Date   

Re: frequency od start

Joel Fournol
 

change vfo A----) B choise ex 7.150 confirm------)ptt  trx down /up fréquency 7.150 vfoA  73"


Le 19/05/2018 à 09:27, aronax37@... a écrit :
When switch on a frequency 6.753. xxx,  allways appears and I have to retune to ham band. How to set 7.000 MHz (for example) to view after switch on? Thank you.
Ivo


Re: Fixed AF out.

Lawrence Macionski <am_fm_radio@...>
 

Can you decode:
On Sun, May 20, 2018 at 03:47 am, Raj vu2zap wrote: "You can buy a ready board on the Bay and just hook it up simply!"
for us English speaking  Americans.. Perhaps supply a URL link..
 


Re: Transmitter Mods

M Garza <mgarza896@...>
 

Doug,
Here is the part number I ordered from Digikey:  
732-10802-1-ND.

Hope it helps,

Marco - KG5PRT 

On Sun, May 20, 2018, 9:03 AM Doug W <dougwilner@...> wrote:
I'm almost embarrassed to ask for help on this but I wasn't born knowing how to do much.  I don't do much with SMT passives and the choices are starting to look endless.  I'm in the middle of a digikey order for another project and was planning to order the inductor and capacitors for Howard's mod while I am at it.  Can somebody steer me in the right direction?  Normally I like to sort through the billions of choices but my gut keeps telling me I am going to order the wrong thing.

Also, Howard your offer to share parts is very generous and if I didn't have other parts I needed to order I would be taking you up on it.
--
www.bitxmap.com


Re: RF power chain mods and improvements..

 

This is a Flir image of one of my BITX40 boards

At 19-05-18, you wrote:
First all changes are on a production uBitx not an older brassboard model.

The first findings are not about power out, I haven't fully tested.

What I did find is at 13.8V all on the 2n3904s in the power chain run very hot
with no signal. How hot 125-130 degrees. Measurements had the first Q90
running at 38ma and for a low level sage thats very high and for a 3904 its
near excessive.

Why is that problem? THe bata sheet says that as we increase the device
current the HFE goes down and leads to reduced gain and, also lots of heat.

Current solution was to increase the bias resistor R81 from 1K to 2.5K but as two parts
Its 1K +1.5K and the 1.5K gets a .1uf capacitor across that so the stage gain is maintained.
This lowers the current to about 20MA (19.6 actual). FYI that means the device is now
dissipating 230mW of power where before it was 390mW. The device max is 500mw
and I"ve found when you get close to that they fail.

One to the drivers. Another noted he tried 2n2219s and they get warm. Likely
it was the bias level alone causing that. The current devices in mine are 3904
and they are hot at 130-135F. Again the bias is wrong (does not allow for
devices with higher than average HFE) and the device current is much too
high In a class AB push pull the current need not be this high. The same
technique of splitting the bias value so the 1K is unbypassed is used and
the same values 1k+1.5K (1.5k bypassed) are more suitable and result in a
16ma standing current per device.

Much of this is the result of transistors being anything but uniform. HFE
variations for 2n3904 is around 50 to 300 and varies with device current.
This is typical. But that also is variable across vendors.

Those changes alone have had no testing for power out at 20M and 10M yet.
That will be the next step. Right now I was trying to get the devices in the
range where they should behave as good as they can.

Allison


Re: Ubitx Encoder #ubitx

Jack, W8TEE
 

I think these should work fine. Just determine what the power, clock, switch, and data pins are and it should be easy to use them. The "clicks" are just mechanical contacts that are made as you rotate the encoder shaft. It's possible to remove the disk that causes the clicks, but there's really no reason to. Optical encoder do not have clicks either, but are usually much more expensive.

Jack, W8TEE

On Sunday, May 20, 2018, 9:56:26 AM EDT, Vixen21 <2find4me@...> wrote:


On Fri, May 18, 2018 at 12:57 pm, kj6etl wrote:
I just bought these but I can feel clicks (steps) while turning. Does this mean they send me a part that isn't an EC11?
What else do I need to search for? I prefer a North American vendor for fast shipment.

