I put a ubitx in a plastic vcr case Lined the case with aluminum foil tape. Figuring that overlap in the tape would be sufficient to connect the pieces capacitively to one another.
Vic, do you do anything special to fix the inductors in place in a mobile application? Have you had any problems running mobile. My sedentary bitx radios surely don't have the adventurous lifestyle of yours.
73
Dave
k0mbt
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Re: Efficient Class E generation of SSB Using the EER Method
I have about 5 papers on this some really old.
Bottom line, it sorta works.
Allison
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Re: Efficient Class E generation of SSB Using the EER Method
This method is on theory. Hans and O discussed it last time we met. It was also used on a few early OSCAR transponders. a paper to this effect is listed in EMRFD.
Jerry
Be careful what you spread. Of course feeding accurate info into a D to A converter can produce the voice, and with some predistortion correct for non linearity in the power stages. But modulating a PLL, that sounds like dreadful analog complexity. I suggest emailing an expert on PA designs, like Paul NA5N versus a debate. Anything that seems real can be tried, but this seems a bit unwieldy to me, but I don't have expertise in modulation.
Curt
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Re: Assembled Ubitx 4.3 with 3.5 Nextion
Gday mate,Would you pack and ship it to Western Australia. ?I don't know what is worth for the unit and for postage,perhaps $180 for both. Paypal is good for me. I have bought a kit myself ?but am a novice so woulike one I know works. Cheers Ross?
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In all my years in amateur radio I've only had one person take advantage of me. I had a set of PC boards made for the old Norcal 40a project and had several extras. One guy asked for a board which I promptly sent out, asking for reimbursement of the postage. He never paid. Apart from that I've had hundreds of experiences with other hams that remind me that we are a unique set of people. Other hams have treated me with kindness and understanding, and are always generous with their time. I hope that I have behaved in the same way to others.?
So sure, maybe there are a couple of jack-wagons out there but they are in the minority. Don't give up! Keep the ham spirit alive, despite the occasional negative experience. I for one will not let them spoil this wonderful community for me. I will continue to be trusting of others and generous with my time. It's the only way that it will continue into the future.?
And to the huge list of guys who have helped me over the years, THANK YOU!?
To keep this at least partially on topic, when I receive the Ebay inductors I'll be able to send 10 in an envelope for $1 to hams inside the USA ($0.55 postage, $0.42 parts, $0.03 envelope). I'll take names after they arrive if anyone is interested.?
73 Mike M. KU4QO
On Sun, Feb 3, 2019 at 12:33 AM Glenn < glennp@...> wrote: and another example, I sent Gerber files to a guy who never even bothered to acknowledge receipt or the time spent producing them as anybody who produces PCB artwork will know is not trivial. Manners seem to have disappeared over time..
vk3pe
._,_
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Hmmm my email address got obscured in that post.. ok, so it's ei4gnb @ yahoo . com
(my call at yahoo.com)
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https://www.ebay.com/itm/300pcs-inductor-coil-smd-680nH-2-4R-size-1210-B82422A3681K-EPCOS-/142986858930
I have hundreds of these here if anyone localish needs them i can slip some in an envelope.. email me ei4gnb@...
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Re: Spurs/Harmonics fixes for v4 based on v5 board design?
Raj,
Thank-you for your information.
All,
I have done a number of tests using the SDRPlay RSP2 as a spectrum analyzer and verified that the BFO setting will impact how much of the "carrier" shows up in the output.? I originally had the BFO set for 11996800 and noted that there was an extra signal right on the dial set frequency.? Using the KD8CEC memory manager software I adjusted the BFO until the non-audio generated signal was reduced by over 20 db.? The optimum (at least to my ears) trade off of sound to reduced carrier was a new setting of 1199550.? It did sound tinnier, however the carrier reduction in the transmit mode would be required to eliminate any tone in the radio that would be receiving my signal.
Note: I was not able to see the same signal detail on the RF Explorer.
