开云体育

Vic

Thanks for posting your mods, I will review and learn some more.

No 0.1 uF sounds way to large to add to c81. If a rig has a severe dip at 40m, like only 2 or 3 watts, adding something like 100 to 300 pF will improve it. Try what you have, it will vary by rig and may not be that sensitive to exact value, just like the real difference between 5 of 6 watts to be barely discernible to the receiving operator.

For v4 harmonics, either substiting axicom relays or adding a separate set of relays on a daughter board should reduce them. Axicom relays appear to also reduce leakage resulting in mixer spurious, on some of our tested units. Others add shielded inductors at l5 and l7. Note harmonics impact bands 20m and below, and mixer spurs on 17m and above.

73 curt wb8yyy

Hi Ted,

I have used incandescent bulbs as dummy loads too. I did that a lot with vacuum tube finals but it works for solid state too. Not only is it *not* a 50 ohm resistive load but the impedance changes dramatically from cold filament to glowing hot filament. Yet - it works.

If you have a light bulb connected to a transceiver (or just your receiver) you will be able to hear many of the stronger signals and they can hear your transmitter too. I have a nice, 100 watt, shielded, 50 ohm resistive dummy load. I can hear a few signals in the receiver with that dummy load and I expect others can hear my transmitter if us light it up. Hams have conducted QSOs on dummy loads. Some of our outdoor antennas are pretty much dummy loads too. Always check for a clear frequency before you start testing your transmitter - even with a dummy load.

73,

Bill KU8H

--
bark less - wag more

I have a v4 uBitX and have made a number of mods that I described and posted with links here:



Hope you find that useful, I really enjoy my rig. I still need to address the low CW power on 40m, but I think a 0.1uf cap paralleled across C81 has been suggested as a fix, so that is on the list.

=Vic=

Oh, and for a dummy load in a pinch [at these power levels], get an 1157 tail light bulb and solder both filaments (pin) & shell (earth) to a male BNC or whatever you're using.

I wouldn't keep it key-down for more than 10-15 seconds; it's not necessarily a well-matched load but it will give the energy someplace to go AND you get visual proof of life.


Ted
K3RTA

K5FJR de K3RTA,

This static of which you speak, is it there mainly when you're transmitting, or at any time? I ask, because it smacks of RF infiltration (or "leakage).

Your other rigs may not have this problem because of more commercial-grade internal shielding or other refinements that are above the price point of a good seed kit like uBitx.?

May I ask the antenna design? I'm mainly curious because you've got a WORKING condo antenna, apparently (uBitx RF issues aside).? I'm trying to get a condo-owning friend to believe she Can do HF from her place.

For yourself, an end-fed half wave using very fine magnet or choke coil wire out to a tree or hanging down against a brick wall might be worth trying, partly because I've been playing with such designs and they seem fine from an RF intrusion point of view.?

So HW?

Ted
K3RTA

Dave, my V6 was doing exactly what your is when I first put power to it.? Then I found out I had the encoder connected to the board and not to the arduino.? You may have checked that but it was not clear in the build directions and I know others have hooked it up wrong too.? The connector on the arduino and the board are the same (I'm not sure what the one on the board is for....remote USB ?)
--
Newbie but getting there, Russ
K5FJR

The short answer is yes.? Here is a link to someone who has done that.? The only issue was alignment of the Nextion screen holes, and he was able to work around by enlarging some of the holes.? He did not elaborate which ones.



BTW, ubitx.net is another good source for information on the uBiTx modes and source files.

73
Evan
AC9TU

Dr. M T Thomas,

What you describe is a common problem with the uBiTx line of transceivers.? It is most often caused by RF getting into the rig, most likely from either the microphone cord or the coax shield. The best way to verify is to connect to an RF dummy load and see if it happens then.? If it does not stick in transmit mode, then it is RF getting back into the microcontroller.

Two solutions and both can be done.
1 - Put a common mode choke or snap-on ferrite in or on the coax from the antenna.? This is to keep RF out of the radio/shack.
2 - Put a snap-on ferrite on the microphone cord just before the plug and/or add 0.1 uF bypass capacitors on the PTT and microphone input.

