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

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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.

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 :-)

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?

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

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

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

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.

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Hi all,

Nice to be on this reflector.
Received my kits yesterday, and will take advantage of all ideas.

-- 
73 de Gerard, F6EEQ
Loc: JN25MA
UFT 270, REF 27177, RCWC 257
Join the fun at 30cw.net
Enjoy cootie sending : sidewipernet.org

This may be of help to other n00bs as well as those without test gear. Fortunately a ham friend not too far away has an inductance measuring tool. The results are interesting, and I think important and likely to affect others.

My output power at 12V was just around or a bit less than 1W instead of 3W.

I thought that I wound the toroids L1-L4 quite well. I thought they we fairly reasonably tight and well spaced. However, here are the readings I got and the effects of removing turns, all of this applies to 30m:

L1: Required or ideal value 1.1uH. 19 turns actual value was 1.22uH, removing turns I got 18 turns: 1.16uH and 17 turns 1.07uH, I thus had to remove 2 turns.

L3: same as L1, expected value 1.1uH with 19 turns, actual value was 1.32uH. Removed turns, 18 gave 1.24uH, 17 turns 1.18uH and 16 turns 1.08uH. . I thus required 16 turns, removing a total of three turns! This is quite a lot, so I suspect that a "normal amateur-amateur first time toroid winder" doesn't manage to wind it as tight as an expert ie non-amateur amateur. Assuming that tighter windings means lower inductance.

L2: expected value is 1.3uH with 20, actual was measured at 1.6uH. Removing turns, 19 gave 1.34uH, 18 was 1.24, so I settled on 19, thus removing one turn.

L4: expected value is 0.78uH with 14 turns. Mine measured 0.88uH. 13 turns gave 0.86, 12 gave 0.79 and 11 gave 0.76, so I settled on 12 turns, thus removing 2 turns.

So on average, I had to remove 2 turns, or 1-3 turns. I have yet to put them all back and measure the power, but hopefully it'll be closer to the expected 3W at 12V.

Another reason I may have had low power output was that my torroid connections may not have been the best... now the ends are properly tinned and will be properly connected, then let's see!

Hopefully the receiver will sprint back to life once I have redone T1...



L2: expected value 1.3uH. 20 turns actual value was 1.6uH. 19 turns: 1.34uH. Here I had to remove only 1 winding.

L3: same as L1, expected value 1.1uH.

Hello VK5EEE,

0.03 mm diameter difference will make zero measurable or effective
change, in fact it's surprising how little defence the inductance is
with even extreme differences in wire OD for winding coils. You could,
if you could fit the windings on in a similar fashion, use 1.5 mm OD
or 0.5 mm and probably not be able to measure an inductance change
even with good test gear. Start re-winding :)

Wednesday, November 1, 2017

--
Best regards, Chris Wilson (2E0ILY)

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You can use your .3mm wire.? Turns count will stay the same.

Lee, w0vt

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? 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?

Oh, better than that Curt -

at 7am this morning I had an email telling me that my order had been shipped - the pixies must be working double shifts.

I better get back to reading those manuals!

Martin? GW3UCJ.

*-*

--
Martin? GW3UCJ.

Swansea Valley, South Wales? IO81CR

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? 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?

You could also use the AADE Filter Design program (http://w1hue.org/filter.html).

Jean-Claude

You could use the Elsie Filter Design program; the free version can use up to 7 components.

Jean-Claude

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Marc

Very carefully look at that 4 winding coil that feeds the receiver, make sure each winding matches the picture. Any that are backwards would mess up the phasing. If alo this looks good, well, check continuity through each winding. Touch pad to pad, don't touch wire, to see if its really connected. The pots not nulling may be an indication of a problem with this coil.? be patient in debug and repair, this is a key matter.? the end result is amazing, worth the toil.

Curt