Hi,
My regards to the chef, on the Stone soup. :-)
I have no fancy test equipment, but I have
a working uBitx v4 board.

I've read thru all the links and emails on the current problems
with the Ubitx's spurious emissions, but can't seem to get
a clear picture of what bands and modes are legal for
transmitting in the US. The sheer number of posts
and technical data is a bit overwhelming.

Could one of you experts, make a simple text table showing
which bands and modes are acceptable on a stock board?
Something like:
This is a fake table for example.
########################
80m no cw, no ssb, no digital modes
60m digital fine
40m no cw, ssb, digital fine
30m digital fine
20m cw , ssb, digital
17m etc
15m etc
12m etc
10m etc
##########################

Thank you,
Joe, KN4OND

Hi Joe

Your question illustrates the reason for my stone soup admonition.

There is no valid answer to your question without additional parameters being set that require precise measurement and monitoring. The table you ask for will be very different depending upon the power level used, the loudness of your voice and the resulting drive level on SSB, the voltage level applied to the PA, etc. The table constructed assuming a power level of 5 watts will be very different for one assuming 1.5 watts or, God forbid, 15 watts.

For those who want to experiment, find problems, devise solutions, and who are willing to defer air operations until they have ascertained their uBitx is compliant, it is a wonderful source of learning and fun in the true spirit of amateur radio. For those looking for a radio to simply package and put on the air as it stands, the uBitx is the antithesis of what ham radio should be.

There is plenty of room and their are plenty of options in our hobby for those who wish to simply operate, gather awards, rag chew, and contest. There are also many options for those who wish to build and experiment to hone their skills and to have a sense of pride and accomplishment for what they have built. The uBitx is ideal for the latter and a nightmare for the former. Neither group of amateurs, the appliance operator or the builder, are better or worse than the other and neither has the inside track on the hobby. But both need to understand what valid equipment choices are available to them.

WA8TOD

Joe, Warren published some pretty good numbers way back, and Allyson probably did also, and basically CW mode was in trouble on all the bands. Single side band not quite so much as long as you didn’t scream into the mic, or use bands higher than 14 MHz. (but still pretty close to in trouble or beyond it many places) It highly depended on how the unit was set up. Ashar Farhan indicated that units properly adjusted were compliant. Others disagreed based on measuring several production units. You, like I, would have to go back and find all their particular posts with their data, to jfind the exact claims. None of this has been adjudicated in any official proceeding.

Harmonics are a problem for most of the bands, where is spurs are an additional problem above the 20 meter band.

It seemed to me that CW was in much more trouble with harmonics, than single side band. I along with several others have introduced ways to reduce the bleed through via the relays around the excellent filters at the end of the power amplifier design. My solution seems to work, and I think others have also shown their solution works (even for the CW problem) on 20 meters & below; individual band pass filters or other solutions would be needed to fix the spur problem beyond the 20 meter band; fixes to the low pass filter do not repair that particular problem.


So I think that people who are concerned about this are going to do some sort of a filter or relay fix on the power amplifier, or replace it all together, and operate on the 20 meter and lower bands. My fix had a total cost in the range of $15 or less and an hours worth of work.

A lot of other people aren’t going to care and will use the unit as it already exists, and because it is so low powered this isnt going to cause that much trouble. It would be a different issue if they all bought high gain external amplifiers and magnified the spurs & harmonics many many times.... that would eventually get noticed


I hope that helps you. Because several people here did such a great detective work figuring out exactly what was the problem with the harmonics, fixing THAT became a rather simple affair.

I’m going to see what the postage cost would be to send out the simple external relay board that I came up with. The board itself only cost $2.50 even after DHL shipping from China. I think it can be mailed out as simple first class mail just with a “non-machinable surcharge” of $.25 or so.

The first radio I had, had severe problems, didn’t work at all, and took me months to make it work. After that it was a joy and I used to make many many contacts. Heathkit HW 16. By comparison, the uBitx is a joy! Much of life is how you look at it. Nothing is perfect, but to disparage items that do have known flaws as complete garbage, I think is an attitude that does not benefit the holder much at all. Take that as some free psychological advice.

Cheers

Gordon

Gordon

My characterization of the uBitx as "garbage" is a term of art, not science. However, when a commercial radio is advertised as "Build the ?BITX transceiver in an evening. A general coverage, 10 watts HF SSB/CW transceiver kit? with features you NEED for operating ease, convenience and versatility. It works from 3 MHz to 30 MHz, with up to 10 watts on SSB and CW, with a very sensitive receiver." it would be reasonable for operators like Joe to assume they would have a compliant radio on the air after an evening's work. This is simply untrue.

