Date   

Re: UbitX I2C GPIO Breakouts?

Mark Kesner
 

Looks like a great idea to me.  I googled the mentioned boards and there is a lot of info on how to use these.  Sparkfun has breakout boards for a similar device for $5 as well as examples and links to the library, etc.

I guess it depends on the firmware you are using and whether there is room to load the library. (?)

Thanks!

Mark
KC4GIA


Re: need Linux users to debug a document

Rod Davis <km6sn@...>
 

Hi Tim,

Thank you for the offer.

I think it would be more useful if you have the actual uBITX radio
in-hand for testing.

You could email me when your rig is on-line.

Thanks,

Rod KM6Sn



On 04/19/2018 08:15 AM, Tim - M0THM wrote:

Hi Rod, I don't have my radio yet awaiting shipping. But if it's just a software thing I will be more than happy to help. I run Ubuntu x64 and Debian 9 and 8 but can spin up some other distros via my hyper-visor if you need.


Tim


M0THM

 


On 2018-04-19 13:50, Rod Davis wrote:

Hi All,

I need one or two Linux users to help debug a uBITX software manual.

All you need to do is follow the instructions in the manual that I will
supply, and report any problems encountered.

Any help would be appreciated.

Please contact me via private email.

Thank you,

Rod KM6SN



Re: Tx frequency selection for FT8 on BITX40 running Allard's sketch #bitx40

Doug W
 

Thanks Gerry.  Interestingly enough I did some searching on the topic of operating FT8 in split mode.  Turns out it is a hotly contested topic in certain circles with very strong opinions on both sides.  I think it is time for me to shift from theoretical to practical and leave the details to the guy with the medal from Sweden.


Tx frequency selection for FT8 on BITX40 running Allard's sketch #bitx40

Gerry Hull
 


Doug,

A picture is worth a thousand words:


No need, or reason, to use offset in the transmitter.  In fact, if you have CAT, WSJT controlls the transmitter frequency.

73, Gerry W1VE


On Thu, Apr 19, 2018 at 10:59 AM, Gerry Hull <gerry@...> wrote:
Within WSJT-X, you pick the transmit and receive frequencies, via the WSJT UI.  These are audio frequencies in your passband, not RF frequencies.

73, Gerry W1VE

On Thu, Apr 19, 2018 at 10:55 AM, Doug W <dougwilner@...> wrote:
First off, thank you both for the replies.  Secondly, if my response came across as harsh that was not the intention.  I think we are now splitting hairs on common practice vs best practice.  Right from K1JT himself in the WSJT-X user manual "To avoid QRM from competing callers, it is frequently desirable to answer a CQ on a different frequency from that of the CQing station. Choose a Tx frequency that appears to be not in use."  I realize for a manually controlled rig it wouldn't be practical to change the Tx frequency every time in a fast action digital mode but wouldn't it make sense to operate in split mode with an arbitrarily selected offset above 7.074.000 but still within 3kHz to reduce noise right at x.xxx.000?





Re: need Linux users to debug a document

Tim - M0THM
 

Hi Rod, I don't have my radio yet awaiting shipping. But if it's just a software thing I will be more than happy to help. I run Ubuntu x64 and Debian 9 and 8 but can spin up some other distros via my hyper-visor if you need.


Tim


M0THM

 


On 2018-04-19 13:50, Rod Davis wrote:

Hi All,

I need one or two Linux users to help debug a uBITX software manual.

All you need to do is follow the instructions in the manual that I will
supply, and report any problems encountered.

Any help would be appreciated.

Please contact me via private email.

Thank you,

Rod KM6SN


Re: Tx frequency selection for FT8 on BITX40 running Allard's sketch #bitx40

Gerry Hull
 

Within WSJT-X, you pick the transmit and receive frequencies, via the WSJT UI.  These are audio frequencies in your passband, not RF frequencies.

73, Gerry W1VE

On Thu, Apr 19, 2018 at 10:55 AM, Doug W <dougwilner@...> wrote:
First off, thank you both for the replies.  Secondly, if my response came across as harsh that was not the intention.  I think we are now splitting hairs on common practice vs best practice.  Right from K1JT himself in the WSJT-X user manual "To avoid QRM from competing callers, it is frequently desirable to answer a CQ on a different frequency from that of the CQing station. Choose a Tx frequency that appears to be not in use."  I realize for a manually controlled rig it wouldn't be practical to change the Tx frequency every time in a fast action digital mode but wouldn't it make sense to operate in split mode with an arbitrarily selected offset above 7.074.000 but still within 3kHz to reduce noise right at x.xxx.000?



Re: Tx frequency selection for FT8 on BITX40 running Allard's sketch #bitx40

Doug W
 

First off, thank you both for the replies.  Secondly, if my response came across as harsh that was not the intention.  I think we are now splitting hairs on common practice vs best practice.  Right from K1JT himself in the WSJT-X user manual "To avoid QRM from competing callers, it is frequently desirable to answer a CQ on a different frequency from that of the CQing station. Choose a Tx frequency that appears to be not in use."  I realize for a manually controlled rig it wouldn't be practical to change the Tx frequency every time in a fast action digital mode but wouldn't it make sense to operate in split mode with an arbitrarily selected offset above 7.074.000 but still within 3kHz to reduce noise right at x.xxx.000?


