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Re: RF power chain mods and improvements..

 

As Allison says, the simulation and the real world won't always agree.
For example, like most spice simulators, it simulates the normally used region and doesn't bother with bounds checking.
So the 2n3904's in your simulation will work quite well with 1kV of Vce and 100A of Ic, if that's what you ask of them.

But in most cases, it's very helpful, allows you to see inside the circuit and figure out what's going on
without filling the room with smoke.? And usually accurate enough.

An RF power amp has a lot of little things that become significant, and can derail a simulation.
Perhaps an extra half inch of trace from ground to IRF510 source, for example.?
Or secondary capacitances in the parts not included in the model.
But still very useful, and generally more or less accurate.
LTSpice helped me figure out what was going on with all the magnetics in the uBitx.

Jerry


On Thu, Jun 7, 2018 at 12:51 pm, Gordon Gibby wrote:
Jerry, thank you so much for that running start on LT spice.
Re: uBitx Encoder information needed.

 

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Check message #45085 Jim - W0EB suggests the?part number in his message?from Digi-Key as being the exact replacement.
?
Rick KN4AIE


From: [email protected] [mailto:[email protected]] On Behalf Of tituskz1g@...
Sent: Thursday, June 07, 2018 5:02 PM
To: [email protected]
Subject: Re: [BITX20] uBitx Encoder information needed.

This encoder is similar to the Bourns PEC11L Series - 11 mm Low Profile Encoder.? Search for part number PEC11L-4115F-S0020-ND at DigiKey.com and click on the datasheet link for this product.? That document should give you information about the type of encoder.? I substituted an encoder with detents, but it did not work well.? The continuous rotation version that came with the kit works better.? If your encoder does not work, check solder connections and wiring.
--
Jon Titus, KZ1G
Herriman, UT USA

Re: Power supply fuses

 

All that PA-PWR goes to is the IRF510 drains.
There's an intrinsic diode from source to drain inside the IRF510 that will?
suck all the PA-PWR you care to give it if that supply line gets reversed.
Hopefully that will blow the 3A fuse.
If not, it will blow board traces and burn out the wire in the two RF chokes into the drains.
That damage is easily fixed, fixing a reverse voltage into the main 12v supply to the uBitx board is not.
Also, a? diode voltage drop into the main uBitx board is not an issue, even when running form a battery,
should do fine with 10 or 11 volts.

But a voltage drop feeding into the IRF510's will impact power out.?
So the fuse+shunt(intrinsic-irf510)diode scheme there is appropriate.

Jerry


On Thu, Jun 7, 2018 at 01:29 pm, <entilleser@...> wrote:
Well, if you're going to use two fuses, don't you need two diodes?
Re: uBitx Encoder information needed.

[email protected]
 

This encoder is similar to the Bourns PEC11L Series - 11 mm Low Profile Encoder.? Search for part number PEC11L-4115F-S0020-ND at DigiKey.com and click on the datasheet link for this product.? That document should give you information about the type of encoder.? I substituted an encoder with detents, but it did not work well.? The continuous rotation version that came with the kit works better.? If your encoder does not work, check solder connections and wiring.
--
Jon Titus, KZ1G
Herriman, UT USA
Re: Power supply fuses

 

Well, if you're going to use two fuses, don't you need two diodes?
Re: Power supply fuses

 

¿ªÔÆÌåÓý

Yes it should work fine,? might knock down the power a little. Would be better with 4 Schotky diodes.

They are going to HEAT!?? Probably over a watt for each of the 2 conducting diodes.? On battery it would be quite a waste of power.

Another detail,? chassis radio ground and 12V - battery input are not common. but separated by a diode?

I put an extra fuse inside the cabinet and just a 1N4007 to ground.? Ty wrapped extra fuse to some wiring.? I have never blow it.


73's

Mike


On 6/7/2018 12:53 PM, martin@... wrote:
I'm a newbie on here and just dipping my toe into the world of BITX's

If you're running the radio at 13.8v is there enough wriggle-room to cope with a 1.4v drop using a bridge rectifier?

Reverse polarity diodes are a blunt instrument when protecting equipment, you still have to find a replacement fuse if you're in the middle of nowhere.

