We were in the middle of thunderstorms, rain and dogs scratching the door.? Undaunted, the bitx40 made it through the static crashes to reach WS4JM a few hundred miles to the North.? It took a few tries to finally get all of the call letters.? Maybe next week the uBitx will be complete-High Power!

73 all

Pat AA4PG

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From: [email protected] <[email protected]> on behalf of Tom VE3THR <muzzmobility@...>
Sent: Sunday, April 22, 2018 7:33:29 PM
To: [email protected]
Subject: Re: [BITX20] BITX QSO Afternoon/Evening, Sunday, April 22, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.

?

Come on guys...my BITX40 is no Maserati but it had an excellent night. 40M peaked about an hour before sunset (my greyline). That random QRM about every 10-15 min might be some kind of radar I'm told. No contests or QRN tonight...S5-S7 noise floor on the big rig. Guess no one is doing laundry tonight in my neighbourhood!
Record number of stations on tonight between 1900 - 2100 HRS Z. Most were well over 5x5 using my 40M dipole @ 30ft. QSO's with N4DR Marc, N6ORS Keith, KN4AIE Rick, WI1B Ken, WA4THR Vic, WA2FZW John, KC1FSZ, AC9RZ Doug and picked a few new ones WA3O Mike, N2HTT Mike, W2NDG, KE0NXP Glenn, AD0RW John and WS4JM Jay.
Mathew S. - get your ticket and join the group. Thanks for the reception reports.
Got my uBITX built and stuffed in a can, finally. Quickly upgraded to KD8CEC's V1.061 firmware. What a huge improvement from the stock version. Still not happy with the calibration settings so work in progress. I suspect the uBITX needs LOT'S OF MIC AUDIO from what I'm hearing up here so keep that mic up close and personal.
Tom VE3THR

Multiple people have explained how to decrease the emitter resistor in the mic amplifier stage to incrase the gain.? ?I didn't think of that, so just built a 1-transistor preamp for it and was quite happy.? ? Also had to do that for another transceiver I owned 30+ years ago.? ?Simple enough to do.? ??

Also be careful, the average power output measured by an analog scale is far far less than the peak if if you push the apparent average way up there....all you'll be doing is pushing the peaks into non-linear splattering.? ?

the older hams used to use oscilloscopes on their outputs so they could actually SEE when they were overmodulating.? ?Impressive amount of concern, I would say!? ? But I did get two of those type scopes for relatively cheap on ebay....use them to show people what signals look like in license classes occasionally.

that's ham radio!

?it isn't meant to be easy

gordon

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From: [email protected] <[email protected]> on behalf of Gordon Gibby <ggibby@...>
Sent: Sunday, April 22, 2018 11:04 PM
To: [email protected]
Subject: Re: [BITX20] Low mic gain, was, show your mic

?

Whenever you wish to FUND that effort, you'll easily find people who will be willing to get on your payroll!!

If you look at that photo, there's a "clue" in that one terminal connects to the CASE.? ? And the legend that I always saw on the similar photo here:? ?? ?is also a good giveaway.

This tutorial is another explanatory bit of information (about the first one that popped up in a google search for electret mic pinout)? ??

That's ham radio!

gordon

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From: [email protected] <[email protected]> on behalf of MAX <max@...>
Sent: Sunday, April 22, 2018 10:57 PM
To: [email protected]
Subject: Re: [BITX20] Low mic gain, was, show your mic

?

Interesting.? That picture has no indication as to which is positive and which is negative.? If I didn’t already know that the upper right connection was ground the picture would be useless.? I am probably offending some people but I’m about fed up.? All of the correct information needs to be gathered in one place.? Call it a manual or whatever you want but ?someone who knows needs to take the time and put forth the effort to put it together.? And then all the incorrect information needs to be removed from the web.?

?

Not a happy camper.

?

Max K 4 O D S.

?

I've Never Lost the Wonder.

?

Antique Electronics Site:

?

?

From: [email protected] [mailto:[email protected]] On Behalf Of Mvs Sarma
Sent: Sunday, April 22, 2018 1:57 PM
To: [email protected]
Subject: Re: [BITX20] Low mic gain, was, show your mic

?

please see the photo here.
?

The right side pin is for Ground.

if i recollect , a reverse polarity was also responding for voice but verey very lowand distorted.

Regards
MVS Sarma
?

?

On Sun, Apr 22, 2018 at 10:15 PM, MAX <max@...> wrote:

Hi sarma.

?

I’m sure I have the polarity correct.? Someone on this list posted a drawing showing how to identify the negative terminal and I wired according to it.? I think the electret mic wouldn’t work at all if polarity were reversed.? What is being powered is an ?F E T source follower.? ?I think I shouldn’t have to raise my voice to get 5 watts output on 40 meters.

