Re: Another message for Uwe, DF1UB
AT steamrail.co.uk
At 02-03-19, you wrote:
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On Sat, Mar 2, 2019 at 09:35 AM,
Peter Russell wrote:
hi Peter,
thats all i see peter.russell@...
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Re: Version 5 board 10 meter SSB Spur Test
#ubitx
Sorry Iz, I simply won't have time to run any more tests for now - maybe in several weeks when I finish the big project I'm working on now.? There are others out there that have the capability to do these tests too, maybe one of them could do it and post the results.? We need more independent, non biased tests from others anyway.
Jim
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Re: Version 5 board 10 meter SSB Spur Test
#ubitx
Thanks Jim, I really appreciate your independent tests. Previous versions, at least ver. 3 had a serious SSB spur issue especially on the 21mhz band, may you perform if possible a test, let's say at 21.3mhz SSB?
Il 02/mar/2019 12:43, "Jim Sheldon" < w0eb@...> ha scritto: Got a single/two tone audio generator in from Pacific Antenna yesterday.? Took about 1.5 hours to build it and check it out.? Made up a cable to go to the microphone input on the uBITX and set the spectrum analyzer up as close to what I was told when I asked Allison for the parameters.
the 16 MHz spur is there and still out of spec by a little.
I had a little less than 50 millivolts Peak to Peak audio at 1 KHz input to the mic jack, 2.6 watts output power (adjusted audio to jus below where output stopped increasing and backed it off until it dropped about 1 dB.
First picture is baseline trace with no signal being transmitted and the 2nd is the actual measurement.
Test frequency was 28.400 MHz.? 2 spurs, 1 at 16.64, 1 at 17.34 and a third spike not too far below the 28.4 carrier frequency that I ignored for this test as I don't know what it is caused by.
I'm primarily a CW operator so when it comes to SSB measurements, I'm a complete novice.? I did do the same check using CW on the same frequency and there were no spurs I could find.
If anyone wants further SSB testing, they will have to do it themselves as I need the spectrum analyzer for a completely other project and a totally different test setup.
Jim Sheldon, W0EB
TSW Project Coordinator
 
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Version 5 board 10 meter SSB Spur Test
#ubitx
Got a single/two tone audio generator in from Pacific Antenna yesterday.? Took about 1.5 hours to build it and check it out.? Made up a cable to go to the microphone input on the uBITX and set the spectrum analyzer up as close to what I was told when I asked Allison for the parameters. the 16 MHz spur is there and still out of spec by a little. I had a little less than 50 millivolts Peak to Peak audio at 1 KHz input to the mic jack, 2.6 watts output power (adjusted audio to jus below where output stopped increasing and backed it off until it dropped about 1 dB. First picture is baseline trace with no signal being transmitted and the 2nd is the actual measurement. Test frequency was 28.400 MHz.? 2 spurs, 1 at 16.64, 1 at 17.34 and a third spike not too far below the 28.4 carrier frequency that I ignored for this test as I don't know what it is caused by. I'm primarily a CW operator so when it comes to SSB measurements, I'm a complete novice.? I did do the same check using CW on the same frequency and there were no spurs I could find. If anyone wants further SSB testing, they will have to do it themselves as I need the spectrum analyzer for a completely other project and a totally different test setup. Jim Sheldon, W0EB TSW Project Coordinator  
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Re: How to get 5W on 10m?
I replaced the cap at the emitter of Q90 with a 470pf instead of the 0.1nF. In the meanwhile I replaced the bifilar antenna wire with a short coax. Output power on 40 marginally diminished from 15 to 12.5w about. The power on higher bands marginally increased from nearly 2w to nearly 2.5w. But the 'instability' issue with full throttle noise on SSB on 10m has disappeared and I can also not attenuate the Vogad output. Overall I am happy with this one component replacement.
Il 01/mar/2019 08:40, "iz oos via Groups.Io" <and2oosiz2= [email protected]> ha scritto: Thanks for all the replies. According to the old schematics of my ver. 3 ubitx C81 should be 0.1nF, so I will see what changes with a 470pf as suggested by Farhan.
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Re: Another message for Uwe, DF1UB
On Sat, Mar 2, 2019 at 09:35 AM, Peter Russell wrote:
hi Peter,
thats all i see peter.russell@...
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Another message for Uwe, DF1UB
I just sent the following email to your jento email address and it bounced.....
OK Uwe, let's try again!
my PayPal details are my email address.....
peter.russell@...
As soon as PayPal tell me you have paid, th SMDs will be in the post.
Let's hope this email gets through.
Peter
---
This email has been checked for viruses by AVG.
