Date   
Re: My uBitx with 5v mod #ubitx

 

Nigel,

Do a test. disconnect the unit from the load aka xBitx. Check the output voltage with the jumper not
installed. Like you accidentally knocked it off!!

If the voltage is more than 5 then hardwire the jumper and solder it. Better safe than sorry.

Raj


At 22-03-18, you wrote:
I used this UBEC @ 5v
https://www.banggood.com/Hobbywing-3A-UBEC-5V-6V-Switch-Mode-BEC-For-RC-Models-p-915037.html?cur_warehouse=CN

It has a small metal screen around it and the ferrite on the 5v output lead plus capacitor on the uBitx board (where I cut the track and soldered the 5v lead onto) forms an adequate LC filter on the 5v DC.
I can't detect any 'noise' on Rx, but as yet haven't transmitted.

I use the UBEC on model aircraft with a video transmitter (FPV) and don't see any noise in the signal.
The video transmitters are quite susceptible to 'dirty' DC and often shows as 'herringbone' lines in the received video.

Nigel.

Making front panel labels

Vic WA4THR
 

I was looking for a way to easily label the front panel of my BitX40 and was pointed to the use of an Avery product. It is a transparent plastic with an adhesive backing and you can print using either an inkjet or a laser printer. You then just cut the strips where you designed the label, peel the backing, and place on the panel. Really easy, and the results are pretty good. One sheet can produce a ton of labels, too. The product is Avery 4397.

=Vic=

Re: How to test speaker resistance

 

At 22-03-18, you wrote:
An ohmmeter isn't the proper tool. That's because what you want to know is the speaker impedance at audio frequencies, not its DC resistance. They are not the same thing.

You might get a reasonable estimate by using a true RMS voltmeter and an audio signal generator. Connect the signal generator to the speaker through a small series resistor, say 10 ohms. At several frequencies, measure the current into the speaker by measuring the voltage drop across that resistor, and measure the voltage directly across the speaker. The impedance at that frequency is then the ratio V/I. Do this at several frequencies across the audio range, since the impedance of the speaker likely varies a lot over that range. The average of the impedance measurements at all frequencies will give you an idea of the speaker impedance.

--
Art Greenberg
WA2LLN
art@...

On Thu, Mar 22, 2018, at 08:25, Dgyuro via Groups.Io wrote:
An ohm meter across the terminals is what it is 8 ohm, 4 ohm etc.
On Mar 21, 2018, at 3:25 AM, David Wilcox via Groups.Io <Djwilcox01=yahoo.com@groups.io> wrote:

OK. I am seeing various resistances listed for speakers. How would I test one? An ohm meter should indicate a short across the coil I would think. Please help.

Dave K8WPE

Re: Mechanical work is done...

kim campbell <swamprabbit1951@...>
 

What are you using for the lettering. If that is dry transfer letters, what is your trick for getting them to look so good. Straight.

Re: My uBitx with 5v mod #ubitx

Nigel G4ZAL
 

I used this UBEC @ 5v
https://www.banggood.com/Hobbywing-3A-UBEC-5V-6V-Switch-Mode-BEC-For-RC-Models-p-915037.html?cur_warehouse=CN

It has a small metal screen around it and the ferrite on the 5v output lead plus capacitor on the uBitx board (where I cut the track and soldered the 5v lead onto) forms an adequate LC filter on the 5v DC.
I can't detect any 'noise' on Rx, but as yet haven't transmitted.

I use the UBEC on model aircraft with a video transmitter (FPV) and don't see any noise in the signal.
The video transmitters are quite susceptible to 'dirty' DC and often shows as 'herringbone' lines in the received video.

Nigel.

Re: How to test speaker resistance

Art Greenberg
 

An ohmmeter isn't the proper tool. That's because what you want to know is the speaker impedance at audio frequencies, not its DC resistance. They are not the same thing.

You might get a reasonable estimate by using a true RMS voltmeter and an audio signal generator. Connect the signal generator to the speaker through a small series resistor, say 10 ohms. At several frequencies, measure the current into the speaker by measuring the voltage drop across that resistor, and measure the voltage directly across the speaker. The impedance at that frequency is then the ratio V/I. Do this at several frequencies across the audio range, since the impedance of the speaker likely varies a lot over that range. The average of the impedance measurements at all frequencies will give you an idea of the speaker impedance.

