Antenna tuner


kf7rcm@yahoo.com
 

This question is directed mainly at Hans, but if anyone knows......
Is there a chance an antenna tuner kit might be in the future?


Daniel KK4MRN <SQLDan2000@...>
 

Hello,
I cannot answer for Hans, but I do have some questions/assumptions.

Manual Antenna Tuner for QRP power with LED SWR Indicator?  
The circuitry could also protect the transceiver while tuning because it will not show an SWR higher than 2:1 to the transceiver (or is it 2.1:1?)
Max is 5 watts power but maybe handle higher power intermittently maybe 10 watts?

Be able to handle QRPp as well?

Probably good to be able to handle balanced lines and antennas feed via a coax.

Any specific antenna will you be using?

Some places offering QRP antenna tuner kits:

Pacific Antenna qrpkits.com has a BLT+ which can work with both a balanced line or coax.
Even though it has Balanced-Line Tuner in its name, it can be used for other antennas as well.

qrpguys.com has various antennas including their z-match.

4 State QRP has their 4S Tuner which is a z-match tuner.

Kanga has multiple tuners

Z-match tuner from Emtech ZM-2 has a kit or fully assembled.  Includes case.  Includes either 2 so-239 or 2 BNC RF Connectors.

qrpme.com used to have a z-match tuner called the Z-Rock Tuner for the RockMite II but this tuner has been discontinued.  Maybe if we bug Rex he might kit again but suggest make it work for other QRP transmitters/transceivers too.
Looks like he still has a switched inductor tuner.

Or you can easily home brew your own z-match tuner.

If you can build a QCX, QCX-Mini, QCX+, or QDX transceiver from QRP Labs, 
you can home brew a z-match tuner. Do an internet search for z-match tuner or calls sign W6JJZ or WB3GCK.  Emtech sells those polyvaricon capacitors.  Or you can get them from Mike's Electronics Parts.  And toroids can come from kitsandparts.com

Bands?  Is 80 meters through 10 meters ok?   It is difficult to include bands like 160 meters and/or 6 meters.

If you will not use a Red LED SWR Indicator, what about including an analog SWR/Power Meter with the design as well?

The 4 State QRP S Tuner has 2 LEDs for the LED SWR Indicator: Red for high SWR and Green for low SWR.  If Solid Red but no green, very high SWR.  If Solid Green but no red, very low SWR (1.0:1).

73 Daniel KK4MRN

On Tuesday, July 12, 2022 at 07:13:34 PM EDT, kf7rcm@... via groups.io <kf7rcm@...> wrote:


This question is directed mainly at Hans, but if anyone knows......
Is there a chance an antenna tuner kit might be in the future?


kf7rcm@yahoo.com
 

To: Daniel KK4MRN-
Thank you for your response. You have given me alot of info to look into and I really appreciate it. I mainly want one for random wire and compromised antennas but hamsticks on a mount to make them into a lossy dipole. I already have an mfj tuner that works great but would like to build one myself and have it as a matched set, (petty, I know). I looked alot at qrpguys but as of this writing they seem to be out of just about everything.
Anyway,
thanks again for your input and I will definatly be looking into all that you send along,
Wayne/kf7rcm.


Daniel KK4MRN <SQLDan2000@...>
 

Wayne, when was the last time you looked at qrpguys?  They recently opened back up after some vacation.   If you see an add to cart button and you can check out, good chance it is in stock.

I understand.  I have a heathkit tuner for my HW-101.  I could use it for my QRP radios, but I prefer a tuner for QRP.  So, I am home brewing a z-match tuner slowly.  To me, the hard part is the enclosure.

73 Daniel KK4MRN



Sent from my Verizon, Samsung Galaxy smartphone


-------- Original message --------
From: "kf7rcm@... via groups.io" <kf7rcm@...>
Date: 7/13/22 1:32 AM (GMT-05:00)
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Antenna tuner

To: Daniel KK4MRN-
Thank you for your response. You have given me alot of info to look into and I really appreciate it. I mainly want one for random wire and compromised antennas but hamsticks on a mount to make them into a lossy dipole. I already have an mfj tuner that works great but would like to build one myself and have it as a matched set, (petty, I know). I looked alot at qrpguys but as of this writing they seem to be out of just about everything.
Anyway,
thanks again for your input and I will definatly be looking into all that you send along,
Wayne/kf7rcm.


