Date   
Re: uBITx v5 - with mods

Curt
 

Ravi

Fantastic on your homebrew scratch build. Based upon all the clues, I wonder if there may be a missing connection at the crystal filter. Either try injecting a signal before and after it. If no signal source, use a wire or antenna to grab some signals and noise at the frequency. Also you might bypass that filter with a wire. If the crystal filter is the issue, then try pressing on each crystal. A smaller chance your BFO is way off, not letting signals through hear that become low enough frequency audio.

Its likely one or two simple things. Yes even touching the input of the audio should cause some buzz.

The ubitx purposely has minimal gain to make an excellent receiver. Audio level to drive a speaker is scarce even when its working well.

Curt

bitx40: low RF ower an dead part in RX path?

Stephan Lauffer
 

Hello!

With the AGC mod from Don nd6t I have a lot of fun with my bitx40 again. Without this strong signals overdrive my RX path somewhere (in LM386?) that much that I had strong distortion with volume poti in round about the middle position and above.

But there are two other problems (maybe default bitx40 behaviour or a broken part??):

1st: My RX signal is very weak.
I checked out several small speakers but I need to set volume to max in any case. The bitx is then not as loud as a normal human voice nearby you. Maybe a transistor in the RX path is a problem? I feed a nf signal ~1kHz with some few mV into C116, C107 and C33. Everytime I get a loud and strong signal. On C31 I did not get a good/strong signal. Maybe in this stage is a problem? Is there a paper/wiki how I could nail this problem down? First I thought about another NF stage witha LM380. But after I get the loud signal with my testsignal I guess this is not needed.

2nd: "White noise"/hiss in the NF signal:
I tried to power the PA independend with > 12V for more HF output. This means: After the power plug I split the PWR IN with a LDO for the main 12V circuit and another wire without the LDO into the PA in. So fare, so good. The very interesting part is that I get high freq hiss in the RX signal path as soon as the input voltage exceeds the 12.0V out plus the drop voltage of the LDO. F.e. this means: Clear RX signal up to 12.7V and high freq noise up from here. The noise reaches its max volume about 13.0V. Is this a general problem as soon as I drive the PA with higher volume or is there a change to solve this issui with better groundings/shields..?

Best regards, 73 an thanks for help,
Stephan dc8lz

Re: Wanted

Martin KM6TCD
 

 
We're a bunch of newbies, most still studying for the exam. We've got a budget of $100. Perhaps could raise a bit more.
So a buit and tested kit would be a good option.
km6tcd

Sent: Thursday, June 06, 2019 at 9:39 AM
From: "iz oos" <and2oosiz2@...>
To: BITX20@groups.io
Subject: Re: [BITX20] Wanted

The ubitx might scare the majority... being too educational. There are by the way really good (low phase noise, good blocking etc) and durable transceivers, like the IC-765. Of course I would vote for the ubitx, but consider the 'hey teacher we don't need education' .

 
Il 06/giu/2019 08:51, "Balasubramanyan Cp" <bsnvu2yc73s@...> ha scritto:
Dear CLUB MEMBERS/OM/YL,
Why not to get uBITX VERSION 5 LSB & CW MULTIBAND 10W QRP from OM Farhan, INDIA ?  It is very very very good IN ALL RESPECT !!!!!!
73s.  Email bsnvu2yc73s@....
 
 
On Wed, Jun 5, 2019 at 8:55 PM Adrian Chadd <adrian@...> wrote:
Yeah, hit me up. I'm local to you (east oakland) and can help you get
a HF transceiver.



-adrian

On Wed, 5 Jun 2019 at 10:38, Martin KM6TCD <peaceofandalus@...> wrote:
>
> Our club is looking for a built, tested, and working transceiver.
>
> Anyone got one they might sell?
>
> km6tcd
>


 

 

 

Re: uBitx V3 transmit probles.

