开云体育

Elecraft has (or used to have) a simple S-meter calibrator that put out a signal that was supposed to be S9 and was pretty inexpensive, if you really need to have accuracy. Then you could check it with another station adjusting their power remembering that each S-unit represents 4X the power (or double the voltage if you are measuring that). If it needs changing you will have to reprogram the second Nano. Having an S3 all the time is about right, that is typically the level of band noise. It should go to zero if the antenna is disconnected. As I said before, with the second Nano mine is agreeing pretty well with a commercial rig in the shack except for the timing as it is a bit slower to respond.

=Vic=

Oh, and here's a link to the thread with some of my investigating and experimenting:

/g/BITX20/topic/bfo_calibration_and_ssb/70940600


Reed

In my experience, you will leak unless you calibrate the BFO to only allow high treble to pass (sound super tinny). The diodes on the mixers just aren't balance well enough to stop the carrier otherwise.


Reed

Hi Folks,

I am using my uBitx with NKK linear. I have reduced the power by using RV1. I have calibrated both BFO and Frequency by watching Mr. Ashaar's video.?

If I increase the drive to 7-8w to get the linear push out a little more power, I get reports saying there's a leak in USB.?I came across this calibration "https://www.hfsignals.com/index.php/ubitx-tuneup/" of the PA. Should I do this for uBitx v6 too. Isn't it factory calibrated ?

Someone else told me to calibrate Carrier preset. Anyone know how to do that ? Or was he referring to the procedure in the above link ?

Thanks in advance,
Belthur ~ vu3gwn

If you are using a 20MHz oscilloscope for measuring the 40-70MHz square wave, you are more likely seeing the loss in the amplifier gain in the scope than genuine drop in si5351 output.
This might be a place where a simple voltage probe with a fast shottky diode detector would work.

I just got things set up to try to do some FT8 with my uBitx v5. I am new to HF in general and have yet to make a QSO.
I can receive fine, but?pskreporter.info says only 6 reports for my about an hour session tonight, all a in the same state a couple states away. To get that I had to get my computers clocked synced up as it was a couple seconds off. I am using CAT control and two simple audio cables from a usb sound card directly plugged into mic and phone on my radio, which is running off power from a 12v SLA battery.
My antenna is a?MFJ-1984LP EndFed 1/2 Wave?strung up 12 ft about in the air from a tree to my pergola, slightly sloping up. I have it grounded as well. This is my best guess as the problem, but I've heard others on here get much better results with similar setups I think. Its supposed to be a no-tune antenna, but I have no swr meter to confirm it has a low swr level like its supposed to.

Anyone have any tips or ideas? I'm a brand new beginner at all this. Thanks very much.

I'm working on the idea of changing my BitX20 to 10 meters.? It was suggested that it would be a lot easier with a Raduino - and I've found a bit of information that might help me as far as the other component changes.

I don't want a Raduino with touch screens or any of the useless fancy stuff - just a basic Raduino that I can hack the software to get the radio on 28mhz (with a few other mods.? I've looked into different ways of making the change, and that seems the easiest.?

Any suggestions as to where I could find a decent working "old-style" Raduino that doesn't have a touch screen or anything like that (I understand that the original version can produce two different frequencies - one for the VFO and one for a LO - all I'd need).? If it's used but still in reliable working condition - no problem (might be better due to very tight budget).

Thanks!
Bob
N4FBZ

Hi,

There is also the question of the load and it's bandwidth. I got bit by all of those "features" decades ago.

73,

Bill KU8H

--
bark less - wag more

Right Mr Tom , i'm using 1:1 scope probe, and the bandwidth specified for the scope is 20MHz.

take an alligator clipped jumper wire and bypass the LPF section - get as close to the receive mixer as possible - and see if you have signals.?

idea number 2 is that the LO is not getting from the PLL to the mixer - check to see how the connectors are seated.

okay I should have listed this first - your BFO calibration may be way off - as mine was.? search the list for v5 bfo calibration - this could be the issue.? if so, when you tune the upper portion of 40m in the evening you might get something when you tune across big AM broadcast stations.?

73 curt

I have not done this yet, but I am so tempted to add a small fan - but only use it when running digital modes.? For CW and SSB I sense the small heat sinks are just fine.?