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Re: Spectrum test on the second V5 build SURPRISING results
#ubitx
Jim,
What I find is each board is different in behaviour. One on my bench now maxes out at 8W on 40M and any more than
4W on 80M results in bad spurs.
Raj
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At 01-03-19, you wrote: I got my 2nd Version 5 uBITX in the other day. I took the time to build it into a nice case and very carefully wired everything up. I actually made up a shielded "digital" cable using the regular wires and encased them in the silver plated shield from some double shielded RG58 sized, Teflon insulated Coax. I connected the yellow ground wire to the "digital' connector end of the shield and also used another short piece of the yellow ground wire connected between the encoder end of the shield and the encoders ground or "C" pin. The shield only extended to just short of the Encoder and the Key lines and PTT line remained unshielded from that point on.
I built it into the same eBAY case that Jack and Al used for their JackAl builds. I did make an aluminum front panel to make it easier for me to mill out the display window and painted it with 3 coats of Testors blue glossy lacquer. The original case bottom, top and panels were heavily painted and not good candidates for grounding so I removed the paint around all holes in the bottom and steel rear panel. I also grounded the panels using solder lugs and some more of that silver plated braid to a single point ground under one of the standoffs the V5 board was mounted on using star washers and tightened them as far as I could without stripping or breaking the screws. I did make up a double shielded, miniature Teflon coax for the RF output cabling. All other wiring was done as twisted pair or twisted multiple pair wires (including those inside the shield).
I just ran the same exact spectrum test I did on the first Version 5 I received from several weeks ago (the first one was in an open frame aluminum chassis and I did use the twisted pair RF connection between the uBITX board and the SO-239 on the rear panel -- I posted those spectrum data in a previous thread and wasn't really happy with the results.
Here is a picture of the 2nd build and the spectrum plots I got using the exact same setup as for the first version. (I saved the spectrum analyzer setup as a "Preset" so I could, as closely as possible, duplicate the previous tests. BTW I did forget to run the test on 60 meters, sorry about that.
Plots are offered here without further comment for you to make your own conclusions.
Jim Sheldon, W0EB
TSW Project Coordinator and Test Engineer
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Re: Spectrum test on the second V5 build SURPRISING results
#ubitx
Well on qsk funny thing I have some of these rigs, a restored hw16 that was a novice rig of mine, a qcx and a K2. Why am I using the ubitx so much on cw one could question my sanity. I learned a lot about k2 kpa100 qsk when I had damaged it. Discovered it uses a xtal oscillator to drive a chain of diodes to create -120 volts to bias the switching diodes. I was playing with Jim a bit who says he doesn't do ssb with his snazzy ubitx.
73 Curt
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Cool Jon,
Looking at the schematic, I think you could just use a DMM diode check function across both.? Measuring the voltage across them with the rig on should give a similar result I think.
Cheers,
Mark.
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Re: Spectrum test on the second V5 build SURPRISING results
#ubitx
Yeah, neat little rig - had one myself with the HG-10A VFO and I loved it. ?QSK with the uBITX as it stands right now will be awful hard on the relays if you shorten the T/R delay to almost zero (it is possible as I've done it) in software. ?Problem other than wear and tear on the relay switching at speed is also the awful clicking of the relays and I really don't want to listen to that. ?You'd have to totally revise the LPF switching to pin diodes or something of the sort to achieve any kind of decent QSK. ?
If you want QSK, buy one of Hans Summers' QCX rigs or one of his QSX's when he finally gets the multi-band version on line for sale.
Me, when I want real good CW operating, I just use my Elecraft K3S as that will do QSK to well over 60 wpm.
Jim, W0EB
------ Original Message ------
Sent: 3/1/2019 9:16:21 PM
Subject: Re: [BITX20] Spectrum test on the second V5 build SURPRISING results #ubitx
Ha, my very first radio, Heathkit HW 16, did effortless QSK. ? it was a joy to operate as a Novice
On Mar 2, 2019, at 04:45, ajparent1/KB1GMX < kb1gmx@...> wrote:
Curt,
Try backing off the power if the drive is excessive the harmonics will fall at a much
greater rate than the power.
As to QSK, change the wiring for the low pass relays so the do not switch for TX to
RX.? FIne a way to replace K3 with a very fast realy or electronic switching.
The replace K1 (the other side of the board) and replace with transistors to switch
DC from RX and TX.? Then you can consider QSK.? Oh and fix all the clicks and
pops without caps to delay the switching.? ? The current arrangement (prior to v3
through 5) you have no less than two relays operating sequentially (K1 triggers
K3 minimally) and relays are slow and two sequentially are slower.
If you are going to do all that might as well add switching for a good Cw bandwidth
filter.? That will spoil you even more.
I have radios (mostly Tentec) that do QSK and its hard to deal with the clunky
TS440S/at, FT817, and the Tempo-One with all the relays clacking.? You do get
spoiled.