Dennis Yancey
 

Thanks, will look at that in a bit.. appreciate the suggestion.
--
72 and God bless
KD4EPG

Re: Wanted

Adrian Chadd
 

Heh, hit me up privately (adrian.chadd@...) - I'll give you a
radio for your club. :)


-a
(kk6vqk)

On Sun, 9 Jun 2019 at 13:36, Martin KM6TCD <peaceofandalus@...> wrote:


We're a bunch of newbies, most still studying for the exam. We've got a budget of $100. Perhaps could raise a bit more.
So a buit and tested kit would be a good option.
km6tcd
Sent: Thursday, June 06, 2019 at 9:39 AM
From: "iz oos" <and2oosiz2@...>
To: BITX20@groups.io
Subject: Re: [BITX20] Wanted

The ubitx might scare the majority... being too educational. There are by the way really good (low phase noise, good blocking etc) and durable transceivers, like the IC-765. Of course I would vote for the ubitx, but consider the 'hey teacher we don't need education' .


Il 06/giu/2019 08:51, "Balasubramanyan Cp" <bsnvu2yc73s@...> ha scritto:

Dear CLUB MEMBERS/OM/YL,
Why not to get uBITX VERSION 5 LSB & CW MULTIBAND 10W QRP from OM Farhan, INDIA ? It is very very very good IN ALL RESPECT !!!!!!
73s. Email bsnvu2yc73s@....


On Wed, Jun 5, 2019 at 8:55 PM Adrian Chadd <adrian@...> wrote:

Yeah, hit me up. I'm local to you (east oakland) and can help you get
a HF transceiver.



-adrian

On Wed, 5 Jun 2019 at 10:38, Martin KM6TCD <peaceofandalus@...> wrote:

Our club is looking for a built, tested, and working transceiver.

Anyone got one they might sell?

km6tcd



Re: [QRPLabs] Preliminary results -- W8TEE/AC8GY Mag Loop Testing

vajra guru
 

I would like to call attention to the work of members of the Elmira Radio Club in refining the EH antenna... Paul VE3PVB and Al VA3TET among others were leaders in the project, taking Ted Hart's work as their starting point, and got some very encouraging results... You can read more here:
Best, Calvin VE3EIT 



On Saturday, June 1, 2019, Alan de G1FXB via Groups.Io <g1fxb=yahoo.co.uk@groups.io> wrote:

Hi Alison,

I recall you done antenna R&D.

RE my comments: feeder radiation?? etc,?? and one of the examples I was eluding to:-

Ever have reason to look at the work of Ted Hart?? W5QJR ? EH antennas in either their or your commercial or hobby capacity?

Perhaps 5, never as many as 10 vearment supporters & no one else in the world could get them to work however "tweaky" the MKII / MKIII designs evolved

Had a massive US Mil. grant for their R&D, nothing. Failed to convince the IEEE with all their techno babble papers as to the theory?

However I bet they have nice retirement homes......


Maybe I'm an old fashioned dinosaur?

Way off topic... but "Do they work?"

a quick yes or no will suffice.?? :-)

--- .???? --- --- ---

regards Alan

??

On 01/06/2019 21:28, ajparent1/KB1GMX wrote:
Alan de G1FXB,

Your correct.?? any testing and I've done a lot with small loops you need lots of??
"shield breakers" or choking to remove the COAX shield as a possible secondary
coupling making it an undesired array and often clouding results or minimally
distorting patterns greatly.

If the RF source is small and self contained it can be at or very near the
feed point and make the problem easier.?? Same applies for receivers
as well.

Generally Loops, large or small, are considered self contained antennas not
requiring ground planes or counterpoises.?? However in the real world those
will exist.?? As a result supports or cables and the very existence of the
ground below it do influence the results.

Allison

Re: RX of uBITx V3 fried - which components to change? #ubitx

Sascha Bohnet | DL5SMB
 

So I am at home again and the troubleshooting begins :-)

Maybe thats's a stupid question, but should there be a DC short within the antenna line between the relais K1 (14) and ground in the signal path?

