Date   

Re: FT8 and power levels

Evan Hand
 

On Tue, Jan 19, 2021 at 07:28 PM, Rafael Diniz wrote:
What is the emission type / signal characteristics of this "FT8"?
FT8 messages are transmitted using 8-tone continuous-phase frequency shift keying (CPFSK). Each transmitted tone or channel symbol conveys three bits.

from 
https://physics.princeton.edu/pulsar/k1jt/FT4_FT8_QEX.pdf

73
Evan
AC9TU


Re: FT8 and power levels

jeanrenier2004
 

Hi Mitchel,

My experience using the uBIT-X in FT8 mode is quite similar.

The uBIT-X has a remarkably sensitive receiver, on a good day I can "hear" FT8 signals from New Zealand (about as far as one can get from Belgium) at -24dB S/N.  Its transmitter is of course limited to QRP levels, I am typically running at 5...6W (continuous, not PEP) into a simple (not so good) 20m dipole. 

FT8 is a great mode inasmuch it gives a more or less objective measurement of the S/N on both sides.  Of the 100+ QSO I made during the past months the average difference between received S/N at my end and the received S/N at the other end is as much as 15dB (in favor of the other guy).  Some are as low as 0dB, some as much as 24dB.

Since the same transmission path, including both antennas, is used for both directions I come to believe that a lot of OMs are transmitting FT8 at 100...200W, levels, some even over 1000W.  Not entirely the intent of Joe Taylor with WSJT-X, but I am afraid it is one of these facts of life. 
It means that I don't even try anymore to make a QSO with a station that come in with a S/N of less than -10dB.  On good days I can still reach out to NE USA and Canada. 

73,  ON4JRT/Jean.


Op 20/01/2021 om 00:54 schreef Mitchel Rought:

A question of curiosity about FT8 and the level of power being used, I have a uBITX v6.2 with a usb dongle running approx.5-7 watts into either a  cobweb, 20m hexbeam, or a 20m delta loop, all antennas are run through a tuner and average < 1.1 swr at the digital freq.
I have made contacts and the average report I get back is anywhere from -13 to-26db
I am curious what everyone else is doing and seeing
thanks in advance


Re: TUNE signal for tuning tuners

Evan Hand
 

Vince,
I have not tried to use a variable voltage on the mixer diodes to control power through the unbalanced ring.  Not sure if that would work, though would be curious as to the theory on how it would work.

You still need to adjust the CLOCK#2 signal of the Si5351 and turn off the other two CLOCKs. 

To do as you are suggesting, you could install a switch between the CW-KEY and R104 to connect R104 to the CW-KEY or to a variable resistor to adjust the voltage that is connected between the CW-KEY and R104.  Throw the switch and then press the CW key/PTT to get a lower level tune signal.  Switch it back to do the normal operation.  It would require that the CW mode be straight key, not keyer and that the CW mode is set in the v6 (not required in prior versions, just need the CW key connected).

Above are speculations, so I could be off.
73
Evan
AC9TU


Re: FOR SALE Ubitx ver 3 in nice metal case

Skip Davis
 

Frank are you looking for a complete in the case UBITX or will an un-assembled kit work?
I have a Ver3 kit here that I’m not going to build because I already have one together that I play with, unboxed of course. I’ve tested the two assemblies (main board and Raduino) and they are working.

Skip Davis, NC9O 

On Jan 19, 2021, at 18:53, kg9hfrank@... wrote:

Is it still available?  I am looking for a uBitz.

--
Frank, KG9H


Re: Easy bitx20 by Inkits.

Sunil Lakhani
 

The wa2eby PCB will be in stock by the end of this month as fresh order has been placed .
We shall update the stock on our website very soon.
Regards
Sunil vu3sua 




Re: I think I damaged my display.uBitx V3

 

I bought some from Amazon.in

At 20/01/2021, you wrote:
Thanks, do you know where I could buy a display or arduino? I've looked but I can't see a source.


Re: TUNE signal for tuning tuners

Vince Vielhaber
 

Not EXACTLY. The nano puts out 5V. I said to vary the voltage to get less out.

Vince.

On 01/19/2021 09:30 PM, Jerry Gaffke via groups.io wrote:
CW-KEY is doing exactly the same thing.
When transmitting CW, CLK2 is programmed to be at the transmit
frequency, CLK0 and CLK1 are shut down,
and a Nano IO pin drives 5v on CW-KEY to unbalance the mixer.

Jerry, KE7ER

On Tue, Jan 19, 2021 at 05:57 PM, Vince Vielhaber wrote:

To get less than full power out, you can vary the voltage from 0-5v.
TP13 (it looks like TP13 anyway) would be a good place to inject
that variable voltage, you'd probably want to use a diode and
resistor in line.

