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Re: uBITX SWR Tolerance #ubitxv6

 

I use an emtech zm-2 tuner and also a ldg z100 tuner. both seem to work 100%.

Im an odd ball,. I like just a little bit of swr on my antennas. 1:5 seems to get out better where i live.I also use rg6u quad shielded cable also.My ubitx loves it. doesnt have a problem.

73
David
ac9xh
good thru hamcall.net,qrzcq.com and FCC
Re: uBITX SWR Tolerance #ubitxv6

 

Niels,

A quick reminder to readjust the bias whenever you replace the finals.

73
Evan
AC9TU
Re: uBITX SWR Tolerance #ubitxv6

 

THIS IS FOR HUMOR AND SMILES!!!!!

Enjoy,
73
David
ac9xh

I came across this on another website .it was originally published in QST magazine 1967:
[picture of G5BD in his shack , click for larger version]
Re: A short video of sBitx working

 

Ashhar and group,

is there a manual or something resembling a spec sheet on the sBitx available anywhere?

I am trying to figure out if it will operate down below the AM Broadcast band,? there is a lot of Ft8
used on our 630Meter band on 474 khz.

Thanks for any info or input

Alan
w7aln
Re: uBITX SWR Tolerance #ubitxv6

 

niels,
If you have a dummy load, try loading into that first to see if anything else is wrong before hooking up your antenna? after re-installing finals and checking surrounding components.

Also, if you have another transceiver, try to preload the tuner to 20 meters first so the antenna will be pretty close to being matched, then hook up your sbitx and see how it works then.

good luck on your sbitx
73
David
ac9xh

On Tuesday, August 2, 2022 at 11:40:51 AM EDT, Niels Jalling <niels@...> wrote:


I can't tell the SWR numbers for my antenna but I have just burned one of the IRFZ24's in the PA.
It was on 20m. Power settings was set to 5 and my antenna tuner didn't even finish the tuning process before the sBitx broke down.
I used to have SWR of 1.4 - 1.6 on the antenna when tuning is done.
Tomorrow I'll get new IRFZ24's
73 de oz9ny, niels

Re: Turn off WiFi on your sBitx

 

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I¡¯m having the same sounds¡­ anywhere from 4 to 8 sounds then a several second pause, then starts again. ? Changing audio level makes no difference. I¡¯ve never tried transmitting¡­ just listened to WWV across town from me and it is a clean stable receiver. ?Tried logging in to my wifi but I still have two red X characters over the wifi symbol
Bob, KO9V, Serial Number 20

On Aug 1, 2022, at 1:57 PM, Niels Jalling <niels@...> wrote:

?When I powered up my new sBitx I heard repeating noise from the loudspeaker. I knew I had seen the problem mentioned somewhere.
Found it on youtube:

Follow the description to turn off the WiFi and the noise goes away.

73 de oz9ny, niels

Re: sBitx doubt

 

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Actually , Farhan had forgotten to update the Schematic on his GithHub page, as a result of which I was searching for a route from the Antenna Connector to the RF port he used.

?

But some pledger privileges came to the rescue and I found the right schematic.

?

I hope the schematic on the Github is updated.

?

I am building a very limited portion of the design. The Exciter and the RPi HAT.

?

I attach herewith my version of the schematic for all reference. This is going to be a TH version of the project, with 1/8W resistors

?

regards

charudatt ¨C VU2UPX

?

From: [email protected] <[email protected]> On Behalf Of Pascal Nguyen
Sent: 03 August 2022 01:09
To: [email protected]
Subject: Re: [BITX20] sBitx doubt

?

Hi Charu
Looking forward to see your design, must be very interesting by rolling your own.

  • What¡¯s ?the catch between the schematic from GitHub (1rst mixer to antenna via LPF) and the updated from Raj (1rst mixer to antenna bypassing LPF)?
  • Do we need a band pass filter for the 1st RX mixer or a single 30MHz LPF is good enough?
  • Has any one successfully booted an RPI 400 (identical to RPI4 without EEPROM) or it¡¯s not compatible?

73 Pascal

Analog - sBITX Schematic.pdf
Analog - sBITX Schematic.pdf

Re: Postman came with a box from hfsignals

 

?got #26!!!!? ?You beat me!!! but i still feel HONORED.? ?Gotta find a power connector and wire it all up.? Should have a logitech mouse/keyboard wireless in the car.? ?Tons of MEETING this week, but nice to have gotten this.? ?It came VERY NICELY PACKED.? ? My neighbor has theXiegu.....each has its points but this is a LARGE milestone in ham radio history, another one due to Ashhar!? (on the left is one of my primitive homebrew "go-boxes" for portable emergency deployments.