--
Art Greenberg
WA2LLN
art@...

On Thu, Mar 22, 2018, at 08:25, Dgyuro via Groups.Io wrote:
An ohm meter across the terminals is what it is 8 ohm, 4 ohm etc.
On Mar 21, 2018, at 3:25 AM, David Wilcox via Groups.Io <Djwilcox01=yahoo.com@groups.io> wrote:

OK. I am seeing various resistances listed for speakers. How would I test one? An ohm meter should indicate a short across the coil I would think. Please help.

Dave K8WPE

Re: How to test speaker resistance

Dgyuro
 

An ohm meter across the terminals is what it is   8 ohm, 4 ohm etc. 


On Mar 21, 2018, at 3:25 AM, David Wilcox via Groups.Io <Djwilcox01@...> wrote:

OK.  I am seeing various resistances listed for speakers.  How would I test one?  An ohm meter should indicate a short across the coil I would think.  Please help.

Dave K8WPE

Re: Any gotchas replacing the TDA2822 with an LM386? #ubitx #ubitx-help

Robert Weiman
 

Thanks! Ordered some (and sockets) last night as mine also came with the WX version.


On Wed, Mar 21, 2018, 3:20 PM John McClun <john@...> wrote:
A drop in replacement - YES.  Look at the data sheets, exactly the same.

--
John
NQ3RP

KMK ver 2017 pcb update

radiomanyo@...
 

Hello everybody !

I found the uBITX accidentally on net surfing. My first impulse was to buy one from hfsignals. Being an older ham used wit constructions and after making lots of pcb to others incl. BITX of all kind I decided to build one myself . I saw the CM2KMK pcb but didn't like the PA , first of all because the transistor is not so easy to find.. So in winter time having long evenings with more or less to do I begin to modify the pcb created by KMK by adding the rest of the original uBITX tx circuits. Also added some mods  found  on forum like : switching the rx input and tx driver input with a relay, putting a pot for adjust the sidetone level, some s-meter circuitry, a fuse for the final stage.It's all tht components. Feel free to use it as it is or you can modify it by your requests. I checked the part I added , not  the imported KMK rx area.I have not  made the pcb yet but in next period  I intend to do , and build the transceiver.
See attached file created with SprintLayout6 . May be called yo6po 2018 version.
All the best from yo6po, Zoli

Re: rv2- messed up setting and txing like mad!!!

Alan -MMØWXT
 

Hi Jerry and all. I hada Chest infection so I have been a ittle quite.

I have however ordered new relays an 10 IRF510's while getting better.

I have checked the board, I have noted on ptt not a single volt coming thru KT! or any voltage getting to lpf stages or tx output.

So I have the exact relays (6) and 10 IRF's to get a decent match from hopefully.
--
MMØWXT
GQRP - #15057

Re: How to test speaker resistance

Peter Elms G0IJU
 

I just measure them with a multimeter on the resistance setting, they measure about two thirds of the impedance,ie, An eight ohm speaker will show as about six ohms at dc and a four ohm about three.
          Nice and easy 73 Peter.


On Wednesday, 21 March 2018, 10:38, Gordon Gibby <ggibby@...> wrote:


Put a 10 ohm  resistor in series with the speaker, run various Audio tones into the series system.  (you could even use one of the birdies in the receiver for this purpose). Measure voltage across speaker, and across resistor and total.

Speaker is a complex impedance . A bit of math and you can compute it’s impedance after measuring the values. 

(You may need an oscilloscope or else and amplifier or transformer  to step the voltages up so you can measure them accurately with the run-of-the-mill voltmeter. )

Back of the envelope estimation: if speaker voltage is about equal to the resistor voltage, Call it  eight ohms.
If half, call it four ohms if half, call it for ohms. If twice, call it  16 to 20 ohms

On Mar 21, 2018, at 06:25, David Wilcox via Groups.Io <Djwilcox01@...> wrote:

OK.  I am seeing various resistances listed for speakers.  How would I test one?  An ohm meter should indicate a short across the coil I would think.  Please help.

