Date   
Re: Sound card interface swivhing

Evan Hand
 

I have used for switching between 2 Raspberry Pis.  Worked well.

Evan
AC9TU

Re: Sound card interface swivhing

d balfour
 

I have put in a dpdt switch in my ubitx. In one position it goes to the mic/speaker and the other position goes to the sound card. You couid put a dpdt switch between two sound cards on the radio side of things.

Re: Sound card interface swivhing

Timothy Fidler
 

He has one sound card in a radio - presumably an SDR tcvr thingy and two computers.    You , D Balfour, ?? have solved another problem - nice try but no cigar.

Re: Homebrew from scratch #ubitx

MVS Sarma
 

Peter,
 Thanks for the new pcb artwork.
 For reasons, I have not been able to open your gerber files using a software "gerber Logix" or under sprint layout that has facility for inputting gerber files.
May I request you gerber files to 274X format please.
regards
sarma
vu3zmv

Re: Homebrew from scratch #ubitx

MVS Sarma
 

I would like to know whether  any other person is able to open these gerber files. If so can he /she help me with a 274X format files of the same.
Peter has already indicated that he would not respond for any message seeking help. Fine, and thanks.

regards
sarma
 vu43zmv


On Sat, Dec 8, 2018 at 1:10 PM MVS Sarma via Groups.Io <mvssarma=gmail.com@groups.io> wrote:
Peter,
 Thanks for the new pcb artwork.
 For reasons, I have not been able to open your gerber files using a software "gerber Logix" or under sprint layout that has facility for inputting gerber files.
May I request you gerber files to 274X format please.
regards
sarma
vu3zmv

Re: a simple spur fix

AndyH
 

No worries Nick - nothing wrong with circles.  hi hi  Revising the thread I see that you were part of it - sorry for the redundant link.

Here are Allison's suggestions for the two RF amps:
45mhz IF replace (Q20, Q21, Q22) with BFR106.  Change R23 to 18ohms.  Change R27 to 39 ohms.
12mhz IF amp change R43 to 18 ohma and put a .1uf in series with 680 ohms across R41.
https://groups.io/g/BITX20/message/51448

Cheers,
Andy

On Mon, Nov 12, 2018 at 08:36 PM, Nick VK4PP wrote:
Thanks Andy.
I have read that, but its all over the place a bit. Probably easy enough if you have a thorough working knowledge of electronics, But for a NOOB like me, I get some of what is said., but really a step by step
replace this with that. and maybe a commoners explanation of what is happening. Could be a good lesson on how these amps work.

My apologies if I seem to be going round in circles. but hey.

Re: a simple spur fix

AndyH
 

Not 'revising' but 'revisiting'.  soz

Two other bits.  Earlier in this thread Farhan reports the benefit of changing R26 and R46 to 220 Ω from 470 Ω.  This is for the stock amps, though - no idea if this is a necessary swap if the transistors are changed to BFR106.
https://groups.io/g/BITX20/message/61586

If you replace Q20/21/22, you want about 6 VDC at the collector of Q20.
https://groups.io/g/BITX20/message/61414

73, Andy


On Sat, Dec 8, 2018 at 04:23 AM, AndyH wrote:
No worries Nick - nothing wrong with circles.  hi hi  Revising the thread I see that you were part of it - sorry for the redundant link.

Here are Allison's suggestions for the two RF amps:
45mhz IF replace (Q20, Q21, Q22) with BFR106.  Change R23 to 18ohms.  Change R27 to 39 ohms.
12mhz IF amp change R43 to 18 ohma and put a .1uf in series with 680 ohms across R41.
https://groups.io/g/BITX20/message/51448

Cheers,
Andy

On Mon, Nov 12, 2018 at 08:36 PM, Nick VK4PP wrote:
Thanks Andy.
I have read that, but its all over the place a bit. Probably easy enough if you have a thorough working knowledge of electronics, But for a NOOB like me, I get some of what is said., but really a step by step
replace this with that. and maybe a commoners explanation of what is happening. Could be a good lesson on how these amps work.

My apologies if I seem to be going round in circles. but hey.

