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Re: RF power chain mods and improvements..

 

Before you hang a 50w Amp I'd consider a band pass filter in line before the
amp to keep the spurs from being amped up and above the max allowable.??

RX is not terrible but I'e found even at 5W If I can hear them on a decent antenna
I can work them.? 10 15 more DB of gain before the mixer would be nice but it s a bit
of effort to add with switching and likely only needed on 10M.? ? If I need 50W I just
use the Triton 540 or the Eagle for the full 100W.? Its rare I do that.

>>replacement of Q 10 also include change of C11 to 470pF and R13 to 8.3 ohm to boost 30 MHz?<<
No don't as that will impact the impedance match just the transistor. The input filter and the mixer pretty
much sets the NF and small changes in gain for the IF isn't going to move that much if any.? Gain before
it makes a big difference if the amp is quiet (say under 2.5DB).

I'd start with a beam (wire yagi, tribander or whatever) then see what you hear and can talk to.??
Its not like you can't mod later.

Allison
Re: K5BCQ kits in BITX40 #bitx40

 

I know it might be demanding ;) but it would have been nice if the shipment date was mentioned.
Checked earlier this week and saw mine were send, bit so far nothing in the mailbox yet.
I know I live at the end of the world so close to the Mexican border. So things could take some time.

Anyone has a clue how long the shipment takes approximately?

John
KG5WJQ?
Re: CW transmit bandwidth #ubitxcw #ubitx

K3OS
 

The issue is not with the keyed waveform but an undulating bandwidth change. ?Using the internal keyer hold the dot paddle (much easier to see than with dashes). ?The bandwidth starts out properly narrow, but after a second or so it quickly spreads to 1KHz+, then back to normal. ?If you continue to hold the paddle this pattern constantly repeats. ?When you send words the same thing happens, but it is more difficult to discern.

Gary


Virus-free.

Re: Different Encoder

 

I'm ?going to give the 2 inch a try turn I down a little to smooth it up then put a light knurl on it. Was the 400 ppr you used an optical or capacitive encoder. The atm103-v is capacitive ?and has a dip switch where you can program it for ppm steps from 48 to over 2000. I was thinking of starting at 48 and going up to get to what works best or that is my intention.

--
Allen ?Merrell
CAT Control

 

I have updated my uBitx to 4.3 as I would like to use CAT to interface with wsjt-x. I have been unable to find any information on how to set this up. I would appreciate hearing from someone who is using CAT with wsjt-x. I'm sure it's a simple procedure to set up, but I just can't find any instructions. Currently I'm using a usb sound card and a FTDI cable for PTT.

?

73, Dennis

W7DRW
Re: LM386 Hiss Suppression on the BITX40 #bitx40

 

There's another possibility, found early on, at low volume levels: too-low resistance from pot. wiper to Earth. Anything from 1k to 10k wiper-to-IC cures it. If you've replaced the (blown?) audio IC with an LM386 and found this hiss, it's a simple cure.

73
Dex, ZL2DEX
Re: Power supply fuses

 

From power jack to power switch.? From power switch through a 5 amp rectifier to 2 fuses, .5a and 3a.. From fuses to the board.? Reverse polarity protection and no blown fuses. The approximately .7 voltage drop of the 5 amp rectifier will not be noticed in your receive or your output to others.
--
Lee - N9LO? "I Void Warranties"

?
Re: Different Encoder

Vince Vielhaber
 

Mine's also a 400. 2" should work fine. The knob I made is close to an inch thick. The only reason I had to go with 2.5" was to cover up the window for the channel selector (case is an old CB base station) otherwise I would've gone with 2". I had 2" on hand, I had to buy the 2.5", 3" was too big and too much waste to turn down to 2.5".

Vince.

On 06/07/2018 07:29 PM, Allen Merrell via Groups.Io wrote:
Vince
How many ppr did the one you used have? I have a piece of 2 inch
aluminum bar stock that I was going to turn down for the knob and
possibly for the flywheel if it is needed.
--
Allen Merrell
--
Michigan VHF Corp.

Re: RF power chain mods and improvements..

Steve Black
 

¿ªÔÆÌåÓý

Today kids probably can't even buy razor blades :-((? Steve kb1chu


On 06/07/2018 02:16 PM, Jerry Gaffke via Groups.Io wrote:

Yup, almost as oldie as me.
From? ? ??
"Since its initial product launch by Motorola at the 1962 IRE Convention, the 2N2222 has become the most widely used and universally recognized?transistor of all time. Billions of units have been manufactured over the past 45 years and there is continuing high volume annual production."

So when it was introduced, I was maybe just starting to think about? building a crystal radio with razor blades and toilet paper tubes.?

Jerry

On Thu, Jun 7, 2018 at 10:48 am, ajparent1/KB1GMX wrote:
Yes, 2n2222A are an oldie.
Re: Power supply fuses

 

on the 3 pin power plug on the ubitx the middle pin is the pa and the pin to the outside edge is the board power
Re: Power supply fuses

 

Be careful, how that PFET thing works is tricky.
Several "how I done its" are out on the web with the PFET in the schematic drawn backwards.
Here's some old threads on reverse polarity protection, everyone has an opinion, some have several.
These point to posts specific to the PFET, but there's plenty more in the threads.
? ??/g/BITX20/message/35632
? ??/g/BITX20/message/35434




On Thu, Jun 7, 2018 at 04:17 pm, Gary Anderson wrote:
Surprised someone has not mentioned using a P-channel power MOSFET for reverse polarity protection this low current application.
(I think someone has on an older thread that this is re-hashing)
You can find them with pretty low Rds these days.? ~ 0.06 Ohms.
That rivals the contact resistance of a relay, plus no power consumed by energizing coils.
(the power loss trade off is power consumed by the relay coils verses the difference between relay contact resistance and Rds)
We are talking < 500mA here.?