Gordon KX4Z
sBit power supply

 

Just got the LRS-150-12 to run it with.? Now all I need is the sBit so I can run.? Waiting for it to ship "sans Pi" as I already have the Pi.

Gerry Sherman

Sent by the Thunderbird
Re: Drive potmeters?

 

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Niels - that sound like a full wave.? I understand that if an antenna is a multiple of a half wave it can be hard to tune.? My suggestion: switch to a manual tuner & use an analyzer (Antuino) to get it to an acceptable SWR.

Gerry Sherman

Sent by the Thunderbird

On 2022-08-02 17:59, Niels Jalling wrote:

I don't know the initial vswr. My antenna is a wire around 20 meters long with an automatic tuner at the end.? Then 5 meters coax between tuner and the rig.
Normally it matches the PA in less than 20 seconds but that may be too long mismatch time for the sBitx.
Band was 20m and transmit level was set to 5,
73 de oz9ny, niels

Re: sBitx doubt

 

Hi Charu
Looking forward to see your design, must be very interesting by rolling your own.

  • What¡¯s ?the catch between the schematic from GitHub (1rst mixer to antenna via LPF) and the updated from Raj (1rst mixer to antenna bypassing LPF)?
  • Do we need a band pass filter for the 1st RX mixer or a single 30MHz LPF is good enough?
  • Has any one successfully booted an RPI 400 (identical to RPI4 without EEPROM) or it¡¯s not compatible?
73 Pascal
Re: sBitx volume control

 

I did try that, it was confusing. Should we put it on tap? The function decoder has a pushbutton that is not used.


On Wed, Aug 3, 2022, 12:08 AM Niels Jalling <niels@...> wrote:
There is one knob I really miss on the sBitx, An easy accessible volume control.

Idea: Fallback for the function encoder when not not called for it could be volume control. Fallback time f.ex. 15-20 seconds.

73 de oz9ny, niels

sBitx volume control

 

There is one knob I really miss on the sBitx, An easy accessible volume control.

Idea: Fallback for the function encoder when not not called for it could be volume control. Fallback time f.ex. 15-20 seconds.

73 de oz9ny, niels
Re: Drive potmeters?

 

I have been operating FT8 for days between a few of us locally here. I have been feeding it into a cobweb antenna that doesn't have a 21 MHz element, the SWR is high but I have the power set to 15 watts.?
Something must have gotten nasty with the antenna.?
- f


On Tue, Aug 2, 2022 at 11:43 PM Niels Jalling <niels@...> wrote:
FT8.

de oz9ny, niels

Re: Drive potmeters?

 

FT8.

de oz9ny, niels
Re: Drive potmeters?

 

Were you on CW? Venu (VU2BVB) blew his PA while running CW. It turned out that the relative level of CW was much higher than other digital modes and I am investigating this. I will know? for sure by tomorrow.
- f

On Tue, Aug 2, 2022 at 11:29 PM Niels Jalling <niels@...> wrote:
I don't know the initial vswr. My antenna is a wire around 20 meters long with an automatic tuner at the end.? Then 5 meters coax between tuner and the rig.
Normally it matches the PA in less than 20 seconds but that may be too long mismatch time for the sBitx.
Band was 20m and transmit level was set to 5,
73 de oz9ny, niels

Re: Drive potmeters?

 

I don't know the initial vswr. My antenna is a wire around 20 meters long with an automatic tuner at the end.? Then 5 meters coax between tuner and the rig.
Normally it matches the PA in less than 20 seconds but that may be too long mismatch time for the sBitx.
Band was 20m and transmit level was set to 5,
73 de oz9ny, niels
Re: Drive potmeters?

 

Yes, thats right. How did you blow them up? Was the vswr high? Which mode were you on?


On Tue, Aug 2, 2022, 9:25 PM Niels Jalling <niels@...> wrote:
I have just burnet the PA IRFZ24's.
Where Is zero for the DRIVE_BIAS POT and PA_BIAS POT?
Is it where you expect it at anti clock wise end.
73 de oz9ny, niels

Drive potmeters?

 

I have just burnet the PA IRFZ24's.
Where Is zero for the DRIVE_BIAS POT and PA_BIAS POT?
Is it where you expect it at anti clock wise end.
73 de oz9ny, niels
Re: uBITX SWR Tolerance #ubitxv6

 

I can't tell the SWR numbers for my antenna but I have just burned one of the IRFZ24's in the PA.
It was on 20m. Power settings was set to 5 and my antenna tuner didn't even finish the tuning process before the sBitx broke down.
I used to have SWR of 1.4 - 1.6 on the antenna when tuning is done.
Tomorrow I'll get new IRFZ24's
73 de oz9ny, niels
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