Date   
Re: Maximum and minimum voltages for uBitX V5?

Dan Pflugrath
 

I have a uBITX version 3 and now a version 5.  On both I use a 4 cell LiPO battery to power the radios that when fully charged is 16.8 volts.  I run the LiPo through the main power switch and fuse to a LM317 voltage regulator for 12 volts (170 - 200 mA) to the main board and the full LiPo battery voltage to the PA .   I monitor the voltage on the LiPo battery to not go below 13.75 volts before recharging.

Re: ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio #ubitx-help #ubitx

Clark Martin
 

If the output MOSFETs are heating up on power up with out being in transmit, they are toast.

Clark Martin
KK6ISP

On Apr 10, 2019, at 8:52 PM, Jens Kaemmerer <jens@...> wrote:

Since the IRF510 heatsinks are getting very hot very quickly right after turning on 
the radio - I am afraid to keep the radio on and potentially cause more damage. 

I am currently thinking of replacing the IRF510s first, hoping that this will fix the 
'overheating' issue. Will try the proposed measurements when the replacement 
IRF510s arrive.

Prior to this issue, I was able to receive all types of signals (SSB, CW, FT8, ...).

Re: ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio #ubitx-help #ubitx

Jens Kaemmerer
 

Since the IRF510 heatsinks are getting very hot very quickly right after turning on
the radio - I am afraid to keep the radio on and potentially cause more damage.

I am currently thinking of replacing the IRF510s first, hoping that this will fix the
'overheating' issue. Will try the proposed measurements when the replacement
IRF510s arrive.

Prior to this issue, I was able to receive all types of signals (SSB, CW, FT8, ...).

-jens (KM6ZJV)

Re: ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio #ubitx-help #ubitx

Ashhar Farhan
 

if the signals have fallen from the waterfall, that means you are unable to receive. IRF510s may not be involved. Are you able to receive SSB/CW signals? You should check your audio cable.

- f

On Thu, Apr 11, 2019 at 7:18 AM Clark Martin <kk6isp@...> wrote:
Check the supply current to the PA with a meter.  If it’s significantly higher than the idle current, say 250-300 mA it’s probably damaged.  To be sure, turn the bias pots to the full clockwise position and check the PA current again.  It should very low, less than 50mA.  If the FETs are damaged they’ll probably be drawing as much as before you dialed down the bias pots.

I would strongly suggest a fan and/or bigger heatsinks.

Clark Martin
KK6ISP

> On Apr 10, 2019, at 6:42 PM, Jens Kaemmerer <jens@...> wrote:
>
> I might have broken the IRF510 MOSFETs with FT8.
>
> This problem started during a longer sequence of FT8
> transmissions - abruptly all signals disappeared from
> the waterfall.
>
> The heatsinks used to get warm/hot only after a longer
> sequence of FT8 TX cycles. Now the heatsinks gets hot
> almost immediately after powering up the radio.
>
> Could this be an indication that the IRF510 MOSFETs
> have been damaged?
>
> How can I diagnose what is still working and what is not?
>
> Has anybody else experienced this problem? If yes,
> how can it be fixed?
>
> Thank you,
>
> -jens (KM6ZJV)
>
> PS: I was using the original heatsinks, radio has been working
> fine for 4 weeks.
>




Re: ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio #ubitx-help #ubitx

Clark Martin
 

Check the supply current to the PA with a meter. If it’s significantly higher than the idle current, say 250-300 mA it’s probably damaged. To be sure, turn the bias pots to the full clockwise position and check the PA current again. It should very low, less than 50mA. If the FETs are damaged they’ll probably be drawing as much as before you dialed down the bias pots.

I would strongly suggest a fan and/or bigger heatsinks.

Clark Martin
KK6ISP

On Apr 10, 2019, at 6:42 PM, Jens Kaemmerer <jens@...> wrote:

I might have broken the IRF510 MOSFETs with FT8.

This problem started during a longer sequence of FT8
transmissions - abruptly all signals disappeared from
the waterfall.

The heatsinks used to get warm/hot only after a longer
sequence of FT8 TX cycles. Now the heatsinks gets hot
almost immediately after powering up the radio.

Could this be an indication that the IRF510 MOSFETs
have been damaged?

How can I diagnose what is still working and what is not?

Has anybody else experienced this problem? If yes,
how can it be fixed?

Thank you,

-jens (KM6ZJV)

PS: I was using the original heatsinks, radio has been working
fine for 4 weeks.

ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio #ubitx-help #ubitx

Jens Kaemmerer
 

I might have broken the IRF510 MOSFETs with FT8.

This problem started during a longer sequence of FT8
transmissions - abruptly all signals disappeared from
the waterfall.

The heatsinks used to get warm/hot only after a longer
sequence of FT8 TX cycles. Now the heatsinks gets hot
almost immediately after powering up the radio.

Could this be an indication that the IRF510 MOSFETs
have been damaged?

How can I diagnose what is still working and what is not?

Has anybody else experienced this problem? If yes,
how can it be fixed?

Thank you,

-jens (KM6ZJV)

PS: I was using the original heatsinks, radio has been working
fine for 4 weeks.





