Re: Compliance Summary - other radios
Yes, shipping, duties and other margins will rise the price quite a lot. It's the same in Europe for reasonably priced US amps like Ameritron that nearly cost as much as a Acom. So I Iook forward for the uAMP...!!!
Il 11/ago/2018 19:05, "ajparent1/KB1GMX" < kb1gmx@...> ha scritto: Iz ooz,
The only RM Italy amps I've seen were the ones with selectable filters.
They worked well and were clean.? The owners liked them.? I thought
them a bit pricey.
Allison
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Key is, on my cell phone I can¡¯t see message numbers, but this is simply building the stylistic schematic ?I drew and took a photograph of a couple days ago. ??
$6 in relays,
i¡¯ll get the board made in China, order five or 10 of them for friends. ?
Use a Dremel or something to cut the unnecessary lines on the original circuit board?
The other components probably add up to three dollars.
Hardest part will be making up some little twisted pair lines or RG 174 coax jumpers. ?
I was really impressed when y¡¯all found that the multiple section filters Asher put in, are. excellent.
I¡¯d like to just keep those if it all possible.
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Gordon, is the drawing in message #56429 basically what you are doing with your board ?
73 Kees K5BCQ
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Re: Proposed fix for Harmonics Issue
Howard fidel ?proposes to ?triple The output capacitance of the filters by dropping the impedance to 25 ohms. ? I suspect this requires rebuilding the output transformer and then adding an additional transformer to get back to 50 ohms.?
If his theory is right , the voltage showing it around the shelters might decrease to 1/third, and thus the power by 10 DB.?
What do others think of this? ??
What would it do to the power handling capability of the inductors & ?and their wiring??
It requires rewinding or creating two transformers, and adding probably 12 capacitors. ?
On another note, might I point out that if this rig had some kind of ALC, that might be a huge help if it is going into a linear amplifier following it! ? Most of the rigs that I have ever played with had some way for a linear amplifier to feed ALC back
to them. ??
On Aug 11, 2018, at 13:02, Howard Fidel < sonic1@...> wrote:
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Hi Gordon:
Before you do all that rework, have you read my post of the ninth? My solution provides a 10dB improvement by design. You need to rewind the output transformer, change all the filter capacitors (uses the same inductors) and add a new 1:2 transformer. It can
be done with NO artwork changes.
Howard
-------- Forwarded Message --------
After much thought, and reading all the threads, and speaking to Allison (who has not commented to me on this yet) I think I have a good solution to the harmonics issue, not the spurs. We know that the problem is capacitance between input and output of the
filters. We estimated that it is 2 pF per a relay. For 80 meters, we have 4 relays, or 8 pF capacitance from input to output. You will note that the filter has a capacitor at its output. This acts as a voltage divider. The bigger we make this cap, the small
the energy will be that comes through, since the larger the cap is, the more attenuation we get from the voltage divider. To get a filter with more capacitance we need to lower the impedance of the filter, so I used 25 ohms. This means that we need to rewind
T11 to get a 25 ohm output impedance. The redesigned filter for 80 meters uses the same inductors as we now have, we just need to change the capacitors to the new values, and add a transformer to the output. If done on the board, this is the only artwork change.
It can also be put in line with the output coax, and then no rework of the PCB artwork is needed. The simulation shows that there is a peak in the filter response caused by the 8 pF cap on the original design at 12.5 MHz and -53 dB. With the new filter this
peak is at 10.5 MHz and is - 64 dB. I think a 10 dB improvement is all we need. The same can be done for each of the other filters, and the improvement will be the same, since the capacitance through the relays goes down as the frequency goes up (fewer relays).
I have attached the simulation files and the filter schematic. I have to design a transformer.?
Howard
<Instrumentsfix.pdf>
<Instruments.pdf>
<80Mmodfilter.pdf>
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Hans,
It looks like the QRP Labs LPF filters are 1.5" x 0.5" and the header pin spacing is 1.3" .....these are all estimates off your documentation drawings. Are they correct ?
73 Kees K5BCQ
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Re: Compliance Summary - other radios
Interesting survey, so, generally speaking, except for the current uBitx, both the Wright brothers and NASA are complaint independently of the cost (!) and the age (!) of the flying object...
Il 11/ago/2018 19:02, "ajparent1/KB1GMX" < kb1gmx@...> ha scritto: When I tested the ubitx it triggered exactly the same question.??
How are the other radios?