As always, the above is my interpretation of my experiences, yours may differ.
73
Evan
AC9TU
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and another example, I sent Gerber files to a guy who never even bothered to acknowledge receipt or the time spent producing them as anybody who produces PCB artwork will know is not trivial. Manners seem to have disappeared over time..
vk3pe
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Re: Spurs/Harmonics fixes for v4 based on v5 board design?
Evan,
It will work EXACTLY the same as SSB - why ? because the BiDi amp is
still powered and amplifying
even in CW mode. giving birth to the Dancing dervishes and all..
Removing power during CW TX to Bidi amps might make a big
difference.
Raj
At 03-02-19, you wrote:
toggle quoted message
Show quoted text
Raj,
I would agree with this for the SSB setup, not sure how that would
work with the CW setting.? Has a test been done to disable Q20 - Q22
to show that this is the case?? That statement also conflicts with
what I am measuring in that the SSB harmonics with a single, dual, or
multi-tone audio signal are lower than the CW signal.? I have also
put a scope on TP12 and see a square wave coming from the si5351, which
would support that there are potentially more harmonics at the input to
the RF power stages for CW than coming from the SSB portion of the
rig.
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Re: Spurs/Harmonics fixes for v4 based on v5 board design?
Evan,
I haven't done any testing with CW as I have no interest.
The other explanation also holds but it was stated by many that it was
the capacitance of the contacts but
I found that the loop inductance of closed set of contacts of the Virtual
and other relays is far higher than
the Axicom relays where the contacts are below the coil.
I guess there is inductive coupling between input and output of a
filter.
Raj
At 03-02-19, you wrote:
toggle quoted message
Show quoted text
Raj,
First of all I want to thank you for always taking time to explain.?
i am learning a lot from you through this forum.
I do have a question on the comment that on message #64580:
"Most spurs are created by the harmonics of the carrier
feeding back to the first BiDi amp. Changing to Axicom relays
- eliminates a lot of these dancing dervishes."
I would agree with this for the SSB setup, not sure how that would
work with the CW setting.? Has a test been done to disable Q20 - Q22
to show that this is the case?? That statement also conflicts with
what I am measuring in that the SSB harmonics with a single, dual, or
multi-tone audio signal are lower than the CW signal.? I have also
put a scope on TP12 and see a square wave coming from the si5351, which
would support that there are potentially more harmonics at the input to
the RF power stages for CW than coming from the SSB portion of the
rig.
Is another possible explanation the feedback that is allowed through the
relays are reducing the effective filtering of the low pass filter??
In reviewing the schematic v4 compared to v5 it looks like HF Signals is
changing the relays being used as the pin outs do not agree and hint that
board layout is also a factor in the filter not being totally
effective.
I really want to get a v5 board to see the total difference.? Will
then use it to upgrade my 2 current ubitx v4.? If you can't tell, I
get a kick out of playing with these, as I do not risk $1000+ if I damage
one, and most of the time should be able to fix it myself.? Also
teaching me a lot about RF that is soo different than the digital world
that I have been in for so long.
Again, Thank-you Raj!
73
Evan
AC9TU
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Making plastic molds for relatively low production runs is very expensive relative to stamping out a metal case, too. You need big runs to make the plastic look economical, which is why it is more often seen in high volume, low power radios.
=Vic=
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Re: Spurs/Harmonics fixes for v4 based on v5 board design?
Peak on frequency transmit is -55db and spur seems to be at -85db, I thought even attenuated should measure the difference in the main on frequency output vs the spur which is 30db then which would be out of compliance right?
