开云体育

Re: Setting grid sBitx

#116373

Isn't it \MYGRID ?

73,

Wojtek

Re: SBITx with Heil headset?

#116372

开云体育

Supposed to be “input transistor”?

Sorry!

Kx4z

Show quoted text

On Mar 19, 2025, at 16:46, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote:

?

So here is a piece about one of Heil dynamic headsets. You can see that they quote an output impedance of 500 ohms.?

The DC impedance may even be lower.

What this means is that it will basically effectively short out the bias voltage. Luckily, capacitor CD 27 will keep that from taking the input chance out out of its normal operating range. So I don’t think any harm will occur. However, the output level of the dynamic element is -60 DB. So basically you aren’t going to have any significant single side band output RF power.

73,

Gordon kx4z?

On Mar 19, 2025, at 15:54, Neil K6NCX via groups.io <neil.fullagar@...> wrote:

?
Thanks. I have a dynamic Mike headset, so I’m not worried about the bias voltage. What I really need to know is what adapter to use.

<preview.png>

Re: Setting grid sBitx

#116371

Neil,??

I mostly operate mine over my network, see below, but click on the "SET" button and a window will pop up, see below.

73,
John
N2LCX

Re: SBITx with Heil headset?

#116370

开云体育

So here is a piece about one of Heil dynamic headsets. You can see that they quote an output impedance of 500 ohms.?

The DC impedance may even be lower.

73,

Gordon kx4z?

Show quoted text

On Mar 19, 2025, at 15:54, Neil K6NCX via groups.io <neil.fullagar@...> wrote:

?
Thanks. I have a dynamic Mike headset, so I’m not worried about the bias voltage. What I really need to know is what adapter to use.

preview.png

Re: zbitx schematics and source code

#116369

On Wed, Mar 19, 2025 at 12:01 PM, Ashhar Farhan wrote:

This is the version that will start shipping in the next 36 hours. We are finally loadng it up!

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

Congratulations!? Perhaps this explains the sudden increase in wspr traffic from Indian farm land...

Re: SBITx with Heil headset?

#116368

Thanks. I have a dynamic Mike headset, so I’m not worried about the bias voltage. What I really need to know is what adapter to use.

Setting grid sBitx

#116367

I’m on a POTA activation 3000 miles from home, and I need to set my grid correctly. It’s still showing my home grid after entering \grid EM73wp multiple times.?

Re: zbitx schematics and source code

#116366

开云体育

Hello Farhan,

Thank you for sharing the details of the zBITX project with us.

The zBITX Front Panel Schematic seems to be missing.

Could you share that too ?

regards

Charudatt

Show quoted text

From: [email protected] <[email protected]> On Behalf Of Ashhar Farhan via groups.io
Sent: 19 March 2025 22:31
To: [email protected]
Subject: [BITX20] zbitx schematics and source code

The zbitx source code is now available on github.?

and?

Please note that this code has not been tested on the sbitx, though it has been derived from the sbitx base.

A few things to note:

1. The 64 bit OS didn't have any significant advantage and using its PulseAudio was adding to the auto start required for the zbitx. Hence, this has been tested to compile on 32 bit Raspberry OS.

2. This works with as well as without the front panel.

3. The schematics are also included.

This is the version that will start shipping in the next 36 hours. We are finally loadng it up!

73, f.?

Re: SBITx with Heil headset?

#116365

This morning, I got busy and tested 4 cartridges I had purchased months ago, and built up another mic for a friend with a DE version.? ?From the results, I wrote the enclosed article, which gives lots more information how to find high output cartridges and make inexpensive microphones.??

You may wish to use a 20K or so resistor to drop the sBitx bias voltage if yours is 12V.? ?I think I did that on some of my earlier units and need to on the one I just updated.? ?

An interesting thing -- my first sBitx (used) had significant variations in the crystal filter ripple response -- this current one seems a LOT less ripple visible across the waterfall.? ?Great going, Ashhar!!

Happy reading!

Gordon KX4Z

sBitxMicArticles.pdf

Re: zbitx schematics and source code

#116364

Farhan,

Thanks! I appreciate you and your team's hard work in this and look forward to the arrival of the zBitx soon.

