Date   
Re: Toroid winding numbers and measurements

Alan G4ZFQ
 

< If I measure with a Fluke LCR mter that's still
in calibration it measures at (from memory) 100kHz. But if I use my
AIM4170 analyser I can measure inductance at the frequency the amp
will be run at, and the inductance value is somewhat different.
Chris,

Somewhat? How much?
What type of inductor?

I've seem Lee's warning many times, I want to know when the variation might be significant.

73 Alan G4ZFQ


This
variance is of course more marked the higher infrequency above the
Fluke test frequency the inductor under test will ACTUALLY see in use.
I suppose a spectrum analyser with a tracking generator would be a
better tool still for messing with them.

Re: Toroid winding numbers and measurements

Alan G4ZFQ
 

An inductor tested at
one frequency will give a different inductance if tested at a different frequency.
Lee,

Have you any examples of this?
All inductors I have tried with a lowish frequency tester and a GDO at working frequency have coincided with a reasonable accuracy.

73 Alan G4ZFQ

Re: Toroid winding numbers and measurements

Jim Sheldon
 

Very good point.  Been over 50 years since I had my theory classes and I had forgotten this point.  I do have a Midnight Design Solutions Scalar Network Analyzer which can measure L at frequencies up to at least 35 MHz with the right fixture.  I'll look into this and see what I can comeup with.

W0EB

Re: Power output on 20 meters.

J68HZ
 

About 30% efficiency...


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


email:  bill@...

 


On Nov 1, 2017, at 11:54 AM, mike@... wrote:

Hi All

I also have a 20M version. The output is about 1.4W on 11.5V taking 400mA on T/X (all these are approx values). We need to get some more information about what is going on i.e. is it a loss through the LPF? ~ so hopefully on Thursday I will use the RF test feature of 9.2 to measure the RF at the following points...........

1. BS170 outputs at the junction of C29 & C30 
2. Junction of C29/C27 & L3
3. Junction of L3 & L2
4. Junction of L2 & L1

Sounds like a plan? That will give 4 RF levels and hopefully more info on where the problem is? There must be some standard figures about the losses through the LPF?

.............and the the nuclear option..........I did think that one option is to parallel up some more BS170's (they arrived this morning) but I am not sure if that is wise when the issue maybe elsewhere?

73
Mike
G0CVZ
  

Re: Toroid winding numbers and measurements

Chris Wilson
 

Hello Lee,

This is very true, I am experimenting with a new power amp and also
a big LPF bank for it. If I measure with a Fluke LCR mter that's still
in calibration it measures at (from memory) 100kHz. But if I use my
AIM4170 analyser I can measure inductance at the frequency the amp
will be run at, and the inductance value is somewhat different. This
variance is of course more marked the higher infrequency above the
Fluke test frequency the inductor under test will ACTUALLY see in use.
I suppose a spectrum analyser with a tracking generator would be a
better tool still for messing with them.

Wednesday, November 1, 2017

One last caveat:  The measured inductance will very with the
frequency used to measure the inductance.  Hans has not told us if
he just calculated it or if he measured the best inductance with
an instrument.  If he used an instrument we would have to know the
frequency used.  In other words if you remove or add turns to
acquire the exact inductance needed but did this at a different
frequency because your meter is on a different frequency, your
results will not be what is required.  In my estimation one is
playing with fire trying to match inductance without knowing the
standard's test parameters.  A lot of hams don't realize
inductance of an inductor changes with frequency.  An inductor
tested at one frequency will give a different inductance if tested at a different frequency.
Lee, w0vt





--

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

n00b question

John Asmussen
 

Hello all,

First off, this is my first attempt at building ANY amateur radio kit. I have been preparing (reading the instruction manual, reading all of the posts on this forum, watching build videos, etc.) and I've laid out a lot of my ideas that I have for this kit on paper.

I ordered the 40m QCX kit and I want to mount my kit in an enclosure. I was reading through the instruction manual and found on page 61 (of the latest instruction manual) this reference to mounting the LCD module off of the main PCB:

"Take care to ensure short cables, or use shielded (screened) cable in order to avoid radiating digital noise into the RF circuits"

What type of shielding are we talking about here?
Plain insulated wire? Foil lined shielding? Braided shielding?
Would 10cm breadboard jumper wires with Dupont connectors cut to the optimal length for the enclosure be an acceptable wire for this?
How much interference could this type of wire actually create?
Is there a "home-brew" solution to shield the wires if its expected to cause interference?

