Date   

Re: More questions

 

I dreamed up a work around for Allards CW mod with mine!

Add a 1K across C107. Feed Allards CW DC voltage to the common of D15/16 through a 10K!
Current flows through the diode and the new resistor to ground to unbalance the mixer.

Bobs your uncle! My elmer used to say!

Raj


At 19/10/2017, you wrote:
Note that this fix is not compatible with Allard's instructions for using the rig on CW.

Also, note that there are two PTT bursts. 
Raj's fix is for the carrier burst that transmits out over the air.
There's also a kerchunk you hear in the headphones.

Jerry, KE7ER


On Thu, Oct 19, 2017 at 01:31 am, Raj vu2zap wrote:
The carrier burst on PTT is due to the C122 charging up through D15 or 16 unbalancing it and allowing a leak.

Quick fix is put a 0.68uF cap from the common of D15/16 to the atten pad R39. A track has to be cut.
If your board has a trimpot there then you can tombstone the pot and add the cap.

A 1K resistor across C107 helps.

The leak is almost eliminated.

Re: uBITX Questions

Jean-Matthieu F5RCT
 

Spectrum at CLK0 (1st LO) with second LO at 57 MHz and third at 12 MHz

Re: uBITX Questions

Jean-Matthieu F5RCT
 

Hello All,

The software version I got from Fahran *-V12.ino I think it is was a draft version and it doesn't work.

I took the release here : https://github.com/afarhan/ubitx
but this version uses an old library of the Si5351. I udpated to the new library and it works !

Did someone connect it to a spectrum analyser ?
there is a LOT of spurious and crosstalk between outputs !
73 de F5RCT

Re: More questions

Gary O'Neil
 

Since abandoning a software hack, I've attempted ferreting out a hardware hack to get rid of the PTT burst, but. I've only been able to cut it back, However; in so doing, I have measured the burst and discovered that it occurs in both CW and SSB modes, and in both cases the burst is consistent and decays after approximately 6 ms. In CW mode there appears to be a built in 15 ms startup delay, which includes the TX-RX delay of 5 ms after keying the relay, As I recall, the switching spec for the relays is 7 ms max., which means PTT_sense is visited within less than 10ms after PTT is activated. Even better... with your scheme, the code will be 7 ms into the task of shutting down the clock before the relay finally switches, bringing the delay down to near zero. I will be giving this a try while waiting for Allard's next release. As gate keeper of the software, he will know the fastest path to toggle the clock.

I'll be looking at implementing the AGC next also. If I understand your suggestion on this, I don't think it will work. The 5V PTT_Sense goes to zero when transitioning to receive. Assuming this is what you wish to sense, this would turn the fet off, causing the audio to go to maximum. His AGC voltage is positive, but it enables him to use the logic FET, which turns off at zero volts.
 
Gary, N3GO

Re: More questions

Gary O'Neil
 

Great Job Dave;

     I spent an inordinate amount of time trying to figure out how to toggle the clock, and finally resorted to looking up the register in the 5351 datasheet. My head started spinning when I attempted to hack into the code to find the best place to do this, then gave up and decided to try using the PTT_sense line without any hardware modification. It didn't occur to me to simply wire or the Mic PTT with PTT Sense. PTT_sense doesn't get sensed until some time after K1 switches, and I gave up on trying to hack the code for the fix.No question that your idea will work... Very elegant indeed. 




Re: Standoff question

 

Compared to you guys I am a teenager at 61!

More than texting I find whatsapp very useful. Both on the phone and PC.
Voice/video calls around the world crystal clear and free!
PC app very useful for keyboard chat and instant exchange of pics etc.

I have been on whatsapp trouble shooting bitxs! much better than email
exchanges.

Raj


At 20/10/2017, you wrote:

Some of us are retired with nothing to do!

Well, at 72 years old, the gal friend bitched so much, I had to buy a lawnmower ( and yes, I paid for it) and mow and weedwack the lawn today!

Now, I can go back to BitXing!

