Re: Sunil Lakhani's AGC board connections to uBITX #ubitx

#61146

Perfect!? Thank you Sunil.? This is even better than the one I first saw and forgot to save.? I saved this in several places now so I won't forget it again - LOL.

73
Jim - W0EB

Re: Sunil Lakhani's AGC board connections to uBITX #ubitx

#61145

Here is the download link JIm

/g/BITX20/files/AGC%20BITX%20UBITX/AGC%20Details.pdf?fbclid=IwAR3gsSFpIW-WgVlFpl3Q9lQjie_gkdJpBMgKUGTwSM_vSECmRuJ3xRHH6cs

New file uploaded to [email protected]

[email protected] Notification

#61144

Hello,

This email message is a notification to let you know that a file has been uploaded to the Files area of the [email protected] group.

File: AGC Details.pdf

Uploaded By: Sunil Lakhani

Description:
LM324 AGC with Analogue VU Meter works for bitx and ubitx .

You can access this file at the URL:
/g/BITX20/files/AGC%20BITX%20UBITX/AGC%20Details.pdf

Cheers,
The Groups.io Team

Re: SolderSmoke Podcast #207 uBITX 15 Mtrs, 60 mtrs, homebrew, antennas, Cubesats

#61143

I have not tried at higher voltage.

With relay change the harmonics drop a lot specially in lower bands. Alsong with harmonics
the spurs drop. L5/7 change will help more but can do without.

What is critical is to keep the drive down. Target 10W on 40M and rest of the bands should be
fine. You can reduce by drive control.

Raj

Show quoted text

At 30-10-18, you wrote:
Raj, what are the spurs like when running finals at higher voltages. 24v has been suggested.

Re: looking for a 40M QRP SSB kit

Timothy Fidler

#61142

The only way to do a Mkars80 conversion is to change the IF to? 12 Mhz and make all the corresponding changes of which there are many.? ?If you want a correct frequency display you will have to get new software from the vendor .For obvious reasons he doss not want to support potential tech idiots with no grasp on something he did not even sell them.? Some have tried to convert it with 10 M IF and is is nest of snakes.? If you don't get the software upgrade it might twork but you will have to have a look up table for the frequencies? (It uses Huf? and Puff VFO so the VFO just locks on last frequency it saw .. it does not use a rotary encoder or the like.? Be? quick.? If you look at the site it is? clear he is going to shut down production for lack o some components , in particular the? VFO? Polyvarcon.? ?It would be a VERY nice radio on 40m as it is fully engineered , not just? box of components chucked together for maximum profit? and with a switched IF and other changes , it could in? fact be an 80/40 dual band tcvr.? TEF? Oct 18 (in case this cget cut and pasted to forward).?

Re: Sideband rejection

#61141

Set the BFO to 11.9965 and see if that works.

Show quoted text

At 29-10-18, you wrote:
After relay change my uBitx 4.3 is now capable for legal CW QSOs. So I did the next step and changed L5,L7 and L1 to 680 / 330 nH.
The first test on SSB via dummyload and 20db extra attenuation direct in the antenna of my good old SDR-IQ shows a rather clean signal in the RF spectrum at 10kHz width - but looking like AM and not like LSB on 3.6 MHz. Test with other stations confirmed that. The carrier is still present and the USB sideband is only 6dB down compared with LSB.
Surely the BFO must be corrected. But how? I followed the instructions, got a AM station with known frequency and set BFO to zero beat. Was then happy, to have a clean reception of all SSB stations on the QRGs where they were spotted.

73 Matthias, DD7NT

Re: Sunil Lakhani's AGC board connections to uBITX #ubitx

#61140

This is for the bitx 20 it goes to the base of transistor? Q2 and ground. Altering the gain at the 1st IF transistor.

Is this the board you are refering to?

I am not sure you can use that AGC board on the Ubitx instead I suggest you take a look at

and also

You dont have to fit the RFgain pot on the front panel though, you could just use the suggested AGC circuit.

Either way you will have to break into the track shown.

Hope that helps.

?

----------------------------------------------------------------------------------------------------

May the Morse be with you!

Re: Sunil Lakhani's AGC board connections to uBITX #ubitx

#61139

Jim?

--
John - N0CTL - Fulltime RV in a 40' motorhome

Re: Dummy Load Resistors

#61137

Here is a power resistor I used in another dummy load. These could be an alternative if the ones specified for this project are hard to find.

I used two on a heatsink. Possibility in oil the wattage these can handle would be increased. The small heatsinks attached, while in the oil would likely help.?

Tom, wb6b

Re: Mike element

#61136

Did you mean this one??