Ken, N2VIP

zbitx schematics and source code

#116363

The zbitx source code is now available on github.?

and?

Please note that this code has not been tested on the sbitx, though it has been derived from the sbitx base.

A few things to note:

1. The 64 bit OS didn't have any significant advantage and using its PulseAudio was adding to the auto start required for the zbitx. Hence, this has been tested to compile on 32 bit Raspberry OS.

2. This works with as well as without the front panel.

3. The schematics are also included.

This is the version that will start shipping in the next 36 hours. We are finally loadng it up!

73, f.?

Re: SBITx with Heil headset?

#116362

开云体育

Learning about mic sensitivity specs:

You’ll likely be disappointed with -50 db mics….

Gordon kx4z

Show quoted text

On Mar 19, 2025, at 04:10, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote:

?You may wish for a lot more sensitivity/ higher output than the Heils provide. ? Around-30 dB is much better …
<image0.png>

On Mar 18, 2025, at 22:29, Neil K6NCX via groups.io <neil.fullagar@...> wrote:

?

Thanks. I have the dynamic mic, and used it successfully with my FT-818.

On Tuesday, March 18, 2025 at 11:12:00 AM PDT, Neil K6NCX <neil.fullagar@...> wrote:

Is anyone successfully using one of the available ?Heil headset adapters for an sBitx? Which one? Or do I need to make my own?

Re: SBITx with Heil headset?

#116361

开云体育

You may wish for a lot more sensitivity/ higher output than the Heils provide. ? Around-30 dB is much better …

Show quoted text

On Mar 18, 2025, at 22:29, Neil K6NCX via groups.io <neil.fullagar@...> wrote:

?

Thanks. I have the dynamic mic, and used it successfully with my FT-818.

On Tuesday, March 18, 2025 at 11:12:00 AM PDT, Neil K6NCX <neil.fullagar@...> wrote:

Is anyone successfully using one of the available ?Heil headset adapters for an sBitx? Which one? Or do I need to make my own?

Re: SBITx with Heil headset?

#116360

Thanks. I have the dynamic mic, and used it successfully with my FT-818.

On Tuesday, March 18, 2025 at 11:12:00 AM PDT, Neil K6NCX <neil.fullagar@...> wrote:

Is anyone successfully using one of the available ?Heil headset adapters for an sBitx? Which one? Or do I need to make my own?

Re: SBITx with Heil headset?

#116359

Hi Neil,

I’ve only used CW since I got the sBitx?but I have looked at the microphone and believe it can be,?though their is a?BUT !

There are two main types of Heil Headsets a pro ( dynamic) or IC (elect). And only one will work, as I found out with the Icom 705.?

Hope that gives you help in determining which type you have etc.?

Regards?

Dennis G6YBC

Show quoted text

On Tuesday, March 18, 2025, 6:12 pm, Neil K6NCX <neil.fullagar@...> wrote:

Is anyone successfully using one of the available ?Heil headset adapters for an sBitx? Which one? Or do I need to make my own?

SBITx with Heil headset?

#116358

Is anyone successfully using one of the available ?Heil headset adapters for an sBitx? Which one? Or do I need to make my own?

Re: Working on my 2nd V2 sBitx

#116357

On Tue, Mar 18, 2025 at 10:44 AM, Gordon Gibby KX4Z wrote:

I have not yet checked the potential reduction in receiver birdies from the aluminum foil shielding of the display cable.

It does not reduce the number of receiving stations, but it significantly increases the sensitivity that can be adjusted with the sensitivity control, which is also visible in the waterfall.

In the unshielded state, it started to get noisy above 50, with shielding this level shifts to around 80.

Gyula HA3HZ

Re: Working on my 2nd V2 sBitx

#116356

Attached is a final document with a list of the reliability-improvements and photos of how I managed to put them in.? ?Amazingly, I didn't break anything!? ?It appears to work just fine afterwards.? ?I have one of the 64-bit setups working and thanks to some help, I can compile this also!? ?

I have not yet checked the potential reduction in receiver birdies from the aluminum foil shielding of the display cable.
I'm away from normal home and don't have a good 50-ohm dummy load so no reliable power output measurements so far, but appears to be at least as good as the previous V2 IRF520 replacement that I did.

