Has anyone run tests on the popular Elecraft KX3 or the Xiegu 5105 for spurs and harmonics?? How do they compare to the uBITX?
Thanks,
Jim W0CHL

Has anyone looked at the Yaesu FT-991 for spectral purity? :)

My .02 on testing everything in sight...

Send me one of each and a pot load of money I'll write a report.?
You can read the manual as the specs called out are accurate.
That will save a lot on currency.

Why is this in the Bitx at all?

Allison

Hey, I'm just curious how all the other portable radio compare....
Are they :"clean"? Specs can be that "special" radio, just for testing.
Your mileage may vary,
Jim W0CHL

开云体育

?Hi Jim,? ?Allison already did that for a motley crew of raidos, including a Heathkit HW-100 and they all were good to go except I think one reallly clunky design.? ?The general thing was that most radios are pretty well engineered.? ?

Gordon

You means spectral purity around the fundamental or the harmonics? Listening to a few hams on VHF, having an SDR receiver, my impression is that around the fundamental they were not very clean. I have to say that many that have that rig have done a simple mod around the mic input to have plenty of punch. Also that radio have also a arsenal of possible equalization. Do the users of these NASA rigs always check for their spectral purity or maybe they take for granted they are clean whatever the mods and equalization?

Hey, I'm just curious how all the other portable radio compare....
Are they :"clean"? Specs can be that "special" radio, just for testing.
Your mileage may vary,
Jim W0CHL

Read the specs.? If they don't have them don't buy it.

As a random comment Elecraft anything tends to be very good.
Some of the new imports are largely unknown.
However my CRkits KNQ7A is good.

Allison

Iz oos,

>>Do the users of these NASA rigs always check for their spectral purity or maybe they take for granted they are clean whatever the mods and equalization?<<

Some do some never even thought of it.? The Anan users tend to be very fastidious and?
a lot of them use the adaptive feedback (distortion error correction).? Very clean as an
example of what technology can do for transmitters.

Allison

Seems there are some that don’t realize that “the law was made for man, not man for the law.” There are those that won’t solder a mic connector or PL-259 without permission of the FCC. On the other side, some could care less about the rules or their impact on others. Then there is the masses in between that see a unique toy that is a lot of fun to get into and will teach you a ton about radio. I guess each of us must answer for ourselves what this hobby is all about.?

If Marconi had been under the FCC, he would have never gotten on the air in the first place.
--
72 and God bless
KD4EPG

That -43dB rule is generous, should be easy enough to meet.
And with thousands of QRP devices out there, the cumulative effect s significant.

Warren's spectrum analyzer screenshots show trouble, though to some not just too alarming.
They were taken with gain adjusted for 2W out to the antenna port.
Crank up the audio to where you get 10 or 15 Watts, and the emissions are much worse.
Having over 10x the unwanted emissions of those prescribed in the regs is not an option.

Going 10x the speed limit through a school zone is not an option either.

Jerry

--

Allison,
? ? ? ? ? ? i have been an early adopter of an ANAN100D .Still? run it daily with Predistortion and CFC etc.
i aslo run the UBitx v3 harmonics spurs and all. Have seen the harmonics and spurs on the Ubitx on my SDR panadpter screen. The price ratio of the ANAN100D to the Ubitx here is greater than 25:1.

Perhaps a future Ubitx ver.XX will feature Predistortion ad CFC tools etc and still be 25 times cheaper than the ANAN XXXX .
73
Sunil VU2MTM

Sunil,

It takes a lot of hardware to get predistortion and CFC to go.
Basic clean is not that hard though even if the Anan is easily 10 to 100X better.
But you have to start with a good design and then take out the easy flaws,
the harder ones are then better isolated.

Allison