I first thought Q3 in ND6DTs AGC was dead as I had a short between Ground and RF-Out. I then replaced it and noticed hat that did not help and Q3 had again a short between Source and Drain.

So i took took out the AGC, tried to find the problem on the small PCB and noticed that the short (about 3 Ohm) was in fact on the uBITX itself. I am a bit bad at reading schematics,
but then i found T2, where the signal path 1 is connected to 6 GND . So this is normal beaviour, am I correct?

Mounting Low Pass Filter Relays On Bottom of Circuit Board

 

While replacing the four low pass filter relays with Axicom units, a thought occurred to mount the relays on the bottom side of the circuit board. The bottom side is mostly a ground plane. Wonder if there might be any advantage in isolation of signals ? Have no way of measuring. Perhaps someone with more RF experience can comment.

Re: Mounting Low Pass Filter Relays On Bottom of Circuit Board

Jim Sheldon
 

Already tried that a long time ago - didn't make much, if any difference on my Siglent SSA 3021X spectrum analyzer so not really worth the trouble IMO.

W0EB

------ Original Message ------
From: "wishbone_aaa" <@Wishbone>
To: BITX20@groups.io
Sent: 6/9/2019 7:51:42 PM
Subject: [BITX20] Mounting Low Pass Filter Relays On Bottom of Circuit Board

While replacing the four low pass filter relays with Axicom units, a thought occurred to mount the relays on the bottom side of the circuit board. The bottom side is mostly a ground plane. Wonder if there might be any advantage in isolation of signals ? Have no way of measuring. Perhaps someone with more RF experience can comment.


Re: RX of uBITx V3 fried - which components to change? #ubitx

Jerry Gaffke
 

Yes, on the uBitx, K1-14 is shorted to ground for DC by T2 pins 1 and 6 by way of L1,L2,L3,L4.
At DC, T2,L1,L2,L3,L4 are all just a few centimeters of magnet wire, and present very little resistance.
At an RF frequency of 3.5mhz and more where our ham bands are, they present significant impedances.

Jerry, KE7ER



On Sun, Jun 9, 2019 at 05:26 PM, Sascha Bohnet | DL5SMB wrote:

So I am at home again and the troubleshooting begins :-)

Maybe thats's a stupid question, but should there be a DC short within the antenna line between the relais K1 (14) and ground in the signal path?

I first thought Q3 in ND6DTs AGC was dead as I had a short between Ground and RF-Out. I then replaced it and noticed hat that did not help and Q3 had again a short between Source and Drain.

So i took took out the AGC, tried to find the problem on the small PCB and noticed that the short (about 3 Ohm) was in fact on the uBITX itself. I am a bit bad at reading schematics,
but then i found T2, where the signal path 1 is connected to 6 GND . So this is normal beaviour, am I correct?

Re: bitx40: low RF ower an dead part in RX path?

Jerry Gaffke
 

Stephan,

Driving 1khz into C31 is not going to give much response because the amplifier at Q3
is operating at 12mhz, and the 0.1uF at C33 will mostly block the 1khz audio frequency. 
The signals through Q3 remain at 12mhz until after going through the mixer at D15,D16,T4,
after which they are at audio frequencies.

Here's an easy way to do a rough check of the gain of each stage of a receiver:
    http://bitxhacks.blogspot.com/2016/12/troubleshooting-bitx40.html
Farhan uses a piece of wire that's maybe a meter or two long as an antenna, nothing attached to the far end of the wire.
Your household environment will have 60hz power hum and lots of RF signals from digital clocks and light dimmers
and natural atmospheric disturbances, all of which get picked up by the wire to provide the test signal.

If the Bitx40 is getting signals strong enough that you need the AGC circuit to prevent the audio from distorting,
that distortion is probably coming from too large of a signal into the Q12 audio pre-amp stage. 
The LM386 audio amplifier should then give plenty of volume.
I suggest you triple check the way the volume control and speaker have been wired up,
perhaps try a larger speaker.
    
