Re: BitX40 collaborate in person? BitX40 Arduino Ham Radio 'show and tell' all welcome
I will do a build post on this but, here is my stock BitX40, on what our club is using as 'workstation'.
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BitX40 collaborate in person? BitX40 Arduino Ham Radio 'show and tell' all welcome
BitX40 Mods on Display in person...
In the spirit of this being a BitX talk group where a lot of sharing goes on.? From the open source nature of the radios themselves to Mr. Farhan¡¯s continuing to comment on others contributions, to the evolution of the many directions that individuals Mods are taking this project....to the BitX40¡®s on Google Maps, to Sunday night QSO parties, we all seem to be reaching out to connect....
In that spirit...
I am asking?? if there any Builders on this board who would be interested in sharing in person, by attending, an in person, bring your BitX40 or other Arduino Core Ham Radio project to a Forum, hosted in an indoor facility in East TN, USA, on January 6, 2018??
On the schedule is Dr. Jack Purdum with a talk on ¡®Tips on Homebrewing¡¯, followed by an open invitation (with entrance) to display ones BitX40 and Mods or other Arduino Core Ham Radio Projects (depending on project, table top of appropriate size will be provided) and then discuss yours and others Projects.? Then, concluding with a Roundtable discussion on ¡®Arduino and Ham Radio¡¯ also attended by Dr. Jack Purdum and hopefully....¡®You¡¯.
I have a few interesting BitX40's lined up at this time.
I see this as an extension of this board....a time and place where ¡®in person¡¯ collaboration will be possible. A chance to ¡®see¡¯ some of these Mods and talk to the person who has done them.
As a bonus, the Hamfest that this is taking place at, its at a large facility that allows indoor tailgating, has accessible features (elevators), and has its own year round RV campground with electric and water hookups. No parking in the grass, flat hard parking for about 2k. Located within sight of Interstate, everything needed at same exit.? The definition of easy.
If this is not appropriate to post here, please delete. Please contact me off board for more information if interested.? Your comments are welcomed.?
My thoughts: comments geared toward collaboration might be okay on board??
?
Craig Thibodeaux
KM4YEC ....? @ .... ? gmail
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Nice on-line heatsink calulator! ....And, consider that this calculation
is for 100% duty cycle.
73, David KB4FXC
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On Thu, 19 Oct 2017, Henning Weddig via Groups.Io wrote: Raj,
I just had a look on the below mentioned data sheet. Fromt there ist
shuts down if the internal chip temperature reaches 180 deg C, but htis
value is not tested in production.
The thermal resistance chip - case is 5 deg C/W.
Assuming an input voltage of 31 V and output voltage of 18 V , the
difference is 13 V?? times 1.5 A gives 19.5 W of dissipated power.
If You have a heatsink with indefinite good thermal conductance the
tempderature rise will be 19.5 W times 5 deg C/W = 97.5 deg C.
For calculating the overall thermal rise, see e.g.
*
*Henning Weddig*
*DK5LV*
Am 19.10.2017 um 13:13 schrieb David McGough:
Hi Raj,
You may not have had a big enough heat sink for the 317T or another
stability problem if it starts to limit current at 0.5A. My experience
with about 31V input and 18V to 25V output has shown 1.5A output reliably,
with stable voltage regulation. For a typical datasheet, see the
"Figure 8. Current Limit" graph on page 5 of this PDF:
...As with all ancient regular ICs, the 317T has been cloned by everyone
and specs may vary. The exact parts I'm using came from National
Semiconductor many years ago.
Why I originally chose the 317T for my project is that it seemed an almost
perfect match for the IRF-510---meaning keeping the 510 within maximum
specs under all load conditions...Again, with a big enough heat sink on
the 510, too! ....And, over the last 5+ years of continuous beacon
operation, I've found this premise to be true.
Anyhow, there are plenty of regulator choices out there! ...Have fun and
homebrew!
