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Re: Corrupt ubitx files?
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??? |
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Re: Harmonics
There's a filter for 20m and 17m.?
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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? . |
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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:
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Re: Harmonics
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 |
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Re: Nextion Basic 3.2 Display will not update
#ubitx
V Zecchinelli
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Try with another SD card I changed 4 cards . |
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Re: Harmonics
>>>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 ? |
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Re: Nextion Basic 3.2 Display will not update
#ubitx
V Zecchinelli
开云体育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:
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Re: Nextion Basic 3.2 Display will not update
#ubitx
V Zecchinelli
开云体育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 |
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Re: Nextion Basic 3.2 Display will not update
#ubitx
开云体育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
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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 |
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Re: Low Power Output for Hendricks BitX20A - Watt meters and Scope readings do not agree....
#bitx20
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 |
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Re: Sunday
david.g3ryp <david.g3ryp@...>
06/20/04???#30??
>>>I wonder how much output everyone's getting from the IRF510?? <<<
?
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 |
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Re: Nextion Basic 3.2 Display will not update
#ubitx
V Zecchinelli
开云体育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. |
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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.? Arv _._ On Mon, Aug 13, 2018 at 11:44 AM ajparent1/KB1GMX <kb1gmx@...> wrote: Tom |
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Re: Nextion Basic 3.2 Display will not update
#ubitx
开云体育You could try downloading directly to the display. It’s slow but it would tell you if the display or card is bad.73
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SV9CVJ Nikos
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