"The front-end diode mixer followed by a Hayward/Kopski TIA makes this a crisp receiver that doesn’t overload easily." Simply untrue. Using this receiver 3 miles away from a 1450 KHz AM broadcast transmitter is impossible through 20 meters due to overload. No other radio I own, including homebrew SDRs has this issue.

"10 watts of low distortion SSB provides you with enough juice to have thousands of contacts on all HF bands." Again, simply untrue. Unacceptable levels of SSB distortion begin at less than 2 watts and result in adjacent channel splatter at any level above that.

I am not bashing. As a basis for experimentation and improvement the uBitx is a treasure. As the basis for a rig to be connected up in one evening and put on the air, it is indeed "garbage".

WA8TOD

开云体育

I simply disagree.?

Gordon you have missed my point by focusing on what you call "disparagement". My "disparagement" is an attempt to inform those who expect to take the radio out of the box, connect it up and operate compliantly as is advertised. That is simply not going to happen.

If your IC-718 were presented in its brochure as being able to switch frequencies and bands five times per second then I would be calling that claim garbage as well. It is not represented that way.

Your "disparagement" is my "information". If you, in good conscience and with all you now know about the uBitx, can say you recommend it as a first or only rig to someone just starting in this hobby and without test equipment or the knowledge how to use it, then we indeed disagree.?

Similar charge for that advice. LOL. Have a great day!

WA8TOD

Warren,

regarding '''The front-end diode mixer followed by a Hayward/Kopski TIA makes this a crisp receiver that doesn’t overload easily." Simply untrue. Using this receiver 3 miles away from a 1450 KHz AM broadcast transmitter is impossible through 20 meters due to overload. No other radio I own, including homebrew SDRs has this issue.'''... 3 miles away are really few! The website on this is clear, it shows un understandable schematics and it is clear it has no bandpass filters that are common in the Softrock for instance. For not having them, the front end seems to me quite good. If you have issues with it you may find a solution adding some preselection. In this case a high pass filter or a high pass tuner may be fine. I know btw that some 7300 users are fond of... attenuators.... !!!!

Once again Iz, that is the point. You know.... and I know, how to recognize receiver overload and what to do about it. "does not overload easily" is subjective..... but when I have one rig out of several dozen that does overload without external measures while none of the others do, then I would want to point out to those without that experience that the "does not overload easily" reference may be a bit of a stretch.?



WA8TOD

开云体育

Or maybe the website simply intends that under normal operating conditions, propagated signals don’t easily overload the radio.....which may be more true in some parts of the world than others.

Well said, Scott.
We should treat the ubitx, and many other HB projects as radio 'build it" kits. I wonder how many other basement projects dont meet spec? I also totally understand where Warren is coming from...many new hams would look at at the price and all the features, without understanding all the implications, and just reading these forums has been a huge education for me.

Interestingly, I have searched the Canadian regs for info on spurs, etc. and can find nothing other than 'must not cause harmful interference'

Now if only the same social conscience as shown here was embraced by manufacturers of consumer electronics,? I might be able to hear something on 80 meters. Just my FWIW.

73 all
Breny

On Tue, Sep 4, 2018 at 01:56 AM, Joe Milosch wrote:

########################
80m no cw, no ssb, no digital modes
60m digital fine
40m no cw, ssb, digital fine
30m digital fine
20m cw , ssb, digital
17m etc
15m etc
12m etc
10m etc
##########################

First item, Digital is SSB!? ?Really!? If SSB is not safe then digital is not either.
Now for those that have been inattentive for the last three months.

########################
80m harmonics, use external low pass filter
60m harmonics, use external low pass filter
40m harmonics, use external low pass filter
30m should be ok cw and SSB-digital
20m should be ok all modes
17m should be ok all modes.
15m CW ok, SSB has spur
12m CW ok, SSB has spur
10m CW ok, SSB has spur?
##########################

By should be ok I mean if your not over driving to try and get some power.

Now with that said in my prior.

The filter is fixable for 80/40/20.? dismount the relays, make some cuts and off to the races.
Whine about doing that?? Time to do some basic technical work.? Your license is so you can!