Replacing the BITX40 (and probably uBITX) relays with just a soldering iron

Ryan Flowers
 

Hi all,

I had to replace one of my relays on the BITX40 recently and I made a video of the method I like to use. I'll be honest- some people aren't going to like my method. But it works for me! 

https://miscdotgeek.com/replacing-relays-in-the-bitx-radios/

--
Ryan Flowers - W7RLF
MiscDotGeek.com
Multi Band BITX40
The BITX40 FAQ

Re: a simple spur fix

freefuel@...
 

the Atmel AVR chip can be clocked up to 20MHz, with that said what frequency would be best if we were to replace the crystal on the Arduino board to shift that birdiey to another less offensive location. 

-Justin N2TOH

Re: LSB signal looking more like AM

joshuaclough4@...
 

Thanks for the replies.
Will double check the sdr. The first time I used it (when it displayed the correct LSB signal) It didn't even have an antenna on it, I've since added an indoor (albeit non-hf) antenna, was hoping it would cut down on the sensitivity to an HF radio transmitting outside (the antenna at least, radio is in the same room).

Second to that, I'll try what someone PM'd, suggesting of using the Raduino V2 digital BFO sketch (evidently after doing the proper mods).
https://github.com/amunters/bitx40-raduino-v2

Congrats to Farhan

Russ KG0BK
 

AMSAT News Service Special Bulletin 341.01
From AMSAT HQ KENSINGTON, MD
DATE December 7, 2018
To All RADIO AMATEURS
BID: $ANS-341.01

On December 3rd, 2018, ExseedSat was launched on a Falcon 9 vehicle
from Vandenberg Air Force Base in California. Part of Spaceflight's
SSO-A: Smallsat Express launch, ExseedSat was built by a team of
Indian radio hams including Ashhar Farhan (VU2ESE), George Phillips
(VU2GT), Gurudutta Panda (VU3GDP), Sasi Bhusan (VU3ELR), and Nitin
Mutin (VU3TYG). Initial telemetry has been received around the world.

At the request of Exseed Space, AMSAT hereby designates ExseedSat as
VUsat-OSCAR 96 (VO-96). We congratulate the owners and operators of
VO-96, thank them for their contribution to the amateur satellite
community, and wish them continued success on this and future projects.

73,
Drew Glasbrenner, KO4MA
AMSAT VP Operations / OSCAR Number Administrator

Submitted by Russ  KG0BK

Re: Congrats to Farhan

Timothy Fidler
 

This URL may be of interest.    The software is a bit flaky but it is usable.  

https://in-the-sky.org/satmap_worldmap.php

ExseedSat after a quick perusal does not appear but  the data is updated from NORAD object data from time to time .. no doubt a  GIF of Ashan's face will  circumnavigate the globe on this site in the future. 

You can select  Amateur radio satellites under select satellites  - the default is mainly GPS satellites.  it is fascinating that as I watch Dec 9th Just after lunch there is only one GPS Sat over the continent  of Oz yet obviously GPS has not dropped out.  The other ones over the Indian ocean and the near Pacific  must be close enough to give the constellation of four  required for a GPS fix. The maps are of course live.

Re: Congrats to Farhan

Timothy Fidler
 

Read "Ashar"  Farhan - I can't edit the post and I am too lazy to repost it to correct the proper noun. TEF

Re: a simple spur fix

Ashhar Farhan
 

it would be easier to just buy 11.052 mhz crystals and shift the IF out. 
- f

On Sun, Dec 9, 2018 at 6:27 AM <freefuel@...> wrote:
the Atmel AVR chip can be clocked up to 20MHz, with that said what frequency would be best if we were to replace the crystal on the Arduino board to shift that birdiey to another less offensive location. 

-Justin N2TOH

Re: a simple spur fix

Clark Martin
 

I’ve seen some gear where the CPU clock frequency can be changed dynamically so any birdies from the CPU can by avoided.  The AVR328 internal clock can be divided down from the crystal frequency under software control in powers of two from 1 to 256.  Obviously if it’s the crystal clock circuit itself that is causing birdies this won’t help.  The code would have to dynamically reset any timing based parameters (baud rate, timers, I2C clock and SPI clock) as well as synchronize the change (not make the change will data is gobbling transferred via any of the serial interfaces).

However there are settings in the clock oscillator which let you change from “full swing” to “low power”.  If the fuses are currently set to use the full swing mode, the low power mode may mitigate the birdies.


