Date   
Re: PA goes mad on some antennas #ubitx #ubitx-help

ajparent1/kb1gmx
 

Is this bitx-40 or bitx20 or uBitx  as they are not the same?

Since it happens with the loop I'd suspect its the radio.  I say that 
as people will run off and blame the endfed half wave.
Generally of the SWR is good its something else.

Things in the radio such as long wires, possible radiation from the board
to antenna connector, grounding issues within the box.

Generally plastic cases being RF transparent are likely to make this worse.

Allison

Re: Tiny SWR Bridge

W3JDR
 

FYI, I posted the LTSpice schematic, so you can analyze if you wish.If there's interest, I can post the whole LTSpice package if anyone requests it.

Joe

Re: PA goes mad on some antennas #ubitx #ubitx-help

Gordon Gibby <ggibby@...>
 

That’s probably radio frequency interference.   With a slightly Squirrley antenna, you may have RF pick up in microphone cables etc., leading to all kinds of weird behavior.   it will look like the radio took off on its own.  Try ferrites, better SWR, better grounding of things together,  that sort of thing


On Aug 13, 2018, at 08:17, "ludwig_t@..." <ludwig_t@...> wrote:

Hello!

Finally I made a few first contacts with my uBitx. Mostly I used the antennas at my local ham radio club, which has dipoles for 80m and 40m and a beam antenna for all the upper bands. At these antennas the uBitx works perfectly and I was also able to make a few DX contacts.

But while trying my Antennas at home, I figured out, that the PA breaks into terrible oscillations on any band while working with an endfed halfwave antenna or a magnetic loop antenna. Sometimes the oscillations occur also on my portable trap dipole.

So does anyone of you have such problems with your Bitx too? And does anyone have an idea, what's going wront with my Bitx?

73,
Ludwig, DM2LCT

PA goes mad on some antennas #ubitx #ubitx-help

ludwig_t@...
 

Hello!

Finally I made a few first contacts with my uBitx. Mostly I used the antennas at my local ham radio club, which has dipoles for 80m and 40m and a beam antenna for all the upper bands. At these antennas the uBitx works perfectly and I was also able to make a few DX contacts.

But while trying my Antennas at home, I figured out, that the PA breaks into terrible oscillations on any band while working with an endfed halfwave antenna or a magnetic loop antenna. Sometimes the oscillations occur also on my portable trap dipole.

So does anyone of you have such problems with your Bitx too? And does anyone have an idea, what's going wront with my Bitx?

73,
Ludwig, DM2LCT

Re: Needed - relay voltage versus frequency for each of the band-pass filter relay drivers #ubitx-help

lwhfac@...
 

If your rig still has the M1 and M2 audio cutoff connections to relay K3, then what you are hearing in your audio is not a transmitter issue, but an RF overload condition from the TX output back into your audio preamp. In another post of mine I described how to eliminate this issue by cutting the paths in the audio from K3. The RF is so strong due to coupling between the contact pairs inside the relay that after you make the mod to not use the relay to interrupt the audio, you can use the righthand connection to the old R70 as a convenient RF pickoff to look at with a 'scope or a spectrum analyzer!
Larry N2AJX

Re: uBITX and nulling the carrier #ubitx-help

lwhfac@...
 

You folks are all saying "carrier leakage". I thought that as well when playing with my rig. It turned out, in my case but I expect yours as well, it is not the carrier but the unwanted sideband. This rig's scheme always uses the upper sideband generated by the balanced modulator in both USB and LSB transmission. You need to look in real close with a spectrum analyzer using 100 Hz resolution bandwidth to see the difference. I have found the sweet spot for the BFO to be 11.9962 MHz, just as many of you have already found. If you can measure the output of the balanced modulator, you should see the carrier being down at least 40 dB from the sideband output. You shouldn't see the carrier in the transmitted signal, especially after the modulator output passes through the crystal filter.
Larry N2AJX

Re: Harmonics

Gordon Gibby <ggibby@...>
 

Hey, very cool Glenn!!!
Also, now I understand what you mean about mounting the relays on the backside.

Great work!



On Aug 13, 2018, at 06:15, Glenn <glennp@...> wrote:

Here's another take on the PCB for the extra LPF switching relays. As per my previous suggestion, fitting the PCB to the edge of the uBITX main board by seam soldering them together.
This preserves a very good ground return.

The PCB uses HK4100F-12v relays which are cheap on ebay. 'Should' be ok for qrp levels.  They are a SPDT type relay and mounted on the back of PCB shown. They are similar in height to existing LPF relays.