Re: CW key sticking with Nextion LCD

Joe Puma
 

At first I wrapped a barrel chock on the wires of Nextion. It helped a little. The I put a .01uf on the blue wire of Nextion and ground and that stopped the key from sticking.

Joe

On Apr 10, 2019, at 12:46 PM, d balfour <davesters@...> wrote:

I didn't follow the link but You might try a torrid on the orange line and/or between the raduino and nextion.


Re: v5 12m/10m Spectrums

ronmhauser@...
 

Hi Curt.  I had to prove it to myself using a spreadsheet when I started reading these, dBm or dBV doesn't matter when comparing peaks within one spectrogram.  Here's my math proof using the peaks from the file 24895_30mWpp_3W.jpg.  All the peaks in the spectrogram are relative to one volt.  The instrument doesn't know the input impedance of the system so it can't do the calculation to change them to dBm.  But all the peaks are using the same input impedance, whatever it is, so it doesn't matter.  The difference between peaks in dB is what we care about, looking for -43dB down from the fundamental.  Right?  For the record the transmitter is terminated in a 50 ohm dummy load and the cable to the instrument is also terminated in 50 ohms ... but mathematically it doesn't matter it's the same impedance at for both peaks in the calculation.




73
--Ron
K0EIA

Re: CW key sticking with Nextion LCD

_Dave_ AD0B
 

I didn't follow the link but You might try a torrid on the orange line and/or between the raduino and nextion.

Re: v5 12m/10m Spectrums

Curt
 

My concern is whether we are measuring a power ratio or a voltage ratio - I am suspicious we could be measuring the latter -- see

https://en.wikipedia.org/wiki/Decibel#Voltage

I am thinking that if the ubitx is loaded at 50 ohms that the instrument may be taking valid data.  But perhaps a conversion to power ratio is necessary.  40 dB in voltage corresponds to an amplitude ratio of 100, while in power it is 10000.  yes note this can be the difference between having spurs at - 43 dB or - 23 dB when the unit is power! 

See if you instrument offers a tutorial on this.  I am thinking that even though voltage is being sensed, possibly the instrument knows how to do the conversion to power (??). 

As I possess a ubitx (v4) with spurious around -33 to - 35 dBc in the upper bands on SSB - I was hoping your v5 to be much better, but I don't want us to jump to that conclusion without careful evaluation.  [The greater news - my box is compliant on SSB up to 17m, and now good on CW - 'just' with a relay transplant to add a second set of relays on a daughter board]. 

Curt

Re: v5 12m/10m Spectrums

ronmhauser@...
 

Well, the AD2 is really a (software defined digital) scope with FFT ... so the front end is a scope front end, the probes are high impedance voltage input.  Therefore the display is relative to voltage, not power.  I can't choose dBm ... BUT ... the measurement between the fundamental and the harmonics and spurs are relative, they are dB down from fundamental.  Changing the reference changes the scale on the left, but not the difference between the peaks.  (Unless I am doing the decibel math wrong, which is possible).

On mine -- on 12m -- with mike gain and RV1 turned down -- I'm calling it FCC compliant with all peaks 43dB down from the fundamental on 12m, either SSB or CW. 

73
--Ron
K0EIA

Re: CW key sticking with Nextion LCD

Joe Puma
 

Thanks Sam!

 

Sent from Mail for Windows 10

 


From: BITX20@groups.io <BITX20@groups.io> on behalf of Sam Tedesco <stedesco619@...>
Sent: Wednesday, April 10, 2019 9:25:17 AM
To: BITX20@groups.io
Subject: Re: [BITX20] CW key sticking with Nextion LCD
 

Re: Microphone choices

 

I bought one for my bitx40 they work out very nice. I take the element out and put it in a mini mic.

http://www.jlielectronics.com/microphones/com-mic-jli-52b/
--
David

 N8DAH
Kit-Projects.com

Shop is open!

Re: CW key sticking with Nextion LCD

Sam Tedesco
 

Re: CW key sticking with Nextion LCD

Sam Tedesco
 

I'm on v3, also. I tried looking for the original post, but couldn't find it. Anyway, your descriptions sounds about right. I thought it was odd back when I tried it for the first time...I have a few ver 3 boards and have used it on every one. I'll keep looking for the original info.

Re: Microphone choices

MVS Sarma
 

Even if one is rich, i suppose that there is no point in investing in mics that zerve high end systems for ham use. We dont really need more than 0.3 to 3Khz at the maximum

Regards
Sarma vu3zmv

On Wed, 10 Apr 2019, 5:04 pm iz oos <and2oosiz2@... wrote:

If you can't afford a Behemoth microphone (hi hi) you may try high sensitivity (around - 24db) electrec elements you may find at large vendors (Mouser etc). I opted for dynamic elements (not for karaoke) plus a homemade vogad compressor.


Il 10/apr/2019 13:22, "David - CA3DPV" <david.parra@...> ha scritto:
My two cents...

First I've tried with a karaoke mic and a audio console 
Good: I get 10W of power without effort, talking quietly
Bad: The signal transmitted is extremely low pitch (very dificult to copy). 

