Re: Crystal Filter Termination
Hi again,
Mini-circuits says (except for DC isolation) RF performance is similar between the types:
73,
Mark
|
Re: Crystal Filter Termination
Hi,
I suspect to simplify construction, they wind all these transformers the same.? Then to use them in that part of the circuit (simplify the traces?) they used them as autotransformers.? Unless, the schematic is not following what was done in the actual construction.? T8 is like that too.? I most often see regular transformers used in situations like this -- not sure if one way is better than the other.
73,
Mark
|
Re: Crystal Filter Termination
The better way would be to use the primary and secondary windings to make a 1:4 transformer..
toggle quoted message
Show quoted text
At 13/03/2020, you wrote: Hi,
Doing some further research, are there any off-the-shelf transformers
that can be used for T5 and T6 (Crystal filter Termination)
Such as this:
Would this work instead of winding one?
Best 73,
Ravi/M0RVI
|
Re: Crystal Filter Termination
Hi Ravi,
I think the ohm ratio is wrong on that one.? From the schematic, the originals look like 2:1 winding ratio autotransformers which will give a 4:1 ohm ratio.? Otherwise I don't see why you can't switch.
73,
Mark.
|
Re: Transmit Output Power (CW)
#v5
Hi Rob,
It would be interesting to see "before" measurements.
One trick on viewing SMD parts is to take a good picture with a smartphone or digital camera and then zoom in to view the fine print.? SMD parts typically don't have real names on them like "2n3904" but have codes.? There are code lists on the web to help translate them though.
To check power at lower power levels (like the ubitx) you can use a diode RF probe.? Easy to make from scratch or as a kit.? Some QRP dummy loads have them built in (e.g. Elecraft, QRPGuys, QRP-Labs all have them).
If I remember correctly, I think changing Q90 and its biasing makes the biggest different in evening the output.
73,
Mark
|
Re: Crystal Filter Termination
Go for it Ravi, good find! much smaller fooprint.
Raj
toggle quoted message
Show quoted text
At 13/03/2020, you wrote: Hi,
Doing some further research, are there any off-the-shelf transformers
that can be used for T5 and T6 (Crystal filter Termination)
Such as this:
Would this work instead of winding one?
Best 73,
Ravi/M0RVI
|
Crystal Filter Termination
Hi,
Doing some further research, are there any off-the-shelf transformers
that can be used for T5 and T6 (Crystal filter Termination)
Such as this:
Would this work instead of winding one?
Best 73,
Ravi/M0RVI
--
I'm here to add more value to the world than I'm using up.
|
Re: uBitx v6 Microphone
#v6
Okay, you can see the hole for the screw, after pulling up the raiduno it wil fit but i think cause of all the problems i had, som contacts will not connect with the motherboard
|
Re: Transmit Output Power (CW)
#v5
I do have a V5 board.? To be clear, I have not yet made any modifications to the transmit chain... the only thing I have done is adjust RV1 to increase the output power on 80M to about 12W.? Before I did that, the pot was set at about half way, so it would be easy enough to turn RV1 back to a half-turn, and it should pretty much be what it was from the factory, +/- a few tenths of a watt.? I could then take reasonable "before" measurements.
I can't tell by looking what Q90 is (tiny little thing...), but based on the official V5 schematic, it should be an SMD 2N3904.? The rest of the pre-driver/driver transistors (6 of them) are all 2N3904, by the looks of them.
My power meter is built into an automatic antenna tuner designed for up to 150W.? So I'm sure it's not super accurate.
Thanks for all the feedback!
