Date   

Re: Harmonics

Glenn
 

Hi Jerry, I guess you addressed your comments to me.
You are correct in the way of fitting the extra LPF relays. Track cuts as detailed by Allison and Gordon basically.

The board was designed to keep the overall height of the (modified) uBITX low. Selfish, as my own case has very little height available.  This board adds approx 31mm (1.4”)  of height over top of the uBITX main PCB.
The relays will stick out about 12-13mm pats the edge of the PCB. (The side where the heatsinks are of course)

Other relay types maybe lower but are much more expensive and perhaps ‘unobtanium’ in other countries.

I’m also in the works of a LPF PCB you describe.  A totally separate LPF board.  Daughterboard if you like. Right now it follows the same series switching of the filters, with relays both ends.  Uses same relay types as uBITX. Nick (VK4PLN) is doing a LPF with more conventional switching. I might change this also. My PCB is designed to fit over the existing area of LPF’s, with the parts removed and transferred to my new board.   The board also could be fitted elsewhere, if space is not an issue. Draft picture below.

While the USA has a -43dBc requirement for spurs and Harmonics, VK and I believe the EU countries have a more rigorious ~-50dBc. This might be a challenge.!


Complete LPF, same Sch as uBITX:-



Re: Harmonics

Kees T
 

OK, I thought it was (now I know why you guys keep talking about a BPF)  ....well, why not change the 20/17 to a 20/17/15 with a sharper roll-off ?  ....really, try it, plot it.  

Let me see if I can find that simple table someone generated on which relay was picked for which band.

73 Kees K5BCQ


Re: Corrupt ubitx files?

Bill
 

Thank you Ralph!!! that worked. I had tried all the baud rates that were in the drop-down window before with no results. Once I had cleared it & entered 38400 every thing worked!
              Bill A.


Re: Corrupt ubitx files?

Ralph Mowery
 

Try another baud rate, Start with 38400 first.

On Mon, Aug 13, 2018 at 5:24 PM, Bill <allerthomes@...> wrote:
Just tried Ubitx manager 1.097, but still having the same problems. read from ubitx reads nothing just an error message. When I fill in a couple of boxes and hit write to, it goes through the motions, but says success =0 at the end.
I am selecting the proper port, 9600 baud, none, 8, one. this has been happening on every version. Any help???
_


Re: Corrupt ubitx files?

Bill
 

Just tried Ubitx manager 1.097, but still having the same problems. read from ubitx reads nothing just an error message. When I fill in a couple of boxes and hit write to, it goes through the motions, but says success =0 at the end.
I am selecting the proper port, 9600 baud, none, 8, one. this has been happening on every version. Any help???


Re: Harmonics

Jerry Gaffke
 

There's a filter for 20m and 17m. 
Also a filter for 15m, 12m and 10m.
No filter for 20/17/15.


On Mon, Aug 13, 2018 at 01:11 PM, Kees T wrote:
Try this for the existing 20/17/15 LPF  .


Re: Auto TX Smart Filter Controller #nano #arduino #filters #ubitx

Tom, wb6b
 

On my I2C LCD I/O Backpack I drove the LCD backlight LED from a PWM output from the Arduino Nano. That allowed me to dim the backlight to any level I wanted, as well as turn the backlight on and off. That code could be added to this Smart Auto Filter code.

Tom, wb6b


Re: Auto TX Smart Filter Controller #nano #arduino #filters #ubitx

Arv Evans
 

Allison

Sounds good.  Then for the power challenged one could put the LCD backlight
on a push-button so it would only be on when needed. 

Arv
_._


On Mon, Aug 13, 2018 at 1:25 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
Arv,

If using an external filter box and the uBITX internal filters remain in place, 
it seems that the external filters would only need to be activated in transmit 
mode.  That could save some power when in receive mode.  

As is they are wired to only be active on TX.  The only get power when
K1 supplies "TX" (K1 pin 1) voltage to the transmit hardware and that
includes KT1-3 and K3.