Thanks in advance for your help!

John G. Asmussen
KF5COM

11. Potentiometer tuning for the Ultimate3

KEN G4APB
 

Hi Hans,
I added the U3S section 11. Potentiometer tuning for the Ultimate3 modifications to my v3.12 version but am getting problems. This is a U3S Transceiver using standard U3 Tx with relay switched LPFs and a standard Rx module with Polyphase board and 7MHz BPF fitted.

I have set Tn mode = 1 in the menu.

Problems are;
1) Upward frequency tuning only in Tx WSPR mode. I can hear clicking on my monitor Rx when the Tune pot is turned to min but the frequency does go lower.
2) In RX mode, upward movement of displayed frequency only, but it does not actually change the LO frequency (using 7mhz band). NO downward frequency either.
3) Loud clicking on Rx audio once pot is away from centre setting (in freq up or down positions)

I measure approx 0.5V on S1 with Tune pot at minimum, and approx 4.5V at max setting, and 2.5V in centre position.
Both S1 and S2 switches functioning ok.

I tried a complete 'RESET' and re-configured all my settings
I have used a 10k linear tune pot with 1k resistors.

Any ideas what may be wrong please.

73 Ken G4APB

Re: Power output on 20 meters.

Leland L. Bahr
 

I always use silver mica capacitors in a pi network.  They cost more but I have never had a problem when using them.

Lee, w0vt


On 11/1/2017 11:22 AM, DL3HRT- Karsten wrote:
It was just trial and error. I realized that I had to spread windings over the whole core. So I decided to remove one turn. I did it with L2 and L3 and have good results now. I stopped at this point and did not change anything else.

What I realized in the thermal images is that the 390pF capacitors heat up.

Regards

Karsten
_.


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Re: Toroid winding numbers and measurements

Leland L. Bahr
 

One last caveat:  The measured inductance will very with the frequency used to measure the inductance.  Hans has not told us if he just calculated it or if he measured the best inductance with an instrument.  If he used an instrument we would have to know the frequency used.  In other words if you remove or add turns to acquire the exact inductance needed but did this at a different frequency because your meter is on a different frequency, your results will not be what is required.  In my estimation one is playing with fire trying to match inductance without knowing the standard's test parameters.  A lot of hams don't realize inductance of an inductor changes with frequency.  An inductor tested at one frequency will give a different inductance if tested at a different frequency.

Lee, w0vt


On 11/1/2017 11:37 AM, w0eb@... wrote:
I'm still waiting for my 40 meter version (#943) but shipping has resumed again as of yesterday so hopefully by the end of this month.

I have all the proper cores for all the toroids called for in the construction manual, and after reading this thread I decided to wind a set and measure the inductance with my AADE L/C meter which has proven to be quite accurate.

To achieve the proper inductance for L4, I had to use 1 turn less than called for so I wound L2 next - same thing - 1 turn less to get the right inductance for the band.  I wound L1 and L3 with 1 turn less and they came out very close to the called for value.

Now, a caveat - NOT ALL TOROID CORES ARE CREATED EQUAL!  Especially if they are Chinese made - LOL. Depending on the actual permeability of the core, the inductance will most likely vary a bit with the same turns count.  Also I saw something earlier about spread of turns VS inductance.  Close winding gives the MOST inductance and if you spread the turns out you will reduce the inductance somewhat.  Not by much but it will be less with wider spaced turns by the theory of inductors and I confirmed this by measuring each of the above coils.  I first used the called for number of turns and they all measured up to a half microhenry high.  Spreading the turns got it down about .2 microhenry but they still were too high so I removed a turn from each which with close to even spacing over the core got them within .02 microhenry which I think should be close enough.  Just my experience with the set of cores I had on hand.  Your mileage will most certainly vary so don't take this as gospel, just as a point of information and a starting point for troubleshooting.

I'm looking forward to receiving my QCX so I can guit it built and hopefully confirm my observations on the LPF coils.

Jim - W0EB


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Re: Power output on 20 meters.

Mike Bowthorpe
 

Hi All

I also have a 20M version. The output is about 1.4W on 11.5V taking 400mA on T/X (all these are approx values). We need to get some more information about what is going on i.e. is it a loss through the LPF? ~ so hopefully on Thursday I will use the RF test feature of 9.2 to measure the RF at the following points...........