Now I use a PC mic (purchased for a few bucks). PTT is a button installed on it.
Good thing: It's a very cheap and small desk microphone (3 USD), 
Bad thing: It's a low gain mic, get 4 or 5 watt only @40m

Re: Microphone choices

iz oos
 

If you can't afford a Behemoth microphone (hi hi) you may try high sensitivity (around - 24db) electrec elements you may find at large vendors (Mouser etc). I opted for dynamic elements (not for karaoke) plus a homemade vogad compressor.


Il 10/apr/2019 13:22, "David - CA3DPV" <david.parra@...> ha scritto:
My two cents...

First I've tried with a karaoke mic and a audio console 
Good: I get 10W of power without effort, talking quietly
Bad: The signal transmitted is extremely low pitch (very dificult to copy). 

Now I use a PC mic (purchased for a few bucks). PTT is a button installed on it.
Good thing: It's a very cheap and small desk microphone (3 USD), 
Bad thing: It's a low gain mic, get 4 or 5 watt only @40m

Re: Microphone choices

David - CA3DPV
 

My two cents...

First I've tried with a karaoke mic and a audio console 
Good: I get 10W of power without effort, talking quietly
Bad: The signal transmitted is extremely low pitch (very dificult to copy). 

Now I use a PC mic (purchased for a few bucks). PTT is a button installed on it.
Good thing: It's a very cheap and small desk microphone (3 USD), 
Bad thing: It's a low gain mic, get 4 or 5 watt only @40m

Re: Poor mans spurs and harmonics check with uBitxandcommercial radio

Joe Puma
 

Yes the uBitx might have some flaws but not hard to find issues with other radios or how a ham is using it, mods, running power, etc. There are a lot of aging radios out there, my 840 is of the latest breed and I was told when I bought it a year+ ago that the owner had recently purchased and  went SK shortly after.  I reviewed the alignment procedure quite a bit but I don’t have the right test equipment to run through the procedures and I’ve been firm on not using the radio a guinea pig, that’s what the uBitx is for.

 

 

Joe

 

 

Sent from Mail for Windows 10

 

From: iz oos
Sent: Wednesday, April 10, 2019 2:51 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Poor mans spurs and harmonics check with uBitxandcommercial radio

 

:) I think the TX of the ubitx has been the most tested, loved and blamed by hams in history. Also because it should be assumed that commercial ones should have no basic issue in terms of harmonics and spurs. However mods in commercial rigs are not that infrequent and the consequences of these should also be thoroughly tested. And of course some might always say, yeah the 840 is an old radio that needs to be 'aligned', you would better off buying a new rig!

 

Il 10/apr/2019 08:01, "Joe Puma" <kd2nfc@...> ha scritto:

Looks like the ubitx screenshot didn’t get attached properly, here they both are again for comparison.

 

 

 

 

 

 

Sent from Mail for Windows 10

 

From: Joe Puma via Groups.Io
Sent: Wednesday, April 10, 2019 1:51 AM
To: BITX20@groups.io
Subject: [BITX20] Poor mans spurs and harmonics check with uBitx andcommercial radio

 

Hi,

 

I just did a quick comparison test between my ubitx and Yaesu ft-840 radio.  I used a SDR on a laptop with a up converter, the SV1AFN with a 200mhz LO. I had a multiband antenna on it from a Yaesu XV-7R, its tuned to receive AM broadcast band. I was using Touchstone and scanning from 200-230mhz (0-30mhz). The ubitx was transmitting around 12watts,  the FT-840 at 10watts but with CW key down and they were both transmitting on antenna EFHW antenna.

 

The ubitx show two spikes that the FT-840 does not show  at all but its almost similar with other spurs. The signal appears stronger with the FT-840 but its spurs are relatively similar to ubitx. Actually the ubitx spurs seem to be relatively less from main signal when compared to FT-840.

 

I have to find a local ham club with some gear to test the uBitx and maybe the FT-840 while I’m at it. 😊

 

 

 

 

 

 

 

 

This is a no TX baseline.

 

 

 

 

Joe

KD2NFC

 

Sent from Mail for Windows 10

 

 

 

Re: uBitx V5 Audio improvement

Jim Tibbits
 

Attached couple of mods I've been using ...One variable audio filter and one mod Re 386 ...
The 386 shows what I measured on the ic with a 10 uF cap pin 1-8 ...flat from near dc to daylight ..What I heard was LOTS of wideband noise ..Cut it with the installed L/C filter ... then installed the op-amp variable filter ..found I did not need the 386 bandpass mod with the variable filter ...both mounted on same board and plugged into U1 socket on V3 board ...dono what would be needed to adapt to ver 4/5

Jim
LM386 Bandpass Filter.jpeg


On Tue, Apr 9, 2019 at 9:26 PM Ashhar Farhan <farhanbox@...> wrote:
Exact!

On Tue 9 Apr, 2019, 12:09 PM Jerry Gaffke via Groups.Io, <jgaffke=yahoo.com@groups.io> wrote:
For LM386 gain that is flat across 300 to 2300 Hz 
and is more than 26dB (no cap) but less than 46dB (10uF cap),
this is done by adding a resistor in series with that 10uF cap.