Date   

Re: #qcx #problem Radio newbie and QCX large audio hum... #qcx #problem

Alan de G1FXB
 

Paul,
I wouldn't try to attack multiple issues all at once.
It sounds from your description the build used to work better than it does now, did you ever get it fully aligned as per instructions?
If not, perhaps spend some time looking over the soldering and making sure the component leadouts are not touching something adjacent, the body of he volume pot has being reported before....
Perhaps spend some time checking the  components are in the right places, miss reading the colour code on resistors easy.


If nothing is apparent concentrate one at a time, start at the beginning of the circuit and work forward.
(If you can make no progress after giving it "a good go", then fair comment go to the next issue.
(Sometime a fault interacts and you are convinced a fault is in one particular area, when it's actually elsewhere...))

Can you take some good photo's of the PCB board, both sides & if you have doubts over  5 or 6 turns on T1 a good enough photo so others can count the number of at least the "small windings"?
I think Hans commented he erred on specifying perhaps too many turns, as its easier to remove rather than add wire.
Also in the front end, C1 can be damaged by the application of excessive heat while soldering. On close inspection does the body or looking through the opaque top does anything look melted?.
Does the adjuster feel smooth when turned all the way around?
(the fixed / movable vanes are separated by polythene plastic dielectric that keeps them separate.)


Alan

On 13/12/2018 12:54, KB3USG wrote:
Hey everyone,

Quick recap--smooshed the volume pot by overtightening it, got "zero"
output, and when tried to unsmoosh the pot, had lots of audio hum. My
BPF was not peaked, and I was going to get back to that as well as check
voltages around the board and compare them to values in the (EXCELLENT)
manual. This radio is being hooked up to a makeshift magnetic loop
antenna (based on G4ILO's (SK) Wonder loop).

Ok, so still could use some help, and thank you again to everyone who's
been reading my messages and to those offering some help and
encouragement.

First things first--replaced the pot with a 10k log-taper pot with a 10k
fixed resistor across the outer pins. I think that I may have wired it
in backwards as it operates in the other direction... livable for now.

The audio hum is a lot better, but not absent. As this really is my
first real radio, I'm still trying to figure out what "normal" is. It
does seem better, at least.

Second thing, peaking the BPF--In the midst of all this, I seem to have
one from the "add more turns" to "remove more turns", but I _think_ that
I made a mistake and didn't have a dummy load connected at one point
(but had my makeshift loop connected). In any case, I have been extra
careful to also try to peak into the dummy load, and have gone from 5
extra turns to removing 6 turns from the starting configuration.

Now, moving the capcitor doesn't seem to have any effect.

I _believe_ that I have made electrical connections, and I can hear some
locally strong signals, so at least the "you need to burn the insulation
off" part seems to have been done (right?). Here's where I could use
some help diagnosing this--why would the capacitor no longer effect the
peaking operation? I'm getting concerned that I'm damaging the board.

Relatedly, I did have some weird behavious with the other peaking
operations where the low audio setting would suddently jump to a very
high value and then jump back. Is it possible to damange the multi-turn
pots?

One last question (well, for this message, at least): I realize now that
my meansurements of T1, pin 5, 6, 7, 8 measure 1.8x volts (x=1,3)
instead of the 2.36 listed in the manual. I measure using the onboard
DVM. It's possible that instead of the five turns for the rest of
windings on T1 that I may have, in fact, six--will this cause a lot of
problems? Would this difference help explain anything else described in
here?

So, I'm really confused that I'm not having any effect on peaking the
BPF (and the other symptoms). I'm a real newbie on all this (first real
radio) so things that you might think "obvious" might not be for me, so
I would appreciate any elmering that anyone is willing to give :) I'm
afraid that I'm ruining my radio instead of making it better. I'm dying
to get this one working (and just might have to build another!)

Thanks for any help,
Paul
KB3USG


Re: #qcx #problem Radio newbie and QCX large audio hum... #qcx #problem

KB3USG
 

Hey everyone,

Quick recap--smooshed the volume pot by overtightening it, got "zero"
output, and when tried to unsmoosh the pot, had lots of audio hum. My
BPF was not peaked, and I was going to get back to that as well as check
voltages around the board and compare them to values in the (EXCELLENT)
manual. This radio is being hooked up to a makeshift magnetic loop
antenna (based on G4ILO's (SK) Wonder loop).

Ok, so still could use some help, and thank you again to everyone who's
been reading my messages and to those offering some help and
encouragement.

First things first--replaced the pot with a 10k log-taper pot with a 10k
fixed resistor across the outer pins. I think that I may have wired it
in backwards as it operates in the other direction... livable for now.

The audio hum is a lot better, but not absent. As this really is my
first real radio, I'm still trying to figure out what "normal" is. It
does seem better, at least.

Second thing, peaking the BPF--In the midst of all this, I seem to have
one from the "add more turns" to "remove more turns", but I _think_ that
I made a mistake and didn't have a dummy load connected at one point
(but had my makeshift loop connected). In any case, I have been extra
careful to also try to peak into the dummy load, and have gone from 5
extra turns to removing 6 turns from the starting configuration.