Re: Transmitter Mods

Gordon Gibby <ggibby@...>
 

howard -- thank you for that review!   The inductor I find is up into the 2-3K  (ohms reactance) range by 20 MHz so it definitely changes the feedback ratio at the higher frequencies.  Capacitors across the emitter resistor likewise reduce the negative feedback at higher F.    This little improvement is one of the coolest things I've read yet about the uBitx power issues --- and also the idea of adding C across the power amplifier output transformer to better match --- 



I'm encouraging our Local ARES group to move into these rigs as a learning platform and also for some, their first HF rig -- can't afford the pricey ones --- wonderful platform for LEARNING.     Getting 10W or so on 80/40/30 would be great for NVIS emergency communications for many of these people.   At at a far far cheaper price than commercial fancy qrp rigs --- so next is to put one of mine in an ammo can for protection.


gordon




From: BITX20@groups.io <BITX20@groups.io> on behalf of Howard Fidel <sonic1@...>
Sent: Thursday, April 19, 2018 10:00 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Transmitter Mods
 
The theory is very simple. The closed loop gain of Q911 and Q912 is set by the ratio of R86/R85, or a gain of 10. Adding an inductor into the path in the feedback loop increases the effective impedance at higher frequencies, adding "peaking" to the circuit, thus making the closed loop gain higher. I think the poor frequency response is in the transformer as well as the transistors hfe falling to under 25 typically at 30 MHz. Also, the open loop gain is also increased by bypassing the emitter resistors for higher frequencies.

The transformer is a 2 to 1 step down, (it looks like a trifilar winding) so the theoretical gain of the stage is 5.

Howard

On 4/19/2018 12:36 AM, ohwenzelph via Groups.Io wrote:
How and why does this mod work? What was the calculation that came up with 220pF and 27 uH? 
For the inductor does it matter how many ma it can handle or what it’s self resonant frequency is?
(doubt I will be able to follow the answer but still curious)
thanks!



for sale

wb7dmx@att.net
 

selling my micro - bitix.
it has  the to-220 mounting kit on each transistor. metal case,
asking  $ 100.00
also replaced the audio chip, added a 9 volt reg. and a socket for  the audio chip.
I just am not happy with its performance.


Re: Tx frequency selection for FT8 on BITX40 running Allard's sketch #bitx40

Gerry Hull
 

Doug,

You are misunderstanding his answer.

You transmit AND receive on the exact center frequency: 7074.000 for 40m.
No offsets, RIT, etc.

The tuning is done in the audio passband.   

73, Gerry W1VE

On Thu, Apr 19, 2018 at 9:33 AM, Doug W <dougwilner@...> wrote:
On Thu, Apr 19, 2018 at 03:09 am, Vic WA4THR wrote:
There may be a misunderstanding of how the digital modes work with today's computer software.
Thank you for the reply but your answer does not address the question.  I have a clear understanding of the receive function which you describe quite well.  The question was are you transmitting right on 7.074.000 or are you offsetting that at all?



Re: wrong shipping address

 

Ouch !  He should immediately email hfsignals@... [ hfsignals @ gmail.com ]. If it has already shipped via DHL, he can use the tracking number to divert the shipment. If India Post ... I have no idea.  And he should correct that paypal address asap.


Re: Transmitter Mods

Howard Fidel
 

The theory is very simple. The closed loop gain of Q911 and Q912 is set by the ratio of R86/R85, or a gain of 10. Adding an inductor into the path in the feedback loop increases the effective impedance at higher frequencies, adding "peaking" to the circuit, thus making the closed loop gain higher. I think the poor frequency response is in the transformer as well as the transistors hfe falling to under 25 typically at 30 MHz. Also, the open loop gain is also increased by bypassing the emitter resistors for higher frequencies.

The transformer is a 2 to 1 step down, (it looks like a trifilar winding) so the theoretical gain of the stage is 5.

Howard

On 4/19/2018 12:36 AM, ohwenzelph via Groups.Io wrote:
How and why does this mod work? What was the calculation that came up with 220pF and 27 uH? 
For the inductor does it matter how many ma it can handle or what it’s self resonant frequency is?
(doubt I will be able to follow the answer but still curious)
thanks!



Re: Tx frequency selection for FT8 on BITX40 running Allard's sketch #bitx40

Doug W
 

On Thu, Apr 19, 2018 at 03:09 am, Vic WA4THR wrote:
There may be a misunderstanding of how the digital modes work with today's computer software.
Thank you for the reply but your answer does not address the question.  I have a clear understanding of the receive function which you describe quite well.  The question was are you transmitting right on 7.074.000 or are you offsetting that at all?


Re: ubitx is available for $109, there are a3 catches

W8RMV
 

Ashhar Farhan,
Made my payment weeks ago.  Haven't heard anything aside from the Paypal payment notification.  Do I ever get a confirmation from you/uBITX prior to shipment?
Thanx - Bob W8RMV


need Linux users to debug a document

Rod Davis <km6sn@...>
 

Hi All,

I need one or two Linux users to help debug a uBITX software manual.