73 curt

The individual heatsinks are cost-cutting and ease-of-manufacture measures.They are necessary because the mounting tabs are directly screwed to their heatsinks and so electrically connected. Mounting the finals using insulating? washer kits isolates them electrically so they can share a (larger/more efficient?) heatsink, but to keep thermal resistance low most such kits require a thermal paste, and that's extra work for Farhan's assember-ladies and quite likely an extra complexity in quality-control (-> extra cost). Upshot: grounded or no, a shared heatsink is possible but requires extra hardware and effort.

The above from long experience and usage in audio amps, similarly class-AB.
It's also possible that at RF ungrounded capacitive coupling may play other havoc :(

de ZL2DEX

Do you group owner, please ban me and remove me from this group someone has hijacked my address, and is apparently Spamming the group with useless trash. So sorry this is happening I am not sure how they managed to do so, my deepest apologies to the group, particularly for all the good things that they do for the hobby.

Steve Levine
Steve

No, the drains are connected to different ends of the output transformer.? Just add an isolation pad and screw insulator and you can mount them both to the same and even grounded heatsink.



The above is just an example.

73
Evan
AC9TU

Luis,

On the mention of the decode of CW, I think it is all about the settings of the radio on the cw signals. I think maybe we have to learn how to set it to decode cw, perhaps incorporate a filter, I have seen there is a filter module that can be added to the ubitx and I have also played around with the IF-S setting while using CWU and CWL. I have gotten some very good decodes of CW, I have played around with the settings on the DSP 1 setting where spectrum and CW decode selection is. Where the spectrum appears I am wondering if the setting to right is the cw speed, it goes from 1-100. What have you been able to figure out on this? what values did you use for your resistors and capacitor? What version of the software did you use for your second arduino nano?

John KD5INM

I am aware that grounding the heatsinks is a no-no, but can the finals share the same larger ungrounded heatsink?

TNX
Tom AB6TN

Luis,

I forgot to mention, I did try to match the color of the wires in the diagrams to my setup and also labeled those wires as to the pins they plugged into. I did solder to the pins A4 and A5 on the main nano on the raduino and those wires have female plugs on them that plug on to A4 and A5 pins of the secondary arduino nano. I was confused as well by the diagram like you were. I tried plugging everything in like the diagram showed but then put it back the way WB2CBA had it and then tried pulling the yellow RX wire and plugging it to the pins on the second nano (D0/RX and D9) with a wire going from the second nano back to the LCD display on pin #5. Everything worked fine after that. The problem I was having was that the display didn't show the frequency although I could hear it changing in the radio itself. We might need to re-draw a new diagram for our version 6 uBitx so those who are new to all this like we were are able to get it going without frustration.

John KD5INM

Luis,

On the settings I think you are talking about the S Meter settings, am I right? I check marked the box and used the S meter assistant button. It inputted the values 1-233 in the boxes from 1-8 and that seems to be working ok. At some time in the future I plan on doing the PO/SWR mod when I get the parts assembled. That sounds like a good idea on what you want to do with etching a board and SMD the parts. That was what I had originally intended to do. I had a piece of copper clad bard that I had intended to cut "islands" on that board using a dremel type tool with a little cutting head that would cut through the copper leaving islands or traces on the board and then dead bug style surface mounting the resistors to it. I couldn't locate that copper board so I found the piece of radio shack perf board and unsoldered the resistors as I had them wired for testing purposes, and mounted them along with the capacitor to the perf board along with the wires and then super glued the nano to the board like you see in the photo. It's all plug and play and I left it that way so that in the future if the nano needs programming updates or added features can be plugged onto it.? I cut the piece of plastic from a scrap piece of plastic case from an old VCR. Plastic like that lends itself to being useful. I have made other plastic parts from that as well. I used a table top wood cutting band saw to cut the piece. It already had the right angle formed in it and it worked perfectly to hold everything in place. I have also used a heat gun to bend plastic as well. A band saw or scroll saw is a great tool to have when making plastic parts and the blades can be had for a very reasonable price. I think I gave about $60 for the craftsman bandsaw at a garage sale.