Vojtech Bubnik
 

Ondra OK1CDJ has a clone of KD1JV altoids tuner
Altoids L Tuner KIT | Hamshop.cz


kf7rcm@yahoo.com
 

Yep, qrpguys are back online.


Dan Quigg
 

Doesn't QRPGuys offer complete instructions, circuit diagram, board layout & BOM & such that would allow one to accumulate the parts & build the device without buying the kit from QRPGuys?


Colin Kaminski
 

My QRP guys triband antenna had a schematic but no board layout. 


kf7rcm@yahoo.com
 

Getting it from qrp-labs save the trouble of finding everything you will need to get but most importantly, you get the PCB. Getting the kit save untold hassle and frustration plus the optional enclosure makes it a "no brainer".
My $0.02.


bojan.naglic
 

Hi,
I have assembled a DIY kit ATU-100 ext 7x7 designed by N7DCC.  Originally it is for 100W and needs at least 5W input to work well.  Then I changed it for QRP use.  It is an easy job.  It works fine up to 40W with a minimum needed input power of 1W.
https://github.com/Dfinitski/N7DDC-ATU-100-mini-and-extended-boards
Hope it helps.

73 Bojan S53DZ


james jones
 

Blew my QDX finals using an ATU-100 set up for QRP.  Bad mismatch on 40 but ATU found tuning solution.  Power in to tuner was shown as 6.8 watts.  Power into to 50 ohm load had been 4.5 watts.  Apparently the QDX saw the mismatch before the solution was attained.  

Pulled the bs170s and radio receives great.  New transistors tomorrow; hope for the best!

Jim w0nkn 


On Jul 13, 2022, at 3:54 PM, bojan.naglic via groups.io <bojan.naglic@...> wrote:

Hi,
I have assembled a DIY kit ATU-100 ext 7x7 designed by N7DCC.  Originally it is for 100W and needs at least 5W input to work well.  Then I changed it for QRP use.  It is an easy job.  It works fine up to 40W with a minimum needed input power of 1W.
https://github.com/Dfinitski/N7DDC-ATU-100-mini-and-extended-boards
Hope it helps.

73 Bojan S53DZ


Curt wb8yyy
 

For qdx operation if you can install a efhw you won't need to use a tuner. Quick to change bands. 

Plan B, a manual tuner that has a provision to resistively load the rig while adjusting it puts less stress on finals. 

ATU is best used when antenna already has a reasonable SWR to begin with. Yes I use them to expand bandwidth of some decently matched antennas. 

Curt


Michael.2E0IHW
 

Would it be possible to add an ALC module to minimise this risk?
Michel UK

On 13/07/2022 22:50, james jones wrote:

Blew my QDX finals using an ATU-100 set up for QRP.  Bad mismatch on 40 but ATU found tuning solution.  Power in to tuner was shown as 6.8 watts.  Power into to 50 ohm load had been 4.5 watts.  Apparently the QDX saw the mismatch before the solution was attained.  

Pulled the bs170s and radio receives great.  New transistors tomorrow; hope for the best!

Jim w0nkn


bojan.naglic
 

I would not go to the ATU with full power.  Use attenuator to do this. Or lower the output for the duration of tuning.  That s why I changet the ATU for QRP.  Transmiting to open or short or to a havy antenna missmatch is risky no matter what. And should be avoided at all times. But... it is a bonus if the finals survive that shock when accidently happens. I ve been there. 

73 Bojan S53DZ


bojan.naglic
 

Sorry, forgot to tell. I am not using the QDX for antenna tuning. I do it with additional PA which is more robust. 

73 Bojan S53DZ


Curt wb8yyy
 

Michael

I think as hams we are fascinated with technology. When someone brought his K2 to field day with its nifty 100 watt ATU I just had to have one. It is quite useful to span full bands in a major contest as my compact yagi and short 80m vertical need the help. Plus it is cool to use lingo from USA circa 1960 something. 