Now, moving the capcitor doesn't seem to have any effect.

I _believe_ that I have made electrical connections, and I can hear some
locally strong signals, so at least the "you need to burn the insulation
off" part seems to have been done (right?). Here's where I could use
some help diagnosing this--why would the capacitor no longer effect the
peaking operation? I'm getting concerned that I'm damaging the board.

Relatedly, I did have some weird behavious with the other peaking
operations where the low audio setting would suddently jump to a very
high value and then jump back. Is it possible to damange the multi-turn
pots?

One last question (well, for this message, at least): I realize now that
my meansurements of T1, pin 5, 6, 7, 8 measure 1.8x volts (x=1,3)
instead of the 2.36 listed in the manual. I measure using the onboard
DVM. It's possible that instead of the five turns for the rest of
windings on T1 that I may have, in fact, six--will this cause a lot of
problems? Would this difference help explain anything else described in
here?

So, I'm really confused that I'm not having any effect on peaking the
BPF (and the other symptoms). I'm a real newbie on all this (first real
radio) so things that you might think "obvious" might not be for me, so
I would appreciate any elmering that anyone is willing to give :) I'm
afraid that I'm ruining my radio instead of making it better. I'm dying
to get this one working (and just might have to build another!)

Thanks for any help,
Paul
KB3USG


Re: Side cutters #tool

Alan de G1FXB
 

Not cheap, but a Lindstrom side cutter nearly 40 years old

Used to cut not as a substitute for a pair of pliers........


Alan

On 13/12/2018 09:32, Mike Bowthorpe wrote:
Hi Paul

You do get what you pay for - I prefer Lindstrom. 

Get one for Christmas?

73
Mike
G0CVZ


Re: Side cutters #tool

David Wilcox K8WPE
 

I have used these for years, but if you cut any iron, steel, or other harder than copper wire throw them away. I have gone through five or six of them in the last 20 years...... but I still love them and pay $18.00 for them at a local hobby store.

TRACK CUTTER -- FOR HO, N & Z RAIL https://www.amazon.com/dp/B015RE67R8/ref=cm_sw_r_cp_tai_bbKeCbK1EBMWX

David J. Wilcox K8WPE’s iPad

On Dec 13, 2018, at 6:01 AM, Patrick York <pyork@comporium.net> wrote:

Xcelite 170M

https://www.amazon.com/Xcelite-General-Purpose-Shearcutter-Diagonal/dp/B0002BBZIS?th=1

73,
Patrick KF4LMZ



Re: Side cutters #tool

Patrick York
 


Re: Side cutters #tool

William Hill
 

On 13/12/2018 09:32, Mike Bowthorpe wrote:
You do get what you pay for - I prefer Lindstrom.
Another vote for Lindstrom.

73, M1BKF


--
Red to red, black to black, switch it on, but stand well back.


Re: Even if Si5351A is replaced, it becomes "si5351 ERROR".Why?

Alan de G1FXB
 

Double check the replacement IC designation is correct?

There are custom variants of this IC
See Note 1/. from another recent thread

https://groups.io/g/QRPLabs/message/29055


Alan

On 13/12/2018 00:49, kdsmkobay@... wrote:
Even if Si5351A is replaced, it becomes "si5351 ERROR".Why?


Re: QCX a Phenomenal Transceiver

Alan de G1FXB
 

There are brief details of a 6 band QCX made possible by creation of Plug-in BPF & LPF modules in the construction gallery by Andreas DM5MU
http://qrp-labs.com/qcx/qcxgallery.html

Alan


On 12/12/2018 23:32, John Kirby wrote:

Kees,

Thanks to Hans the QCX is an excellent learning platform

To cover three bands ..
With few exceptions I built and aligned a 30m QCX to specks...

1) I did not install LPF on QCX PCB because you will need different LPFs for different bands and Hans has several (to include switchable) QRPLabs options
2) I installed T1 on bottom of PCB for ease of solder/unsolder...ing, turns out no fiddling was required for 40, 30, 20
3) C1 requires fiddling to cover three bands (two bands no problem) and of course must be tweeked each band changeI I have two variable caps on PCB ... Note too the variable caps supplied with kit do not tolerate much heat and/or fiddling I destroied several and ended up using two variable ceramic units
4) I fiddled with L4 enough to determine I needed a better understing of class E amplifier "efficency" so  L4 = STET for 30m

Remember too based on much discussion here on the list... different LPFs produce different RF output levels, fiddling with LPFs can be a delightful learning experience

Replacing the onboard audio filter with different designs and bandwiths was an OUTSTANDING learning experience

72 73
John
N3AAZ


Re: Side cutters #tool

Mike Bowthorpe
 

Hi Paul

You do get what you pay for - I prefer Lindstrom. 

Get one for Christmas?

73
Mike
G0CVZ


Re: U3s Frequency drift / stability #u3s #wspr #problem

JC - EA2KV
 

Hi Bruce,
Tks.  Will try with Park freq.
The heat sink is already installed on the crystal and the U3s is inside his black Al box.
The point is that the drifting seems never ending even outside RX windings.