I've used a bridge rectifier with the incoming 13.8v on the AC inputs and, whatever way round you connect it, you will always get the correct polarities on the +ve and -ve sides.

Martin

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...
Re: K5BCQ kits in BITX40 #bitx40

 

On Thu, Jun 7, 2018 at 01:01 pm, Joe wrote:
I was wondering if my 2 AGC boards were sent yet?
Kees has been updating his list.? Check here...
/g/BITX20/files/K5BCQ/K5BCQ%20AGC-Audio%20Kit%20OrdersALPH.ods
?
--

Re: Power supply fuses

 

I think that bridge rectifier is a bad idea.
Leaves your rig antenna port ground a diode drop away from your power supply ground.
A single schottky power diode in series with the supply coming into the main ubitx 12v supply line
would be a better idea, fused at 1/2 Amp.? If you hook up the power supply wrong, it just won't work.
So hook it up right.
I would feed PA-PWR separately, without a diode, and fuse it separately at 3 Amps or so.


On Thu, Jun 7, 2018 at 12:53 pm, Martin / G4VZO wrote:
I'm a newbie on here and just dipping my toe into the world of BITX's

If you're running the radio at 13.8v is there enough wriggle-room to cope with a 1.4v drop using a bridge rectifier?

Reverse polarity diodes are a blunt instrument when protecting equipment, you still have to find a replacement fuse if you're in the middle of nowhere.

I've used a bridge rectifier with the incoming 13.8v on the AC inputs and, whatever way round you connect it, you will always get the correct polarities on the +ve and -ve sides.

Martin
Re: Power supply fuses

 

Hello?

For my uBitx I use a Pacific Antenna kit named VoltTattler.
This montage has the following features:

- Simple through-hole construction
- Draws only around 1 mA in normal use.?
- Reverse polarity protection.
- Programmable Thresholds over a range of 4V to over 27V.
- Single button programming with audio feedback.
- Audible announces activation with power on and indicator with LED flashing green.
- Audibly announces by Morse code when input voltage exceeds user programmed thresholds.
- Flashing Red and Yellow LEDs indicate that a voltage limit has been exceeded.
- 3V digital status signals are available on a header
- Cheap protection for low voltage DC equipment.

interesting to avoid inversions of polarities and portable QRP, in battery operation to know the state of health of your batteries.

73 QRO from F1BFU

2018-06-07 21:10 GMT+02:00 entilleser via Groups.Io <entilleser@...>:

The "Fix reverse polarity" section on suggests a 0.5A fuse for the "rig" and 2A fuse for the "finals," but does not specify which wire is which.? The schematic says that the brown wire is "PA-PWR," but I am too much of a newphyte to be certain if this means the same as "finals" or "rig."


Re: K5BCQ kits in BITX40 #bitx40

 

I was wondering if my 2 AGC boards were sent yet?


Thanks
VE1BWV
joe Basque


On Wed, Jun 6, 2018, 11:18 AM Don, ND6T via Groups.Io <nd6t_6=[email protected]> wrote:
For those wondering if the K5BCQ AGC and ClickFix kits work with the BITX40, they do! The AGC works just as well as in the ¦ÌBITX and the ClickFix is, by far, the quietest modification that I have tried. The latter uses the PTT line for keying the receive preamp but that is all explained on the web site. No software changes are necessary unless you use the AGC board as an S meter source (which I recommend) and that is only to calibrate the display to accommodate the improved dynamic range. 73, Don

Re: Power supply fuses

[email protected]
 

I'm a newbie on here and just dipping my toe into the world of BITX's

If you're running the radio at 13.8v is there enough wriggle-room to cope with a 1.4v drop using a bridge rectifier?

Reverse polarity diodes are a blunt instrument when protecting equipment, you still have to find a replacement fuse if you're in the middle of nowhere.

I've used a bridge rectifier with the incoming 13.8v on the AC inputs and, whatever way round you connect it, you will always get the correct polarities on the +ve and -ve sides.

Martin
Re: RF power chain mods and improvements..

Gordon Gibby
 

¿ªÔÆÌåÓý

Jerry, thank you so much for that running start on LT spice.


On Jun 7, 2018, at 13:33, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

Here's an outline of how to get dangerous with LTSpice:

Download the free LTSpice from Linear Tech:
? ??
It primarily targets the various MSoftWindows operating systems.
They also have a version out now for Mac OS-X.
Will run under linux with Wine.