-Rob KC4UPR
|
Re: uBitx v6 Microphone
#v6
Ok¨¦ iedereen, bedankt voor het beantwoorden. De C die ik op de microfoonlijn moet plaatsen, is misschien een oplossing? Maar voorlopig heb ik gisteren geprobeerd om de radio stap voor stap in elkaar te zetten ... Ik ben begonnen met het moederbord en daarna heb ik de raduno erop gezet. Ik heb de draden aangesloten en ...... het werkt, audio niet zo geweldig en microfoon ook niet zo geweldig, maar geen toon aan de zijkant. Maar .... toen probeerde ik de voorkant van de sluiting te plaatsen en ik zag (vanmiddag maak ik foto's) dat het raduno bord en het scherm niet in de voorkant passen ?? Ik moet de raduino ongeveer 5 of 6 mm uit de connector trekken. De montage van de raduino is slecht en past niet goed. Dus ik heb wat kleine o-ringen gevonden and i am gonna place them under the mainboard for just that .5mm rise. The next problem is that the hole's for mike, phones and volume are ?on the right place...?? so this story continues
|
Re: Transmit Output Power (CW)
#v5
Well ...anything you've got is better than nothing ...back in the old days, folks used a wave-meter (gdo in diode position) to check for spurs/harmonics ..was hoping for some before/after measurements...ah well
thanks, Jim
On Friday, March 13, 2020, 1:59:53 AM UTC, Rob French (KC4UPR) <kc4upr@...> wrote:
Jim, no, I don't really have a way to check for that.? I suppose I could use my SDR dongle as a poor man's spectrum analyzer??? See what other spikes I get in the spectrum when I transmit?
I will note that, at the low end of 80 meters, prior to turning up RV1, I was only getting ~6.5W, so I'm wondering if my uBITX wasn't quite adjusted right from the factory... I wasn't getting 8 W anywhere.? Although, that probably also gets to Dave's point about different power meters, different measurements.
|
Re: Transmit Output Power (CW)
#v5
If you have a decent amp meter you can adjust RV2 and RV3. Don't try and set them by ear. Review. the procedure on line. All three RV adjusters adjust the final power out be it ditties or voice.? I got one unit that was weak on transmit and turning up RV1 brought it up to spec.
I have a spread sheet that has the approximate RF voltage at each transmitter stage as collected by my 30 year old scope. You would want an oscope to compare. Basically you see that each transformer decreases the voltage substantially but the 3 transistor array more than makes up and by the time it is to the next? transformer it is stronger than it was when it entered the prior stage.?
Personally I would not want to do a two tone test at this point.?
If you have done any modifications you are not in a position to see what if any difference they are making. Best return to stock to make that as good as possible.?
If yours is a v5 it should have the improved transistors in it. No? You should verify.?
I looked through this post and was not sure of the model version.?
--
73
Dave
|
Re: Transmit Output Power (CW)
#v5
Hi Rob,
Well, what is the power meter you are using?? If it's a 100-200W maximum meter, certainly it will not have much accuracy down below 10W.
Do you have, or could you get, an oscilloscope?? That is a good method for setting SSB power out (using a 2-tone test signal).
73,
Mark
|
Re: uBitx v6 Microphone
#v6
The BFO settibg depend on the crystal filter that your board has. Thus each board is unique . You may not use ithers' bfo setting.? Sarma vu3zmv
Rene
Lets get a bfo setting value from another v6 or v5 owner. That would get you close. We can address transmit audio later. Let's keep the steps small, no bold changes yet.
Curt wb8yyy
|
Re: Transmit Output Power (CW)
#v5
Jim, no, I don't really have a way to check for that.? I suppose I could use my SDR dongle as a poor man's spectrum analyzer??? See what other spikes I get in the spectrum when I transmit?
I will note that, at the low end of 80 meters, prior to turning up RV1, I was only getting ~6.5W, so I'm wondering if my uBITX wasn't quite adjusted right from the factory... I wasn't getting 8 W anywhere.? Although, that probably also gets to Dave's point about different power meters, different measurements.
|
Re: uBitx v6 Microphone
#v6
for a BFO frequency that works for my V.6 is 11.056.0
|
Re: uBitx v6 Microphone
#v6
Rene
Lets get a bfo setting value from another v6 or v5 owner. That would get you close. We can address transmit audio later. Let's keep the steps small, no bold changes yet.