And we are too Old for "LOL" or Texting!


Life is a Beach!

Mike, WA6ISP





On 10/19/2017 3:55 PM, John P wrote:
It's so nice to have too much time on your hands! Â LOL!Â
--
John - WA2FZW


-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID 
"MotDog@..."
Mike@...

Re: More questions

Brent Seres
 

Thanks so much for all of the suggestions. I have the receive kerchunk circuit well using the 2n7000 circuit. I look forward to Allard's update.

73
Brent

Re: Standoff question

John P
 

Hey Mike, I'm only 2 years behind you and between radio projects, airplane projects, house projects, etc. etc. I don't know when I ever had time for work! 
--
John - WA2FZW

Re: Standoff question

Michael Hagen
 

Some of us are retired with nothing to do!

Well, at 72 years old, the gal friend bitched so much, I had to buy a lawnmower ( and yes, I paid for it) and mow and weedwack the lawn today!

Now, I can go back to BitXing!

And we are too Old for "LOL" or Texting!


Life is a Beach!

Mike, WA6ISP





On 10/19/2017 3:55 PM, John P wrote:
It's so nice to have too much time on your hands!  LOL! 
--
John - WA2FZW

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Re: [Bitx40] tests on 20 meters rx

 

I've done some more upgrades to the 45W HF  ($14) Ebay amp, knocking off about a dozen parts and improving the purity overall . I figure the XL primary of the final balun is not matched to the parasitics of the push pull FETs and that's messing with the lower HF purity. Check the logs on the hackaday link in the last msg for the mods and improvements.

Here is the progress so far:


--
AncelB, MIT EE6002

Re: More questions

Allard PE1NWL
 

On Thu, Oct 19, 2017 at 02:02 pm, m0wid wrote:
My hack for the carrier pulse was to take the PTT from the mike directly into the Raduino (same input as PTT sense in Allards code but with pull up enabled) and then add code to turn off the clock from the Si5351, output the PTT to the relays, wait 50ms (may be able to reduce this but for SSB is no problem) then turn the clock on again.
Dave, thanks for sharing this clever idea to suppress the carrier pulse!
I tried it out and even with the standard PTT setup it works great!
So it's not necessary to take the PTT from the mike directly into the Raduino as you did.
It's just two lines of extra code. I'll include your idea in the next version v1.26, along with some other improvements.
To be released soon.
Thanks!

73 Allard PE1NWL

Re: Standoff question

John P
 

It's so nice to have too much time on your hands!  LOL! 
--
John - WA2FZW

Re: Standoff question

Thomas Noel
 

1.8 terafurlongs per fortnight


Caveats:

1. I am not a degreed mechanical engineer.
2. My meds might not be properly titered.
3. The second paragraph above is my conjecture, unsupported by experience and previously unreviewed by competent authority.
4. Fitness for any specific use is purely coincidental.
5. Use of anything in the commentary above is solely at the risk of the user as it is submitted for its entertainment value, if any and no other use is recommended, authorized, or intended.

Thomas Noel
kf7rsf

On Oct 19, 2017, at 2:05 PM, Ashhar Farhan <farhanbox@...> wrote:

i know that m3 screws fit and i measuree the height with the scale in my tools drawer. For those who insist on metric purity, do the math. Anyone got the speed of light in furlongs per fortnight yet?
- f

On 20 Oct 2017 2:29 am, "Michael Hagen" <motdog@...> wrote:

Ash,

Hey, you are mixing Metric with our wonderful SAE Imperial sytem!

Ha..Ha..

They are 0.427" long.


On 10/19/2017 1:47 PM, Ashhar Farhan wrote:
m3 thread on half inch stanoffs
- f

On 20 Oct 2017 1:51 am, "Barrett O" <ogebarrett@...> wrote:
Hey guys I'm looking to buy some extra standoffs of about the same size that come with the bitx to mount some buck converters. does anybody know what size the standoffs are?

Barrett
KG5SSO

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...