With that said .... one can disable all but K3 and with three etch cuts and
jumper TX RF direct to K3 pin16 around the filters completely.  It should
save about 120-150 mA.

Allison


Re: Substitutions

Arv Evans
 

Tim

What in the world are you talking about?  Sounds like your reply may be to an
old post from 3 or 4 years ago.  Maybe you responded to some other discussion
group but did in on the BITX20 group by accident?

Arv
_._


Re: Harmonics

Kees T
 

Try this for the existing 20/17/15 LPF  ....make the three coils all 350nH with a 47pF in parallel (easy to tack on), the capacitors at the ends are both 220pF, the other two are both 360pF. Like Allison (and everyone else....) says, the spurs move with tuned frequency.....these traps are for ~39MHz and only to vary the LPF roll-off, not to "trap" any 23.xx MHz.

73 Kees K5BCQ


Re: Nextion Basic 3.2 Display will not update #ubitx

V Zecchinelli
 

Thanks Nikos.  I ordered some new SD cards to try.


On 8/13/2018 3:38 PM, SV9CVJ Nikos wrote:
Try with another SD card I changed 4 cards .


Re: Harmonics

ajparent1/KB1GMX <kb1gmx@...>
 

>>>have been playing with simulation of the 15 meter spur problem.  It seems that 
a series LC trap on the filter output might work but only if the trap has very low 
resistance and if it is exactly on the spur frequency.  Even then LTSpice simulations 
indicate that a couple of db might be lost on the upper end of 15M.  When I added 
a few ohms to the trap to make it broader it caused loss that extended well into the 
ham band.  <<<

Arv,

Consider a series connected parallel tuned trap (High L, low C).

I tried a series trap and the amp went into oscillation at the trap tuned frequency.
I quickly abandoned that approach.

Allison





 


Re: Nextion Basic 3.2 Display will not update #ubitx

SV9CVJ Nikos
 

Try with another SD card I changed 4 cards .


Re: Nextion Basic 3.2 Display will not update #ubitx

V Zecchinelli
 

Thanks Joe.  I tried 2 SD cards I had but I have used them many times in RPI projects so I have ordered a couple new ones.  For power I tried USB port on PC and 5V 3A supply I use with QRP-LABS U3S so I know it is good.  I have also ordered a USB-TTL cable. 

73 Vince N1VIN



On 8/13/2018 2:01 PM, Joe wrote:
Hi,
I have seen this issues several times

1. Make sure your power source is good.
2. Try another microsd card.

Usually one of the above clears the problem

Joe
VE1BWV



On Mon, Aug 13, 2018, 2:47 PM V Zecchinelli <n1vin@...> wrote:
I have spent most of today searching through messages and wiki to no avail.  I am using the basic 3.2 Nextion display and am trying to upload the tft file I downloaded from ubitx.net.  SD card is 8Gb and is formatted FAT32 and tft file copied to it.  When I insert the card into the Nextion display it shows Baud:   9600 and SD Card Update....... and stalls at that point.  I have waited as long as an hour.  Am  missing something or perhaps I procured a bad Nextion or SD card?
Thank you for any input.
73 Vince N1VIN


Re: Nextion Basic 3.2 Display will not update #ubitx

V Zecchinelli
 

Thanks a lot Pat.  I found the cable on Amazon and it is on it's way.  I very much appreciate your input.

73 Vince N1VIN



On 8/13/2018 3:28 PM, pat griffin wrote:
I am not home and it has been a bit since I did it. You will need an ftdi usb to serial cable ($15 or so) Connect it to the computer USB port and the other end (4 pins) to the 5v, grd, rx, and tx pins on the display. Then select the port in the editor and the download or upload I forget what it is called. I may have left out a step but that’s basically it
Pat


On Aug 13, 2018, at 1:53 PM, V Zecchinelli <n1vin@...> wrote:

Thanks Pat.  Sounds like a great idea but not sure I know how to do that.  Would I cobble together a USB to connect to the 5V, RX, TX, GND?  At this point the display is not connected to the uBitX.  I have 5V & GND connected to USB adapter and computer.