The list includes:
FT817, Argonaut 505, Triton m540, Eagle, KNQ7A, 20 Slopbucket, Kitsandparts 1W (cw only),
and homebrew SSB monoband radios for 40,20,15,10.? For ancient to compare to I
warmed up the HW101, Siltronix 1110C, and Tempo-one as an excuse to make sure
they were ok and put a little time on them.??
The verdict was all passed with margin.? Some the margin was more than 20db.?
For example my 1977 (manufacture date) Tentec Triton M430 the specs said not?
less than -60dbc and it was better than spec 43 years later for everything.? The?
modern OK mines about 12 years old) FT817 was spec or better.??
The poorest exceed spec was the 20M Small wonder labs White Mountain
SSB as harmonics were-43dbc (at max power 3W) and the peak was?
second harmonic with the rest better and carrier was -46dbc.? Not?
bad for a 20 year old design and in use for the last 14 years.
A recent build is the 20M slopbucket a KD1JV design.? Harmonics better?
than -45 for second and better for higher. Carrier was -49db.
For many simple radios the second harmonic is to be watched because?
of the single ended output as its also harder to filter.? the WM20, Slopbucket,
and KNQ7A and nearly all of mine fall into that category.? They pass.
Also I can take any radio and push it to get truly horrific results.? Can't
blame the radio for that.
The tube rigs were interesting as once dialed up for the band it was good
but over driven or tuned up wrong the second harmonic could climb out of
accept range.? Considering the output of both of those were only single
section pi networks for the outputs one would expect worse.? OF note
was that spurs other than harmonics were not at all strong most being
better than -55dbc.? This is attributed to much filtering (tuned preselection)
in the lower level stages and the driver as well.? Considering the
Siltronix 1011C? goes back to the days was 11M was a?ham band
it was fine on 10M and fun.
Filtering in the early stages does help and all do it that way with low
pass filters for harmonic clean up due to the amplifiers used.? AS a result
spurs were non existent or very low.
One odd item as a response...? I have a siltronics 100W "cb" amp.
With mods (bias circuit added) for class AB1 (1a standing current)?rather
than class B (zero bias) the push pull amps is close to that of Motorola AN63
with MRF454s.? So I tested it without the nominal low pass filters used with
it.? The drive was FT817 at 5W so the output was about 63W for 80 and 40
(works well higher but not tested for this) and harmonics were -38DBC for
second harmonic and -33dbc for the third harmonic the rest were lower.? Of
course it didn't pass but as to calling it filthy, not so?much.? ? With external
filters normally used in place in the results were easily 15db (for second)
and 23db (for the third)?which is better than required.? With harmonic
suppression in the? mid -50s, 53dbc and 56dbc for both bands case closed.
The filters, a set of filters built almost like those for the ubitx using the
same values?with differences, bigger toroids, higher voltage caps and used a?
dual section 4 position switch. Covers 80-60, 40, 20-17, 21-29mhz.
I built it?last year so I never thought?to try it with ubitx but based on?
this it would clean it up.
Allison
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Re: Test for solving Spurs
#ubitx
All,
When looking on the schematic of the ?BITX I am wondering why the
LO inputs of the mixers must have a 6 dB attenautor.? Is there a
reasonable explanation?
As we already know the SI5351 is limited in output power. My fear
is taht the diodes within the mixer are nto driven hard enough so
that their on and off state is not a function of the LO signal but
also depends on the RF signal applied to it.? From my
understanding a balanced unit will always attenuate even
harmonics? (here 2* IF = 90 MHz) better than any odd harmonics.
Also the SI5351 outputs rectangular drive signals which in my
opinion is perfect for fast switching action within the diodes.
The transformers will limit the harmonics of the driving signal,
so it might be more or less a sinosoidal.? It then only the peaks
of thsi signal will switch teh associated dioe on, any RF signal
of significance will shift the "on-time" meaning distortion and
unbalancing. Could thsi be a soruce of the second harmonic within
the mixer?
Henning
DK5LV
Am 11.08.2018 um 21:56 schrieb Jerry
Gaffke via Groups.Io:
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Allison,
Yes, most of what I had in my last post was gleaned from your
older posts.
I posted in response to Henning's warnng about using a better
45mhz transistor:
? ? "Using e.g. BFR106 instead could worsen the spur problem."
Here's Warren's plot for 15m:
? ??/g/BITX20/photo/65861/2
There's a fair bit of dirt showing that's lower in freq than the
15m fundamental.
Is that stuff real, or an artifact of the test setup?
Warren used a 1mhz RBW and 1mhz VBW, are the results accurate
enough for our purposes?