I did that on my B40 and it worked well. I put the pot right on the
front panel.

Vince.


Re: no audio beyond very quiet static #ubitxv6 #ubitxv6-help #v6

Skip Davis
 

John measure Q90 base to emitter junction, if close to zero it has shorted. I measured about 500ohms. This will cause no output and loss of receive and it is still in circuit during receive.

Skip Davis, NC9O 

On Jan 19, 2021, at 16:18, John Scarlett <John329@...> wrote:

The wires for volume control must be ok as the volume does adjust and all the wiring connectors match the photographs I had previously taken.
That being said it does seem likely that something must have been touched or dislodged while I was working possibly one of the many coils or even heat transferred to the wrong component while de-soldering.
I will check all the connection's around the PA transistors and look for touching wires on the coils as the video suggested and let you know the results.

73
John M7CPT


Re: TUNE signal for tuning tuners

Jerry Gaffke
 

CW-KEY is doing exactly the same thing.
When transmitting CW, CLK2 is programmed to be at the transmit frequency, CLK0 and CLK1 are shut down,
and a Nano IO pin drives 5v on CW-KEY to unbalance the mixer.

Jerry, KE7ER


On Tue, Jan 19, 2021 at 05:57 PM, Vince Vielhaber wrote:
To get less than full power out, you can vary the voltage from 0-5v. TP13 (it looks like TP13 anyway) would be a good place to inject that variable voltage, you'd probably want to use a diode and resistor in line.

I did that on my B40 and it worked well. I put the pot right on the front panel.

Vince.


New Rig? - Re: QUESTION for All - EASY BITX - HP 2800 series Schottky Diodes for Mixer

Tom, wb6b
 

On Wed, Jan 13, 2021 at 10:30 PM, Ashhar Farhan wrote:
On my bench is a new rig coming up that is built for high performance, hybrid sdr capabilities.
When do we get to learn more?

Tom, wb6b


Re: TUNE signal for tuning tuners

Vince Vielhaber
 

On 01/19/2021 08:22 PM, Evan Hand wrote:
Frank,

It is not clear to me what you are asking. If you have a uBITX then the
method that Bob describes is the easiest. If your question is how to do
that, then here is the way that it is done in the v3 and later,
displaying the v6 schematic:


The way that works is that the first mixer (T1 and T2) is being
unbalanced by a 5 volt signal from the Nano on the CW-KEY line. This
forward biases 2 of the diodes in the mixer and allows the LO signal
that has been changed to the frequency that is to be transmitted to be
applied to the amplifier stages.



It should be noted that the power output will be the full power for that
band.
To get less than full power out, you can vary the voltage from 0-5v. TP13 (it looks like TP13 anyway) would be a good place to inject that variable voltage, you'd probably want to use a diode and resistor in line.

I did that on my B40 and it worked well. I put the pot right on the front panel.

Vince.
--
K8ZW http://www.metalworkingfun.com http://www.hamradio.fun


Re: FT8 and power levels

Rafael Diniz
 

What is the emission type / signal characteristics of this "FT8"?

Thanks,
Rafael

On 1/19/21 8:54 PM, Mitchel Rought wrote:
A question of curiosity about FT8 and the level of power being used, I
have a uBITX v6.2 with a usb dongle running approx.5-7 watts into
either a  cobweb, 20m hexbeam, or a 20m delta loop, all antennas are
run through a tuner and average < 1.1 swr at the digital freq.
I have made contacts and the average report I get back is anywhere
from -13 to-26db
I am curious what everyone else is doing and seeing
thanks in advance


Re: TUNE signal for tuning tuners

Rafael Diniz
 

Just set CW keyer to hand-key and key the radio, you'll get a continuous
CW for tuner adjustment. I'm adding a "TUNE" button in my ubitx v6
interface code for this.

Rafael

On 1/19/21 8:30 PM, kg9hfrank@gmail.com wrote:
This past weekend, I went back in time and reviewd posts back to 2018.

About half way through I started taking notes but... I did not take
any notes on how to unbalance the balanced modular to get a signal out
for using a tuner.

Anyone have that info available?  

If I recall the ham disabled a resistor causing an imbalance and a
steady signal came out which he used to tune his tuner.  He turned it
on and off with a toggle switch.