73, David KB4FXC
On Thu, 19 Oct 2017, Raj vu2zap wrote:
i.e LM338 - my choice over a LM317 series. 317 starts limiting current
quite early even with minimum rise in temperature. I don't recommend
it for anything over 0.5A unless the in-out voltage difference is a few
volts!
Raj
At 19/10/2017, you wrote:
If you are going to build a linear regulator to power the drain
of the IRF510, why not use a LM336? It is good to 5A throughput
at those voltages. A smaller one would do for powering the board
directly, even a LM7805 if the voltage drop is not too great.
Don't forget the reverse voltage protection!
john
AD5YE
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I continue to be amazed with the community that has grown around this radio.? I was checking up on bitxmap.com this morning I thought I would share some statistics with the group.? In just over 4 months we have 229 builder/operators listed and almost 11,000 views.? By way of comparison, google.com gets that many hits in .07286 seconds.? Now we just need someone to set up a radio in Antarctica and we will have all 7 continents. 
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Raj,
I just had a look on the below mentioned data sheet. Fromt there
ist shuts down if the internal chip temperature reaches 180 deg C,
but htis value is not tested in production.
The thermal resistance chip - case is 5 deg C/W.
Assuming an input voltage of 31 V and output voltage of 18 V ,
the difference is 13 V? times 1.5 A gives 19.5 W of dissipated
power.
If You have a heatsink with indefinite good thermal conductance
the tempderature rise will be 19.5 W times 5 deg C/W = 97.5 deg C.
For calculating the overall thermal rise, see e.g.
Henning Weddig
DK5LV
Am 19.10.2017 um 13:13 schrieb David
McGough:
toggle quoted message
Show quoted text
Hi Raj,
You may not have had a big enough heat sink for the 317T or another
stability problem if it starts to limit current at 0.5A. My experience
with about 31V input and 18V to 25V output has shown 1.5A output reliably,
with stable voltage regulation. For a typical datasheet, see the
"Figure 8. Current Limit" graph on page 5 of this PDF:
...As with all ancient regular ICs, the 317T has been cloned by everyone
and specs may vary. The exact parts I'm using came from National
Semiconductor many years ago.
Why I originally chose the 317T for my project is that it seemed an almost
perfect match for the IRF-510---meaning keeping the 510 within maximum
specs under all load conditions...Again, with a big enough heat sink on
the 510, too! ....And, over the last 5+ years of continuous beacon
operation, I've found this premise to be true.
Anyhow, there are plenty of regulator choices out there! ...Have fun and
homebrew!
73, David KB4FXC
On Thu, 19 Oct 2017, Raj vu2zap wrote:
i.e LM338 - my choice over a LM317 series. 317 starts limiting current
quite early even with minimum rise in temperature. I don't recommend
it for anything over 0.5A unless the in-out voltage difference is a few
volts!
Raj
At 19/10/2017, you wrote:
If you are going to build a linear regulator to power the drain
of the IRF510, why not use a LM336? It is good to 5A throughput
at those voltages. A smaller one would do for powering the board
directly, even a LM7805 if the voltage drop is not too great.
Don't forget the reverse voltage protection!
john
AD5YE
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Jerry,
Yes, this will not work with Allards CW. If an nano output is used to
unbalance the two diodes
may work. I have not tried it.
The other thump on rx needs the other fix!
Raj
At 19/10/2017, you wrote:
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Note that this fix is not
compatible with Allard's instructions for using the rig on CW.
Also, note that there are two PTT bursts.?
Raj's fix is for the carrier burst that transmits out over the air.
There's also a kerchunk you hear in the headphones.
Jerry, KE7ER
On Thu, Oct 19, 2017 at 01:31 am, Raj vu2zap wrote:
- The carrier burst on PTT is due to the C122 charging up through D15
or 16 unbalancing it and allowing a leak.
- Quick fix is put a 0.68uF cap from the common of D15/16 to the atten
pad R39. A track has to be cut.