I'm still chewing on this from your post? ?56613,
would be less ambiguous if I knew something about spectrum
analyzers.
"FYI: if you run video bandwidth down far enough you
can get a 10db?
error and also clean up the baseline, save for it will
be wrong.??
Anything less than 30khz (for 3-30mhz span) on the
Rigol and a less?
than 1:3 radio of RBW and VBW will yield low readings.?
With the?
HP8568B less than 10khz and 1:3 give errors.? Also
sweep rates less?
than 300mS give sampling errors.
The test in my case was radio, Bird model 43 wattmeter,
NArda 30db attenuator,?
Telonics step attenuator, Spectrum analyzer.? ?With 10W
indicated on the Bird
BOTH machines of known calibration will read low if set
up wrong.? For the?
Rigol I could not get an accurate 10W (40DBM)
indication with 3khz RBW
and 1Khz VBW (is was short by 11db) at 311mS sweep and
3-30mhz span.
If I lowered the span to 10mhz it was off by 3db.? At
1mhz the indication?
was under 1db of correct.? ?For the setup you used I
add 10db.? If I make the?
VBW 30khz it gets better but its still off."
Jerry
On Sat, Aug 11, 2018 at 12:11 PM, ajparent1/KB1GMX wrote:
?I did this back in early June, your even had comments
on it.??
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Gordon, is the drawing in message #56429 basically what you are doing with your board ?
73 Kees K5BCQ
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Someone asked about the inductors, they only supply the relay coil currents which is I think 25 mA. ?The ones that I ordered from digikey are rated for 260 mA. ?Understand that the filter currents only go through the contacts, not through the relay coil¡®s of
course!
Keyes asked for a schematic: ?actually have it written down quite yet, but it¡¯s pretty simple, will get that done and then take a photograph of it
I¡¯m not certain whether to just use twisted pair or full coax RG- 174, to feed this, ?but I¡¯m going to provide grand connections for whatever at each RF input and the output?
I¡¯ll write the whole thing up and provide Gerbers.
Perhaps some enterprising soul can make kits out of it....?
Given that the device is so close to the requirements, one would think that simply avoiding the inside-the- relay capacitance would solve this issue
Gordon
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Mark :?
The LPFs from QRP labs should work just fine for this. ?
I am planning to do the same thing as you, except that my outboard filters will
actually be located inside the uBITX enclosure, as I have lots of space.
Cheers
Michael VE3WMB?
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Re: Test for solving Spurs
#ubitx
Allison, Yes, most of what I had in my last post was gleaned from your older posts. I posted in response to Henning's warnng about using a better 45mhz transistor: ? ? "Using e.g. BFR106 instead could worsen the spur problem." Here's Warren's plot for 15m: ? ?? /g/BITX20/photo/65861/2There's a fair bit of dirt showing that's lower in freq than the 15m fundamental. Is that stuff real, or an artifact of the test setup? Warren used a 1mhz RBW and 1mhz VBW, are the results accurate enough for our purposes? I'm still chewing on this from your post? ?56613, would be less ambiguous if I knew something about spectrum analyzers. "FYI: if you run video bandwidth down far enough you can get a 10db?error and also clean up the baseline, save for it will be wrong.??Anything less than 30khz (for 3-30mhz span) on the Rigol and a less?than 1:3 radio of RBW and VBW will yield low readings.? With the?HP8568B less than 10khz and 1:3 give errors.? Also sweep rates less?than 300mS give sampling errors.The test in my case was radio, Bird model 43 wattmeter, NArda 30db attenuator,?Telonics step attenuator, Spectrum analyzer.? ?With 10W indicated on the BirdBOTH machines of known calibration will read low if set up wrong.? For the?Rigol I could not get an accurate 10W (40DBM) indication with 3khz RBWand 1Khz VBW (is was short by 11db) at 311mS sweep and 3-30mhz span.If I lowered the span to 10mhz it was off by 3db.? At 1mhz the indication?was under 1db of correct.? ?For the setup you used I add 10db.? If I make the?VBW 30khz it gets better but its still off."Jerry
On Sat, Aug 11, 2018 at 12:11 PM, ajparent1/KB1GMX wrote:
?I did this back in early June, your even had comments on it.??
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Mark :?
The LPFs from QRP labs should work just fine for this. ?
I am planning to do the same thing as you, except that my outboard filters will
actually be located inside the uBITX enclosure, as I have lots of space.
Cheers
Michael VE3WMB?
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Re: Harmonics measured by Warren. How bad?