1. BS170 outputs at the junction of C29 & C30 
2. Junction of C29/C27 & L3
3. Junction of L3 & L2
4. Junction of L2 & L1

Sounds like a plan? That will give 4 RF levels and hopefully more info on where the problem is? There must be some standard figures about the losses through the LPF?

.............and the the nuclear option..........I did think that one option is to parallel up some more BS170's (they arrived this morning) but I am not sure if that is wise when the issue maybe elsewhere?

73
Mike
G0CVZ
  

Re: Toroid winding numbers and measurements

Jim Sheldon
 

I'm still waiting for my 40 meter version (#943) but shipping has resumed again as of yesterday so hopefully by the end of this month.

I have all the proper cores for all the toroids called for in the construction manual, and after reading this thread I decided to wind a set and measure the inductance with my AADE L/C meter which has proven to be quite accurate.

To achieve the proper inductance for L4, I had to use 1 turn less than called for so I wound L2 next - same thing - 1 turn less to get the right inductance for the band.  I wound L1 and L3 with 1 turn less and they came out very close to the called for value.

Now, a caveat - NOT ALL TOROID CORES ARE CREATED EQUAL!  Especially if they are Chinese made - LOL. Depending on the actual permeability of the core, the inductance will most likely vary a bit with the same turns count.  Also I saw something earlier about spread of turns VS inductance.  Close winding gives the MOST inductance and if you spread the turns out you will reduce the inductance somewhat.  Not by much but it will be less with wider spaced turns by the theory of inductors and I confirmed this by measuring each of the above coils.  I first used the called for number of turns and they all measured up to a half microhenry high.  Spreading the turns got it down about .2 microhenry but they still were too high so I removed a turn from each which with close to even spacing over the core got them within .02 microhenry which I think should be close enough.  Just my experience with the set of cores I had on hand.  Your mileage will most certainly vary so don't take this as gospel, just as a point of information and a starting point for troubleshooting.

I'm looking forward to receiving my QCX so I can guit it built and hopefully confirm my observations on the LPF coils.

Jim - W0EB

Re: Power output on 20 meters.

DL3HRT- Karsten
 

It was just trial and error. I realized that I had to spread windings over the whole core. So I decided to remove one turn. I did it with L2 and L3 and have good results now. I stopped at this point and did not change anything else.

What I realized in the thermal images is that the 390pF capacitors heat up.

Regards

Karsten

Re: Power output on 20 meters.

Karl Schwab
 

Ben; keep us posted on your findings with your 20m build as I have one coming in the mail soon!  Tks, Karl


On Wednesday, November 1, 2017 11:26 AM, "Ben Bangerter, K0IKR via Groups.Io" <bwbangerter@...> wrote:


On my just-completed unit, with a 12 V supply (11.6 V on the collector of Q6) I am seeing 1.2 W output (22 V p-p into 50Ω) on key down, rising to 1.6 W after ~ 10 sec (25 V p-p).  I removed C29, the dc blocking cap at the input to the filter and fed my signal generator (AD9850-based homebrew) into the filter at that point and measured the output into a 50Ω load at the input to my TEK 2247A scope.  I saw a loss of 2.32 dB at 14.000 MHz, 2.49 dB at 14.100, and 2.56 dB T 14.200.  This seems excessive.  1.5 W is only a half S unit below the expected 3 W, but with a report of RST 319 it could be important!  Guess I need to work on the lpf a bit.

Ben  -  K0IKR


Re: Power output on 20 meters.

Ben Bangerter, K0IKR
 

On my just-completed unit, with a 12 V supply (11.6 V on the collector of Q6) I am seeing 1.2 W output (22 V p-p into 50Ω) on key down, rising to 1.6 W after ~ 10 sec (25 V p-p).  I removed C29, the dc blocking cap at the input to the filter and fed my signal generator (AD9850-based homebrew) into the filter at that point and measured the output into a 50Ω load at the input to my TEK 2247A scope.  I saw a loss of 2.32 dB at 14.000 MHz, 2.49 dB at 14.100, and 2.56 dB T 14.200.  This seems excessive.  1.5 W is only a half S unit below the expected 3 W, but with a report of RST 319 it could be important!  Guess I need to work on the lpf a bit.