- If your board has a trimpot there then you can tombstone the pot and
add the cap.
- A 1K resistor across C107 helps.
- The leak is almost eliminated.
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Note that this fix is not compatible with Allard's instructions for using the rig on CW.
Also, note that there are two PTT bursts. ?
Raj's fix is for the carrier burst that transmits out over the air.
There's also a kerchunk you hear in the headphones.
Jerry, KE7ER
toggle quoted message
Show quoted text
On Thu, Oct 19, 2017 at 01:31 am, Raj vu2zap wrote:
The carrier burst on PTT is due to the C122 charging up through D15 or 16 unbalancing it and allowing a leak.
Quick fix is put a 0.68uF cap from the common of D15/16 to the atten pad R39. A track has to be cut.
If your board has a trimpot there then you can tombstone the pot and add the cap.
A 1K resistor across C107 helps.
The leak is almost eliminated.
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? ? ? Hello everyone, anyone ever thought of replacing the relay by switching to transistor? I made some hopes with this but did not measure the delay of the two switches, it's just an idea!? ? ?Jorge PY2PVT _._
I tried the relay idea Brent, and it did nothing, so don't go hacking your board on the hope this is going to fix your problem. I still see a burst of full carrier for ~ 6 ms immediately after PTT is applied. I see the same result in CW mode, except there's a pause after the burst before the carrier comes on for the first code element is transmitted. The timing is almost precise on this, but I haven't found anything in the code that seems to correlate with it. The 6 ms does correlate with the relay switching speed, but it seems I'm puzzled on this issue again. Either I'm still overlooking something, or I botched the hack on my board.
Sorry about that.
Gary, N3GO
-- ? 73 de Jorge PY2PVT
? Campinas SP
? GG67MD
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Hi Raj,
You may not have had a big enough heat sink for the 317T or another
stability problem if it starts to limit current at 0.5A. My experience
with about 31V input and 18V to 25V output has shown 1.5A output reliably,
with stable voltage regulation. For a typical datasheet, see the
"Figure 8. Current Limit" graph on page 5 of this PDF:
...As with all ancient regular ICs, the 317T has been cloned by everyone
and specs may vary. The exact parts I'm using came from National
Semiconductor many years ago.
Why I originally chose the 317T for my project is that it seemed an almost
perfect match for the IRF-510---meaning keeping the 510 within maximum
specs under all load conditions...Again, with a big enough heat sink on
the 510, too! ....And, over the last 5+ years of continuous beacon
operation, I've found this premise to be true.
Anyhow, there are plenty of regulator choices out there! ...Have fun and
homebrew!
73, David KB4FXC
toggle quoted message
Show quoted text
On Thu, 19 Oct 2017, Raj vu2zap wrote: i.e LM338 - my choice over a LM317 series. 317 starts limiting current
quite early even with minimum rise in temperature. I don't recommend
it for anything over 0.5A unless the in-out voltage difference is a few
volts!
Raj
At 19/10/2017, you wrote:
If you are going to build a linear regulator to power the drain
of the IRF510, why not use a LM336? It is good to 5A throughput
at those voltages. A smaller one would do for powering the board
directly, even a LM7805 if the voltage drop is not too great.
Don't forget the reverse voltage protection!
john
AD5YE
|
Gary,
The carrier burst on PTT is due to the C122 charging up through D15 or 16 unbalancing it and allowing a leak.
Quick fix is put a 0.68uF cap from the common of D15/16 to the atten pad R39. A track has to be cut.
If your board has a trimpot there then you can tombstone the pot and add the cap.
A 1K resistor across C107 helps.
The leak is almost eliminated.