Dave K8WPE


Re: Newest addition to the shack!

Nelson
 

Howdy Tim,

An S-38A to be exact.  It is one of two I have. I like to use it for SWL. The other one is waiting to be brought back to life along with way too many other old radios in my shop.  Up next is a Central Electronic CE-10 and 458 VFO I got at a Hamfest in Puyallup a week or so ago.  I have one in the equipment rack but the new one does not have a scratch on it.  But right now the uBITX is front and center.  I am thinking of getting another just to experiment with.

Nelson
KG7GYS



On Wed, Mar 21, 2018 at 8:00 PM, Tim Gorman <tgorman2@...> wrote:
Nice! I like your boat anchor gear. Is that an old S-38 I see?

tim ab0wr

On Wed, 21 Mar 2018 16:53:46 -0700
"Nelson" <ngtdlt@...> wrote:

> I got my uBITx wired up today and powered it up this afternoon.  Not
> much on the air but I did go out to my jeep and fired up my Yaesu
> FT-817ND on 10 meter and had my wife listen down in the shack.  She
> said it hurt her ears it was so loud (I had the AF Gain up all the
> way) but other than that it worked fine.
>
> Now I just need to get the microphone wired up and/or a key wired up
> so I can test the transmitter portion.  For the key I think I will
> just make an adapter from the 1/4" mono plug I use on my other rigs.
> The mic I will use is a mic that I use with my Baofeng UV-5.  I will
> modify the plugs to be separate plugs for the mic and external
> speaker.  I just need to get a couple of the appropriate size jacks.
> Dang I wish Radio Shack still had a store in town.  As it is, I will
> need to mail order the plugs for the mic external speaker and key.
> In the mean time I will spend some time surfing the bands and
> listening on it :-)
>
> Attached is a picture of it in the shack.
> Nelson
> KG7GYS







--
I always thought the Universe was a wonderfully strange place until I studied Particle Physics - I now know the Universe is, in fact, profoundly odd in nature

Re: Microphone, simple fix.

Arv Evans
 

On Wed, Mar 21, 2018 at 11:14 PM, Mvs Sarma <mvssarma@...> wrote:
a mic element at 2.5, may i call it costly !!

Regards
MVS Sarma
 

On Wed, Mar 21, 2018 at 8:04 PM, John McClun <john@...> wrote:
Denny -

There may not be any stores left but RS is still in the e-com business.  Try this element:
https://www.radioshack.com/products/electret-microphone-element-with-leads

--
John
NQ3RP



Re: Microphone, simple fix.

MVS Sarma
 

a mic element at 2.5, may i call it costly !!

Regards
MVS Sarma
 

On Wed, Mar 21, 2018 at 8:04 PM, John McClun <john@...> wrote:
Denny -

There may not be any stores left but RS is still in the e-com business.  Try this element:
https://www.radioshack.com/products/electret-microphone-element-with-leads

--
John
NQ3RP


Re: RD16HHF1 power curve flattening...some

MVS Sarma
 

we can get mpsh10 in smd MMBTH10 AND  the pin out is same as present device.
 They are cheap enough on ebay.  Hope the info helps.

regards
sarma
 vu3zmv

Regards
MVS Sarma
 

On Wed, Mar 21, 2018 at 5:11 PM, John <passionfruit88@...> wrote:
Hello Nik,

How did you go with the feedback issue?

My power amp mods in summary:  finals as RD16HHF1s, feedback resistors R261/R262 as 820 Ohms, Transformer 2T primary / 3T secondary on BN43-202, 180pF across the output transformer primary and 330pf across R87/R88. That's all...in a way.

Heavily inspired by Erhard's (DF3FY) information as displayed on uBitx.net.

Results per band at 14V supply, RV1 at %60, RD16's biased at 250mA each:
Band      output power   Total current
80M        22W                         2.9A
40M        20W                         3.2A
30M        16W                         2.3A
20M         16W                        2.7A
17M         15W                        2.4A
15M         12W                        1.6A
12M         12W                    not measured
10M         12W                        1.7A

At 22W the output transformer does get warm but not the LPFs.