Also download this file:??

Kick off LTSpice.
Click File, then Open, browse for that ubitx_pa.asc file you just downloaded.
Should display a schematic of Q90 on out through the finals for the uBitx.

Click the RunningMan menu icon (5 over from the left edge) to run the simulation.
It should open a second window to show waveforms, but the window will be empty.
Click on nodes in the schematic to see the voltage waveform at that point.
Double clicking will erase all other waveforms and just show the last one selected.
Click where wires enter into part symbols to see currents there.

Edit part values by clicking on that value.
Edit wires by using the Scissors icon to cut away wires, then using the Pencil icon?
to add new wires.? (You first have to click somewhere in the schematic to select that window.)
You can add grounds, caps, coils, resistors and diodes by clicking on their icon in the menu bar.
Click the AND-GATE icon to explore the various other parts available to you.

Someday, click the Help menu item, browse the destructions.

LTSpice is an incredible gift from LinearTech to the electronics hobbyist and professional engineer.
It has a full catalog of the various LinearTech products and complete demo circuit simulation models for each.
Fortunately, it is also a first rate generic analog simulator with an easy to use interface.

Jerry, KE7ER


On Thu, Jun 7, 2018 at 09:37 am, Jerry Gaffke wrote:
I'm not one that takes easily to new tools,?
but found LT-Spice easy to get started with.
Changes can be hacked in and checked faster than it takes for my soldering iron to heat up.
You can easily instrument voltage, current, power dissipaton, and much more.
It's worth a couple hours of fiddling with to get started.
I'm no expert, but let me know if you get hung up on those first steps.
Re: Power supply fuses

 

¿ªÔÆÌåÓý

Speaking of Fusing and Over-Current protection.

I am experimenting with an LT6108 for a Real Fast over current limiter.

The circuit show is my 2 PCB, the LT part is fussy about getting reset.

I have it Latch Up, so you power down to reset.

The ap note says less than 5uS to shut down.

I got new PCBs coming.? The first go around I could not get LT to reset, it needs a 10uS pulse to get out of over

current condition.? I have a tiny (SOT 23-6) Pic programmed to do that.?

The PCB is about 1 3/4" x 1 1/8".? Should fit on back inside panel somewhere where power comes in on most chassis?


So 5uS seems like a really fast fuse to me?

73's

Mike, WA6ISP


On 6/7/2018 12:14 PM, ajparent1/KB1GMX wrote:
Finals, PA-PWR, output devices... the same.

The other is rest of rig.

PLEASE, put the fuses before the polarity protect diode.? Example Fuse, reverse polarity protection diode, radio.

Allison 

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Ilimit5ASch.pdf
Ilimit5ASch.pdf

Re: CW transmit bandwidth #ubitxcw #ubitx

 

So it's narrow when the key is down continuously, but a string of dots is 1khz wide?
That would be envelope shaping.? Has to do with how quickly the transmitter turns on and off when you key it.
Here's somebody who has looked at this:
? ??/g/BITX20/message/51423


On Thu, Jun 7, 2018 at 12:37 pm, K3OS wrote:
Just got a v3 board running today.? I was monitoring CW on my IC7300 and noticed that when transmitting, i.e., a string of dots or dashes, the bandwidth would widen to 1Khz then return to very narrow.? ?This occurred at a periodic rate if I held the dot or dash lever.? Internal keyer was used.? When sending text the same issue occurred but it was more difficult to spot.? Initial test was 40 meters, 12 watts out, but same results on 20, 8 watts out all into a dummy. 12.2VDC power supply.?

Any clues to why this happens and what can be done?

Gary K3OS
Re: RF power chain mods and improvements..

 

Here's another shot at embedding my Mouser search, maybe this one will work:
? ??



On Thu, Jun 7, 2018 at 12:37 pm, Jerry Gaffke wrote:
Here's a Mouser search for stuff with Vce of 12v+, Ic of 600ma+, Ft of 300+:
?
CW transmit bandwidth #ubitxcw #ubitx

K3OS
 

Just got a v3 board running today.? I was monitoring CW on my IC7300 and noticed that when transmitting, i.e., a string of dots or dashes, the bandwidth would widen to 1Khz then return to very narrow.? ?This occurred at a periodic rate if I held the dot or dash lever.? Internal keyer was used.? When sending text the same issue occurred but it was more difficult to spot.? Initial test was 40 meters, 12 watts out, but same results on 20, 8 watts out all into a dummy. 12.2VDC power supply.?