(See two tone test screen shots)
toggle quoted message
Show quoted text
On Sat, Feb 2, 2019 at 12:36 PM, ajparent1/KB1GMX wrote:
On Thu, Jan 31, 2019 at 08:05 PM, Dave Space wrote:
o my results with RSP1A are interesting transmitting at 7.150MHZ into a 40 db attenuator I was getting up to -55db on the RSP_SAS Spectrum analyzer at frequency 5 mhz up and down there were spurs at about -85db.? Higher than that I saw various spurs only to -95 or so.? I was seeing with the rtl-sdr? -30db spurs but I was also seeing near 0db at 21mhz and scope fft was showing something at 28MHZ even after swapping the relays. But I don't see anything at all that high in the 21mhz-28mhz range with the sdrplay.<<<<
If you say -85db with a 40 DB attenuator isn't that -45db when you correct for the attenuation???
When you add the required attenuation that becomes an offset to the scale.
The difference?? _45db is not terrible, -85DB competes with the best (and is unlikely).
Allison
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Re: Spurs/Harmonics fixes for v4 based on v5 board design?
Two tone test results - 700 and 1900 tone.
(background for others - I have the axicom relays fixes and Raj's L5 and L7 fix)
This is using the mic transmitting LSB at 7.150MHZ
toggle quoted message
Show quoted text
On Fri, Feb 1, 2019 at 10:24 AM, Evan Hand wrote:
Verify the input level for the audio.? I ran into those when I increased the audio input level (showed up as higher power out, though that was probably because of the extra garbage being amplified).? I adjusted the output of the audio generator to match the CW power level,? being read on an Nissei SWR/Power meter between the rig and the dummy load, when I noted that the spurs dropped down in relative level.? Another way to tell for me is when the audio from the rig speaker gets distorted.? There is a lot of leakage being detected by the muting Q74 MOSFET.
On my rig, using the RSP2, I did not get 2 peaks with the two tone audio, instead there were 3.? I did not figure out how to determine what the third spike was.? I am assuming that it is the carrier getting through the SSB filter.? Did not get the frequency measured, so will do that this weekend (working now).
73
Evan
AC9TU
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Re: Efficient Class E generation of SSB Using the EER Method
On Fri, Feb 1, 2019 at 09:35 PM, Tom, wb6b wrote:
I think that would be a cool way to build a SSB transmitter. I've been doing some reading as I'm investigating the possible use of a FPGA for creating a SSB signal to drive my uBITX (in this case the signal will be feeding a linear TX chain). In the analog days it seems the results were somewhat marginal. One technique described splitting things up so the carrier was "FM" modulated (I imagine that is an over simplification) and the envelope was used to modulate the carrier with another class D audio range amplifier modulating the voltage to the class E final.
The central feature is doing half the work DSP at 16mhz (arduino uno or nano speeds) and a little analog.
Yes the carrier is sorta FM... what it is and needs to be is the mic audio signal stripped to the frequency content
and added (or subtracted) to the base frequency.? FM tends to revolve around a central frequency and has
more sidebands.? In the analog world we would hard limit the audio and mix it with a carrier the result would
have sidebands of the base plus sum (or difference).? That limiting thing in the digital realm takes processor
speed. The other half is then modulating an amplifier with a signal that represents the envelope of the audio
at audio rate and is used to re-create the power out for the driving level.? ?The simplest form of that is not
more than 100years old and known as AM save for that has carrier(largely useless save for the detector at
the other end needed it then) and both sidebands (both sum and difference of the source signal applied
to carrier).? SSB removes the carrier? and the receiver uses a BFO as replacement.? the excess
sideband can be filtered away or using Analog signal processing, we can inhibit the unwanted
sideband.? Phasing side band is more than 80 years old.? Filter mode of sideband has about the same
origin.
All of the digital techniques do that and its all math but at some point the result is RX audio or TX RF.
The fastest designs grind the numbers and drive an D/A and feed the rest directly to the antenna
without the need for frequency change and on RX grab the spectrum using a very fast A/D and
process the data down to the desired signal.? Just about all the radios with IF DSP do this but
at 12 or 30khz with conversion to user frequency as that was were the tech was 20 years ago.