Hi Curt,
Tks to you too.  The Unit has been running during three days. ,means lots of calibration cycles.
I even tried with Cal Step Time: 10 - 240,   or 30 - 240, you know.... faster freq ref change but never findind a point arround where to be +/- stable inside the RX window.

 73 - ea2kv


Re: Shack clock contrast adjustment

M0RON
 

You fit either the wire jumper or a resistor but not both. 
Andy
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.


Re: U3s Frequency drift / stability #u3s #wspr #problem

Alan G4ZFQ
 

I'm only working on WSPR mode.  After certain time (depending on the Cal steep config.) the TX freq gets out of the RX window; What Im missing?  thanks for any light you may give.
Frame Start: 10 - 02
Cal Step Time: 10 - 120

José,

Tell us your full configuration. What TX frequencies?
How many active frames, number of transmissions in 10 minutes?
Is it really doing a calibration cycle?

73 Alan G4ZFQ


Re: GPS and frequency stability with a U3s

Alan G4ZFQ
 

Does the GPS correct the reference frequency in a U3s?
John,

Yes.
I noticed my
frequency drifting a bit in WSPR reports with the standard 27 Mhz crystal board. Yes I do park at 150 Mhz. The main reason I bought the GPS kit was for precision frequency and frequency stability so I don't understand.
But not continuously
I have done quite a of searching here but haven't seen this question addressed.
I'm sure it is all described, the calibration takes place after the TX.
Drift then can occur. http://www.qrp-labs.com/ultimate3/u3s.html AN01

73 Alan G4ZFQ


Re: Even if Si5351A is replaced, it becomes "si5351 ERROR".Why?

Alan G4ZFQ
 

Even if Si5351A is replaced, it becomes "si5351 ERROR".Why?
I think you need to tell us more.
Why was it replaced, are you sure it was done properly?

73 Alan G4ZFQ


Re: Shack clock contrast adjustment

KEN G4APB
 


it is just to accommodate the different spacing between fitting a link header or a resistor. The tracks are linked/

Ken G4APB


Re: Side cutters #tool

Al Sines
 

Paul,

Buy a good quality tool from Xcelite and you should be fine. I own several Xcelite side cutters for years and they perform well. Just make sure you only use them for small gauge wire or you will damage them. 

The other pair I have and really like is a CHP-170 side cutters. They are made in Italy and are very nice quality. Hakko sells them as P/N CHP-170. You can find them on Amazon https://www.amazon.com/Hakko-CHP-170-Micro-Cutter/dp/B00FZPDG1K/ref=mp_s_a_1_2?ie=UTF8&qid=1544679557&sr=8-2&pi=AC_SX236_SY340_QL65&keywords=chp-170+micro+cutter&dpPl=1&dpID=414t7uLh8KL&ref=plSrch

I have been using these for several years now and they perform well. 

73, Alan
W3AL



On Dec 12, 2018, at 20:08, turnsouth via Groups.Io <turnsouth@...> wrote:

Have my 40m QCX ordered and am waiting (somewhat) patiently for the status to switch from "complete" to "shipped", but in the mean time I want to ask a tool question from other builders.

What is your favorite brand / type of side cutters for trimming leads after soldering?

I usually just pick up a decent pair of 4-5 inch ones with a small head. They work well for a while, but after a few projects the blades end up getting notched near the tip from all the trimming making them more difficult to use, and in need of replacement. Just wondering if anyone has any recommendations for a good long lasting pair of side cutters.

Thanks
Paul


GPS and frequency stability with a U3s

John Canfield <bucket@...>
 

Does the GPS correct the reference frequency in a U3s? I noticed my frequency drifting a bit in WSPR reports with the standard 27 Mhz crystal board. Yes I do park at 150 Mhz. The main reason I bought the GPS kit was for precision frequency and frequency stability so I don't understand. 

I have done quite a of searching here but haven't seen this question addressed. 

73 de John WB5THT 


Even if Si5351A is replaced, it becomes "si5351 ERROR".Why?

kdsmkobay@...
 

Even if Si5351A is replaced, it becomes "si5351 ERROR".Why?


Side cutters #tool

turnsouth@...
 

Have my 40m QCX ordered and am waiting (somewhat) patiently for the status to switch from "complete" to "shipped", but in the mean time I want to ask a tool question from other builders.

What is your favorite brand / type of side cutters for trimming leads after soldering?

I usually just pick up a decent pair of 4-5 inch ones with a small head. They work well for a while, but after a few projects the blades end up getting notched near the tip from all the trimming making them more difficult to use, and in need of replacement. Just wondering if anyone has any recommendations for a good long lasting pair of side cutters.

Thanks
Paul


Re: U3s Frequency drift / stability #u3s #wspr #problem

@CurtisM
 

Jose

Another aspect is needing several calibration cycles before the PLL is well calibrated.  in my case it was 5 or more. Since then my U3S is sufficiently stable from a cold start, with none of the advanced features you have. Do try parking up at vhf as suggested. I did not learn enough about this in the manual, but from messages here. Somewhere there is a message from Hans suggesting higher cal parameters for a newly installed unit or controller. It would be nice to have this instruction in the manual.

Curt