The three terminal Low-Dropout-Regulator should work fine if used with the recommended bypass caps.
You don't say which LDO you are using, here's a datasheet for the popular LM7812 (and many variants of it).
They recommend a 0.22uF cap to ground at the input pin of the regulator to avoid oscillation,
which may very well be the source of your noise problem.  (Maybe just two common 0.1uF caps in parallel.)
A 0.1uF cap from output pin to ground is not a bad idea.
 
Jerry, KE7ER


On Sun, Jun 9, 2019 at 09:32 AM, Stephan Lauffer wrote:

Hello!

With the AGC mod from Don nd6t I have a lot of fun with my bitx40 again. Without this strong signals overdrive my RX path somewhere (in LM386?) that much that I had strong distortion with volume poti in round about the middle position and above.

But there are two other problems (maybe default bitx40 behaviour or a broken part??):

1st: My RX signal is very weak.
I checked out several small speakers but I need to set volume to max in any case. The bitx is then not as loud as a normal human voice nearby you. Maybe a transistor in the RX path is a problem? I feed a nf signal ~1kHz with some few mV into C116, C107 and C33. Everytime I get a loud and strong signal. On C31 I did not get a good/strong signal. Maybe in this stage is a problem? Is there a paper/wiki how I could nail this problem down? First I thought about another NF stage witha LM380. But after I get the loud signal with my testsignal I guess this is not needed.

2nd: "White noise"/hiss in the NF signal:
I tried to power the PA independend with > 12V for more HF output. This means: After the power plug I split the PWR IN with a LDO for the main 12V circuit and another wire without the LDO into the PA in. So fare, so good. The very interesting part is that I get high freq hiss in the RX signal path as soon as the input voltage exceeds the 12.0V out plus the drop voltage of the LDO. F.e. this means: Clear RX signal up to 12.7V and high freq noise up from here. The noise reaches its max volume about 13.0V. Is this a general problem as soon as I drive the PA with higher volume or is there a change to solve this issui with better groundings/shields..?

Best regards, 73 an thanks for help,
Stephan dc8lz

Installing BCI and Kit-Projects AGC

Joel Trenalone
 

Hello All,
I have been working on a UBITX V5 and am installing both a BCI filter and the Kit-Projects AGC. According to what I have read regarding the BCI FILTER and the Kit-Projects AGC, both are installed by cutting in the RF receive path between K3 & K1. 

The way I read the schematic, the receive path travels from the antenna through K3 to K1 and on to the receiver. All the instructions (Kit-Projects and UBITX.net) show the AGC installed immediately after K3, then install the BCI then onto K1 (in that order). 

My my question is for the AGC to work properly, shouldn’t it be installed after the BCI filter (So the AM broadcast is filtered out)?

Please excuse my ignorance, but before I cut the trace and install these two modifications, I want to make sure they are in the right order,

Thanks in advance,
Joel KD6AGW :)

Re: Installing BCI and Kit-Projects AGC

Jerry Gaffke
 

The AGC board operates on two different signals in the radio.

AGC attenuation level is determined by measuring the audio signal level
after all of the filters that pick out only your signal of interest.
The AGC board is physically placed in the incoming RF path (not in the audio section)
so it can best attenuate the very low level signal coming in from the antenna.  

You might be right that the BCI filter would be better placed in front of the AGC board,
this could help if incoming AM broadcast band signals are 10 times stronger than all the shortwave signals.
But if the AGC board's RF attenuator is sufficiently linear, it won't make any difference.
I don't see any advantage in having the BCI filter after the AGC attenuator.

Jerry, KE7ER


On Sun, Jun 9, 2019 at 09:52 PM, Joel Trenalone wrote:
Hello All,
I have been working on a UBITX V5 and am installing both a BCI filter and the Kit-Projects AGC. According to what I have read regarding the BCI FILTER and the Kit-Projects AGC, both are installed by cutting in the RF receive path between K3 & K1. 