Similar track cutting mods as Gordan has stated, except a variation in the 400nH LPF section so all inputs are on the egde of the uBITX board.  The PA output feeds the board at the end nearest the heatsinks. ie a very short coax cable is required.  Four short (5mm) wire links from the edns of the LPF sections to this board. You can see the 4 holes down the left side which is actually rotated left 90deg when fitted.

The transistor relay driver stages have been duplicated, but can also be not fitted, as pads are provided for this also. All relay coils are bypassed both sides and along the tracks too.  I might add some ferrite beads also.

The PCB is approx 36 x 50mm in size.

<LPF_EXTRA_RELAYS_DRAFT pcb_v3.jpg>

ubitx bands

terry hughes
 

the kdcec manual says that it can be set to any ham band

does that include the 60 mtr (5 Mc/s) band

terry gm4dso

Re: Harmonics

Glenn
 

Here's another take on the PCB for the extra LPF switching relays. As per my previous suggestion, fitting the PCB to the edge of the uBITX main board by seam soldering them together.
This preserves a very good ground return.

The PCB uses HK4100F-12v relays which are cheap on ebay. 'Should' be ok for qrp levels.  They are a SPDT type relay and mounted on the back of PCB shown. They are similar in height to existing LPF relays.

Similar track cutting mods as Gordan has stated, except a variation in the 400nH LPF section so all inputs are on the egde of the uBITX board.  The PA output feeds the board at the end nearest the heatsinks. ie a very short coax cable is required.  Four short (5mm) wire links from the edns of the LPF sections to this board. You can see the 4 holes down the left side which is actually rotated left 90deg when fitted.

The transistor relay driver stages have been duplicated, but can also be not fitted, as pads are provided for this also. All relay coils are bypassed both sides and along the tracks too.  I might add some ferrite beads also.

The PCB is approx 36 x 50mm in size.

Re: Tiny SWR Bridge

W3JDR
 

Hi Allison,
Thanks for the compliment on the picture.

It's a pretty straight-forward Breune bridge, but I'll put up the schematic when I get a chance to edit it with actual values...maybe today. The novelty, if any, is mountIng it right on the connector and using the center pin as the transformer primary.

When I do these things from my tablet, I tend to take shortcuts and fill in details later. Mea Culpa.

W3JDR
Joe

Re: high frequency noise from speaker

JJ1FXF
 

Jerry,

Thanks again for ur reply.

OK, 3 Nanos are on the way now and I will order another 3 Nanos so I can try 6 of them this time.

Yes, I know that I need Nanos without pins soldered.

Maybe I’ll solder “both sides long pins” then I can use in anyway later.

So far, my uBitX is working good, I could listen some HAMs on 7MHz and could transmit 5W on CW and 10W PEP on SSB if I shout to the mic.

Next to do is to build a transmittable antenna.

Again, thank you so much. I’m enjoying my uBitX now.

BR,

// hiro, JJ1FXF



2018年8月13日(月) 14:46 Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io>:

Hiro,

I would think with 3 or 4 Nano's you would have one without the objectionable tone.
The processor clock frequency is determined by a 16mhz ceramic resonator
which can be off by perhaps plus or minus 100khz.
Since it is probably the 3'rd harmonic of the 16mhz resonator creating the tone,
if it is off by 10khz, then the tone would be 3*10khz = 30khz.

Buy Nano's that do not have the pins soldered in such as this:
    https://www.amazon.com/Elegoo-Arduino-ATmega328P-without-compatible/dp/B0713XK923
To plug the Nano into the Raduino's socket on the v4 uBitx, the pins must be soldered 
into the top side of the Nano, not the bottom side where the pins usually are.

Jerry


On Sun, Aug 12, 2018 at 10:24 PM, JJ1FXF wrote:
Many thanks, Jerry.
 
It seems that my issues is the same one discussed at the thread you pointed out.
 
I happeningly ordered some extra Arduino Nano for my another projects, so let me try to switch Nano at first.
 
What do you think How many of Nano I can buy to get the right one?
 
I’m just asking you the possibility. No commitment, of course.
 
// hiro, JJ1FXF
 
 

Re: 2 ten ohm resisters and button Mic element

jfein2000@...
 

Ok.     Guess I am a bit long in the too but i grew up with 4 band coding......the last being tolerance.  These resistors are five bands hence the error on my part.  Also the first two bands looked like brown but under a magnifying glass they are not they are red.  The value of the two resistors is 2.2 kohms.  Tested on an old analog Heathkit vom and a modern digital vom both agree.  So I have to assume they are meant to be used with the paddle although they are not 10 kohms.  Thanks for all the comments.  Cheers Jeff

Re: ubitx compared to Elecraft or Xiegu for spurs #ubitx

iz oos
 

You means spectral purity around the fundamental or the harmonics? Listening to a few hams on VHF, having an SDR receiver, my impression is that around the fundamental they were not very clean. I have to say that many that have that rig have done a simple mod around the mic input to have plenty of punch. Also that radio have also a arsenal of possible equalization. Do the users of these NASA rigs always check for their spectral purity or maybe they take for granted they are clean whatever the mods and equalization?