Allison every time I post something on this board I do so with full expectation that you will respond in affirmation, having done the same test and arrived at the same conclusion previously, backward, and in heels, and simply neglected to publish your results. I am in awe of your purview and prescience.
Seriously though, less pontification and more solutions would be welcomed. Most on this board are looking to avoid and solve problems rather than to worship at the altar of higher knowledge. Let's all vow to improve the solutions to pontification ratio here going forward.
WA8TOD
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Re: #ubitx SSM2167 mic compressor speaker feedback issue - resolved
#ubitx
here is the picture i found of your connections... 
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Re: #ubitx SSM2167 mic compressor speaker feedback issue - resolved
#ubitx
HI John,
I just had a problem understanding where you put the 10k pot to adjust the output of the amp.
the write up on:?
says this:
John also has a 10K adjustable potentiometer between the ¡°out¡± connection on the module and the original Mic input to the uBitx.??
I just don't quite understand that.. I would think you would put the pot on the output, at the + output of the module and the purple wire going to the microphone element itself ?
kevin
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Re: Compliance Summary - other radios
Too repeat.... and not have to answer the private emails...
RE: external amp filter:
>>a set of filters built almost like those for the ubitx using the
same values?with differences, bigger toroids, higher voltage caps and used a?
dual section 4 position switch. Covers 80-60, 40, 20-17, 21-29mhz.
I built it?last year so I never thought?to try it with ubitx but based on?
this it would clean it up.<<
That means:
The value for the capacitors are the same as are the values for the
inductors and capacitors as used in ubitx.? Just grab a copy of the
schematic and read them off.? Its not a secret.
I didn't use relays, I used a 2 pole four position switch. this was
build a year pre ubitx.
I did use larger toroids and higher voltage caps to allow 100W.??
Or Goodle/Bing/DUCKDUCK go:? Building low pass filters.
Allison
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Gordon,
Great ! ....activity everywhere. Can you also supply the schematic ?
73 Kees K5BCQ
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Will the LPF boards from QRP Labs work as outboard filters? I¡¯m thinking of ordering some, along with the relay board, but I want to be sure they¡¯ll work before I do. I understand I¡¯ll need to roll my own filter selection scheme. Mark. ? AA7TA?
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Re: Test for solving Spurs
#ubitx
Jerry,
They are!? The two sources are the 45mhz IF and the LO...? ?
Thanks for repeating some of the posting on the 5351,? The output is too low to attenuate
(for better matching) and that amkes issues worse but even if the mixers where driven
fully like I did and reported on the bench way back your still get all of the mixer products.
I did this back in early June, your even had comments on it.? Nothing has changed save
for Warren looked at CW, something I'd only glanced at and yes we problems.
I did that work then to verify I was not nuts...? Not one part of this test used ubitx
as its a test of what DBMs as used in uBITX do best possible case and degrade
conditions from there.
To rehash:
Again the bench test was a MiniCircutis ZLW-2 packed mixer with SMA connectors.
Mixer is then terminated on all ports with 6db pads (minicircuits SMA attenuators)
its fed with not anemic LO from a signal generator at 73 mhz and 13dbm (assures that we have 7dbm, ideal).
A second clean generator provides the 45mhz signal.
What at the output:
LO and all its harmonics (not all the same level)
The "IF" 45mhz and all its harmonics
And with a reasonable level for the 45mhz "IF" we get:
All the possible sums and differences of any combination of those and then
at lower levels any sum or difference of their results and so on out to about
5th order as then they are a bit weak and not a problem.
So that is a lot of signals and only the low order ones are significant.
IF we push the IF signal up to more than -10dbm? approaching 1db compression?
all of those signals are still there but the relative levels grow much bigger.
Bigger than what?? The desired 28mhz.??
Since I have them filter the output of the mixer after the 6db pad with a 30mhz Werlatone T2534
low pass filter.
What do we get... well all the sums and differences above 30mhz are attenuated by the filter.
But the differences below 30mhz are still very much there as the filter did nothing to them
as we expect it to.
Whats there... 28mhz, that pesky spur and and the higher order mixes that add to the?
"grass" but are at least 50DBC down.
We turn up the 45MHZ to -7dbm we are into overload and some of the 50DB down stuff
has grown alarmingly as expected (we are well into overload and very non linear) and the?
17mhz spur is now about 23db down from the LO at 7dbm.? For comparison back with the?
nice low 45mhz drive it was almost 41db down.? So it needed to be filtered but even a
trivial one would take that out.? at over load we need a decent one to knock it down?
by 20DB at least.
IF we starve the mixer we get to the wow that nasty level about 10db sooner.
