Arv Evans

Bill

Thanks for the info on latching relays.  I've worked on lots of electronics over the years but
have no experience with small size latching relays.  Big ones I worked on were for industrial
power (big power!) systems and used solenoid release mechanisms.

My little binary progression ATU works but having a chart for each band makes it easier to
do the manual tune thing.  I can see where use of latching relays could be a definite advantage
in most cases.

Arv
_._

On Sat, Aug 25, 2018 at 7:42 PM J68HZ <bill@...> wrote:

Hey Arv… Oh the binary approach does work.  Eventually.   My comment was more along the lines that it’s the most inefficient way to get to a match.  I did a lot of research around algorithms used to solve the classical binary tuning problem years ago (8 discrete coil, 8 discrete capacitors… 65535 combinations.).  The best hunting algorithm uses a newton gradient approach to finding the solution (calculate the derivative basis your swr readings).  It’s also the fastest of the hunting algorithms.  Smarter approach… one used by most military tuners… it to calculate the real and imaginary parts of the load at the frequency of interest.  Then calculate the transform to give you exactly 50 ohms real… and implement that as a solution.  It’s like plotting the load on a smith chart and drawing the two-step solution to get to 50 ohms.  It’s obvious from the diagram what to do.  Since there can be a bit of error in the calculations, these algorithms usually either stop and live with a tiny bit of SWR or they then switch to a halving algorithm to tough up the SWR by looking at reactive components on either side of the calculated solution.  This is also covered in Sabin’s book.   This approach is way faster than the binary/ hunting approach unless you start at the solution to begin with… at which time they both have about the same solution time!

Latching relays.  I started looking for some good quality, small,  latching RF relays capable of 100 watts.  I found two types… a single coil-reverse voltage to change state (must be magnetic), and dual coil models (flip flop).  I eventually settled on the dual coil model as they are easier to implement than reversing the coil polarity.  I found what I needed on Alibaba… It was a direct from the factory deal for several hundred.  I asked for a sample to try first.  When I was satisfied they worked, I bought several hundred.

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Moderator – North American QRO Group at Groups.IO.

email:  bill@...

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Arv Evans
Sent: Saturday, August 25, 2018 10:22 AM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] QSX radio feature requests

Bill

My own QRP ATU uses binary progression of inductances with a 0-150 pf

variable cap and a switch for adding another 150 pf fixed C.  It doesn't seem

to be too much of a stretch to have the C values also binary progression.

Might take a bit of thought for those not used to programming in machine

code but it does seem doable.

I'm curious about how small latching relays work.  My only experience in

that area is with much larger units.  They had two coils, one to operate the relay

and another to release the lock.  Do the small ones work that way. or is

there some other methodology?  Magnetic latch?

Arv
_._

On Fri, Aug 24, 2018 at 8:17 PM J68HZ <bill@...> wrote:

Woah, wait.  Toggle switches to replace the relays???!!!!  So how do you propose that would work… do a binary search towards a low SWR solution?  That reminds me of loading the operating system into an ATARI 8080 system using front panel switches…  could take forever and a few days.  If you are worried about current draw, go with latching relays.  Back in March, I bought several hundred latching relays for \$0.89 each… yes they can be had cheap if you buy them right from the source.

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Moderator – North American QRO Group at Groups.IO.

email:  bill@...

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Arv Evans
Sent: Friday, August 24, 2018 8:18 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] QSX radio feature requests

Glen

The K3NG ATU is an interesting design but uses several relays.  That is fine for automation

purposes, but I wonder if the design could be reproduced with a handful of DPDT rocker or

toggle switches replacing the relays.  Maybe there needs to be 2 versions of this well thought

out design, one that is automated and another that is manual for low current draw and increased

battery life for portable use.

Arv
_._

On Fri, Aug 24, 2018 at 6:27 PM Glenn <glennp@...> wrote:

The K3NG ATU lends itself to home brew.   And changes to the power level required. My own build I estimate at around 20-30W and uses smd 2-3kV caps (overkill) and the usual relay switching of L&C. Two relays are used to switch the ends for L-C or C-L. I used standard relays, not latching, due to cost here in VK. Control board uses a NANO with a 0.96" OLED display.

vk3pe

 Virus-free. www.avg.com

J68HZ

This is what the old Harris RF-601 tuner did…

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Moderator – North American QRO Group at Groups.IO.

email:  bill@...

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Glenn
Sent: Saturday, August 25, 2018 8:54 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] QSX radio feature requests

There's also an interesting approach shown  by W8MQW in QEX, Dec 2016.

vk3pe

 Virus-free. www.avg.com

Steve Black

I am still interested too. Steve kb1chu

On 8/24/2018 10:51 PM, J68HZ wrote:

Hardware is done and…and  I must say it works extremely well.  One of the best projects I’ve ever designed.  I’m Just waiting/ helping Jack with his JackAl project so that I can coerce him into helping me with the coding for this project.  As designed, it can work as an integrated-to-a-radio 100W tuner, or just stand-alone.  Speaks several languages to do that.  What I particularly like about it is that is tunes in less than a second worst case (even with my kludgy excuse for code).  Stay tuned.  It’s still on target for \$35 or less.  Probably will be selling kits at Dayton next year.

I can’t post on the uBITx group any more so I guess you’ll hear it here first!

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Moderator – North American QRO Group at Groups.IO.

email:  bill@...