But we also can be practical. These manual tuners such as the zm2 with their tune switch inserting protection resistors and an effective led for matching are cool in a different way. We can slow down to manually tune for much of operating. Likely some enterprise in UK may kit a nice manual tuner that does this, or shop for the cores and variable caps at the next ham rally over there. Cheers. 

Curt wb8yyy 


Evan Hand
 

Hi Jim,

Before installing the new BS170s, I suggest you verify that IC5 (74ACT08) is still working.  It is easier to test with the BS170s removed.  The best way is with an oscilloscope, but you can get a good approximation by measuring the DC voltage on all of the BS170 gate pads before you install them.  You should read 2.5volts.

73
Evan
AC9TU


Roelof Bakker
 

Hello all,

Consider this: all legacy 100W commercial HF transceivers which have an in-built ATU are
reducing the output power to about 10W in tuning mode.

The reason is to protect the ATU against excessive voltages.

I doubt if any automatic tuner rated for 100W will be happy when tuned with 100W and the same
applies for the transceiver.

MFJ has a warning regarding maximum power at tune up for their auto ATU's: 100W with fold-back
and 20W without fold-back for a 200W model.

I don't know if I would be very happy to rely solely on the transceiver's final protection
circuitry (power fold-back at high SWR).

Analogue, the QDX rated for 5W output won't budged when using an automatic ATU and using 0.5W
in tuning mode.

I don't own a QDX, but my 40M QCX was saved by the current limiting of my power supply when
accidentally tuned with 4W output. With 1W output no problems are encountered.

To sum it up, it is not realistic to expect unprotected finals to survive when tuned at full
output.

73,
Roelof, pa0rdt


James Daldry W4JED
 

Hi, James

Take a low voltage transformer, connect a couple wires to the low voltage winding, and while holding the wire ends, connect a common 1.5 volt battery between the wires. When you disconnect the wires you will drop them, because the collapse of the magnetic field in the coil will generate a voltage spike several hundred volts in magnitude. Now, try it again with a 100 ohm resistor across the winding. No spike. Now - makes no difference if the switch is a relay controlled by a microcontroller or a manual knob switching the inductance - it's a switch, a voltage, and an inductance.

Add a 3 db 50 ohm pad to the input of the tuner when tuning. The tuner will still receive 2+ watts to play with, and the resistors will greatly reduce the voltage spikes.

73

Jim W4JED

On 7/13/22 17:50, james jones wrote:

Blew my QDX finals using an ATU-100 set up for QRP.  Bad mismatch on 40 but ATU found tuning solution.  Power in to tuner was shown as 6.8 watts.  Power into to 50 ohm load had been 4.5 watts.  Apparently the QDX saw the mismatch before the solution was attained.  

Pulled the bs170s and radio receives great.  New transistors tomorrow; hope for the best!

Jim w0nkn 


On Jul 13, 2022, at 3:54 PM, bojan.naglic via groups.io <bojan.naglic@...> wrote:

Hi,
I have assembled a DIY kit ATU-100 ext 7x7 designed by N7DCC.  Originally it is for 100W and needs at least 5W input to work well.  Then I changed it for QRP use.  It is an easy job.  It works fine up to 40W with a minimum needed input power of 1W.
https://github.com/Dfinitski/N7DDC-ATU-100-mini-and-extended-boards
Hope it helps.

73 Bojan S53DZ


James Daldry W4JED
 

Nope. Not even waving at fast enough.

Jim W4JED

On 7/13/22 18:28, Michael.2E0IHW via groups.io wrote:

Would it be possible to add an ALC module to minimise this risk?
Michel UK

On 13/07/2022 22:50, james jones wrote:
Blew my QDX finals using an ATU-100 set up for QRP.  Bad mismatch on 40 but ATU found tuning solution.  Power in to tuner was shown as 6.8 watts.  Power into to 50 ohm load had been 4.5 watts.  Apparently the QDX saw the mismatch before the solution was attained.  

Pulled the bs170s and radio receives great.  New transistors tomorrow; hope for the best!

Jim w0nkn