My 1W, QCX, and SB (1 and II) all do QSK very well without pops and clicks.
So it can be done but many radios retrofitting it would be painful.
Allison
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Firstly, Pat: please bear in mind that Farhan's English, while very good and probably the best of the 'team' in India, is a second language.
Now, Pat: Fourth bullet sentence? IS the first, not another. Not everyone wants to use the supplied volume pot, and what they have or want to use may not have a switch. Even those who do or have may not wish to use a/the switch.
Fifth bullet sentence means that in *any* case the switch is not needed here. With no power to PWR1 (the 'main' connection), the PA gets no volts to bias on the FETs so the Power Amplifier is not active: it may be fed separately, bypassing the switch - and even (with care, read on...) greater Voltage therefore power output! PA PWR is required in some form if you want or need to transmit!
The Raduino is supplied with 12V in parallel with PWR1 as depicted, but it is recommended (from experience otherwise posted here in the Group) that a 'dropping' resistor (12 ohms, 3 Watts) be put in series with the positive line to dissipate some of the power the on-board regulator must deal with - too keep it cool and avoid the possible need for a heatsink. Others have recommended retro-fitting a capacitor (470uF electrolytic, observe polarity!) 'after' that resistor to lessen/eliminate audio clicking often found as frequency is changed. I had 5.1 ohms 3W and 220uF to hand (scrapped from a switch-mode power supply), and they serve quite nicely.
Hope that helps
73
Dex, ZL2DEX
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Re: Spectrum test on the second V5 build SURPRISING results
#ubitx
Ha, my very first radio, Heathkit HW 16, did effortless QSK. ? it was a joy to operate as a Novice
On Mar 2, 2019, at 04:45, ajparent1/KB1GMX < kb1gmx@...> wrote:
toggle quoted message
Show quoted text
Curt,
Try backing off the power if the drive is excessive the harmonics will fall at a much
greater rate than the power.
As to QSK, change the wiring for the low pass relays so the do not switch for TX to
RX.? FIne a way to replace K3 with a very fast realy or electronic switching.
The replace K1 (the other side of the board) and replace with transistors to switch
DC from RX and TX.? Then you can consider QSK.? Oh and fix all the clicks and
pops without caps to delay the switching.? ? The current arrangement (prior to v3
through 5) you have no less than two relays operating sequentially (K1 triggers
K3 minimally) and relays are slow and two sequentially are slower.
If you are going to do all that might as well add switching for a good Cw bandwidth
filter.? That will spoil you even more.
I have radios (mostly Tentec) that do QSK and its hard to deal with the clunky
TS440S/at, FT817, and the Tempo-One with all the relays clacking.? You do get
spoiled.
My 1W, QCX, and SB (1 and II) all do QSK very well without pops and clicks.
So it can be done but many radios retrofitting it would be painful.
Allison
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Re: Spectrum test on the second V5 build SURPRISING results
#ubitx
If on CW we are truly just using a square wave for a signal then Jim is correct, the LPF for 80m is just not sufficient. The 3rd harmonic on a square wave is what, about 10db below the fundamental? So we are seeing some rejection but it just isn't sufficient. The same thing applies to 40m. I suppose it could be the relays letting some of the 3rd harmonic leak by in both cases. tim ab0wr On Fri, 01 Mar 2019 18:32:31 -0800 "ajparent1/KB1GMX" <kb1gmx@...> wrote: Tim,
You forget the drive to the amp is the keyed CW output of the 5351
which is by default a square wave.? If you don't get? square waves
from the amp that would indicate a very severe high frequency roll
off.
Push pull if balance is good tend to have low second and even order
harmonics. Typical push pull tend to have third and higher order odd
harmonics. as its not balanced for that.? That assuming the drive
signal is not square to start with.
So yes your right, the 3rd harmonic is earlier in the chain, the
source.
The other half is if you getting more than 10W at 80m and 2-3W at 10m
overdrive is accentuating it.
We have been through all this last summer.? Likely not less than 500
messages about this and related.
Allison
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Re: Spectrum test on the second V5 build SURPRISING results
#ubitx
Curt,
Try backing off the power if the drive is excessive the harmonics will fall at a much
greater rate than the power.
As to QSK, change the wiring for the low pass relays so the do not switch for TX to
RX.? FIne a way to replace K3 with a very fast realy or electronic switching.
The replace K1 (the other side of the board) and replace with transistors to switch
DC from RX and TX.? Then you can consider QSK.? Oh and fix all the clicks and
pops without caps to delay the switching.? ? The current arrangement (prior to v3
through 5) you have no less than two relays operating sequentially (K1 triggers
K3 minimally) and relays are slow and two sequentially are slower.