The way I read the schematic, the receive path travels from the antenna through K3 to K1 and on to the receiver. All the instructions (Kit-Projects and UBITX.net) show the AGC installed immediately after K3, then install the BCI then onto K1 (in that order). 

My my question is for the AGC to work properly, shouldn’t it be installed after the BCI filter (So the AM broadcast is filtered out)?

Please excuse my ignorance, but before I cut the trace and install these two modifications, I want to make sure they are in the right order,

Thanks in advance,
Joel KD6AGW :)

Re: Installing BCI and Kit-Projects AGC

Curt
 

Joel

no such thing as ignorance here - hopefully we are all still learning! 

this is what I see:

The AGC operates on downstream signals, after the IF filtering.  The sensing part of the AGC does NOT see the AM (medium wave) signals. 

The AGC does its attenuation with MOSFET devices.  My experience with devices is that their linearity does vary with bias - I am thinking they can be less linear when given an in-between bias.  So I think your logic is best - to put the filter first so that the AGC attenuator does not experience large out-of-band energy. 

Of course - if your ubitx is not operated anywhere near a many-kW AM station -- then it may not matter at all. 

73 Curt

PS - Mr Magoo here (me) with poor vision is straightening out the signal-strength meter wiring connected to a VK3YE circuit.  I like this AGC, and the meter is now working decently.  Instead of Peter's configuration in parallel with the LED, I have it in series via a shunt resistor.  It better represents signal strength than the parallel implementation.  You guys can snicker at this 'minority' AGC circuit but it works nicely.  Best wishes with whatever circuitry you all are using - this is a cool rig! 

Re: uBITx v5 - with mods

Ravi Miranda
 

Hi Sarma, Farhan, Curt,

Thank you all for replying so quickly. I have carried out the following:


a. I have used KD8CEC v1.20 for uBITx V5
b. The #define has been set for V5
c. I have an approx. 100mV signal now (10MHz) and injected that. On
hearing low output at the output, I proceeded to do the math to
calculate the values at each stage.

Here are the equations used. Assuming USB

1. IF_A_FREQ = VFO FREQ - INP_FREQ [IF_A_FREQ ---- should be a value
of 45MHz so that it can get through the 45 MHz crystal filter
+/-7.5Khz]
2. OP_FREQUENCY = IF_LOCAL_OSC - IF_A_FREQ [OP_FREQUENCY ---- should
be centred on 11.0592 000 (or thereabouts) to get through the Ladder
filter
3. AUDIO_OUT = BFO_FREQUENCY - OP_FREQUENCY [If both match correctly,
we get a ZERO Beat] if the BFO_FREQUENCY > OP_FREQUENCY we get LSB and
the other way we get USB.

Using these calculations, I arrived at a frequency difference of 6660
[strange number if you get the drift :-) ] No pun intended.

With no calibration, I got nothing, not surprising as the frequency was way off.

Using a frequency meter, I set the calibration of the XTAL from
25.000.000 to 25.003.090 (This value was found using
https://groups.io/g/BITX20/wiki/Si5351-Calibration-Sketch)
The pitch of the tone may have changed, not sure at this stage it was very late.

Using the IF Shift menu option I moved the IFShift to 6660, and the
tone was clearly there. [LOUD]

Having set this right (so far), I tried the whip antenna in the
balcony (sorry no dipole). There are no signals to be heard at all. So
I have the following questions.
1. Should I change the VFO base frequency to 45.005.000 (given that
the two inductances at both sides are pulling the crystal filter off?
If so what is the best value to set this to, and where in the program
2. Are the equations above correct
3. Instead of the IFShift of 6600 should I be thinking of changing the
#define SECOND_OSC_USB (56054200l)
#define SECOND_OSC_LSB (33940800l)
to better take into account the shift and therefore bring the shift
(as shown in pt.3 above to 0)
4. To improve reception of signals with my antenna, should I add an RF
preamp prior to the antenna input? This could be switched in via a
relay and not kept in the transmit path (not really sure here as I
haven't managed to test transmit section yet.
5. What are the effects of setting lower or higher current values for
SI5351(2,4,6,8)

Is there a worked example that has
a. BASE_VFO_FREQUENCY
b. USB_FREQUENCY
c. LSB_FREQUENCY
d. BFO_FREQUENCY

I can then use the calibration program to generate these three signals
and do measurements?