Allison

Hi Joe and all others in the group,

I've been a ham for more than 60 years and have built several dozens of radio kits. I've owned the best equipment available in times past and having had years of experience in engineering. But, alas, I have very severely downsized and am now living in a cramped apartment not allowing the spacious DX station that I had less than two years ago. Then, along came the uBITx. It does have a thump when t/r switching and it may have spurs and harmonics. However, my son, KA1LOR, who lives 1/2 mile away doesn't hear any problem with this little rig. At a nominal 10w max out, it isn't going to bother anyone, other than the critics. After all, it is a $120 radio! Enjoy it! It is one of the rare bargains in this great hobby of ours. Make hardware mods, hack the sketches that give it character, but most of all, enjoy it. I thoroughly enjoy seeing the fun people are having with this little radio, so keep on being creative with it.?

72/73 - George, K1DX

On Tue, 04 Sep 2018 07:42:15 -0700
"ajparent1/KB1GMX" <kb1gmx@...> wrote:

Thanks to all who replied to this thread.
I look forward to any inexpensive filter kits
being made available, and for now, I'm not going
to worry about a 10 watt signal until someone complains.

As for digital being ssb, wouldn't the bandwidth being used
be a factor? SSB uses the full sideband whereas the digital modes
use significantly less. Or dosn't that matter. I'm thinking
of the need not to use too much audio drive.

Good chart, just what I was hoping for. If I stick to 20m, I
should be alright.

Joe

On Tue, Sep 4, 2018 at 01:56 AM, Joe Milosch wrote:

########################
80m no cw, no ssb, no digital modes
60m digital fine
40m no cw, ssb, digital fine
30m digital fine
20m cw , ssb, digital
17m etc
15m etc
12m etc
10m etc
##########################

First item, Digital is SSB!? ?Really!? If SSB is not safe then digital is not either.
Now for those that have been inattentive for the last three months.

########################
80m harmonics, use external low pass filter
60m harmonics, use external low pass filter
40m harmonics, use external low pass filter
30m should be ok cw and SSB-digital
20m should be ok all modes
17m should be ok all modes.
15m CW ok, SSB has spur
12m CW ok, SSB has spur
10m CW ok, SSB has spur?
##########################

By should be ok I mean if your not over driving to try and get some power.

Hi Joe,

The digital modes use SSB and put the tones in through the mic amp. The bandwidth of the SSB filter determines the maximum width that will pass through - not the minimum. When you connect your computer to you SSB radio to do the digital modes you will see a number of different signals on your screen. All of those without changing your radio dial. Because - as you have said - those digotal signals are much narrower than speech. Therefore =, quite a few will fit into the same spectrum as *one* voice.

Putting a five amp fuse in your power supply doesn't force five amps out of it. Rather, it limits the current to 5 amps. Just like that SSB filter limits the bandwidth to about 2.5 or 3 kilocycles.

I hope this helps.

73,

Bill KU8H

--
bark less - wag more

Bill

Your analysis is true so long as the tones, or the voice if that is your mode, do not overmodulate either the audio or the RF chain. In the case of the uBitx running 10 watts of SSB, whether it is voice or tones, one or both of those stages are significantly over-modulated to the extent they put splatter into the adjacent channels on either side. This splatter will not affect anyone listening to the SSB channel but will dramatically affect those 3 KHz up and down from that channel. The effect is far worse than on a full-featured SSB transceiver in that there is no ALC or compression to control the level.

My unit, a sample of one, over-modulates at any power level greater than 1.5 watts. Most do not care as you can hear most days on 7200 KHz..... but for those who do, you are on notice.

WA8TOD

We should have some way to indicate when too much mike gain is applied.
A diode, cap and resistor watching either audio or IF or RF peak signal levels, sending that to
a Nano analog pin should be sufficient.? Firmware shows a warning in the LCD if level exceeded.
I'd go with that, and a pot for mike gain.

If you insist on ALC:? /g/BITX20/message/56796?

Jerry

Hi Warren,

There are all kinds of abuses that are possible. But the question was about the digital modes actually being SSB signals. I only addressed that. It turns out that music does not go well through an SSB filter since it wants 10 kilocycles of spectrum (or more). I play live music with other musicians (that might be abusive too) and we generate much more than 10kc of audio spectrum.

73,

Bill KU8H

--
bark less - wag more

Hi Arv,

It is more likely the work that is being discussed and done here will be incorporated into a new version and not squelched the new version.

73,

Bill KU8H