Raj
toggle quoted message
Show quoted text
At 19/10/2017, you wrote: I tried the relay idea Brent, and it did nothing, so don't go hacking your board on the hope this is going to fix your problem. I still see a burst of full carrier for ~ 6 ms immediately after PTT is applied. I see the same result in CW mode, except there's a pause after the burst before the carrier comes on for the first code element is transmitted. The timing is almost precise on this, but I haven't found anything in the code that seems to correlate with it. The 6 ms does correlate with the relay switching speed, but it seems I'm puzzled on this issue again. Either I'm still overlooking something, or I botched the hack on my board.
Sorry about that.
Gary, N3GO
|
i.e LM338 - my choice over a LM317 series. 317 starts limiting current
quite early even with minimum rise in temperature. I don't recommend
it for anything over 0.5A unless the in-out voltage difference is a few
volts!
Raj
toggle quoted message
Show quoted text
At 19/10/2017, you wrote: If you are going to build a linear regulator to power the drain
of the IRF510, why not use a LM336? It is good to 5A throughput
at those voltages. A smaller one would do for powering the board
directly, even a LM7805 if the voltage drop is not too great.
Don't forget the reverse voltage protection!
john
AD5YE
|
I tried the relay idea Brent, and it did nothing, so don't go hacking your board on the hope this is going to fix your problem. I still see a burst of full carrier for ~ 6 ms immediately after PTT is applied. I see the same result in CW mode, except there's a pause after the burst before the carrier comes on for the first code element is transmitted. The timing is almost precise on this, but I haven't found anything in the code that seems to correlate with it. The 6 ms does correlate with the relay switching speed, but it seems I'm puzzled on this issue again. Either I'm still overlooking something, or I botched the hack on my board.
Sorry about that.
Gary, N3GO
|
A 10-T pot is not strictly required but highly recommended.
The code will still work with a standard pot.
73 Allard PE1NWL
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On Wed, October 18, 2017 20:38, Paul Avona via Groups.Io wrote: Do I also need to install a 10 turn pot? ??
Paul
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If you are going to build a linear regulator to power the drain
of the IRF510, why not use a LM336? It is good to 5A throughput
at those voltages. A smaller one would do for powering the board
directly, even a LM7805 if the voltage drop is not too great.
Don't forget the reverse voltage protection!
john
AD5YE
|
Do I also need to install a 10 turn pot? ?
Paul
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Hi Brent;
? ? ?Gotta say; I share your glee with this radio. I¡¯ve been heads down on ¡°fixing some of the more serious woes of this rig the past couple of weeks, while resisting the urge to alter the as-is configuration. ?It¡¯s not useful to others to do otherwise. I need to spend some time documenting my findings though; both to defend them, as well as my fix recommendations.
? ? ?It¡¯s been helpful that this radio is so simple to simulate and analyze. The fate and fixes almost jump out at you. :-) I¡¯m still new to this project and list though, and I haven¡¯t yet found the repository of sanctioned upgrades and fixes. Much of what I¡¯ve discovered and conquered has likely already been addressed; so my apologies in advance for not doing the research to find them.
? ? ?The issue you describe is related to the PTT pop issue. The hard answer is that it¡¯s inherent in the current design. DC Xmt power is applied in advance of the decay in the Rcv DC supply. Hence; both are simultaneously enabled for the duration that the Rcv DC supply holds up. This is exacerbated by D10, and the sequential switching of K1 followed by K2 which keeps the audio preamp connected to the PA... albeit briefly (up to ~ 7 ms) following enabling of the mic amp.?
? ? ? I¡¯ve conquered the transmit pop, but in full disclosure, I¡¯ve not yet implemented the following ?receive side fix that I have in mind. ?It should address your problem nicely, but you¡¯ll be on your own, as there¡¯s always the risk of a snafu I failed to spot. If you wish to stick your neck out though, give this a try:
? ? Observe that the right side of K2 does the T/R antenna ?switching, While the top section of K1 grounds the now disconnected wire, and thus serves no purpose. Sever the connections at K1 pins 12, 14. Jumper K1 pins 12 and 3 and your done. The keying of K1, now dumps the receive supply to ground before the transmitter circuits become enabled.?