This is what I just received.
https://www.ebay.com/itm/US-Stock-5x-Rotary-Encoder-Switch-EC11-Audio-Digital-Potentiometer-Handle-20mm/371842294877?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649


Re: 4 pin microphone cobra

Marc Jones
 

Rx isnt needed as the radio receives with the n ed for any special mic connections ,  braid is common, You then have the transmit wire and the audio wire , Audio wire is normally inside the braid so as to shield it , You may need to put a capacitor in series with the audio wire to block DC .


On Sun, 20 May 2018 at 13:58, حمد المزين
<hamad.kalid@...> wrote:
Hello everyone i want to ask about how can i wiring the cobra 4 pin microphone , cobra 4 pin microphone has 4 elements (TX,RX,Audio, Ground) but the ubitx has only 3 pin for mic which is Mic to ( audio) , PTT to TX , GND to ground and what about the RX ? 


Re: Transmitter Mods

Doug W
 

I'm almost embarrassed to ask for help on this but I wasn't born knowing how to do much.  I don't do much with SMT passives and the choices are starting to look endless.  I'm in the middle of a digikey order for another project and was planning to order the inductor and capacitors for Howard's mod while I am at it.  Can somebody steer me in the right direction?  Normally I like to sort through the billions of choices but my gut keeps telling me I am going to order the wrong thing.

Also, Howard your offer to share parts is very generous and if I didn't have other parts I needed to order I would be taking you up on it.
--
www.bitxmap.com


Re: Ubitx Encoder #ubitx

Vixen21
 

On Fri, May 18, 2018 at 12:57 pm, kj6etl wrote:
I just bought these but I can feel clicks (steps) while turning. Does this mean they send me a part that isn't an EC11?
What else do I need to search for? I prefer a North American vendor for fast shipment.

This is what I just received.
https://www.ebay.com/itm/US-Stock-5x-Rotary-Encoder-Switch-EC11-Audio-Digital-Potentiometer-Handle-20mm/371842294877?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649


Re: testing wsjtx on linux

Ashhar Farhan
 

I was following the youtube video on ubitx.net. Same settings. 


On Sun, 20 May 2018, 18:29 brad martin, <emclinux@...> wrote:
I have had success with the version 1.8.0 I did not know there was a 1.9 out and I can give it a go later. But what setting are you using for it and if you start via the command line does it show any errors printed when you connect?

Brad
KG5SPR
On Sun, May 20, 2018 at 6:46 AM Ashhar Farhan <farhanbox@...> wrote:
I downloaded and installed the 1.9.0 rc 4 from wsjtx home site for linux (a .deb file for ubuntu), i then installed it. however, it still gives me the time out error of the previous hamlib libraries. 
has anyone successfully installed the linux version with ubitx support?

- f 


Re: Help, can't change frequencies on uBitx

Paul Galburt - K2AYZ
 

Maybe too simple a thought, but make sure your key pullup resistor (4.7K) is actually connected.

73, 

Paul K2AYZ


Re: RF power chain mods and improvements..

ajparent1/KB1GMX <kb1gmx@...>
 

BS170 thats a MOSFET 60pf input capacitance adds complications and would require a
bias adjustment for every one.  Not  a good choice.  A 2n7000 is a similar device
and I have 2n6661 that I"ve used in the past at RF.  There is no plan to use mosfets
in the driver or predriver stages.  Generally the gate to drain capacitance is problematic
for stability.

I've already listed MPSH10/MMBTH10 as candidates.  I am waiting on sot and to92 from supplier.


Allison


Re: testing wsjtx on linux

brad martin
 

I have had success with the version 1.8.0 I did not know there was a 1.9 out and I can give it a go later. But what setting are you using for it and if you start via the command line does it show any errors printed when you connect?

Brad
KG5SPR

On Sun, May 20, 2018 at 6:46 AM Ashhar Farhan <farhanbox@...> wrote:
I downloaded and installed the 1.9.0 rc 4 from wsjtx home site for linux (a .deb file for ubuntu), i then installed it. however, it still gives me the time out error of the previous hamlib libraries. 
has anyone successfully installed the linux version with ubitx support?