On 8/13/2018 2:33 PM, pat griffin wrote:
You could try downloading directly to the display. It’s slow but it would tell you if the display or card is bad.
73
Pat aa4pg


On Aug 13, 2018, at 1:02 PM, Joe <joeman2116@...> wrote:

Hi,
I have seen this issues several times

1. Make sure your power source is good.
2. Try another microsd card.

Usually one of the above clears the problem

Joe
VE1BWV



On Mon, Aug 13, 2018, 2:47 PM V Zecchinelli <n1vin@...> wrote:
I have spent most of today searching through messages and wiki to no avail.  I am using the basic 3.2 Nextion display and am trying to upload the tft file I downloaded from ubitx.net.  SD card is 8Gb and is formatted FAT32 and tft file copied to it.  When I insert the card into the Nextion display it shows Baud:   9600 and SD Card Update....... and stalls at that point.  I have waited as long as an hour.  Am  missing something or perhaps I procured a bad Nextion or SD card?
Thank you for any input.
73 Vince N1VIN



Re: Nextion Basic 3.2 Display will not update #ubitx

pat griffin
 

I am not home and it has been a bit since I did it. You will need an ftdi usb to serial cable ($15 or so) Connect it to the computer USB port and the other end (4 pins) to the 5v, grd, rx, and tx pins on the display. Then select the port in the editor and the download or upload I forget what it is called. I may have left out a step but that’s basically it
Pat


On Aug 13, 2018, at 1:53 PM, V Zecchinelli <n1vin@...> wrote:

Thanks Pat.  Sounds like a great idea but not sure I know how to do that.  Would I cobble together a USB to connect to the 5V, RX, TX, GND?  At this point the display is not connected to the uBitX.  I have 5V & GND connected to USB adapter and computer.


On 8/13/2018 2:33 PM, pat griffin wrote:
You could try downloading directly to the display. It’s slow but it would tell you if the display or card is bad.
73
Pat aa4pg


On Aug 13, 2018, at 1:02 PM, Joe <joeman2116@...> wrote:

Hi,
I have seen this issues several times

1. Make sure your power source is good.
2. Try another microsd card.

Usually one of the above clears the problem

Joe
VE1BWV



On Mon, Aug 13, 2018, 2:47 PM V Zecchinelli <n1vin@...> wrote:
I have spent most of today searching through messages and wiki to no avail.  I am using the basic 3.2 Nextion display and am trying to upload the tft file I downloaded from ubitx.net.  SD card is 8Gb and is formatted FAT32 and tft file copied to it.  When I insert the card into the Nextion display it shows Baud:   9600 and SD Card Update....... and stalls at that point.  I have waited as long as an hour.  Am  missing something or perhaps I procured a bad Nextion or SD card?
Thank you for any input.
73 Vince N1VIN


Re: Auto TX Smart Filter Controller #nano #arduino #filters #ubitx

ajparent1/KB1GMX <kb1gmx@...>
 

Arv,

If using an external filter box and the uBITX internal filters remain in place, 
it seems that the external filters would only need to be activated in transmit 
mode.  That could save some power when in receive mode.  

As is they are wired to only be active on TX.  The only get power when
K1 supplies "TX" (K1 pin 1) voltage to the transmit hardware and that
includes KT1-3 and K3.

With that said .... one can disable all but K3 and with three etch cuts and
jumper TX RF direct to K3 pin16 around the filters completely.  It should
save about 120-150 mA.

Allison


Re: Low Power Output for Hendricks BitX20A - Watt meters and Scope readings do not agree.... #bitx20

ajparent1/KB1GMX <kb1gmx@...>
 

Timothy,

>>all due respect Allison Bitx20A is a dual IRF510/A  class B  design with substantial drive frm small signal drivers .

What is a bitx20A?  

Also I made no assumption any Bitx has a Class A amp most builds I've seen would either oscillate or melt
at 1-2 A no signal drain current.    Most people run them starved at 50ma to lower the gain of the IRF510
and that near class B.

