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Current Draw & Power Output Question

Bill Cromwell
 

The information I read says it is aligned at the factory and other information from HS Signals says that 'alignment' and 'calibration' are the same things. The expectation is that it works right out of the box which HF Signals also says. Mine worked right out of the box. As advertised. Touching up the 'calibration' or 'alignment' made it work 'more better'. I would guess at the factory they get it as close as they can as quick as they can and we can finish it when we get it.

But..again..mine worked right out of the box just as HF Signals said it would. Golden screwdrivers and diddle sticks universally always go the wrong way on the first try. If we don't know what we're doing and we do it anyway we get in trouble. That has been true since the beginning of radio more than two weeks ago (and maybe longer). On here we can help somebody who got lost to find their way. Most of the messages here try to do that.

73,

Bill KU8H

On 09/26/2018 09:05 AM, M Garza wrote:
Doing a smoke test does not include setting the BFO!
No where on the site does it mention that the kit comes pre-calibrated.
The software is written to get the frequency close to being aligned.
Due to differences, some people have to calibrate.
As for the bias adjustment, if it was not transmitting, I would think it
might need to be reset. It is transmitting. RV1 probably needs to be
adjusted to get a little more drive.
There are alignment procedures for a reason. Don't assume that the kit
can be put together and you get instant use. It has to be aligned.
Even the high $$ equipment has alignment procedures.

Marco - KG5PRT

On Wed, Sep 26, 2018, 6:17 AM Timothy Fidler <engstr@...
<mailto:engstr@...>> wrote:

iz. don't confuse the poor bugg_r There is a procedure for set up .
he needs to follow the procedure to get optimum output in SSB. Now
you bring up a red herring. What I would find annoying is to see
that there appears to have been ZERO set up on the test bench in
India (he mentions it did not Rx as received either). You wonder if
it was even turned on to check for smoke leaks ??

--
bark less - wag more

iz oos
 

Indeed Russ, it may have been just by fluke but mine arrived perfectly aligned (actually almost perfectly, 100-150hz off the actual frequency) so I assumed that in most cases it was delivered calibrated.


Il 26/set/2018 16:10, "Russ Hines" <russ@...> ha scritto:
And right off the bat... I wonder why this is mentioned on the HF Signals website?

"The µBITX comes pre-aligned. You should do this only if you really think it is out of alignment."

http://www.hfsignals.com/index.php/ubitx-tuneup/

73,
Russ
WB8ZCC

Russ Hines
 

And right off the bat... I wonder why this is mentioned on the HF Signals website?

"The µBITX comes pre-aligned. You should do this only if you really think it is out of alignment."

http://www.hfsignals.com/index.php/ubitx-tuneup/

73,
Russ
WB8ZCC

M Garza <mgarza896@...>
 

Doing a smoke test does not include setting the BFO!
No where on the site does it mention that the kit comes pre-calibrated.  The software is written to get the frequency close to being aligned.  Due to differences, some people have to calibrate.
As for the bias adjustment, if it was not transmitting, I would think it might need to be reset.  It is transmitting.  RV1 probably needs to be adjusted to get a little more drive.
There are alignment procedures for a reason.  Don't assume that the kit can be put together and you get instant use.  It has to be aligned.  Even the high $$ equipment has alignment procedures.

Marco - KG5PRT 

On Wed, Sep 26, 2018, 6:17 AM Timothy Fidler <engstr@...> wrote:
iz. don't confuse the poor bugg_r There is a procedure for set up .  he needs to follow the procedure to get optimum output in SSB.  Now you bring up a red herring.  What I would find annoying is to see that there appears to have been ZERO set up on the test bench in India (he mentions it did not Rx as received either). You wonder if it was even turned on  to check for smoke leaks ??

Timothy Fidler
 

iz. don't confuse the poor bugg_r There is a procedure for set up .  he needs to follow the procedure to get optimum output in SSB.  Now you bring up a red herring.  What I would find annoying is to see that there appears to have been ZERO set up on the test bench in India (he mentions it did not Rx as received either). You wonder if it was even turned on  to check for smoke leaks ??

iz oos
 

Why don't you measure the power and current draw in CW key down?


Il 26/set/2018 12:02, "Curt M." <Kc3hjp@...> ha scritto:
Thanks guys, I had sort of considered that the Bird 43 was probably not showing peak power being that it’s not capable of without the add on kit being done to the meter so that confirms my thoughts. Thanks 

I’m using a relatively new, Fluke meter that of course could have an issue but it jives with another meter that I have so I suspect it’s probably close enough. 

I may re-bias being that the uBitx was supposed to be in alignment when I received it and it was nowhere near being able to tune a signal when I first powered it up. I had to do the calibration and BFO adjustment before I could tune anything in. I suspect that it may have been skipped over when it came to factory setup. 

Curt M.
 

Thanks guys, I had sort of considered that the Bird 43 was probably not showing peak power being that it’s not capable of without the add on kit being done to the meter so that confirms my thoughts. Thanks 

I’m using a relatively new, Fluke meter that of course could have an issue but it jives with another meter that I have so I suspect it’s probably close enough. 

I may re-bias being that the uBitx was supposed to be in alignment when I received it and it was nowhere near being able to tune a signal when I first powered it up. I had to do the calibration and BFO adjustment before I could tune anything in. I suspect that it may have been skipped over when it came to factory setup. 

Timothy Fidler
 

Russ et AL , these are the Bias instructions  straight from the  ubitx website.

It would seem to me that the unit went in the box without bias being done.   Rebias (not sure about the Re.. it may never have been done ??) is at his own risk. It seems to be a ticklish operation as the bias limit resistors are a SNAFU it seems. They appear to have been specified on basis of what the 5V reggy could supply with the potentiometers bottomed out  and not on basis of keeping bias volts in a reasonable range.  The current the chap is quoting is so low cw the below that he might like to check his DVM is in fact in spec...OTOH.....

  • Switch off the rig
  • Locate the two PA bias presets (the blue square ones)
  • Set both the presets  to fully clockwise position, gently.
  • Attach a dummy load or a low SWR antenna and switch the rig on
  • Attach a current meter to the power supply so can monitor the current draw
  • Switch on
  • Press the PTT without speaking ( no modulation)
  • The current draw should be between 470 mA and 500 mA
  • Slowly increase one of the two presets until the current increases to by 100 ma
  • Do the same for the other preset (the total current should have increased by 200 ma now)

Russ Hines
 

Lurk mode: OFF

You did.
"On 40m it looked like my power was about 5w."

Let me preface the rest of my reply with this - every once in a while, I do something foolish.  Like make a post.  You open yourself up for more BS than need be.  Who needs that?  But since I'm seeing the same voices here most of the time, I thought I'd add a different one.  Mine.  Not concerned about the song, just hoping I'm in the same hymnal. ;-)

A stock Bird 43 displays average power but not PEP which is what you're kind of interested in for SSB.  Being that as it may, let's make some assumptions and take your 12v source voltage and multiply it by what you indicate your currents are:

12v x 166 mA is just under 2 watts.  From what I gather from your post, this is the DC power your radio uses during receive.

12v x 540 mA is about 6-1/2 watts.  This is the DC power consumption on transmit with no RF output.  THIS is actually what we call idle current.  We can set the operating point of the IRF510's looking at this current.

12v x 1.02 A is about 12 watts.  This is total DC power consumption during transmit.  With RF output. 

Okay so far?  Good deal.  From what I read on this forum, and based on measurements of my own uBitX, the 2 x  IRF510 final amp isn't terribly efficient at 12v, this drive and output power level, but again let's assume we're as efficient as we need be.  For SSB, class A/B finals are somewhere in the 50-55% range efficiency.  You're pipping your Bird wattmeter at 5 watts, so your DC-to-RF efficiency is around 42%.  In reality, it's probably worse, but you'll likely not pop the FET's at this level.

IMHO, not great, but not terrible.  Lots of assumptions.  But it's better than what I see on my rig right now (I'm still hacking on it, installed several of Allison's suggestions, more to go).

Wait, it gets better.  A Bird 43 isn't frequency selective and this radio has spurs/harmonics issues.  Some of that output is not on frequency, or maybe even on 40m.  How much?  Beats me, you'll have to measure it.  My radio's what I call reasonable, around -40 dBc according to my Rigol SA.  That's 40 dB down from carrier.  Not technically legal as far as "spurious radiation" is concerned.  But it gets much worse on 20m and higher, and at higher than 3 watts or so output.  Make another assumption and say several milliwatts.  You can read or let others here tell you about the gory details... and hem and haw about -43 dBc no doubt. ;-)

Better news is, you're making contacts with the rig and, it's hoped, having fun.  Could be worse, you could be an "appliance operator."  But you obviously chose a different path.  Good for you.

So, unless you want to improve what you have, get your hands dirty, and suffer slings and arrows from forum denizens, my suggestion is stay on 40m, stay at 5 watts or less, and sin no more.  Otherwise, jump in with more questions, heat up the soldering iron, and dive into your uBitX.

BTW, the short answer to your original question is, currents sound about right to me for a few (more than 2) watts RF out or so on this radio. YMMV.

Ain't radio fun?

Lurk mode: ON

73,
Russ
WB8ZCC

Curt M.
 

I should have mentioned that my tests were on 40m

Curt M.
 

Hello everyone, I’m just curious what kind of current draw I should be seeing?  Here are my readings:

166mA Idling
540mA Keyed w/no audio
1.02A with loud hello into the mic

The reason I ask this is that I put my radio into my Bird 43 and a 25w dummy load on the other side of the meter. I was using the lowest HF slug that I had which is 25w. On 40m it looked like my power was about 5w. I was thinking that I should see closer to 10w running the radio on 12v. 

I’ve made about 10 contacts all over the US so I know I’m getting out but I thought I should see more power out. Not sure if I need to do the tune procedure on the RV1 & RV2 or not?

Curt