Re: Standoff question

John P
 

I bought a bag of 100 1/4" nylon spacers from McMaster-Carr for a couple of bucks. They take a 4-40 screw. I bought them longer than needed and cut them to the required length for whatever I'm using them for. Besides using them for the BitX board, I put spacers between the display and Raduino and have used them on a number of other projects.
--
John - WA2FZW

Re: Standoff question

Ashhar Farhan
 

i know that m3 screws fit and i measuree the height with the scale in my tools drawer. For those who insist on metric purity, do the math. Anyone got the speed of light in furlongs per fortnight yet?
- f

On 20 Oct 2017 2:29 am, "Michael Hagen" <motdog@...> wrote:

Ash,

Hey, you are mixing Metric with our wonderful SAE Imperial sytem!

Ha..Ha..

They are 0.427" long.


On 10/19/2017 1:47 PM, Ashhar Farhan wrote:
m3 thread on half inch stanoffs
- f

On 20 Oct 2017 1:51 am, "Barrett O" <ogebarrett@...> wrote:
Hey guys I'm looking to buy some extra standoffs of about the same size that come with the bitx to mount some buck converters. does anybody know what size the standoffs are?

Barrett
KG5SSO

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Re: More questions

m0wid
 

I have only had my bitx40 for a week but am having lots of fun with it. Great receive audio. My hack for the carrier pulse was to take the PTT from the mike directly into the Raduino (same input as PTT sense in Allards code but with pull up enabled) and then add code to turn off the clock from the Si5351, output the PTT to the relays, wait 50ms (may be able to reduce this but for SSB is no problem) then turn the clock on again. Eliminated the spurious transmission entirely and reduced but not eliminated the pop on the speaker. 
Agc is next hack. Wondering about feeding the 5v PTT out to the relays also into Farhans audio agc circuit via a diode after the diode for rectifying the audio signal. I guess this will turn the fet on effectively shorting the input to the audio amp hopefully before the relays change over.  The time constant in the agc may also remove the tx-Rx pop. Anyone see any problems with that?
 
Dave M0WID
 

Re: Standoff question

Michael Hagen
 

Ash,

Hey, you are mixing Metric with our wonderful SAE Imperial sytem!

Ha..Ha..

They are 0.427" long.


On 10/19/2017 1:47 PM, Ashhar Farhan wrote:
m3 thread on half inch stanoffs
- f

On 20 Oct 2017 1:51 am, "Barrett O" <ogebarrett@...> wrote:
Hey guys I'm looking to buy some extra standoffs of about the same size that come with the bitx to mount some buck converters. does anybody know what size the standoffs are?

Barrett
KG5SSO

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Re: Standoff question

Michael Hagen
 

They are 3mm 0.5 thread.  Metric, and the ones with male stud are not cheap.   Double female holes are the most common.

Mouser or Digikey or surplus vendors would have 4-40 US thread.

The distance on the LCD connector is 0.427".  I make them on the 3D printer and use #4 sheet metal screws.  That allows the LCD to be parallel.

Hole about 0.110" works fine.  I would make them for you, you just do the postage?

The printer takes about 15 min, and I make 6-8 at a time.  They are ABS filament.

Mike, WA6ISP






On 10/19/2017 1:21 PM, Barrett O wrote:
Hey guys I'm looking to buy some extra standoffs of about the same size that come with the bitx to mount some buck converters. does anybody know what size the standoffs are?

Barrett
KG5SSO

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Re: Standoff question

Ashhar Farhan
 

m3 thread on half inch stanoffs
- f

On 20 Oct 2017 1:51 am, "Barrett O" <ogebarrett@...> wrote:
Hey guys I'm looking to buy some extra standoffs of about the same size that come with the bitx to mount some buck converters. does anybody know what size the standoffs are?

Barrett
KG5SSO

Standoff question

Barrett O
 

Hey guys I'm looking to buy some extra standoffs of about the same size that come with the bitx to mount some buck converters. does anybody know what size the standoffs are?

Barrett
KG5SSO