>>>It would seem that in this age of DSP processors and such this should be a realizable design. In my limited searching I haven't found much on realized designs. I'm really interested if others with more experience in this, know of working designs. <<<<
If you have a MPU fast enough to do dsp (STM32F4 at 180mhz is fast enough) then the mainline techniques
can get you a very good SSB signal and also do the RX as well.
As to realized designs I give you softrock (RX), SDR2GO, Flex radio, ANAN 100, KX2, KX3, K3S, IC7300...
And just about any IF DSP radio in the last 20+ years.? However there are several ways to do it and the
EER form we are talking about has never been very successful. One amp I know of was SGC 500W,
very short market life.
Allison
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Re: Spurs/Harmonics fixes for v4 based on v5 board design?
On Thu, Jan 31, 2019 at 08:05 PM, Dave Space wrote:
o my results with RSP1A are interesting transmitting at 7.150MHZ into a 40 db attenuator I was getting up to -55db on the RSP_SAS Spectrum analyzer at frequency 5 mhz up and down there were spurs at about -85db.? Higher than that I saw various spurs only to -95 or so.? I was seeing with the rtl-sdr? -30db spurs but I was also seeing near 0db at 21mhz and scope fft was showing something at 28MHZ even after swapping the relays. But I don't see anything at all that high in the 21mhz-28mhz range with the sdrplay.<<<<
If you say -85db with a 40 DB attenuator isn't that -45db when you correct for the attenuation???
When you add the required attenuation that becomes an offset to the scale.
The difference?? _45db is not terrible, -85DB competes with the best (and is unlikely).
Allison
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Re: Spurs/Harmonics fixes for v4 based on v5 board design?
Really good question.? When I was working on my receive signal issues I found those resistors were attenuating my signal a lot in the receive path,? I tested with and without them and I got a better receive signal with them in place.? Since in parallel they are dividing the resistance to reduce it a bunch
Parallel resistance measures 40 ohms at r17 (39 ohm resistor I think added to each by the colors I think) and 20 ohms at R37.? ? Not sure of the type since I pulled them off a very many many year ago high school project I found lying around.? They look bigger than my 1/4 watt resistors I bought recently.
I think those are in the receive path only so hopefully shouldn't impact my transmit issues.? I didn't have any surface mount resistors to add so went with those.
toggle quoted message
Show quoted text
On Sat, Feb 2, 2019 at 09:12 AM, Truffies wrote:
Question you have two big resistors to right and left of new L% and L& what are they and for and type?
-----Original Message-----
From: Dave Space <davesspacebar@...>
Sent: Feb 2, 2019 11:17 AM
To: [email protected]
Subject: Re: [BITX20] Spurs/Harmonics fixes for v4 based on v5 board design?
Thanks Raj.? I already replaced all 5 relays just to be safe with axicom ones and now also the L5 and L7 fix.? Would it be possible to add a low pass filter into the transmit chain somewhere to prevent that mixer product?
On Fri, Feb 1, 2019 at 10:14 PM, Raj vu2zap wrote:
What inductors did you use, please share a pic.
There is always a carrier leak at 12Mhz and 12-7 = ~5 Mhz could be what you see.
Most spurs are created by the harmonics of the carrier feeding back to the first BiDi amp. Changing to Axicom relays
eliminates a lot of these dancing dervishes.
Raj
At 02-02-19, you wrote:
Thanks I'll try the two tone test next. Tonight I replaced L5 and L7 Raj's fix to see if I noticed any differences. Using LSB on 7.15 into 40db attenuator get-55db main signal and I see some sort of spur at around 5MHZ that is about -85db, doesn't fluctate with voice it's constant when I key the transmitter. Wonder what could be producing around 5 MHZ.
I wonder if the v5 board redesign changes next might help. Might see if I can figure out where on the board that could be introduced.
</davesspacebar@...>
|
Re: Spurs/Harmonics fixes for v4 based on v5 board design?