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Kelly Jack
Sent: Friday, August 24, 2018 9:34 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] QSX radio feature requests

Bill,

How are going with your tuner project?

Regards

Simon
VK3ELH

 Virus-free. www.avg.com

John VA7JBE

There was an autotuner project by Martin AE7EU published last year as part of a power amplifier that might be adapted to the QSX.  The details are here: http://ae7eu.com/index.php/quickie-50-amplifier/

ajparent1/KB1GMX

I'm going to take a liberty to sane something....

There is the group Antennas (groups.io) where some of this coversation has migrated to.
It might be more appropriate there.

Allison

jmh6@...

Hi All,

"It might be more 'appropriate' there."

Then again you didn't ask. Or did you?

John

On Sun, 26 Aug 2018, ajparent1/KB1GMX wrote:

I'm going to take a liberty to sane something....
There is the group Antennas (groups.io) where some of this coversation has
migrated to.
It might be more appropriate there.
Allison

John VA7JBE

Hi John,

That's hurtful, non-constructive, and negatively impacts our sense of community.

Other John

ajparent1/KB1GMX

What you missed is the conversation is already spread across the two sites.
Its hard to have community when its hard to figure out who is replying to whom
and where.

Other than its was a suggestion.  That what might, rather shall or should means.

Allison

Greg Wasik

Yes I agree with all of the comments about not asking for features that should come later... However, I do have one that I think might be reasonable

Would it be possible to have the LPF filters on a plug in boards - kind of the same approach as used with the Ultimate 3?  -  I was thinking about how much easier it would be to have that same approach on the QCX as well. One could then fully test and mod the LPF as needed externally from the transceiver main board.. Perhaps even the  T1 or equivalent and other band specific parts could be mounted on plug in boards, therefore maybe it would be possible to have a multiband rig just by swapping RF and LPF boards?

Alan de G1FXB

Re: Multiband QCX

Find the work of  Andreas DM5MU using plug in LPF & T1 assemblies in his 6-band QCX
at the bottom of the QCX Gallery page

Alan

On 28/08/2018 16:49, Greg Wasik wrote:
Yes I agree with all of the comments about not asking for features that should come later... However, I do have one that I think might be reasonable

Would it be possible to have the LPF filters on a plug in boards - kind of the same approach as used with the Ultimate 3?  -  I was thinking about how much easier it would be to have that same approach on the QCX as well. One could then fully test and mod the LPF as needed externally from the transceiver main board.. Perhaps even the  T1 or equivalent and other band specific parts could be mounted on plug in boards, therefore maybe it would be possible to have a multiband rig just by swapping RF and LPF boards?

KEN G4APB

Hi Greg,
Hans has said this QSX could become a 10 band radio as a later option. I did wonder how this would be achieved as looking at the photos it does seem that a single band Rx BPF is implemented on the main board. I think the same for the Tx LPF, I am not sure if this radio uses the tuned T1 approach? So I assume that an 'add on' board similar to the LPF 'switched relay board' used in the U3S would be used. Interesting problem now is for each band it would need both an LPF AND a BPF. I guess with an add-on board but twice the size, the original plug-in U3S LPF/BPF boards maybe could be used.
I may be wrong, but it would make setting BPFs and LPF on frequency much easier if they could be removed and tested stand-alone.

I also saw another report saying the PA may be good up to 4m, so this raises some interesting possibilites too.

73 Ken G4APB

ajparent1/KB1GMX

Ken G4apb,

The assumption is the box and board are the same.  Its all speculative
based on the monoband 40M radio.  A bigger box kit?  Unknown.

The power amp has power to 70mhz, gain is down to about 22db and
the output transformer may not be optimum up there.  I ran the source
up to see if it quit higher up.  Its optimum to 30mhz.  That it works higher
is a plus.

What I can't speak to is the QSD detector for the IQ good at 6 and 4.
I see no one in the VHF world using them and I tried them and
rejected it.  They were much too noisy for 6M weak signal work
even with 20db of very quiet E-Phemt gain (minicircuits PHA5351+).

OPINION: I'd not suggest it for manufacture as really how many are
6 and 4 m users?   Its partly why we see so few kits for VHF and up
other than transverters.  They are tougher to build and specs are
generally tighter (least USA and ITU countries).    A transverter can
be built for higher performance and likely more power.

First we walk, running comes with practice.

Allison

Chris Wilson

Hello Allison and Hans

Many thanks for the detailed reply, I will take on board both yours

Friday, August 24, 2018

On Fri, Aug 24, 2018 at 02:54 AM, Chris Wilson wrote:
I would value Allison's opinion on how important FET lead lengths and
trace routing and widths, and those of FET driver IC's remain at LF
and MF as I am fond of experimenting "down there", particularly with
Class D amps. I suspect it is still important as gate and drain
traces seem to respond to careful minimisation of lead lengths and
usage of wide traces.
Its very simple, IF you want long leads stay near DC. Look leads for high current
fast rise time pulses are essentially no different hat upper HF to VHF CW signals.
Think of this way would you intentionally put a choke in series with the three legs?
Of course not but yet many don't consider a 40nh lead as important.
I've used those driver ICs to 13.56mhz.
More of same for wide traces and ground planes.
Or from a different view point Hans did it right and it works to VHF.
Allison _._,_._,_

--

2E0ILY
Best regards,
Chris mailto:chris@...
--
Best regards, Chris Wilson (2E0ILY)