Curt wb8yyy
|
Re: Transmit Output Power (CW)
#v5
Here are a couple of tone clips that might be useful; 700-1900 is
2 tone? 300 and 3000 are voice BW max & min. I use another SDR
spectrum display to check spectral purity for things like
harmonics. depending where you feed it into system you might have
to fashion an atten pad
cheers
On 2020-03-11 10:05 p.m., Matthew
Chambers NR0Q via Groups.Io wrote:
toggle quoted message
Show quoted text
why? he already did the test with CW which will give the
maximum power out vs a whistle which will vary and may have a
complex signal component and reduce how much power you see on
a non-peak reading meter. in radio shops we always test in
either CW or FM for max power out, and then in AM to set the
carrier level.
Matthew Chambers, CBT, NR0Q
Owner/Engineer
M Chambers Communications
Engineering LLC
PO BOX 855, Moberly, MO
65270
Mobile (660)415-5620
On Wed, Mar 11, 2020 at 9:57
PM Joe Puma < kd2nfc@...> wrote:
Do the same test but in SSB. Give a steady
whistle. ?
Joe
KD2NFC?
On Mar 11, 2020, at 10:13 PM,
Rob French (KC4UPR) <kc4upr@...>
wrote:
?
I've collected all my parts to do Allison's
transmit chain modifications (BFR106, 2N2222, 11 ohm
resistors...).? I'm ready to go... but I wanted to
QC my output power first.? Now, I have noticed on 40
meters (where I spend most of my time), that the
output power is low, so now that I finally have a
power meter, I went ahead and tuned RV1 while
transmitting into a dummy load.? I tuned RV1 to get
12W output on 3.500 MHz, and then checked the output
power across the rest of the bands.? This is what I
got... is this representative of what other people
have seen?? I know I'd seen reports of crazy low
output power (<1 W) on 10 meters, which I did NOT
observe here, obviously.? (Note, all of these were
done with CW.)
|
Frequency
|
SWR
|
Power (W)
|
|
3500000
|
1.00
|
12
|
|
4000000
|
1.00
|
9.4
|
|
5332000
|
1.00
|
6.3
|
|
5405000
|
1.00
|
6.2
|
|
7001000
|
1.00
|
6.7
|
|
7300000
|
1.00
|
5.6
|
|
10100000
|
1.00
|
5.2
|
|
10150000
|
1.00
|
4.7
|
|
14000000
|
1.01
|
6.6
|
|
14350000
|
1.01
|
6.2
|
|
18068000
|
1.02
|
5.5
|
|
18168000
|
1.02
|
5.5
|
|
21000000
|
1.04
|
5.8
|
|
21450000
|
1.05
|
8
|
|
24890000
|
1.04
|
4.1
|
|
24990000
|
1.04
|
4
|
|
28000000
|
1.04
|
4.8
|
|
29700000
|
1.03
|
4
|
Any thoughts?? (a) Are these typical of what others
have observed?? (b) What can I expect from the
transmit modifications, relative to this?? Higher
output on 30, 20, 17?
Thanks!
-Rob KC4UPR
PS - Random aside.? So I am using KD8CEC firmware
version 1.2.? I noticed something weird on 40
meters... If I tune to exactly 7.000.000 MHz, or
lower, in the 40 meter band, I hear the T/R relay
switch and the display indicates in CW transmit, but
there's 0 W output power.? But if I tune to
7.000.010 or higher, it's fine.? It's kind of like
it's enforcing transmit restrictions, except that
the ONLY place that it seems to do this is on the
bottom end of 40 meters!? I've tried to trace code
behavior for the band limiting, and could not
identify anything that would make this happen.? Has
anyone else observed this???
|
Re: Transmit Output Power (CW)
#v5
Just a random thought ...do you have any way to check for harmonics/spurs at these settinjgs?