Many thanks for taking time to help me with this.

Best 73,

Ravi/M0RVI


On Sun, 9 Jun 2019 at 17:31, Curt via Groups.Io
<wb8yyy=yahoo.com@groups.io> wrote:

Ravi

Fantastic on your homebrew scratch build. Based upon all the clues, I wonder if there may be a missing connection at the crystal filter. Either try injecting a signal before and after it. If no signal source, use a wire or antenna to grab some signals and noise at the frequency. Also you might bypass that filter with a wire. If the crystal filter is the issue, then try pressing on each crystal. A smaller chance your BFO is way off, not letting signals through hear that become low enough frequency audio.

Its likely one or two simple things. Yes even touching the input of the audio should cause some buzz.

The ubitx purposely has minimal gain to make an excellent receiver. Audio level to drive a speaker is scarce even when its working well.

Curt


--
I'm here to add more value to the world than I'm using up.

Re: Antuino

 

Any idea when the Antuino will available to the general public?

Joel
N6ALT

Re: [QRPLabs] Preliminary results -- W8TEE/AC8GY Mag Loop Testing

GM4CID
 

Brings to mind the crossed field loop antenna of Maurice Hately GM3HAT.

I could never make up my mind as to the veracity of his claims, what do others think?

Article at http://www.infotechcomms.net/downloads/GM3HAT_CFL.pdf

73 Bob GM4CID


Re: Nextion display cutout and mounting. #ubitx #ubitx-help

_Dave_ K0MBT
 

My firmware won't run both the two line display and the nextion display. When I plug in the two line display I don't see proper characters.

What this suggests to me is that if you can see the 2 line display you need different settings in the firmware to allow the nextion display to work.

I have stl files for the 2.8 3.2 and 3.5 versions of the display if you want to print them.
dave
k0mbt

Re: Installing BCI and Kit-Projects AGC

KE2GKB
 

Hey guys! 
So the agc bias is actually determined by what it in the audio passband not the RF passband. It works as a variable attenuator on the RX path based off the demodulated audio out as bias.

In short it honestly should not matter if it's before or after the BCI! 

Personally I would put the BCI before it no need to risk greater distortion on receive due to overload on any of the parts but hey. 

73

On Mon, Jun 10, 2019, 8:29 AM Curt via Groups.Io <wb8yyy=yahoo.com@groups.io> wrote:
Joel

no such thing as ignorance here - hopefully we are all still learning! 

this is what I see:

The AGC operates on downstream signals, after the IF filtering.  The sensing part of the AGC does NOT see the AM (medium wave) signals. 

The AGC does its attenuation with MOSFET devices.  My experience with devices is that their linearity does vary with bias - I am thinking they can be less linear when given an in-between bias.  So I think your logic is best - to put the filter first so that the AGC attenuator does not experience large out-of-band energy. 

Of course - if your ubitx is not operated anywhere near a many-kW AM station -- then it may not matter at all. 

73 Curt

PS - Mr Magoo here (me) with poor vision is straightening out the signal-strength meter wiring connected to a VK3YE circuit.  I like this AGC, and the meter is now working decently.  Instead of Peter's configuration in parallel with the LED, I have it in series via a shunt resistor.  It better represents signal strength than the parallel implementation.  You guys can snicker at this 'minority' AGC circuit but it works nicely.  Best wishes with whatever circuitry you all are using - this is a cool rig! 