Raj, First of all I want to thank you for always taking time to explain.? i am learning a lot from you through this forum. I do have a question on the comment that on message #64580: "Most spurs are created by the harmonics of the? carrier?feeding back to the first BiDi amp. Changing to Axicom relays
eliminates a lot of these dancing dervishes."
I would agree with this for the SSB setup, not sure how that would work with the CW setting.? Has a test been done to disable Q20 - Q22 to show that this is the case?? That statement also conflicts with what I am measuring in that the SSB harmonics with a single, dual, or multi-tone audio signal are lower than the CW signal.? I have also put a scope on TP12 and see a square wave coming from the si5351, which would support that there are potentially more harmonics at the input to the RF power stages for CW than coming from the SSB portion of the rig. Is another possible explanation the feedback that is allowed through the relays are reducing the effective filtering of the low pass filter?? In reviewing the schematic v4 compared to v5 it looks like HF Signals is changing the relays being used as the pin outs do not agree and hint that board layout is also a factor in the filter not being totally effective. I really want to get a v5 board to see the total difference.? Will then use it to upgrade my 2 current ubitx v4.? If you can't tell, I get a kick out of playing with these, as I do not risk $1000+ if I damage one, and most of the time should be able to fix it myself.? Also teaching me a lot about RF that is soo different than the digital world that I have been in for so long. Again, Thank-you Raj! 73 Evan AC9TU
|
Assembled Ubitx 4.3 with 3.5 Nextion
This project has run it's course and it's time to move on to the next one. For sale assembled ubitx ver 4.3 with nextion display. I built this one over the past 6 months. It was my testbed while I helped Rich Neese with his nextion screens. It works great full output. the mods are as follows It a 3.5 in Nextion screen using Rich Neese's screen. The heatsinks on the finals have been replaced with one large heatsink DC insulated from the irf-510's. It has a LM-386 audio amplifier board installed for better receive audio. It has a second arduino nano installed for KD8CEC's DSP and Smeter mod. It is in a homemade 1/8 inch birch plywood box with the raduino, second nano and nextion screen in a separate shielded compartment in the front. I have added a 1/4 jack for a CW key in the back along with a 1/4 mic plug in on the side. The mic input has a blocking cap installed to remove the dc bias on it so I could run a Turner plus 3 desk mic on it. I also added a tune button on the front so I could send a carrier to operate my ldg auto tuner. I really don't know what it's worth. Make me a reasonable offer.?
Photos here
/g/BITX20/album?id=84040
--
N5KBP
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Re: Spurs/Harmonics fixes for v4 based on v5 board design?
Question you have two big resistors to right and left of new L% and L& what are they and for and type?
-----Original Message-----
From: Dave Space
Sent: Feb 2, 2019 11:17 AM
To: [email protected]
Subject: Re: [BITX20] Spurs/Harmonics fixes for v4 based on v5 board design?
Thanks Raj.? I already replaced all 5 relays just to be safe with axicom ones and now also the L5 and L7 fix.? Would it be possible to add a low pass filter into the transmit chain somewhere to prevent that mixer product?
On Fri, Feb 1, 2019 at 10:14 PM, Raj vu2zap wrote:
What inductors did you use, please share a pic.
There is always a carrier leak at 12Mhz and 12-7 = ~5 Mhz could be what you see.
Most spurs are created by the harmonics of the carrier feeding back to the first BiDi amp. Changing to Axicom relays
eliminates a lot of these dancing dervishes.
Raj
At 02-02-19, you wrote:
Thanks I'll try the two tone test next. Tonight I replaced L5 and L7 Raj's fix to see if I noticed any differences. Using LSB on 7.15 into 40db attenuator get-55db main signal and I see some sort of spur at around 5MHZ that is about -85db, doesn't fluctate with voice it's constant when I key the transmitter. Wonder what could be producing around 5 MHZ.
I wonder if the v5 board redesign changes next might help. Might see if I can figure out where on the board that could be introduced.
|
_Dave_ AD0B
Raj vu2zap
Vic WA4THR