while tuning for "maximum smoke" is one way to do it, what you are measuring with the power meter is ..along with the fundamental frequency, ALL the spurs/harmonics/random trash being radiated...would be great to see some measurements of them before the modding as well as after
Jim
On Thursday, March 12, 2020, 2:13:41 AM UTC, Rob French (KC4UPR) <kc4upr@...> wrote:
I've collected all my parts to do Allison's transmit chain modifications (BFR106, 2N2222, 11 ohm resistors...).? I'm ready to go... but I wanted to QC my output power first.? Now, I have noticed on 40 meters (where I spend most of my time), that the output power is low, so now that I finally have a power meter, I went ahead and tuned RV1 while transmitting into a dummy load.? I tuned RV1 to get 12W output on 3.500 MHz, and then checked the output power across the rest of the bands.? This is what I got... is this representative of what other people have seen?? I know I'd seen reports of crazy low output power (<1 W) on 10 meters, which I did NOT observe here, obviously.? (Note, all of these were done with CW.)
|
Frequency
|
SWR
|
Power (W)
|
|
3500000
|
1.00
|
12
|
|
4000000
|
1.00
|
9.4
|
|
5332000
|
1.00
|
6.3
|
|
5405000
|
1.00
|
6.2
|
|
7001000
|
1.00
|
6.7
|
|
7300000
|
1.00
|
5.6
|
|
10100000
|
1.00
|
5.2
|
|
10150000
|
1.00
|
4.7
|
|
14000000
|
1.01
|
6.6
|
|
14350000
|
1.01
|
6.2
|
|
18068000
|
1.02
|
5.5
|
|
18168000
|
1.02
|
5.5
|
|
21000000
|
1.04
|
5.8
|
|
21450000
|
1.05
|
8
|
|
24890000
|
1.04
|
4.1
|
|
24990000
|
1.04
|
4
|
|
28000000
|
1.04
|
4.8
|
|
29700000
|
1.03
|
4
|
Any thoughts?? (a) Are these typical of what others have observed?? (b) What can I expect from the transmit modifications, relative to this?? Higher output on 30, 20, 17?
Thanks!
-Rob KC4UPR
PS - Random aside.? So I am using KD8CEC firmware version 1.2.? I noticed something weird on 40 meters... If I tune to exactly 7.000.000 MHz, or lower, in the 40 meter band, I hear the T/R relay switch and the display indicates in CW transmit, but there's 0 W output power.? But if I tune to 7.000.010 or higher, it's fine.? It's kind of like it's enforcing transmit restrictions, except that the ONLY place that it seems to do this is on the bottom end of 40 meters!? I've tried to trace code behavior for the band limiting, and could not identify anything that would make this happen.? Has anyone else observed this???
|
Re: uBitx v6 Microphone
#v6
There is other software, but none of them are going to solve your problems.? They change some of the operation, or add features that are not there now.? Nothing to solve the calibration, low audio,? and feedback issues you have listed so far.
My recommendation is to put the radio back together and then follow the instructions for calibration from Farhan in this YouTube video:
The BFO calibration page used in the video is here:
If you follow the steps in the video, you should be able to get the ubitx receive function working.
I did not follow all of the mic/audio issues you are having, however the most common is low audio followed by RF feedback through the coiled mic cord back into radio.
There is no easy solution for the low audio other than a new mic or addition of a preamp.
The RF feedback is solved with .01 mF across the lead from the mic to ground inside the ubitx chases and a snap on ferrite over the straight part of the mic cord just before the connector.? I do not have a v6 so can not send you a picture of how and where to add the capacitor.? Hopefully someone on the message board can help with that.
I feel sorry for you that you are having so much trouble with the kit.? I hope you can look at it as an opportunity to learn and a hunt to fix the problems.? For me that has been the most fun that I have gotten from the 3 that I own.
Good luck in the reassembly and calibration.
73
Evan
AC9TU
|
Raj vu2zap
_Dave_ AD0B