If you are going to do all that might as well add switching for a good Cw bandwidth
filter.? That will spoil you even more.
I have radios (mostly Tentec) that do QSK and its hard to deal with the clunky
TS440S/at, FT817, and the Tempo-One with all the relays clacking.? You do get
spoiled.
My 1W, QCX, and SB (1 and II) all do QSK very well without pops and clicks.
So it can be done but many radios retrofitting it would be painful.
Allison
|
Re: Spectrum test on the second V5 build SURPRISING results
#ubitx
Tim,
You forget the drive to the amp is the keyed CW output of the 5351 which is by
default a square wave.? If you don't get? square waves from the amp that would
indicate a very severe high frequency roll off.
Push pull if balance is good tend to have low second and even order harmonics.
Typical push pull tend to have third and higher order odd harmonics. as its not
balanced for that.? That assuming the drive signal is not square to start with.
So yes your right, the 3rd harmonic is earlier in the chain, the source.
The other half is if you getting more than 10W at 80m and 2-3W at 10m overdrive
is accentuating it.
We have been through all this last summer.? Likely not less than 500 messages
about this and related.
Allison
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Re: Spectrum test on the second V5 build SURPRISING results
#ubitx
Odd order harmonics are typical of a square wave. f, 3f, 5f, ..... This tells me somewhere in the amplifier chain there is a stage that is being overdriven significantly and the output of the amp is flat-topping, i.e. creating a psuedo-square wave by lopping of the top and/or bottom of the signal it is amplifying. The second harmonic is usually created by an amplifier that is driven outside it's linear operating range but not driven into flat-topping. In essence the operating line looks a little like a parabola. The equation of a parabola has a squared term which, when the trig is done reduces to a cos(2wt) term in the output. It may be that the 2nd harmonic is generated in the final stage and adjusting the bias is keeping stage more linear. But if it isn't changing the 3rd harmonic then I would guess it is being generated somewhere further back in the amp chain. It would be interesting to see if reducing the drive potentiometer reduces the 3rd order harmonic. tim ab0wr On Fri, 01 Mar 2019 12:27:26 -0800 "Jim Sheldon" <w0eb@...> wrote: Ok Ashhar,
I did your bias change while watching the 2nd and 3rd harmonic on 80
meters.? Sorry, but changing the bias reduces the heck out of the 2nd
harmonic but has very little effect on the third.? The attached
picture shows the final results.
I now have the tone generator kit, and after I finish writing this
I'll start building it so I can do the single and two tone tests on
the rig.
Jim, W0EB
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Thanks! And the same with the Raduino? And which tab on the volume control is the switch?
On Fri, Mar 1, 2019 at 2:56 PM Don, ND6T via Groups.Io <nd6t_6= [email protected]> wrote: Pat,
Just wire the PA power to the switch in addition to the rest of the radio. It was intended as a means to supply the RF power amplifier with a higher voltage if desired. That also makes it easier to monitor how much current that Power Amplifier is using (great for setting the bias current). Nothing magical. Just wire it so that it is switched and protected like the rest of the transceiver. -Don
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Re: Spectrum test on the second V5 build SURPRISING results
#ubitx
That's correct and I knew that. ?I only ran the test because Farhan asked me to. ?I was quite surprised that he would be thinking the adjustment would change the third. Harmonic.
After I posted those results I re-adjusted the bias properly and even harmonics are now in the noise floor as they should be.
Jim
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On Mar 1, 2019, at 7:34 PM, jim via Groups.Io < ab7vf@...> wrote:
Bias on Push-pull finals will NOT change 3rd harmonic ..Balanced the 2nd harmonic will go away (mostly)...Odd harmonics won't null, even ones will
Jim
On Friday, March 1, 2019, 12:34:22 PM PST, Gordon Gibby < ggibby@...> wrote:
Thanks for running that test! Sad to say that the bias and drive did not cure the issue ??
I am trying to raise finances to go buy a spectrum analyzer myself, and then I¡¯ll actually put a bit of miniature coax to the outboard relay board that I built and find out if my early successful ?tests are confirmed. ?
Certainly the filters can always be improved if that is the issue. ?
Gordon
On Mar 1, 2019, at 22:30, Jim Sheldon < w0eb@...> wrote:
Yes, I know Gordon, but changing the bias and dropping the drive did not have enough effect on the harmonics on 80/40 to eliminate the problem.? The lowest LPF needs a sharper upper cutoff frequency in order to get rid of them.? Beyond my expertise.
Jim
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Re: Nextion 2.4 from Amazon
It appears to have the correct attributes, and, I'm happy with my Itead 2.8" screen.? Happy building!
Ted
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Raj vu2zap
Jim Sheldon
Ted