Any clues to why this happens and what can be done?

Gary K3OS
Re: RF power chain mods and improvements..

 

Here's a Mouser search for stuff with Vce of 12v+, Ic of 600ma+, Ft of 300+:
? ??1z0y4diZ1z0y4ciZ1z0w69sZ1z0wajfZ1z0s5p6Z1z0w3wpZ1z0w6rxZ1yxzg4rZ1z0w65eZ1z0w693Z1z0w6r0Z1z0w64vZ1z0w6i8Z1z0w6xnZ1z0wa4fZ1z0w6fhZ1z0vzb6Z1yyb05lZ1z0w6ylZ1yy9vthZ1z0w5kaZ1yyyiibZ1z0wa61Z1yyziiqZ1yyzhtqZ1yyzh82Z1yyzht3Z1yyzhfuZ1yyz8ghZ1yyzhg7Z1yyzheyZ1yyyjktZ1yix7auZ1yyzh3lZ1yyzg3zZ1yyyiicZ1yyzh56Z1yyzhofZ1yyyt0tZ1yyzhtgZ1yyzhg2Z1yyx4b4Z1yyx4b1Z1yyx39cZ1yyx41aZ1yyx4qeZ1yyx39eZ1yyzhiuZ1yyx41d

Most of the hits are 2n2222 variantes.
This one looks promising, dissipates over a Watt if you give it some copper:
? ??https://www.mouser.com/ProductDetail/Diodes-Incorporated/DXT2222A-13?qs=sGAEpiMZZMshyDBzk1%2fWi5S7e8F%2fC6%252bHGC8aVJqhk4k%3d

That Nexperion has a data sheet with both the SOT-23 and the TO-236, just says 250mW max, I'd guess the TO-236 can do more:
? ??

And if you want to try something that isn't 55 years old, there's this, dissipates over a Watt:
? ??


There's more, but the above show we could stick with 2n2222 and friends at $0.15 each in quantity.
All the cheap ones are surface mount, through-hole is now a weird specialty item.?
Perfect for hfsignals if they roll the board.

I'd bet we could use them in the existing through-hole positions, standing them up on their legs
and soldering some copper foil to the tab.? Though the through hole 2n2222a in the metal can would
make a lot more sense for re-working the old boards.

Jerry, KE7ER


On Thu, Jun 7, 2018 at 11:38 am, Jerry Gaffke wrote:
What's absolutely astounding is that it's still a good choice.
The 2n2222a has slightly better specs than the original 2n2222, but not by much.
Re: Power supply fuses

 

Finals, PA-PWR, output devices... the same.

The other is rest of rig.

PLEASE, put the fuses before the polarity protect diode.? Example Fuse, reverse polarity protection diode, radio.

Allison
Power supply fuses

 

The "Fix reverse polarity" section on ubitx.net suggests a 0.5A fuse for the "rig" and 2A fuse for the "finals," but does not specify which wire is which.? The schematic says that the brown wire is "PA-PWR," but I am too much of a newphyte to be certain if this means the same as "finals" or "rig."
Re: RF power chain mods and improvements..

 

In the old parts box I have Ck722s, 2n107, a few SB100,? 3n35 and 36(tetrodes!)
and the first JFETs (GM almost 900uS, modern parts like J310 are about 20,000)
also a pot load of the?early computer transistor 2n1304,5,6 (FT of 15mhz).

Keep in mind when the CK722 was introduced at $7.50 each it was labeled as
the first transistor for hobby use at an affordable price!? For that year $7.50 would
buy about 35 loves of bread then.??

Another oldie was the 2n5109, they were in use back in 1970 in communications gear.

The real roachs are the 12ax7, 6AU6, and 6146 (and other hollow state devices).?
Someday I have to do a simple compact SSB transceiver using 5899 and 6CW4s
and maybe 5763 (QRP).? ?Heater circuit will likely use more power than uBITX at
full transmit power on 80.

Allison
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