- f 


4 pin microphone cobra

حمد المزين <hamad.kalid@...>
 

Hello everyone i want to ask about how can i wiring the cobra 4 pin microphone , cobra 4 pin microphone has 4 elements (TX,RX,Audio, Ground) but the ubitx has only 3 pin for mic which is Mic to ( audio) , PTT to TX , GND to ground and what about the RX ? 


Re: pin 2 of raduino board seems to have gone to CW TX full time after boot message.

ajparent1/KB1GMX <kb1gmx@...>
 

John,

One L or two it still sounds like my name.  ;)

I had noticed but could not find the earlier reports but I remember seeing them.

The usual checks like is there a short/leakage path to ground come up no.

If I put a milliamp meter in the between pin2 (raduino) and 5V it start up open
and after the init display with the version number it then goes to 25ma.  It does
not power up that way so its not an input failure.

That suggests its programmatically triggered. The analog input pc1A1 can be a
digital output if so programmed as I'm familiar with the atmega328 and arduino..
That suggest an bug in the code.

Next step is reprogram...  That will be a while as I have other things for the next week
so time will be short for working on this.  My first pass is to drop some simple code
in to run the display and check that pin.

I'll report here.


Allison


Re: pin 2 of raduino board seems to have gone to CW TX full time after boot message.

ajparent1/KB1GMX <kb1gmx@...>
 

Read the post please.  The resistor is in place and that pin requires a very hard connection to5V.
So hard its drawing 25ma!

That not it.

Allison


Re: Fixed AF out.

 

Not a problem, depends on the signal level you want.

Since BITXs dont have AGC you may be better off with a level control to increase or decrease the audio drive to
your decoder/pc. You can buy a ready board on the Bay and just hook it up simply!

Raj

At 20-05-18, you wrote:
Maybe asked before? I'd like to add a fixed AF jack for FT-8. Anybody done this yet? I do have extra 2822's. Thanks!!


testing wsjtx on linux

Ashhar Farhan
 

I downloaded and installed the 1.9.0 rc 4 from wsjtx home site for linux (a .deb file for ubuntu), i then installed it. however, it still gives me the time out error of the previous hamlib libraries. 
has anyone successfully installed the linux version with ubitx support?

- f 


Fixed AF out.

victorladeira@...
 

   Maybe asked before? I'd like to add a fixed AF jack for FT-8. Anybody done this yet? I do have extra 2822's. Thanks!!
                                                                                                                                                 Victor AL3K


Re: Arduino evolution

tdelozie
 

An affordable samd21 with FPGA combo. That’s a lot of processing in a power efficient package. Perhaps sdr and dsp functionality?
kf5nwc


Re: Low Power Output for Hendricks BitX20A - Watt meters and Scope readings do not agree.... #bitx20

ab2ts
 

Ok,  some improvement.  Readings are a bit more uniform.

I checked the frequency compensation of my probes and the 10x was out of adjustment, 1x was OK.   Adjusted the frequency compensation capacitor in the 10x position and both 10x and 1x looked good.   (In retrospect this makes sense because the compensation capacitor is part of the 10x voltage divider network.)

Now I read 54 Vpp  (7.3 W) with the 10x probe and 44.8 Vpp (5.0 W) with the 1x probe which is in nice agreement with my -20 db coupler 46.8 Vpp (5.5 W).   The 10x and 1x still differ but are in much better agreement than before.  My Watt meters read 5 to 6 Watts.   I can't say why the 10x probe reads high.  I expect the 1x probe to be low since the probe is only rated to 6 MHz in the 1x position.   I have no feel for the frequency variation of my -20 dB coupler.


I can get 7.2 Watts out if I crank up the drive, however the output is no longer stable; even with the Martiens mod.   So I have turned it down below 6W.   

Did anyone really ever get a stable 12 Watts out of the Hendricks Bitx20A?