Show quoted text

On Sat, Oct 27, 2018, 1:12 PM Frank Dinger , EI7KS <ei7ks.frank@...> wrote:

Chinese on-line retailers sell electrets with external amplifier on a 15x20mm board complete with separate 5 pin header.? This unit seem to be very effective for BITX radios.? Past week? I received 2 pcs .

Frank? ,? EI7KS

Re: SolderSmoke Podcast #207 uBITX 15 Mtrs, 60 mtrs, homebrew, antennas, Cubesats

#61135

Raj, what are the spurs like when running finals at higher voltages. 24v has been suggested.?

Re: Sideband rejection

#61134

Better yet, repeatedly do both steps until no further adjustment is needed.
I have no idea how the two different adjustments might affect each other with the firmware you are using.

Show quoted text

On Mon, Oct 29, 2018 at 09:17 AM, Jerry Gaffke wrote:

I suggest you set the BFO first, then calibrate the rig to be on the correct frequency.

Re: Sideband rejection

#61133

I don't know what firmware you are using or what instructions you are following.
Tuning for zero-beat makes sense to me when calibrating the si5351 reference oscillator
so the rig is on the correct frequency.
But tuning for zero-beat does not make sense when setting the BFO offset with respect to the 12mhz filter.

I don't think many firmware releases calibrate using algorithm of post???/g/BITX20/message/54501
or tune the rig following the algorithm of post??/g/BITX20/message/44278
That being the case, there may be weird dependencies between calibrating and setting the BFO,
I suggest you set the BFO first, then calibrate the rig to be on the correct frequency.

To set the BFO, I suggest you tune in an amateur SSB station, then set the BFO for best received audio.
Ideally, find a station where the operator's voice is similar to your own (low, medium, or high pitched).
When transmitting, the filter will be doing the same thing to your voice as rig does when receiving.

Jerry?

Show quoted text

On Mon, Oct 29, 2018 at 08:55 AM, Matthias Zwoch wrote:

Surely the BFO must be corrected. But how? I followed the instructions, got a AM station with known frequency and set BFO to zero beat.??

Sideband rejection

#61132

After relay change my uBitx 4.3 is now capable for legal CW QSOs. So I did the next step and changed L5,L7 and L1 to 680 / 330 nH.
The first test on SSB via dummyload and 20db extra attenuation direct in the antenna of my good old SDR-IQ shows a rather clean signal in the RF spectrum at 10kHz width - but looking like AM and not like LSB on 3.6 MHz. Test with other stations confirmed that. The carrier is still present and the USB sideband is only 6dB down compared with LSB.
Surely the BFO must be corrected. But how? I followed the instructions, got a AM station with known frequency and set BFO to zero beat. Was then happy, to have a clean reception of all SSB stations on the QRGs where they were spotted.

73 Matthias, DD7NT

Re: Sunil Lakhani's AGC board connections to uBITX #ubitx

#61131

Merci, but no - what I am looking for is NOT in this .rar.

Jim

Re: uBitX CW Sidetone Volume

Marko Pavlicevic

#61130

All this when TX is off!

Re: uBitX CW Sidetone Volume

Marko Pavlicevic

#61129

Raj, I will try this.

Bill... tried that, but when keying the transmitter, I still hear the bumping of Raduino... even if the CW TONE line is grounded.

Re: Sunil Lakhani's AGC board connections to uBITX #ubitx

#61128

Hello

Voici le fichier .rar

73 QRO

F1BFU - Fr

Show quoted text

Le?lun. 29 oct. 2018 à?14:38, Jim Sheldon <w0eb@...> a écrit?:

Thanks Art, I already have that file and the actual schematic with connections shown is NOT in that .rar.? There was another one that got posted somewhere that actually had the connections for IF-1 and IF-2 shown on the AGC schematic but I need to know where those points actually are on a uBITX V4 board.? That's what I cant seem to find.

Jim

--

Gilles - F1BFU/FR

AGC.rar

Re: Sunil Lakhani's AGC board connections to uBITX #ubitx

#61127

Thanks Art, I already have that file and the actual schematic with connections shown is NOT in that .rar.? There was another one that got posted somewhere that actually had the connections for IF-1 and IF-2 shown on the AGC schematic but I need to know where those points actually are on a uBITX V4 board.? That's what I cant seem to find.

Jim

Re: Sunil Lakhani's AGC board connections to uBITX #ubitx

#61126

开云体育

Jim

?

Agc kit file

?

Art N2AJO

?

Show quoted text

From: [email protected] <[email protected]> On Behalf Of Jim Sheldon
Sent: Monday, October 29, 2018 9:00 AM
To: [email protected]
Subject: Re: [BITX20] Sunil Lakhani's AGC board connections to uBITX #ubitx

?

That's not the AGC board, that's the front panel board to one of Sunil's cases.? The AGC board is a separate kit from them.

Jim

Virus-free.

AGC.rar