? ? ? I¡¯m guessing that it¡¯s not easy to sever the connection at K1 pin 16; otherwise the top portion of relay K1could be used to dump transmit power to ground when switching to receive as well by simply grounding pin 12. That would be the preferred fix.?
? ? ? While at K1, shunt the coil with a diode. D7 does nothing as wired.?
? ??
? ? ? Swap D18, and R127, or simply jumper across the old D7 location. A diode in lieu of R127 greatly accelerates the power-up of the mic amp. Also add 20 to 100uF from the top of C-123 to the top of C-124... plus side to C-124. Together, these changes nullify the PTT carrier spike (pop!) at the beginning of a SSB transmission.
? ? ?Finally; place a short jumper between the VFO input side of L4 and the emitter of Q8. This bypasses the first two VFO Impedance buffers that band limit the Raduino clock and starves the first LO in USB mode. No need to remove the unused buffers, as they don¡¯t interfere. This fix yields +6 to +7 dBm into the first mixer at both 5 and 19 MHz, and results in full transmit power out, good sensitivity (0.1uV) and RF dynamic range to +25 dB over S9 in all modes.?
? ? ?All but the relay wiring fix and miswired D7 were derived via simulation, and verified on my BITX-40. I also added a 1uF ceramic cap across the PTT to suppress switch bounce noise from chattering the relays.
? ? ?I zapped the SPOT port of the Rudino¡¯s Nano, so I¡¯m limping along until I can get it replaced. I always seem to fat probe stuff when I¡¯m eager to get stuff done. <sigh>
? ? ?Good luck with the mods. I hope you¡¯re having as much fun as I am having.
72 es 73
Gary, ?N3GO
? ? ?
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toroid and capacitor power handling (EFHW tuner question for bitx40)
I've got a SOTABEAMS mountain tuner and a couple pico tuners that I'm using to get into EFHW antennas.
I'd like to build one that I can use with a bitx40 with a full 20w output, but I can't seem to find info on the breakdown voltage on the caps used in these 6-10w tuners, so I can't seem to figure out just how heavy-duty my cap needs to be.
Also, what's the deal with toroids and power handling? ?How do I determine how much power a given wound toroid can handle at RF?
I plan on building a Match-22 tuner as described in "Hand Carried QRP Antennas," but I'd love for it to be able to take a full 20W so I can use my bitx or my TJ5A with it.
Thanks,
Jake
KE0GYC
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The 5W out is at 28MHz, where the IRF510 efficiency is worse than
awful...I'll try a LM317T supply on my BITX40 and report the results. The
317T can provide up to about 1.5A.
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On Wed, 18 Oct 2017, Jerry Gaffke via Groups.Io wrote: 5w out powered from an LM317 sounds fine.
And yes, the current limiting would be very handy.
20w out of the bitx40 with the irf510 at 24v would not work quite so well.
On Wed, Oct 18, 2017 at 08:04 am, David McGough wrote:
Output power after the LP filter is about 5W (+/-).
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even LT1083CP can well be managed upto 7amps of load. being a low drop regulator
?one can manage a trafo with 24V secondary ?
On Wed, Oct 18, 2017 at 8:55 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: 5w out powered from an LM317 sounds fine.
And yes, the current limiting would be very handy.
20w out of the bitx40 with the irf510 at 24v would not work quite so well.
On Wed, Oct 18, 2017 at 08:04 am, David McGough wrote:
Output power after the LP filter is about 5W (+/-).
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5w out powered from an LM317 sounds fine.
And yes, the current limiting would be very handy.
20w out of the bitx40 with the irf510 at 24v would not work quite so well.
toggle quoted message
Show quoted text
On Wed, Oct 18, 2017 at 08:04 am, David McGough wrote:
Output power after the LP filter is about 5W (+/-).
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Craig Thibodeaux
Raj vu2zap
Allard PE1NWL