Wound back RV1 to get 9-10W on the high frequency bands and 16-18W on the lower ones.

All the best,

73, John (VK2ETA)


Re: RD16HHF1 power curve flattening...some

Nick VK4PP
 

HI John.

Sorry, I was a bit unclear.
CW power is normal, no effect there, I get the full 20+w output.

But the SSB is low now... I will check it over tonight, try it with and without again, and post up a few pics.

Cheers.

Re: RD16HHF1 power curve flattening...some

John <passionfruit88@...>
 

Hello Nik,

I am confused. A 100uH and 1nF filter has a cutoff frequency of 503KHz, so am not sure how it can affect your audio.

You also mentioned CW, and CW works directly on the unbalance of the mixer and does not come near the audio circuit, therefore I can't understand how it affect you power out.

Are you sure there is not something else?

Also I placed the low pass filter on the input of the SSM2167 module (if you still have it in-line).

But either way it should not affect your power out.

All the best,

73, John (VK2ETA)

Re: how to reset the calibration

Jacob Farnes
 

Yes, tune the carrier to 0Hz (tone  goes quiet/away). In mine a high-pitched tone appeared and confused me, so take your time and try to ignore the birdy signal.

The problem with doing it to an AM station is that you can reverse USB and LSB, so having something to check immediately after calibrating is a good idea. FT8 tends to be busy enough even when the ragchew nets have gone to sleep.

If you can't hear them on 7.074 LSB (except for the one guy in low tones), but booming in on 7.074 USB you've got it right.

When I got my uBitx, the sidebands were reversed from the factory in the Raduino. Which was fine until the auto-sideband switch flipped it back on me. That's where I started to check the tuning and calibration.

I kept seeming to make it worse each time I tried to make the calibration. Took a week off to clear my head and come back to looking at it.

I hope I've been helpful despite seeing a few details I could be more explicit about.

73 de Jacob AG7CT

Re: rotary encoder failed #ubitx-help #parts

Tim Gorman
 

Dana,

Does the encoder actually work? Can you change frequency?

You might be better off add a small normally open pushbutton switch
near the encoder and paralleling it onto the two encoder
switch terminals.

It would be a lot cheaper and easier to do and is actually something
several people have done. Trying to push the encoder switch without
turning the dial is, quite frankly, a pain. I plan to do this to mine
the next time I open the case!

tim ab0wr

On Wed, 21 Mar 2018 18:40:41 -0700
"Dana Marcy" <ve6kbi@...> wrote:

Hello fellow hams:
I seem to have damaged my tuning encoder so that it can't work
right(button push doesn't work).  Please can anyone recommend a
suitable replacement from either Mouser, Digikey or ebay.  I searched
all over in Calgary, and harder than hens teeth to source. 73 Thanks

Re: Newest addition to the shack!

Tim Gorman
 

Nice! I like your boat anchor gear. Is that an old S-38 I see?

tim ab0wr

On Wed, 21 Mar 2018 16:53:46 -0700
"Nelson" <ngtdlt@...> wrote:

I got my uBITx wired up today and powered it up this afternoon.  Not
much on the air but I did go out to my jeep and fired up my Yaesu
FT-817ND on 10 meter and had my wife listen down in the shack.  She
said it hurt her ears it was so loud (I had the AF Gain up all the
way) but other than that it worked fine.

Now I just need to get the microphone wired up and/or a key wired up
so I can test the transmitter portion.  For the key I think I will
just make an adapter from the 1/4" mono plug I use on my other rigs.
The mic I will use is a mic that I use with my Baofeng UV-5.  I will
modify the plugs to be separate plugs for the mic and external
speaker.  I just need to get a couple of the appropriate size jacks.
Dang I wish Radio Shack still had a store in town.  As it is, I will
need to mail order the plugs for the mic external speaker and key.
In the mean time I will spend some time surfing the bands and
listening on it :-)

Attached is a picture of it in the shack.
Nelson
KG7GYS