Il 13/ago/2018 01:28, "VE3MIC via Groups.Io" <ve3mic=yahoo.com@groups.io> ha scritto:
Has anyone looked at the Yaesu FT-991 for spectral purity? :)


On Sun, Aug 12, 2018 at 5:07 PM, Jim Reagan
Has anyone run tests on the popular Elecraft KX3 or the Xiegu 5105 for spurs and harmonics?  How do they compare to the uBITX?
Thanks,
Jim W0CHL

Re: high frequency noise from speaker

Jerry Gaffke
 

Hiro,

I would think with 3 or 4 Nano's you would have one without the objectionable tone.
The processor clock frequency is determined by a 16mhz ceramic resonator
which can be off by perhaps plus or minus 100khz.
Since it is probably the 3'rd harmonic of the 16mhz resonator creating the tone,
if it is off by 10khz, then the tone would be 3*10khz = 30khz.

Buy Nano's that do not have the pins soldered in such as this:
    https://www.amazon.com/Elegoo-Arduino-ATmega328P-without-compatible/dp/B0713XK923
To plug the Nano into the Raduino's socket on the v4 uBitx, the pins must be soldered 
into the top side of the Nano, not the bottom side where the pins usually are.

Jerry


On Sun, Aug 12, 2018 at 10:24 PM, JJ1FXF wrote:
Many thanks, Jerry.
 
It seems that my issues is the same one discussed at the thread you pointed out.
 
I happeningly ordered some extra Arduino Nano for my another projects, so let me try to switch Nano at first.
 
What do you think How many of Nano I can buy to get the right one?
 
I’m just asking you the possibility. No commitment, of course.
 
// hiro, JJ1FXF
 
 

Re: high frequency noise from speaker

JJ1FXF
 

Many thanks, Jerry.

It seems that my issues is the same one discussed at the thread you pointed out.

I happeningly ordered some extra Arduino Nano for my another projects, so let me try to switch Nano at first.

What do you think How many of Nano I can buy to get the right one?

I’m just asking you the possibility. No commitment, of course.

// hiro, JJ1FXF



2018年8月13日(月) 12:39 Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io>:

Here's an old thread about audio tones in the receiver,
possibly due to beat notes between harmonics of the 12mhz bfo and the 16mhz Nano processor clock.
    https://groups.io/g/BITX20/message/54576
Easiest solution if you have a v4 uBitx with the socketed Nano:  replace the Nano

Jerry


On Sun, Aug 12, 2018 at 07:58 PM, JJ1FXF wrote:
Though it took a little longer time, finally my uBitX seems to be working very well now, for which thank you for advices here so far.

Then, another question to ask you who experienced the same issue.

I hear high frequency noise behind the band noise that my iPhone freq meter says it’s about 2,700Hz. (I’m not sure if this app is reliable or not)

My uBitX is not in a metal case, yet. And I use a small powered speaker.

Maybe it comes from Raduino or main board of uBitX, or possibly the 12v power supply.

Since I’m planning to bring my uBitX to a local lab in order to measure its spurious emission this coming Wed, I’d like not to mod much things on hardware coz it may possibly bring another trouble to me.

I just hope that some capacitor in the line of speaker or some small mod can solve this issue at this moment.

Looking forward to your advice.

Thanks!

Auto TX Smart Filter Controller #nano #arduino #filters #ubitx

Tom, wb6b
 

Hi,

I wan't to build a filter I can use with the uBITX. However, I don't want to build a filter that is strictly tied to the uBITX. 

So I'm building a standalone Low Pass Filter box that will work as an add on filter for the uBITX as well as become a general purpose piece of Ham equipment I can use over and over for other needs.

It uses an Arduino to measure the frequency you're transmitting on and select any individual or combination of filters you like. The proposed design uses a set of filters and a relay switch board; such as to ones by QRP Labs. But, the Sketch code should be easy enough to modify for whatever you like.

The controller can show he selected filter with LEDs or with an optional LCD display, and show the transmit frequency as well.

I'll need to order parts and build mine to finalize the design. However, I built and tested a prototype with a signal generator. 

