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M1 M2 M3 M4 (as you show on left) are the screw hole ground pads on the PCB. Not the same as the audio nodes M1 M2 that are routed to the K3 relay.

Rgds,
Gary

It reduces the gain and thus instabilities at low frequencies.

Those points go to the TR relay located on the left lower portion of the schematic if i remember right (am at work and can't look it up)

John

Hello all.?
There has been one small part of the schematic that has always confused me

What role does M1? and M2 play. It looks like they are grounded yet that would not make sense. As the radio receives M1 would be shorted to M2.
--
73
Dave

I am thinking instability. That leads to oscillations that can kill the device. Rick Campbell had some nice design articles in QST on this. Others may be out there.

Curt

I just discovered this link today and am enjoying its study.
Refering to??lines 19 to 32 if I modify a band defination (for instance writing in line 23?{ 3500000UL, 3600000UL, 80, "80"},) will this put new edges to the 80m bands according to my IARU area and prohibit TX outside of these limits ?

73 - Pierre - FK8IH

On Sun, Apr 11, 2021 at 06:24 PM, barry halterman wrote:

Andrea, I too have had that problem and RF was getting into my UBITX from the key paddle. I used some small diameter coax and a snap on ferrite to solve my issue.

Good luck

Barry

K3bo

thanks for all reply, i will try to put some ferrite to try to stop this RF,?

73 de IW0HK Andrea

Hi Jerry,

I just realized the manual wasn't linked in the readme.md in the code, so I've added that link now (thanks for the nudge, Jim S). For your reference:


Reed

On 2021-04-11 16:05, John Cunliffe W7ZQ wrote:

They should be easy having a gain of 20db on HF I get that much on 2m
from a pair of them.Careful though, with the gain

Indeed. That's why I always stuck with grounded grid for my tube amps. Much more stable. When I first ordered the uBITX ( impatiently waiting... ) I thought of doing a single-sweep-tube amp for it, or maybe a single 6146B. That
was before I found out just how far the solid state stuff had come.

- Jerry KF6VB

do aim for stability and cleanness over raw power - and keep in mind this simple math:

each time you increase power 4X this is 6 dB, and roughly it is one S-unit.? if we start with 10 watts, 40 watts is one S-unit stronger and 160 watts is 2 S-units total -- so don't sweat for every watt.? a small amplifier could help your ubitx - but if you seek out big signals on SSB - the funny thing is many of them can hear you as is.? I remember the central Eu station that scolded me for giving my call twice and we doubled on the second one.?

keep learning along the way.?

Curt

Jerry, KF6VB,

Ooooh, an excellent opportunity for the QRP operator.
Stuff a slingshot, a motorcycle battery, some magnet wire, and that new uBitx?
into a daypack, head on up that hill.?
That sort of thing is even easier now that winter is done.

Don't forget the six pack of beer.
You earn it doing the hike.

Jerry, KE7ER

Hi Jerry,

There's no compile-time requirements to use the favorites.

To set a favorite, tune to the frequency you want to save, then short press the star icon, and finally long press the desired memory slot (on the right of the screen) to save it. To recall, press the star icon, then short press the favorite slot (again on the right) desired.

I only programmed 4 slots because that's all that would fit on the screen nicely, however there is plenty more space in the EEPROM if you wanted to modify the code to store more.


Reed

Short and long press works as for me.? Works with a press of the favorite on the screen button, or the encoder wheel function button.
There are only 4 favorites.
Rgds,
Gary

They should be easy having a gain of 20db on HF I get that much on 2m from a pair of them.Careful though, with the gain they have you can easy get into feedback situations if you are not careful with the placement, relays, and shielding.

John

I
On 2021-04-11 11:34, Arv Evans wrote:

High power amplifiers seems to be the antithesis of where we are
going on a mostly QRP based discussion group. Some may disagree,
and they are entitled to do so, but please respect the fact that this
is
basically a QRP focused group.

*** I apologize for that. Basically, I was excited to be doing ham
radio for the first time in many years, and this was the group I was
connected to. I'll try to keep the power down :).

- Jerry KF6VB

I assembled a v.6 last night, and installed Reed's firmware. Playing around with it, I cannot make sense out of the favorite frequency function. Do the favorites need to be defined in a sketch prior to compiling? I tried short/long presses trying to transfer the frequency into the selected favorite, and it doesn't appear to work. Also, I am wondering if you are limited to 4 favorite frequencies. I looked at Reed's documentation on Github, but still came up blank. Any help would be appreciated. Thanks.

On 4/11/21 11:59 AM, jerry@... wrote:

? I know this isn't the right forum for this - anybody know of
a forum for people building linear amps?

There is the Hardrock line of amp kits:




and a forum on Google groups:




-Dj


--
Dj Merrill - N1JOV
Currently Flying: Glastar
Previously: Cessna 150 - Glasair 1 FT - Grumman AA1B