Ben  -  K0IKR

Re: Power output on 20 meters.

 

Hi DL3HRT, your name would be good. So why take 1 turn from L1 and L2 but not L3, L3 is part of the LPF also, just curious. I would think that if L2 is high in inductance and attenuating the output that L3 would be the same. I have the same low output on my 20 meter QCX, (1.6 watts), so I would like a more definitive solution to figure out exactly what to do as I don’t want to hack my board up experimenting with different things. Thanks for your help.

Joel 
N6ALT

On Nov 1, 2017, at 2:37 AM, DL3HRT <dl3hrt@...> wrote:

Hi all,

I did some optimization on the low pass filter. Finally I had to remove 1 turn from L2 and 1 turn from L3. Power output is as expected now.

I recorded some thermal images with my Seek Reveal Pro. The QCX was running in WSPR-beacon mode with almost continuous transmission. The BS170 heated up to almost 100°C. I think that is safe without heatsink.
<DL3HRT _ BS170 heating.PNG>

<DL3HRT _ 20m_QCX _ output power.png>

Re: Toroid winding numbers and measurements

 

Scrap that... with headphones plugged in those configuration items are now working, though it doesn't make a nice pure sound on 20m but a loud pulsing sound. We'll get there, I should just have stuck to making it 30m only :-)

Re: Toroid winding numbers and measurements

 

Sorry I stand corrected, n00b's pay not attention! Follow the manual... it does say if the power is low, remove a turn or two...
Now, having done everything at once... new problem: when I turn on and go to BPF menu I get only "1" for 30m, and "4" for 20m... but I tried to get something that may work on both 20m and 30m, so I wound this time 31:3:3:3 -- priority is to get this working no 30m, I'll try removing 1 to 30, and hope I don't have to make 4, 4, 4 as the BPF does say for 20m it will cover down to 9.6 MHz without too much loss I think. I also removed some turns on L1-L4 also with aim of getting it working for 30/20m.

Not tried on receive antenna yet, but, when I get to do the adjustments of I-Q bal frequency, Phase Lo and Hi frequency, I now have NO bars moving at all! So something appears to be very much amiss... I will do some more checking tomorrow with the help of someone experienced, e.g. connections of those toroids, and various voltages etc but, I'm just wondering if anyone knows that no data at all (no bars, nothing moving) in those adjustment menus may indicate as to a possible fault?

Re: Toroid winding numbers and measurements

Nick Norman
 

Morning all,

This is down to tolerance in the core material, the tightness will make (approximately) 0 difference to the inductance - coverage of the circumference will change it (or is that what you meant by tightness?)
I think the specs are for 80% coverage.
HTH

Nick
M0HGU

--
73 Nick M0HGU

Re: Toroid winding numbers and measurements

Alan G4ZFQ
 


This may be of help to other n00bs as well as those without test gear.
Or it might confuse them more:-) Do I do it this way or as the instructions say?
The design should allow for tolerances, most constructors do not have reliable measuring gear. I agree, most inductors I wind test higher than specified but how many of them will significantly affect performance? (I believe tolerances in the core material are the reason.)

If you find a single critical winding then report it.
I'm not sure that rewinding all in one go is going to be particularly helpful, Hans should have factored in usual tolerances but maybe got one a little too close.

My output power at 12V was just around or a bit less than 1W instead of 3W.
It would be good to know a single reason, if there is one.

Assuming that tighter windings means lower inductance.
Not sure, I've never heard that one, spreading/compressing to fine tune, yes.

73 Alan G4ZFQ

Re: T1 - wire thickness alternative

Jim Kortge
 

On 11/1/2017 3:26 AM, VK5EEE wrote:
I made a mistake on my T1 and it's likely easier to rewind using new wire as otherwise it may be short... instead of the 0.33mm wire can I use 0.3mm wire without detrimental effect?
Yes, the wire size is mostly unimportant.

Secondly, will I need to calculate a different number of windings than the 30, 4, 4, 4 for 30m for the default 0.33mm wire?
No, use the same turns ratio with the smaller wire.  You'll have a bit more space for winding using the smaller wire.  I used #32 on the toroid for my 80-Meter OCX large winding, so didn't overlap the turns.  Worked great!

72 and GL,

Jim, K8IQY