All you need to do is follow the instructions in the manual that I will
supply, and report any problems encountered.

Any help would be appreciated.

Please contact me via private email.

Thank you,

Rod KM6SN


Re: Transmit indicator light.

Gary Anderson
 

Hi Max,
I'm assuming that you have an enclosure from Sunil (VU3SUA) by the description.  He has pictures on his website showing how he has done the  RX/TX LED wire-up.
The website is  https://amateurradiokits.in/
the pictures are the second and third from the last.

He is picking up the 12V RX and TX control signals from the uBITX RX/TX relay by soldering wires to the bottom of the uBITX PCB.  He also picks up the ground from the relay.  He then routes 3 wires (RX,TX,GND) to a small prototype board with series current limiting resistors on RX and TX.  No reason you couldn't put your resistors anywhere along that route.  I would have put them right on the PCB.

Regards,
Gary
AG5TX


Re: Tx frequency selection for FT8 on BITX40 running Allard's sketch #bitx40

Vic WA4THR
 

There may be a misunderstanding of how the digital modes work with today's computer software. Typically you leave the rig on a fixed frequency, like 7074, and "tune" the audio passband of 3kHz on the waterfall on the computer. It is really quite remarkable to see 20+ signals in the passband that would hold a single SSB signal

=Vic=
WA4THR


Re: [SPF:fail] Re: [BITX20] Help me! annoying ticking in the audio #bitx40help

SaMa photo SaMa photo
 

thank you :)




Da: BITX20@groups.io <BITX20@groups.io> per conto di Dexter N Muir <dexy@...>
Inviato: giovedì 19 aprile 2018 02:17
A: BITX20@groups.io
Oggetto: Re: [SPF:fail] Re: [BITX20] Help me! annoying ticking in the audio #bitx40help
 
UTP is best for balanced circuits. It gives a minor shielding to single-ended signals, but its use there is mainly just for grouping, keeping 'looms' tidy. The copper bulk of multiple wires can give a minor improvement  to that effect.
73
Dex, ZL2DEX, ex-telephone (exchange) tech.


Re: Help me! annoying ticking in the audio #bitx40help

SaMa photo SaMa photo
 

thank you :)




Da: BITX20@groups.io <BITX20@groups.io> per conto di ajparent1/KB1GMX <kb1gmx@...>
Inviato: mercoledì 18 aprile 2018 23:20
A: BITX20@groups.io
Oggetto: Re: [BITX20] Help me! annoying ticking in the audio #bitx40help
 
Long leads are trouble.

Also its more like you have a poor ground on the chassis or otherwise know as a ground loop.
To that end make sure all of your grounds are to a single common point.


Allison


Re: Help me! annoying ticking in the audio #bitx40help

SaMa photo SaMa photo
 

Thank you
I will try to follow your advice! If you refer to the transistor mounted alongside the raduino, it heats up a lot !!!
Now I have made a new discovery! He receives nothing! Whether with an antenna or without changing anything! :(
Now I will try to check all the welds on both boards.
What I do not understand is that they must provide me with a working product! If I want to improve it then it's my thing! They say that every card is numbered and tested! But mine ???




Da: BITX20@groups.io <BITX20@groups.io> per conto di Dexter N Muir <dexy@...>
Inviato: mercoledì 18 aprile 2018 22:33
A: BITX20@groups.io
Oggetto: Re: [BITX20] Help me! annoying ticking in the audio #bitx40help
 
Acknowledged, Raj.
The regularity of the ticking points to the processor loop due to the old library. Upgrade to latest (CEC?) firmware fixes that.

My point, however, is the vulnerability of the audio circuits. The LM IC of the Bitx-40 was vulnerable to instability (not always evident) as the 'in' pin got taken to ground by the volume control wiper, and that 'bottom-end' increase here indicates that same vulnerability. I venture the increase at higher volumes is likely 'bleed-through' from the unused channel - its 'in' pin has a low resistance to ground, and it could well be constantly 'ticking', not evident until the 'used' channel's input sees higher impedance/resistance of the pot.
Better regulation/filtering of the Raduino's power improved much in the Bitx-40- this 'ticking' (as frequency was changed), and overall stability. How hot is your 7405 regulator, SaMa photo SaMa photo? Mine got quite hot, dropping 5V (12V less the 5V out and 2V 'overhead' for effective regulation), so quite possibly running near its limits. Dropping that input voltage to about 8V with a resistor (a scrapped 51-ohm 3-watt did that nicely) gave the opportunity to better filter its input with a good hefty capacitor (I had a scrapped 1000uF to hand, 200uF didn't quite 'cut the mustard'), meaning any 'impulse' from the Raduino (the si5351) had less chance of getting through to the main board's supply.
I'd seen reports of distorted audio at low levels, too, and that was cured with the vulnerability/instability by the resistor to the 'in' pin. Now, if the TDA chip has a similar input circuitry it may well have that same vulnerability - on both channels! QED.
Hope the convoluted logic makes some sense ...
73
Dex, ZL2DEX