Or a circular firing squad. Have you looked at uBitx.net

Now don't flame me guys....

Reading all these questions about what build goes with what Nextion size and
what options are supposed to be activated reminds me of Abbot and Costello -
Who's on First.

rOn

开云体育

My XYL purchased an Ubitx for me late last year. It is a V4. Board. I had time to start on the recommended fixs this weekend. I have replaced the relays with the Axicoms. Does anyone in the U.S. have the SMD inductors for L5 and L7 for sale? I hope to put this in a pelican style case with a tuner and power source to use for portable ops. Thanks to everyone here for their vast wealth of knowledge. I have learned so much about these radios and electronics in general reading this board.
Russell Ward W8ARD
Columbus Ohio

The reality of mobile ops is they antennas used will be inefficient for bands below 20mhz.
Reason is loading coils are a required thing to tune out the reactance of a short antenna.
There is no way around that.?

FOr 20M antenna efficiency is about about 8ft tall will be reasonable about 33% as its pretty
close to 1/2 size.? Center fed is about the best.

For 40M its about 1/4 size and allowing for the fact that cars are a terrible counterpoise for
the antenna so efficiency under 10% are the norm.? IF you can tolerate a taller than 8ft
antenna that helps, center loaded is best.? Do not use an antenna tuner as you at the wrong
end of the cable.? Its best if the tuner is at the base of the antenna.


K0BG has a very complete site on how to get the best out of a mobile antenna.

I run 40M mobile QRP using KNQ7A or FT817 and the antenna is a cheap 40M 8ft
centerfed whip?with mods.? The mods are a 9 turn 1-inch dia coil from the base to
ground to load the antenna.? Then the antenna itself has the longest whip section
possible at the top and is tuned by removing some of the plastic shrink and removing
turns to keep it as long as possible.? This is more efficient than shortening the whip
to tune it.? Its good for about 30khz either side of where tuned.? ? Using a tuner to
get more bandwidth results?in?a significant loss in efficiency as they antenna is then
untuned. I verified this with a field strength meter.? However those antennas are
cheap (about 20$) and I can carry two (one for 7163, and 7250) in the bed of the pickup.??

Ignition noise it a problem with the car/truck... fix it and then you hear the other near you.

Allison

Yes, and one can score some nice LiPo cells from a cordless drill?battery pack?and get a charging controller for the intended voltage (12v, 16v, etc) on eBay with separate leads to sense each 4v step of the battery pack for balanced charging.


Ted
K3RTA??

My end-of-the-world build has a kit type bulit into the faceplate and it seems to work OK. I added two switches to switch the two variable caps in or out independently which seems to help in some cases to add or subtract in that way. I haven't logged contacts on that build as of yet though I haven't been out with it, either.

The transformer of an EFHW? matching network matches the 50 ohm transmitter
to an expected impedance into the wire of between 2500 and 3000 ohms.

Power is Volts*Amps, or Volts*(Volts/Ohms).
At 5 Watts of RF power,? ? 5watts = Volts*Volts/3000ohms,? ?therefore? Volts = sqrt(3000*5) = 122 Volts RMS.
At 100 Watts, it's still around 548 Volts RMS, not yet kilovolts

The polyvaricons are rated for something around 100 Volts:
? ??

Generally, you can press a polyvaricon somewhat beyond 100 Volts.
A polyvaricon works at 5 Watts for an EFHW, though?an air-variable cap would be a better choice.
If an air gap does arc over, it will self-repair once the ionized air circulates out.
And an air gap capacitor has a higher Q, and thus lower losses.

The qrpkits Sota Tuner successfully uses a polyvaricon:in an EFHW tuner:
? ??
They claim a max of 5 Watts CW, 10 Watts PEP.
On 10 Watt peaks, that would be? sqrt(3000*10) = 173 Volts RMS.
Perhaps they are more concerned about heating than they are about arcing?

Anything other than a resonant EFHW will be lower impedance,
and thus lower voltages across a tuning capacitor.

Jerry, KE7ER

Well, as asked (by someone months ago, forgot whom), here are some pix of my mobile-purposed uBitx -

?/g/BITX20/album?id=86462&p

That is exactly what I was wondering Vic. I will give it a shot tonight.?

Thanks
Bill
KE8EYM

IF-S is basically controlling the BFO on receive. If you adjust the BFO (shown as USB Calibration in Memory Manager) by the amount you have been adjusting your IF-S then you will correct that error and not have to use IF-S and your transmit will be corrected as well.

=Vic=

If You have set up correctly, then comfortable listening will likely require some IF-S to shift the bandpass downwards, adding more lower end, but all the way to the right sounds like You are way off.. I'm about 20% for nice even audio on the waterfall in JTDX, and less scratchy audio for phone. (V4 board)

Dear Pratap jee,
Your power inside is really welcome .
?One could take out the rig to field, with some end fed or a fold-able vertical antenna and used for an hour.?

Other mods are curiously awaited. Being a QRP, perhaps you can use PVC gang caps.?

Regards
sarma
vu3zmv

Hi Cristian,
Please upload a screen shot of your error.
?secondly, please check whether you have set the port and Port has recognised? the CH340G? usb interface.
Finally define the chip as atmega328, and if possible as old bootloader.
the Arduino Nano is also to be selected.

all the best
regards
sarma
vu3zmv
?

error Receive Length = 0/1027