I quickly found an app note from TI.
Re: Different Encoder

 

Vince
How many ppr did the one you used have? I have a piece of 2 inch aluminum bar stock that I was going to turn down for the knob and possibly for the flywheel if it is needed.
--
Allen ?Merrell
Re: Power supply fuses

 

Surprised someone has not mentioned using a P-channel power MOSFET for reverse polarity protection this low current application.
(I think someone has on an older thread that this is re-hashing)
You can find them with pretty low Rds these days.? ~ 0.06 Ohms.
That rivals the contact resistance of a relay, plus no power consumed by energizing coils.
(the power loss trade off is power consumed by the relay coils verses the difference between relay contact resistance and Rds)
We are talking < 500mA here.?

I quickly found an app note from TI.


Regards,
Gary
AG5TX
Re: uBitx Encoder information needed.

Mike aka KC2WVB
 

I ordered this as a replacement. Visually it is identical. Works well with...too.


Order Details
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Your salesorder number is 54975240.
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PEC11R-4020F-S0012-ND
ENCODER ROTARY
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Available
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Price
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13301.68000(USD) 8.40
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On Thu, Jun 7, 2018, 12:11 AM Dennis Yancey <bigbluedry@...> wrote:
I have 2 items I need info on.

first, does anyone have the specs for the stock encoder for the uBitx?

second, have any of you had to make software changes to get a KY-040 encoder to work properly?

Thanks for your help.

THANK YOU K5BCQ

 

THANK YOU KEES K5BCQ for your wonderful service to the uBITX community.

Mike N6CMY
Re: RF power chain mods and improvements..

 

Allison
Thanks for all mod proposals and great discussions. Just got my v3 unit after two month of delivery struggle throw the postal service here in Sweden. Now starts all the fun. I have one question that I think partly has not been covered by this thread apperently as it is about power mods. However, Farhan stated the the RX NF should be around 14 dB as there are no preamp and a passiv diod mixer. Perhaps OK for lower band but how about 28 Mhz. I saw in your final? mod statement that you had change the post mixer IF transistor to a better Ft version? BFR 106. I guess that will improve the NF slightly but is it enough. Will there be a need for a preamp also on the Rx side for the higher bands? Of course you can always argue that with low power output there are no advantage to hear stations you can?t reach. But if you hang on a 50 W PA I guess there is a need for some kind of improvement of the receiving performances at least on 10 M. And will the replacement of Q 10 also include change of C11 to 470pF and R13 to 8.3 ohm to boost 30 MHz?
Ulf sm0cgl since 1959
Re: K5BCQ kits in BITX40 #bitx40

 

Thanks
Joe
VE1BWV


On Thu, Jun 7, 2018, 5:11 PM Doug W <dougwilner@...> wrote:
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: Different Encoder

Vince Vielhaber
 

I used one of those on a CB-to-10 mod I had done. I had to modify the software to ignore some pulses from it 'cuze it was too sensitive. I made the knob for it out of 2.5" aluminum round bar. Give that thing a good spin with that knob on it and it turns for a good long time! But to make a fine adjustment, no problem at all. Clean and smooth.

Vince - K8ZW.

On 06/07/2018 05:56 PM, Allen Merrell via Groups.Io wrote:
I have been looking into using a different encoder, I have an optical
400ppr which is very smooth (fresh from China) looks to be good quality
but is close to 2 inches in diameter. I ran across a neat looking
capacitive unit that can be set from 48 ppr to over 2000 ppr which
looked interesting to me. They say they have a longer life than the
magnetic or optical. The one I was looking at was made by CUI and the
number of it is AMT103-V. I ordered one from Mouser. The shaft goes
through it which I close to what I wanted . I plan on using a bearing on
each side of the encoder with a flywheel (metal disc) on the back side
which should have a good free spinning motion. Speed is going to depend
on how fast the arduino can read it so this is where the adjustable ppr
setting would come in handy.
--
Allen Merrell
--
Michigan VHF Corp.

Re: Power supply fuses

 

I assume you were vaguely pointing in the direction of the relay trick, powering the coil through a diode.
That's a good solution, one I might use for a KW rig someday
Or even 100 Watts.
Though I'd still have a fuse.

For the uBitx, and me not being a mechanical engineer, diodes and fuses seem quite appropriate.
This rig has too many relays already.? ;-)


On Thu, Jun 7, 2018 at 03:07 pm, K9HZ wrote:
Reversing diodes shorting/ blowing fuses and diodes in series with power leads, brute force, works but is quite unnecessary. See more far more elegant solutions at .
Power supply fuses

 

Reversing diodes shorting/ blowing fuses and diodes in series with power leads, brute force, works but is quite unnecessary. See more far more elegant solutions at .

?

Dr.?William J. Schmidt - K9HZ

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