When you press the Key the display shows that you are transmitting and you hear the relay click.?

In my ubitx I have a built in sound card with a usb cable for sound control. I have a dpdt switch that I can switch it from ssb/cw to digital like ft8. It controls both mic input and speaker output.

Large heat sinks were installed with a fan and custom shroud. Running full power with out an antenna didn't overheat the transistors.?

Lastly I designed a linear regulator to power the radio and power it with an old laptop power supply. I power the finals directly with the laptop supply.?

I have just opened a new Shop and will be selling my kits and other goodies via the site from now on. Keeping track by hand via spread sheet was getting a bit much.

More zero beat kits are coming and should be up soon. I have 2-3 pre-orders that will still be taken care of.

The AVC auto volume control (AGC) is coming very soon and will have it posted soon as I can.

Thank you all none of this would have been possible without support from the groups

A Big thanks to KE2GKB for his help and support, he will also be a go to for support.

I will be adding more DiY radio related items very soon.

--
David

?N8DAH

On Thu, Nov 29, 2018 at 03:55 PM, inftechllc wrote:

Linear Amp Kit

You might want to do some reading here or over at about spurs and harmonics before you start thinking about amplifiers.? When you go from a whisper to a shout small problems can become big problems.
?
--

If you are going to go with the nextion the TR/RX light would be redundant. The Nextion display has a button/label that changes colors from green to red.

--
N5KBP

I am working on a new larger enclosure (Desktop/Base) for my uBITX and wanted to know your must have mods/upgrades to add to the design.? I plan to include a nextion touch display and builtin power supply.? ?I am looking primarily for three mods:

• Linear Amp Kit
• PreAmp Kit
• Tx/Rx Light setup

But would also like to know anyone's "must have" mods and upgrades.

Thanks in advance for all the help!?

开云体育

?ha, ha!!? ?Next time I see that elusive fella I'll be sure to tell him you appreciated the hours and hours he spent!

Cheers,

Gordon

Thanks!? I feel a white noise/SDR test coming on.

I'm using your books - thank you for documenting your work with Winlink and ALE!? And please pass on a 'thank you' to Mr. Prepperdoc as well.

Andy

开云体育

Well, I suspect at LEAST 2 kHz. ?I think mine is more like 1800 hz. ?Optimal is probably 2.4 kHz

I've been using mine for Winlink as well.? My sloping 'S' shaped 40/20 attic dipole isn't optimum by any means, and I sometimes have to jump from station to station to get a reply, but it does move email through the network.

My mic connector is the 4-pin Kenwood type so I can move the Signalink between my TS-530S and the ?BITX.

Doc Gordon - how wide should the bandwidth be for Winlink?? Heaven help me - there might be another tweak in the queue.? hi hi hi

73, Andy, KG5RKP?

Hi Don,
I pulled the board and tested with sig gen on input and only the scope on the output.? Same huge crossover distortion.? The
(simple) circuit looked OK and the + input bias was 1/2 Vcc.? That chip is going to the waste bin!

Have hundreds of 741 devices in the junque box.? Used one - Works great.
The output is terminated into the high side of a 1K pot.? The wiper feeds an old TBA-810 circuit for several watts (if I want it ;) of output audio.

Woody ?? KZ4AK

No, left open.? Had not experienced a problem before this.?? But then, there is this ;)
A new board using a 741 is working great.
Woody? KZ4AK

On 11/29/2018 4:35, Skip Davis via Groups.Io wrote:

Woody the LM358 is a dual op-amp so did you terminate the unused op-amp? If not then it could be the cause of your distorted output.

Skip Davis, NC9O

--

Try a 1458 instead. It has the same pin-out and is drop-in compatible with a much higher output capacity. I mention this since it appears that you are feeding a lower impedance than what it is capable of driving since that is the waveform that one would expect if doing so. What are you driving? I substituted an LM380 as an output AF amp in the V4 and it does very well. No pre-amp needed.
73, Don

--

Raj and group,

Farhan was also suggesting a filter to remove the 12mhz spur in the transmitted output
that resulted from crosstalk from clk0 into clk2 at the si5351.
Should that be included in this recommended cure-all?
I still feel the best way to deal with the 12mhz spur might be a high pass filter on clk2
rather than a tuned (and finicky) notch filter.

Do the new inductors for the 45/90mhz LPF have to be a specific kind of shielded inductor?
Or can we get by with any old 1206 surface mount inductor?

How much better are the results when L5,L7 are replaced with shielded
surface mount inductors?? Are we legal without that change?

At one point, Raj saw better results with the torroids at L1,2,3,4 replaced with?
shielded surface mount inductors.? Is that still the case?

There was some discussion about different coils in the various Axicom relays,
has it been determined that the higher current coils are required
to reduce coupling sufficiently?

Ideally we would have web references to specific easily obtained
parts for the relays, caps, and inductors needed to clean up the uBitx.
Even better, perhaps somebody could provide a kit of appropriate parts.
But I think this should wait till a specific list of recommended mods is nailed down,
and we know that the results are repeatable.?

Would be very cool if there was a cheap way to see this trouble in a stock rig,
and to verify that it works better after the fixes have been applied.?
For example, use a second receiver (a second uBitx?) to check uBitx transmissions
for the 12mhz spur and the?45mhz-DialFreq spur?
I assume the transmitted signal would have to be attenuated by 40dB or so
to prevent damage to the receiver, attenuate by an additional 43dB when
listening for spurs.? And put rig under test plus dummy load in a Faraday cage.
Can the procedure include checks for harmonics, at least on the lower bands?

The previous method of adding a second 45mhz crystal filter is no longer recommended.?
This new 330uH-51pf-330uH low pass filter to knock out the 90mhz harmonic of the 45mhz IF
goes into the same position as that 45mhz crystal filter did, but works better.
It does not attenuate the desired signal so much as the 45mhz crystal filter did.


Sarma asked:
> will the smd inductors in post PA lpf mode, take that power?

Answer: NO

Raj said:
> This has nothing to do with the spurs issues.??
I believe that should read:
? ?This has nothing to do with the harmonic issues.

Leave the post PA LPF's with the stock torroids, the new smd inductors will not take the power.
The harmonics thru the post PA LPF's at L11 through L22 are fixed by just swapping out
the relays at KT1,2,3 with Axicom relays, the stock relays are not very suitable for RF.
There are other methods of fixing the post PA LPF's, these involve adding extra relays,
or?adding a band specific low pass filter external to the rig in line with the antenna coax.

We need to finish this up with a detailed and complete list of recommended mods
so folks can use their uBitx with confidence.? Very few have a spectrum analyzer.

Jerry, KE7ER

开云体育

Well I’ve used them several times successfully. The audio band width is not quite as large as one would like. ?You can change some capacitors in the Crystal filter to fix that if you wish; I haven’t yet?

@ Ashok Khachar: Screen Saver mode was disabled.

Uploaded the default .tft program, which is flashed in factory before shipping from =>
The "white screen issue poped up after 3min again!!

Guys,

This has nothing to do with the spurs issues. Just a test to see if the SMDs are as good as the
toroids. I am pleased that smd is a good alternative at signal stages.

For a cure all I stand by - change KT1/2/3 to Axicom relays, change L5/7 for good measure and
ad Farhans LPF filter for another good measure.

Raj

At 29-11-18, you wrote:

Sharmaji, this is on a test jig.

At 29-11-18, you wrote: