I believe you need at lest 6" x 6" x 2.5"
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Re: IRF510 amplifier failures
I agree, I blew a 510 by
messing with the bias adjustment. My meter was
not reading the 100 ma, so I cranked up all the way full CCW.
Out of the box
it worked! My uBitX works with over 5 watts out, I'm leaving it
alone. If
it works, leave the power alone and skip to fix the other
problems (pop,
agc etc.) Mic that came with unit works well without
amplification.
Stay QRP and look for us Sunday 7178 7278.
Ed W0OIC
On 1/30/2018 11:05 AM, Jerry Gaffke via
Groups.Io wrote:
toggle quoted message
Show quoted text
We have thousands
of uBitx's and Bitx40's out there now, an occasional post to the
forum about?
a blown IRF510 is inevitable
My opinion is that SWR is not what blows the IRF510's, especially
when operating from 12v.
Biggest issue is that the heatsink is quite small, especially if
operating continuous duty in some digital mode
and/or feeding the IRF510's more than 12v to get higher power.
Also, be aware that the gate bias adjustments are backwards
(clockwise is minimum), and get very touchy
as you approach the transition region, so once the drain current
starts going up it is not much of a turn?
to go from the optimal 100ma to a very hot IRF510 with 3A of drain
current.
And be aware that the heatsinks as shipped are not insulated from
the IRF510 tab (connected to the drain).
I'd guess most failures are due to overheating and messing up when
adjusting for 100ma of drain current.
A temp sensor and foldback current limiting would avoid these
troubles if you want a safety net.
Other failures due to screwdrivers in the works or flying leads
touching the wrong spot and other such snafus.
Reverse DC is not a problem for the IRF510.? It has an intrinsic
reverse diode from source to drain,
will blow the traces or coils between it and the power supply.?
Or, with some foresight, the fuse
you put into that power supply lead.? Where you need reverse
protection is going into the remainder
of the board, be it Bitx40 or uBitx.? A 1n4148 diode would
suffice, a 1n400x would not get quite so hot,
but there is no problem with running all that stuff at 0.7 volts
less.??
Having a full wave rectifier in line with the power supply to the
IRF510's would reduce the voltage
there by 1.4 volts.? And have a significant hit on output power
available.
In post 22597, KB1GMX reports:
My experience with IRF510s is extensive and much different. ?I
rarely kill one even during experimenting.? I use them for RF
power though 6M. ?How much 8 in a parallel 4x4 push-pull at 6M
running 225W! ?My favorite is two in a push pull amp
(K500r/wa2eby design) with 28V running about 55W on 40m and 37W
at 10M and after 6 years of wrong antenna and all sorts of usual
havoc its still running with the same pair.?
So the IRF510 is capable of being worked very hard, and still
surviving when driving a high SWR.
Testing an antenna system with no more than 12v into the IRF510
should be fairly bulletproof.
If you want to reduce power further, reduce the drive level to the
final using R136 on the Bitx40, RV1 on the uBitx.
Again, note that these pots work backwards, fully clockwise is
minimum drive.
Jerry, KE7ER
On Tue, Jan 30, 2018 at 04:54 am, John Brock wrote:
I have not
received my uBitx yet. I¡¯ve been? reading this forum for about
two weeks. Looks like PA failures is a huge problem.
Are the two
main causes reverse DC power and high SWR?
For the DC
polarity problem how about a full wave rectifier at the DC
input? Two diode voltage drop a problem with this approach?
What would be
the best way to limit PA? power out to a very small value to
allow a manual tuner to be used for the SWR issue?
?
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uBITX AGC - Adafruit TPA2016, A Success!
#ubitx
Hi Group.
Now, I haven't tried many AGC solution on the uBITX, only 2, the VK3YE, and ADAFRUIT TPA2016 I2C module.
The VK3YE solution I found messed with the audio quality, made it all scratchy, and still didnt handle local 100w stations well...
Now after playing with the TPA for a few days I am very happy with the results.
Audio has good depth and AGC is reponsive, also gives a nice increase in gain.
One trick to others who want to impliment this, you will need to add some code to the Adafruit library to implement the enableNoiseGate(false); function.
We need to turn the NoiseGate off or else the AGC will not ramp up with only background noise and you will not hear anything until a loud signal comes on.
Also the speaker output is NOT grounded, you need to isolate you SPK jack so that the - from the TPA2016 are direct to the speaker with no chassis grounding...
Best part in my opinion, is that ALL the AGC related settings are customisable if your want, if not, just use the voice settings from the datasheet, I have and they work great!
I will post up some code tonight... and a few pics....
73, Nick VK4PLN
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this would make for a great desktop case
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Re: I did it again.. i plugged the arduino pins on reverse
I can deal with the language barrier.
Podemos emplear espanol si quieres, pero no he practicar lo unos veinte anos.
You do have to describe what is going on in detail if we are to fix this through forum posts.
Otherwise you will have to find somebody there to help you in person.
But I think I understand your situation now.
You have a uBitx, the only complaint remaining is that when you press the PTT switch
it does not go into transmit mode.? No clicking from the relays.?
I assume the uBitx continues to receive with PTT pressed.
Check these points of the uBitx with a voltmeter, measuring voltages to ground:
When you press the PTT switch, the orange wire into pin 5 of the 8 pin connector into the Raduino
should go from high (about 5v) to low (about 0 volts).
? ??
The Nano on the Raduino sees that low from the PTT switch and responds?
by driving the T/R pin high into the uBitx main board.
The voltage at the top of C150 as seen in the lower left of the uBitx schematic goes from 0 volts to around 5 volts:
Here's the uBitx schematic:
? ??
The 5 volts at signal T/R turns on transistor Q15, which will make pin 9 of relay K1 go from 12 volts down to near 0 volts.
With the coil of relay K1 now energized, K1 pin 3 should go from 12 volts to zero volts to remove power from the receive circuits
and K1 pin 5 should go from zero volts to 12 volts to power the transmit circuits.
The pin numbering of the relays is kind of funny, it is numbered as if it has 16 pins,
but some of the pins are missing.? Here's the view from the bottom of the board.
Pin 1 has a square pad:
16? ? 1
X? ? ?X
14? ? 3
X? ? ?X
12? ? 5
X? ? ?X
X? ? ?X
9? ? ?8? ??
Best Regards,
Jerry,? KE7ER
toggle quoted message
Show quoted text
On Tue, Jan 30, 2018 at 01:10 pm, C¨¦sar EA3IAV wrote:
Don¡¯t worry. I will not make you read anymore. I thought It was clear what I explained. If you don¡¯t understand something you may ask. Not to mention English is not my first language. But it is easier for you to make a compilation of my clumsiness. Radio works and receives but ptt is?not working. No relais noise. No swiching. ?Somehow despite of all connections seem to be good as i teaces continuity. That wire was the only execption I did to make sure there is a connection between that pins I described.
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Re: IRF510 amplifier failures
What many people fail to realise when using a diode bridge for
reverse polarity protection is it means neither of the power wires
are at ground potential.? If used in vehicle with battery having
one terminal grounded the grounds are not at same potential.? So
your metal case and vehicle body have a diode drop difference.
Cheers,
Will
ZL1TAO
On 31/01/18 06:05, Jerry Gaffke via
Groups.Io wrote:
<SNIP>
Reverse DC is not a problem for the IRF510.? It has an intrinsic
reverse diode from source to drain,
will blow the traces or coils between it and the power supply.?
Or, with some foresight, the fuse
you put into that power supply lead.? Where you need reverse
protection is going into the remainder
of the board, be it Bitx40 or uBitx.? A 1n4148 diode would
suffice, a 1n400x would not get quite so hot,
but there is no problem with running all that stuff at 0.7 volts
less.??
Having a full wave rectifier in line with the power supply to the
IRF510's would reduce the voltage
there by 1.4 volts.? And have a significant hit on output power
available.
<SNIP>
On Tue, Jan 30,
2018 at 04:54 am, John Brock wrote:
I have not
received my uBitx yet. I¡¯ve been? reading this forum for about
two weeks. Looks like PA failures is a huge problem.
Are the two
main causes reverse DC power and high SWR?
For the DC
polarity problem how about a full wave rectifier at the DC
input? Two diode voltage drop a problem with this approach?
What would be
the best way to limit PA? power out to a very small value to
allow a manual tuner to be used for the SWR issue?
?
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Re: Message authorization
John
I could join you to the group but would not know the configuration you might
want for the subscription.? It would be better if you were to go to the group
Arv? K7HKL
_._
On Tue, Jan 30, 2018 at 2:24 PM, john robertson <kk6gkradio@...> wrote: Greetings, will you allow me to send messages to the group?? I have a working BITX40 but could use some help in updating the firmware.
Thanks, John Robertson
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Re: Message authorization
Here is a link to Allard's software.
?The instructions are on that page.
Marco - KG5PRT?
On Jan 30, 2018 3:24 PM, "john robertson" < kk6gkradio@...> wrote: Greetings, will you allow me to send messages to the group?? I have a working BITX40 but could use some help in updating the firmware.
Thanks, John Robertson
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Re: uBITX woes, feeling disheartened.
#ubitx
I may want the raduino board James ...
