seriously.... many 73... Mike va3mw
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K0BG
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« Reply #12 on: September 30, 2011, 06:38:51 AM »

I received an e-mail back from Bill Kantz, N2VZ, owner of Turbo Tuner. He said that he has had some medical problems. Add some insult, both AES and HRO now carry his products. He assured me all remaining customer issues will be handled in due course.
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WD5GWY
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« Reply #13 on: September 30, 2011, 02:44:24 PM »

Good to hear that you heard back from him.
I am curious about your statement"Add some insult, both AES and HRO now carry his products." Is there something I am missing here? I would think it would be
a good thing if he is able to use outside vendors to handle sales and customer
service. I have used HRO in the past and not had any issues with them.
Never bought anything from AES.
I do hope that Bill's health problems get better and he can get back on track.
james
WD5GWY
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K0BG
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« Reply #14 on: October 01, 2011, 04:22:26 AM »

It is called order quantity. I suspect they've both ordered a stocking quantity, and one has to remember that both have multiple stores. Been there, done that!
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