Also, be sure that you have good earth ground on the case of the uBiTx.

It always helps to include the version of BiTx when asking for help on this site.? There are multiple models and versions of the BiTx radios, and the best solution can be based on which one you have the issue with.

Hope this helps.
73
Evan
AC9TU

is it possibble to replace the screen /ardino with a 2.8 "nextion and a new aruino then use? cec 's software? dave c

many thanks evan

Thanks for the suggestions.? As for RF leakage, I'm in a situation where my dummy load is in a different state so can't do that.? I also have an issue with grounding since I'm in a condo with limited access to 'ground.'? But my other HF rigs seem to be OK with the same feed line.?

And I'd like to get a new volume control but with nothing being shipped from India at this time (and who knows for how long), that is probably out of the question.? I've inspected the solder on the control and they look fine under magnification.? Not a difficult job to replace if/when that becomes a viable option.? In the mean time, I'm trying to find a good speaker as that MIGHT be part of the volume issue.? I'm going to try spraying the control next to see if that will help.

Thanks again, this group is a great source of info for us, especially those with limited technical knowledge.
--
Newbie
K5FJR

Hi Ian,

About the static noise with the volume knob: i had my ubitx v6 running with factory software and hardware for about a week just fine with no noise or static.?
After getting lost doing the calibration, decided to download and reinstall the factory software again.?
Then is was when the static issue on the vol knob presented itself.?

It would only happen when i touched the knob. But if i touched the knob while touching the antenna connector it would stop. The weird thing is that it would only stop by touching the antenna while holding the knob, i tried touching various ground points and no change.?

Last week i changed to the nextion 2.8 and the cec software and the issue dissapeared. I did this on a spare arduino, so i still have the stock one loaded with the factory stuff.?
Once i get everything situated with the cec software, i want to go back and look into the static issue, since to me it seems to be software related.?

KO4BYI
Luis.?

Sorry for bumping up an old thread, but this was my last resort for this Specan project. I am planning to built one and I am requesting all to respond on this topic as W9CTW originally asked. Craig have you done some progress on this project so far. What is your outcome. Please let us know.

Thanks & Regards
Ashok

Curt,

? ? ? What was the H bracket used for that is mentioned on Carroll County site?

Tom
w9kkq

Like some other folks, I have an unbuilt v.4. I've waited to build it until the dust settled over the fix for the harmonics and spurs. I've begun putting it together and realized how hard it is to find good information specific to the v.4. Not because it isn't there but because at the time the fixes and mods were written up they weren't identified as v.4. I'm not saying anyone was lacking in any way, it was the current version and people wrote issues, mods, and fixes. They didn't know that we'd later have a v.6 that was quite different from the v.4.?

Based on a comment by Curt in an earlier post (ubitx 4 - want a fresh start, need guidance) he posted a link with some great uBitx v.4 build information.? ? ? ? ? ? ?

I just wanted to put it here with an easily searchable title for other v.4 builders

?

Dave,

We are now into territory where I cannot provide a lot of help.? We will need to wait for someone else with a v6 to chime in. I would check that the screen is plugged into the Raduino board correctly, as well as the encoder.? Also check the solder connections on the encoder.? There should be a ground connection on the center pin of the 3 pins side.

You could try testing the encoder out of the rig with an ohmmeter.? Should be able to see off and on states as you turn the encoder for each of the two inputs.? This could also be done with the power on, provided you can get to the contacts to measure the voltage.? It should vary between 0 and roughly 5 volts.

I have no experience with the touch screen on the v6.? The touch screens that I am using on my v4 and v5 rigs are Nextion with a single serial connection and a built-in controller.

One more suggestion; do not post a new topic if you are still working on the same issue.? For those like me, we read through the history of the topic before trying to answer the question or provide an opinion.? If you post with a new topic each time that history is hard to follow.? For any follow-on comments, just reply to this topic.

73
Evan
AC9TU