So there are a bunch of things going on and the best solution that is available if to filter
output for only the desired signal (band pass) as low pass lets a few go that are always
there.
Allison
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Are the inductors rated for at least
1/2 A of current?
On 8/11/2018 3:00 PM, Gordon Gibby wrote:
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First rough draft at a daughterboard that allows off board
right-hand-side filter switching..... without having to??rebuild
the filters etc.
Will check more carefully.? ?If anyone sees really stupid
layout issue, please speak up.? ? Capacitors 0.1 uf? ?Inductors
(surface mount)? 100 microhenries.? ??
All,
I'm going for some daughter boards to see how well this works
(below). I still like using the exact components off the stock
uBITX board. I would mount the 3 diodes on the uBITX board and
the 2N3904 they drive on the daughter board, along with the 8
relays.
Hans,
What are the dimensions of one of the QRP Labs LPF boards
(distance between the 2 sets of 4 pin headers and overall
width/length and height with components of the board and if
you offer unpopulated LPF boards.?
Michael,
I agree that a Nano would offer more flexibility as would a
CD4028 for selection of additional filters beyond 4.....but
the rework gets more complex and the cost goes up. Good luck
to you and your design, that's what it's all about.
73 Kees K5BCQ
----------------------------------------------------------------------------------------------------------------------------------
I was thinking of something less costly.....such as: the
existing? TXA, TXB, and TXC all drive 2 relays each (on both
ends of the LPFs). Then you add a 3 diode "OR" to those 3
select lines to drive the 4th relay which, in it's normally
closed state, "has picked" the 4th LPF (as it does today on
the uBITX). Activation of any of the three pulls it "off" the
LPF and grounds it. That would only require 3 diodes and a
2N3904 driver for 4th relay.
RF IN and RF OUT is bussed to the 4 relays.
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First rough draft at a daughterboard that allows off board right-hand-side filter switching..... without having to??rebuild the filters etc.
Will check more carefully.? ?If anyone sees really stupid layout issue, please speak up.? ? Capacitors 0.1 uf? ?Inductors (surface mount)? 100 microhenries.? ??
toggle quoted message
Show quoted text
All,
I'm going for some daughter boards to see how well this works (below). I still like using the exact components off the stock uBITX board. I would mount the 3 diodes on the uBITX board and the 2N3904 they drive on the daughter board, along with the 8 relays.
Hans,
What are the dimensions of one of the QRP Labs LPF boards (distance between the 2 sets of 4 pin headers and overall width/length and height with components of the board and if you offer unpopulated LPF boards.?
Michael,
I agree that a Nano would offer more flexibility as would a CD4028 for selection of additional filters beyond 4.....but the rework gets more complex and the cost goes up. Good luck to you and your design, that's what it's all about.
73 Kees K5BCQ
----------------------------------------------------------------------------------------------------------------------------------
I was thinking of something less costly.....such as: the existing? TXA, TXB, and TXC all drive 2 relays each (on both ends of the LPFs). Then you add a 3 diode "OR" to those 3 select lines to drive the 4th relay which, in it's normally closed state, "has picked"
the 4th LPF (as it does today on the uBITX). Activation of any of the three pulls it "off" the LPF and grounds it. That would only require 3 diodes and a 2N3904 driver for 4th relay.
RF IN and RF OUT is bussed to the 4 relays.
|
All,
I'm going for some daughter boards to see how well this works (below). I still like using the exact components off the stock uBITX board. I would mount the 3 diodes on the uBITX board and the 2N3904 they drive on the daughter board, along with the 8 relays.
Hans,
What are the dimensions of one of the QRP Labs LPF boards (distance between the 2 sets of 4 pin headers and overall width/length and height with components of the board and if you offer unpopulated LPF boards.?
Michael,
I agree that a Nano would offer more flexibility as would a CD4028 for selection of additional filters beyond 4.....but the rework gets more complex and the cost goes up. Good luck to you and your design, that's what it's all about.
73 Kees K5BCQ
----------------------------------------------------------------------------------------------------------------------------------
I was thinking of something less costly.....such as: the existing? TXA, TXB, and TXC all drive 2 relays each (on both ends of the LPFs). Then you add a 3 diode "OR" to those 3 select lines to drive the 4th relay which, in it's normally closed state, "has picked" the 4th LPF (as it does today on the uBITX). Activation of any of the three pulls it "off" the LPF and grounds it. That would only require 3 diodes and a 2N3904 driver for 4th relay.
RF IN and RF OUT is bussed to the 4 relays.
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