--
Frank, KG9H


Re: TUNE signal for tuning tuners

Evan Hand
 

Frank,

It is not clear to me what you are asking.  If you have a uBITX then the method that Bob describes is the easiest.  If your question is how to do that, then here is the way that it is done in the v3 and later, displaying the v6 schematic:


The way that works is that the first mixer (T1 and T2) is being unbalanced by a 5 volt signal from the Nano on the CW-KEY line.  This forward biases 2 of the diodes in the mixer and allows the LO signal that has been changed to the frequency that is to be transmitted to be applied to the amplifier stages.  



It should be noted that the power output will be the full power for that band.

The other way would be to use FT8 software or similar to generate an audio tone that can be adjusted in level for the power needed to activate the tuner.

A third option would be tu use CW-TONE or generate a tone on the unused A7 pin to feed the mic input through a variable resistor.  This would take modifiying the Nano code.

Of the three, I use either the CW or Audio tone from FT8 software.

73
Evan
AC9TU


FT8 and power levels

Mitchel Rought
 

A question of curiosity about FT8 and the level of power being used, I have a uBITX v6.2 with a usb dongle running approx.5-7 watts into either a  cobweb, 20m hexbeam, or a 20m delta loop, all antennas are run through a tuner and average < 1.1 swr at the digital freq.
I have made contacts and the average report I get back is anywhere from -13 to-26db
I am curious what everyone else is doing and seeing
thanks in advance


Re: FOR SALE Ubitx ver 3 in nice metal case

kg9hfrank@gmail.com
 

Is it still available?  I am looking for a uBitz.

--
Frank, KG9H


Re: TUNE signal for tuning tuners

Bob Lunsford
 

Simple way is to use the Manual Key option and CW mode to use the PTT for a +/-10W CW signal that will tell the tuner what frequency to center on for tuning. Maybe someone else can suggest a hard-wire way but this for me is the simplest way.

Bob — KK5R

On Tuesday, January 19, 2021, 6:30:47 PM EST, kg9hfrank@... <kg9hfrank@...> wrote:


This past weekend, I went back in time and reviewd posts back to 2018.

About half way through I started taking notes but... I did not take any notes on how to unbalance the balanced modular to get a signal out for using a tuner.

Anyone have that info available?  

If I recall the ham disabled a resistor causing an imbalance and a steady signal came out which he used to tune his tuner.  He turned it on and off with a toggle switch.

--
Frank, KG9H


TUNE signal for tuning tuners

kg9hfrank@gmail.com
 

This past weekend, I went back in time and reviewd posts back to 2018.

About half way through I started taking notes but... I did not take any notes on how to unbalance the balanced modular to get a signal out for using a tuner.

Anyone have that info available?  

If I recall the ham disabled a resistor causing an imbalance and a steady signal came out which he used to tune his tuner.  He turned it on and off with a toggle switch.

--
Frank, KG9H


Re: no audio beyond very quiet static #ubitxv6 #ubitxv6-help #v6

John Scarlett <John329@...>
 

The wires for volume control must be ok as the volume does adjust and all the wiring connectors match the photographs I had previously taken.
That being said it does seem likely that something must have been touched or dislodged while I was working possibly one of the many coils or even heat transferred to the wrong component while de-soldering.
I will check all the connection's around the PA transistors and look for touching wires on the coils as the video suggested and let you know the results.

73
John M7CPT


Re: no audio beyond very quiet static #ubitxv6 #ubitxv6-help #v6

Jerry Gaffke
 

Yes, get the receiver working first.

Here's an old video Farhan created to show how to take a meter of wire as an antenna to
pick up local QRN around the house, and strobe that wire to each stage of the receiver
progressing back from the audio amp until you reach a point where it no longer
makes scratchy noises in the audio.  That tells you about where the problem is.
    http://bitxhacks.blogspot.com/2016/12/troubleshooting-bitx40.html
The video is about the old Bitx40, but should work on the uBitx too.

Though first look for obvious stuff.  Maybe a wire broke off of your volume control?
Maybe a wiring harness got plugged back into the board wrong?
Are the RX stages getting 12v power? 
Note that the audio amp is powered from "12V", other receiver stages from "RX", but only when receiving.
    
If you replaced the PA transistors and now the receiver doesn't work,
sounds like you must have touched something else in the process.

Jerry, KE7ER



On Tue, Jan 19, 2021 at 11:36 AM, John Scarlett wrote:
Total loss of power output occurred 1st that Is why I replaced the PA transistors.
As it seemed likely that I'd blown my finals I replaced both with genuine RD16HHF1's.
After doing this I had no audio beyond very quiet static so also replaced audio chip and checked TX/RX relay.
Still no sound beyond very quiet static so didn't even try to TX.
Any ideas what else it could be would be appreciated?
 
73
John M7CPT

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