(Data from the other replacement I did on the previous unit:? from post: /g/BITX20/message/115243 )

IRF520? Infineon? ?biased for about 0.3Amp total idling current

3pf TVS diodes on gates instead of the previous huge zeners (which Ashhar says don't stop the problems)

MODE = CW? ?Power measured by Siglent scope and mathematically voltage -> 50 ohm power

Frequency? ? 100% drive output power? ? hw_settings.ini? ? Comment

3.5010? ? ? ? ? ? ? ?32W? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? .0037? ? ? ? ? ? ?Gets a little less power than on 40, similar setting to IRFZ24N

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? my earlier notes suggest I got a little more power than this, with the IRFZ24N's

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? and gate zeners, so the IRF520 may be a little inferior here.

7.010? ? ? ? ? ? ? ? ? 33.3? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?.0028? ? ?

10.1? ? ? ? ? ? ? ? ? ? 22.6W? ? ? ? ? ? ? ? ? ? ? ? ? ? ? .0028? ? my notes indicate I was in the range of 21W with IRVZ24N & gate-zeners

14.01? ? ? ? ? ? ? ? ? 16W? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?.0032? ? my notes here on IRFZ24N don't make sense

18.1? ? ? ? ? ? ? ? ? ? ?9.33? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?.0061? ? ? ? ? ? ?? the gate circuit reactance issue here?

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?notes indicate I got 11-12W with IRVZ24N's

21.01? ? ? ? ? ? ? ? ? 16.6? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? .0054? ?notes indicate I could only get 15W with IRFZ24N & gate-zeners

24.9? ? ? ? ? ? ? ? ? ? ?12.3? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?.0063? ?notes indicate I could only get 10W with IRFZ24N & gate-zeners

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?likely due to their huge capacitance

28.0? ? ? ? ? ? ? ? ? ? ?11.52W? ? ? ? ? ? ? ? ? ? ? ? ? ? .0063? ?notes indicate I could only get 8W with IRFZ24N & gate-zeners

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? likely due to their huge capacitance

Without a dummy load, I made some initial measurements and adjusted the coefficients on the new unit and on several bands came up with very similar coefficients, suggesting that the circuitry and devices are performing reasonably similar.? ?I think I'm getting in the range of 40W on the two lowest bands, at around 12 watts on 10 meters.? ?These numbers are quite adequate for me!? ?I like having the additional robustness against excessive drive that the TVS diodes may bring, and the additional robustness against SWR-issues, that the 100V (drain-source limit) that the IRF520's give.? ?(Ashhar selected the IRF510 for the V3 with the same drain-source voltage capability).? ?Be careful to buy 520's from reputable sources and there are versions out there with inferior specifications.

Gordon KX4Z

sBitxUpgrade.pdf

Re: zBit thoughts

#116355

Yes, Gerry, I agree.? ?I don't know the particulars of the not-yet-released zBitx, however, presuming it either has a "send relay output" (or equivalent) or one can be added, it should be a fine option for the exciter transceiver for a transverter (as I have recently tested using the sBitx V2 in such a role).

The electrically controlled transmit/receive switching appears to be important for satellite work (though I have no personal experience) because the "vox" type control just doesn't "hold in" with SSB speech (which I verified with one of the Ukranian-sourced transverters).? ?If the send output doesn't exist, it should be easily added as some of us have already done on the sBitx.

And you are right about gpredict.? Ashhar Farhan suggested this software, apparently using it himself for this purpose.? ?I downloaded it and installed it on an sBitx and it ran well once I used a display with enough pixels to be able to see the entire page (some of the dialog boxes have fixed dimensions and without being able to get to the buttons at the bottom, you couldn't get out of the choices).? ?I also found that the sBitx 32-bit firmware could be listed as a radio interface under "preferences" and perfectly accepted the calls to port 4532 from gpredict operating on the same device.? ?and obeyed the commands to track Doppler shift, without the need for rigctld (the function is provided right within sBitx).? ? This was quite nice!? ?gpredict allows you to enter the local oscillator of a (mixer-type) transverter.? ? Now not having the unit in hand I can't prove that all will fit and work acceptably on the zBitx but if there is space and speed, it should work.? ??

Gordon KX4Z