?

Regards.

?

Max K 4 O D S.

?

I've Never Lost the Wonder.

?

Antique Electronics Site:

?

?

From: [email protected] [mailto:[email protected]] On Behalf Of Mvs Sarma
Sent: Sunday, April 22, 2018 3:44 AM
To: [email protected]
Subject: Re: [BITX20] show your mic

?

Max,

?please check whether the mic body is connected to chasis ground.

i mean the positive bias voltage for mic should come on independent pin and NOT to the body pin of the eletret element.

In case you are using a dynamic mic, perhaps we need more gain and your need to shout appers logical.

regards

sarma

vu3zmv

Regards
MVS Sarma
?

?

On Sat, Apr 21, 2018 at 11:27 PM, MAX <max@...> wrote:

Speaking of mics, I have to raise my voice almost to the level of shouting to get 5 watts out on 40 meters.? Is this normal or should I look for a problem?

?

Regards.

?

Max K 4 O D S.

?

I've Never Lost the Wonder.

?

Antique Electronics Site:

?

?

From: [email protected] [mailto:[email protected]] On Behalf Of Mvs Sarma
Sent: Saturday, April 21, 2018 7:17 AM
To: [email protected]
Subject: Re: [BITX20] show your mic

?

I had grabed a taperecorder mic with 3.5mm mono pin.
?replaced the cable with 2+shield.had a small pushed switchmounted and wired.
?repalced the 3.5mm momo pin to stereo pin. Here is a image of my mic.The pp9 battery helps to imagine the mic size.
regards
?sarma
?vu3zmv

?

?

From: [email protected] [mailto:[email protected]] On Behalf Of Mvs Sarma
Sent: Sunday, April 22, 2018 1:57 PM
To: [email protected]
Subject: Re: [BITX20] Low mic gain, was, show your mic

?

From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Sunday, April 22, 2018 1:43 PM
To: [email protected]
Subject: Re: [BITX20] Low Mic Gain, was, show your mic

?

Twiddling the bias pots is dangerous, can easily blow the IRF510's.
The bias pots get set at the factory for around 100ma of drain current
as described in the tuneup section on hfsignals.com.
Output will become more non-linear as those bias pots get turned down,
and quiescent transmit power consumption goes up as they get turned up.?
Not much of an effect on power out.? I suggest you not mess with them.

The drive pot at RV1 on the uBitx does directly affect power out,
also the resistor in the mike amp that Raj pointed out for you.

Be aware that too much drive to the final will splatter all over the band.

Jerry


On Sun, Apr 22, 2018 at 10:15 am, Skip Davis wrote:

Max your uBITX has three trim pots on it. Two are blue square unit labeled RV2 and RV3 these are together on the board and adjust the bias to the finals. The third one is RV1 which adjusts the drive level. There are instructions in the the file section on the group site to adjust the bias pots which may help improve your ssb output if yours isn’t set high enough.
Try searching the archives to learn about it and the pitfalls you might encounter.

?

From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Sunday, April 22, 2018 1:25 PM
To: [email protected]
Subject: Re: [BITX20] Ubitx.net site correction #ubitx-help #ubitx

?

We've had a wiki up for a year or more:
? ? /g/BITX20/wiki/home
And it is a good idea.
The ubitx.net site offers the alternative of a curated site.
?
Jerry


1000 people editi
On Sun, Apr 22, 2018 at 10:25 am, W7PEA wrote:

The ubitx.net site says the wiring diagram for the volume control is incorrect. Its it now correct.


^^ that page should be pulled or updated to reflect that change.

A wiki would be a great idea for the community so we can maintain the information together.
-W7PEA

?

?

From: [email protected] [mailto:[email protected]] On Behalf Of W7PEA
Sent: Sunday, April 22, 2018 12:26 PM
To: [email protected]
Subject: [BITX20] Ubitx.net site correction #ubitx-help #ubitx

?

The ubitx.net site says the wiring diagram for the volume control is incorrect. Its it now correct.


^^ that page should be pulled or updated to reflect that change.

A wiki would be a great idea for the community so we can maintain the information together.
-W7PEA

?

Max your uBITX has three trim pots on it. Two are blue square unit labeled RV2 and RV3 these are together on the board and adjust the bias to the finals. The third one is RV1 which adjusts the drive level. There are instructions in the the file section on the group site to adjust the bias pots which may help improve your ssb output if yours isn’t set high enough.
Try searching the archives to learn about it and the pitfalls you might encounter.

?

I am in the process of re-purposing a very old microphone as you can see in they lower picture, FEB 1944.? A new microphone cable should be here next week.?? The carbon element inside was bad so I went for a MAX9812 Microphone on a board for $1.75 on eBay.? This microphone was not from a telephone.? Any guesses?