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Re: I did it again.. i plugged the arduino pins on reverse
On Tue, Jan 30, 2018 at 01:10 pm, C¨¦sar EA3IAV wrote:
If you don¡¯t understand something you may ask. Not to mention English is not my first language. But it is easier for you to make a compilation of my clumsiness.
Jerry is asking, and he's not making a compilation of your clumsiness.? He is, however, making a compilation of all the issues you have had with the radio to get a thorough understanding of what might be causing the trouble. The situation is complicated and the symptoms you describe are confusing.? Blowing a regulator on the Raduino is very odd.? Losing the connection between the 3V3 and C1 on the Raduino board is also very odd.
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Greetings, will you allow me to send messages to the group?? I have a working BITX40 but could use some help in updating the firmware.
Thanks, John Robertson
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Re: 7 Pins, 8 Pins, What's a Pin Between Friends?
To add another data point, my first run ¦ÌBITX came 2 x 8 pin, 1 x 3 pin, 1 x 2 pin harnesses.
By running the pattern backwards does Violet regain her virtue?? (please apply apologies in advance if needed)
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Re: uBITX woes, feeling disheartened.
#ubitx
Hello,
Who is the member of this group that has the bad uBitx with all the relay/other issues? Please contact me about your uBitx. I have a new in the box uBitx I might be will to swap for you damaged one, but I need to know what shape it¡¯s in physically.
After all these posts you seem to be getting nowhere and I hate to see problems like this unresolved, no strings or catch I haven¡¯t built mine and you could use it more than me at the moment.
toggle quoted message
Show quoted text
On Jan 30, 2018, at 13:18, K5ESS < k5ess.nothdurft@...> wrote: The pin numbering on these relays is inconsistent? i.e. reversed in some cases. Either will work OK by taking this into consideration. Mike K5ESS ? From: [email protected] [mailto:[email protected]] On Behalf Of David Beal
Sent: Tuesday, January 30, 2018 9:36 AM
To: [email protected]
Subject: Re: [BITX20] uBITX woes, feeling disheartened. ? Hi Nick,?
I got the same relay and am equally confused as the pinout for both the original relay (Virtual) and this replacement (Panasonic) appears to be the same (across 1/16 on both pinouts); yet the schematic shows the coil across pin 8/9 per:??/g/BITX20/message/40439
Oddly, the data sheet for this relay which I posted here:?/g/BITX20/message/40440? is no longer available.??
Further, this post:??/g/BITX20/message/26983? indicates coil across 1/16 also.?
I'm going to disconnect PA power this weekend and use an ohm meter to trace through the relays per someone else's suggestion.??
Dave
--
Dave Beal
AE6RQ
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Re: I did it again.. i plugged the arduino pins on reverse
Don¡¯t worry. I will not make you read anymore. I thought It was clear what I explained. If you don¡¯t understand something you may ask. Not to mention English is not my first language. But it is easier for you to make a compilation of my clumsiness. Radio works and receives but ptt is?not working. No relais noise. No swiching. ?Somehow despite of all connections seem to be good as i teaces continuity. That wire was the only execption I did to make sure there is a connection between that pins I described. 
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Re: 7 Pins, 8 Pins, What's a Pin Between Friends?
Good idea to keep the colors consistent,
I had no clue what color scheme was chosen for your 7 pin harnesses.
I'll credit you with the point about colors being backward with respect to pin numbers,
as it hadn't occurred to me.? (For those that don't quite follow, the wire colors would
otherwise agree with the resistor color band code.)
toggle quoted message
Show quoted text
On Tue, Jan 30, 2018 at 12:43 pm, Arvo KD9HLC wrote:
I'm going to keep the colors the same as the wire up diagram
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Re: 7 Pins, 8 Pins, What's a Pin Between Friends?
I'm going to keep the colors the same as the wire up diagram, so I'll be using black to A on the encoder on one and black to the speaker ground on the other.? I'll add a violet from a spare for the mic.? The violet is not used on the Raduino socket.
And you make an interesting point, that the numbers from pin numbers 1-8 seem to be backward with respect to the colors.
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Re: uBitx audio potentiometer question.
I suppose you could try a 250k volume control pot, but it may not work very well.
The TDA2822M datasheet claims a minimum input impedance of 100k.
? ??
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On Tue, Jan 30, 2018 at 12:30 pm, Dennis Yancey wrote:
How would you expect a 250k audio taper pot work? I have a load of these from guitars and amp repair/build.
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Re: uBitx audio potentiometer question.
How would you expect a 250k audio taper pot work? I have a load of these from guitars and amp repair/build.
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ekelley
Nick VK4PP
Arvo W0VRA
James Lawrie