--
Tim Keller - KE2GKB
https://shop.kit-projects.com

Re: uBITx v5 - with mods

Sandeep Lohia
 


On Mon 10 Jun, 2019, 6:40 PM Ravi Miranda, <ravimiranda@...> wrote:
Hi Sarma, Farhan, Curt,

Thank you all for replying so quickly. I have carried out the following:


a. I have used KD8CEC v1.20 for uBITx V5
b. The #define has been set for V5
c. I have an approx. 100mV signal now (10MHz) and injected that. On
hearing low output at the output, I proceeded to do the math to
calculate the values at each stage.

Here are the equations used. Assuming USB

1. IF_A_FREQ = VFO FREQ - INP_FREQ  [IF_A_FREQ ---- should be a value
of 45MHz so that it can get through the 45 MHz crystal filter
+/-7.5Khz]
2. OP_FREQUENCY = IF_LOCAL_OSC - IF_A_FREQ [OP_FREQUENCY ---- should
be centred on 11.0592 000 (or thereabouts) to get through the Ladder
filter
3. AUDIO_OUT = BFO_FREQUENCY - OP_FREQUENCY [If both match correctly,
we get a ZERO Beat] if the BFO_FREQUENCY > OP_FREQUENCY we get LSB and
the other way we get USB.

Using these calculations, I arrived at a frequency difference of 6660
[strange number if you get the drift :-)  ] No pun intended.

With no calibration, I got nothing, not surprising as the frequency was way off.

Using a frequency meter, I set the calibration of the XTAL from
25.000.000 to 25.003.090 (This value was found using
https://groups.io/g/BITX20/wiki/Si5351-Calibration-Sketch)
The pitch of the tone may have changed, not sure at this stage it was very late.

Using the IF Shift menu option I moved the IFShift  to 6660, and the
tone was clearly there. [LOUD]

Having set this right (so far), I tried the whip antenna in the
balcony (sorry no dipole). There are no signals to be heard at all. So
I have the following questions.
1. Should I change the VFO base frequency to 45.005.000 (given that
the two inductances at both sides are pulling the crystal filter off?
If so what is the best value to set this to, and where in the program
2. Are the equations above correct
3. Instead of the IFShift of 6600 should I be thinking of changing the
#define SECOND_OSC_USB (56054200l)
#define SECOND_OSC_LSB (33940800l)
to better take into account the shift and therefore bring the shift
(as shown in pt.3 above to 0)
4. To improve reception of signals with my antenna, should I add an RF
preamp prior to the antenna input? This could be switched in via a
relay and not kept in the transmit path (not really sure here as I
haven't managed to test transmit section yet.
5. What are the effects of setting lower or higher current values for
SI5351(2,4,6,8)

Is there a worked example that has
a. BASE_VFO_FREQUENCY
b. USB_FREQUENCY
c. LSB_FREQUENCY
d. BFO_FREQUENCY

I can then use the calibration program to generate these three signals
and do measurements?

Many thanks for taking time to help me with this.

Best 73,

Ravi/M0RVI


On Sun, 9 Jun 2019 at 17:31, Curt via Groups.Io
<wb8yyy=yahoo.com@groups.io> wrote:
>
> Ravi
>
> Fantastic on your homebrew scratch build. Based upon all the clues, I wonder if there may be a missing connection at the crystal filter. Either try injecting a signal before and after it. If no signal source, use a wire or antenna to grab some signals and noise at the frequency. Also you might bypass that filter with a wire. If the crystal filter is the issue, then try pressing on each crystal. A smaller chance your BFO is way off, not letting signals through hear that become low enough frequency audio.
>
> Its likely one or two simple things. Yes even touching the input of the audio should cause some buzz.
>
> The ubitx purposely has minimal gain to make an excellent receiver. Audio level to drive a speaker is scarce even when its working well.
>
> Curt
>



--
I'm here to add more value to the world than I'm using up.