I built the bitx20 and it was a single device. Maybe  your talking about the hendricks bitx20 could as it had
BS170 push pull driving IRF510 push pull  However, its was unspecified so I covered the known case.

For the Hendricks they could do much more if they didn't break into oscillation first.  Most I got to see were
better power oscillators than transmitters.  Minor changes tamed them and usual was 12-15W.

Both cases 70V PP would be 24W output across 50ohms , you would only get that with the PA at
more than 18V.  or its an incorrect measurement.

Allison


Re: Sunday

ajparent1/KB1GMX <kb1gmx@...>
 

david.g3ryp <david.g3ryp@...>
06/20/04   
>>>I wonder how much output everyone's getting from the IRF510?  <<<
 
A recurring question.  So basics...

The IRF510 is a power MOSFET with max ratings of 5.6A, 100V, and 43W power dissipation ratings.
There  are a few "yes but..." around those but for the moment we dispense with that.

The power you can obtain is a function of two things the devices gain (well over 13db power gain)
and the amount of drive power.  There is a maximum for drive power as you can literally burn out
the MOS (metal oxide layer) of the fet. The hard DC limit for that is 20V, so the AC peak to peak
should be well under that.  In practical circuits that works the real voltage is much less typically
under 6V.

Now class of operation:

Class A The current flows at the output waveform for the full 360 degrees of a cycle
at the output.  You depart Class A if the current required causes an  increase in
operating  current.  An IRF510 biased at 2A will do at 12V about 24W input power
and about 8W output power (and lots of heat use a good heatsink!).  This means
usually has a low efficiency typically 30% or so.

Class B  The current flows only for half the cycle.  This is more efficient but care
has to be taken to keep the signal clean at the output connector.  It can be
non-linear as well distorting SSB.

Class C The current flow is less than 180 degrees (half cycle) and is more of a pulse.
With good output filters this produces efficiency in the 70% region and for CW or 
high level AM (plate,collector or drain) modulated amplifiers.  Not used for SSB!

For some applications and to obtain better efficiency  we can bias between Class A
and Class B and this is very common with Class AB or AB1 being the usual for
big tube linear amps and many of the solid state types.  The number after the AB
generally signifies how fare between pure Class A and pure Class B we are.

The typical use of IRF510 is class AB or abouts with a minimum of 50 mA of bias.
It is not always optimal and will depend heavily with the design of the amplifier.
Generally it does not determine over a wide range what the power out will be.

So if you some radio that only gets 2w or a friend that gets 20 the real reason
is clearly not the IRF510.  it comes down to if you only get 2W its likely becase
you only put in maybe 50mW and the other guy put in 1W.  

Allison







Re: Nextion Basic 3.2 Display will not update #ubitx

V Zecchinelli
 

Thanks Pat.  Sounds like a great idea but not sure I know how to do that.  Would I cobble together a USB to connect to the 5V, RX, TX, GND?  At this point the display is not connected to the uBitX.  I have 5V & GND connected to USB adapter and computer.


On 8/13/2018 2:33 PM, pat griffin wrote:
You could try downloading directly to the display. It’s slow but it would tell you if the display or card is bad.
73
Pat aa4pg


On Aug 13, 2018, at 1:02 PM, Joe <joeman2116@...> wrote:

Hi,
I have seen this issues several times

1. Make sure your power source is good.
2. Try another microsd card.

Usually one of the above clears the problem

Joe
VE1BWV



On Mon, Aug 13, 2018, 2:47 PM V Zecchinelli <n1vin@...> wrote:
I have spent most of today searching through messages and wiki to no avail.  I am using the basic 3.2 Nextion display and am trying to upload the tft file I downloaded from ubitx.net.  SD card is 8Gb and is formatted FAT32 and tft file copied to it.  When I insert the card into the Nextion display it shows Baud:   9600 and SD Card Update....... and stalls at that point.  I have waited as long as an hour.  Am  missing something or perhaps I procured a bad Nextion or SD card?
Thank you for any input.
73 Vince N1VIN