Clark Martin
KK6ISP

On Dec 8, 2018, at 4:57 PM, freefuel@... wrote:

the Atmel AVR chip can be clocked up to 20MHz, with that said what frequency would be best if we were to replace the crystal on the Arduino board to shift that birdiey to another less offensive location. 

Re: Congrats to Farhan

Dexter N Muir
 

Echoing the congrats, but ... Timothy and others: please note how Farhan spells the other part of his name (given or family? his locals evidently call him Ash). That part is pronounced as he writes it: two syllables, Ash and har. I'm not sure if there's an accent or dictionary-style diacritical mark or two in there - the Indian Sanskrit-based script might describe the pronunciation more fully. English gives a general idea but is sometimes half-hearted.
...just a mark of courtesy and respect ...
73 de ZL2DEX

Re: a simple spur fix

Jerry Gaffke
 

We believe the audio tones on some rigs come from harmonics of the 16mhz processor clock
beating with harmonics of the 12mhz BFO.  Most rigs don't have this, since the 12mhz
ceramic resonator is not very accurate, can be off by 100khz or so. 
That, and us old guys have lost the ability to hear anything much over 3khz.

Could drive the processor clock from the BFO, near 12mhz.
Should not create tones when it beats against itself.
The si5351 can glitchlessly transition that BFO by 3khz if we wish to switch from
low side to high side BFO (to switch between LSB and USB, keep clk1 on the high side.)

The 16mhz crystal resonator on the Nano is extremely small, will be tough for some to remove.
Perhaps leave it in place, overpower one end of it with a wire from the 12mhz BFO.
So this fix might be a matter of just adding one wire, and some new firmware on the Nano.

The ATMega328P has an internal processor clock generator that can be selected,
though it is even less stable than the ceramic resonator, and thus the birdies unpredictable.
Might be worth trying, as no hack is required except to the firmware.
Will be required to use the internal clock at startup until the si5351 is programmed
if the BFO is to be used as the processor clock.

Moving the crystal filter frequency to 11.052mhz should work, maybe that will show up on v5.
But matching 8 crystals for frequency, replacing the existing 12mhz crystals, evaluating
the filter passband given whatever crystal parameters you happen to have, and adjusting
caps and impedances for the desired bandwidth and filter ripple may be more than
most here want to take on.

If you have a good inspection microscope and no coffee, might be possible to swap
out the 16mhz ceramic resonator.  Any funny number for a frequency is likely to work
better than what we have.  We think we have trouble with 3*16 = 48mhz = 4*12.
If the processor were moved to 13mhz,  the first beat note I see is at 13*16= 208mhz = 16*13.
Those high harmonics will be very weak, won't get much better than that.
Remember to also avoid beats with clk1, at 45-12=33mhz and 45+12=57mhz.

Jerry, KE7ER



On Sat, Dec 8, 2018 at 04:57 PM, <freefuel@...> wrote:
the Atmel AVR chip can be clocked up to 20MHz, with that said what frequency would be best if we were to replace the crystal on the Arduino board to shift that birdiey to another less offensive location. 

-Justin N2TOH

2nd 45MHz filter - Power loss

Woody
 


With stock R27, Power output close to most reported.  Added 45MHz xtal filter, no transformer.  Power dropped significantly.  Added cap and transformer.  Power up slightly, not much.  Interesting, the power drop below 10 MHz...
For those who have done this mod, how does it compare to your result regarding power output?
Here is my result:


Thanks, Woody  -  KZ4AK

Re: 2nd 45MHz filter - Power loss

ajparent1/KB1GMX
 

Woody,

Yes but....  Did you try resetting RV1 to regain some of the power?

Also testing I did showed that for some filters the center frequency was 
not nearly as offset as others as Mine and two other were closer to 45mhz than
stated and implemented in the Raduino firmware.  The result is adding a second
filter can have you down the band pass skirt and less power.

Try a small amount of C say 10 to 15pf across the filter input and output to "tune it".

Allison

Re: LSB signal looking more like AM

ajparent1/KB1GMX
 

joshuaclough4@

Start with carrier balance pot and adjust with NO MODULATION for minimum power out.
There should be a noticeable null at about mid rotation.

Likely the carrier frequency setting is off as well and inside the filter band pass.  


Allison