I'm releasing the preliminary design to everyone now because it is complete enough for people to try out on their own filter designs. It makes using outboard filters really easy, and I think people will like it. I welcome feedback on improvements people make while building their own "Auto Filters" with the controller.

The code for the controller is here: https://github.com/mountaintom/TX_Auto_Filter


----


Tom, wb6b

Re: Harmonics

Gordon Gibby <ggibby@...>
 

I barely know how to do this, but I uploaded the design document, and the zipped gerber files (which pcbway.com was happy with) to this github directory:


https://github.com/ggibby1/uBitxExternalRelays




From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Sunday, August 12, 2018 11:15 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Harmonics
 

I bit the bullet and submitted files to pcbway, for 10 printed circuit boards for external relays. 


While I was at it, I threw on a small bit of circuitry to give me a 3 terminal regulator and a backwards diode etc so if  I need to regulate a voltage for the receiver downwards, i can do that.  


printed circuit boards are amazing.     My local ARES group absolutely reduced their building time by at least 80% when I switched to giving them printed circuit boards that just have to be populated, rather than piont to point wiring.   My own building time went down similarly though i was much faster than beginners of course.



My plans are to get them this optional external relay set,  and also an optional daughter board with the popfix for those with v3 boards and maybe the AGC also..... but all that is in the future.   FIRST just to help them learn how to wire up the ubitx, with a bit of resistance in the speaker line if they have the IC amplifier.    ​  One step at a time!


I just got PAT working for the very first time on WINMOR....amazing....will give us winlink access from raspberries to uBitx transceivers.    


Gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of Kees T <windy10605@...>
Sent: Sunday, August 12, 2018 10:53 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Harmonics
 
On Sun, Aug 12, 2018 at 09:14 PM, Gordon Gibby wrote:

​Hi Keyes --- I wasn't following so not sure if this is for OUTPUT or as a preselector for the PA stage.   I don't know exactly how to read your PCB's but a few questions:

 

1.  I don't see the ground connection on the motherboard for the ground pins of the filter trays.

2.  Did you want to isolate the relay coils  input versus output?   I don't see inductors / capacitors to avoid energy getting AROUND the filters via the coils, the coil wiring and then out the other coil.

 

Gordon,

The ground pins on the filter trays are connected to the ground plane on the board and there are 3 grounds and the coax shields which return to uBITX ground. I'll also send the ground plane image. Does not have anything to avoid energy getting around the coils. Just basic LPF design, if/when the LPF is not used, both ends of that LPF are grounded. Relay contacts are redundant and bifurcated.

73 Kees K5BCQ

Re: high frequency noise from speaker

Jerry Gaffke
 

Here's an old thread about audio tones in the receiver,
possibly due to beat notes between harmonics of the 12mhz bfo and the 16mhz Nano processor clock.
    https://groups.io/g/BITX20/message/54576
Easiest solution if you have a v4 uBitx with the socketed Nano:  replace the Nano

Jerry


On Sun, Aug 12, 2018 at 07:58 PM, JJ1FXF wrote:
Though it took a little longer time, finally my uBitX seems to be working very well now, for which thank you for advices here so far.

Then, another question to ask you who experienced the same issue.

I hear high frequency noise behind the band noise that my iPhone freq meter says it’s about 2,700Hz. (I’m not sure if this app is reliable or not)

My uBitX is not in a metal case, yet. And I use a small powered speaker.

Maybe it comes from Raduino or main board of uBitX, or possibly the 12v power supply.

Since I’m planning to bring my uBitX to a local lab in order to measure its spurious emission this coming Wed, I’d like not to mod much things on hardware coz it may possibly bring another trouble to me.

I just hope that some capacitor in the line of speaker or some small mod can solve this issue at this moment.

Looking forward to your advice.

Thanks!

Re: ubitx compared to Elecraft or Xiegu for spurs #ubitx

Gordon Gibby <ggibby@...>
 

​Hi Jim,   Allison already did that for a motley crew of raidos, including a Heathkit HW-100 and they all were good to go except I think one reallly clunky design.   The general thing was that most radios are pretty well engineered.   


Gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of Jim Reagan <jimreagans@...>
Sent: Sunday, August 12, 2018 11:22 PM
To: BITX20@groups.io
Subject: Re: [BITX20] ubitx compared to Elecraft or Xiegu for spurs #ubitx
 
Hey, I'm just curious how all the other portable radio compare....
Are they :"clean"? Specs can be that "special" radio, just for testing.
Your mileage may vary,
Jim W0CHL

Re: ubitx compared to Elecraft or Xiegu for spurs #ubitx

lkorahul
 

Put decent RF devices in uBitx and then we compare for sure...

Rahul VU3WJM