Date   
Re: ND6T AGC S Meter Calibration

Nick VK4PP
 

Hi Mark.
I cant help, but I am in the same boat. I have built 3 (1 diy, 2 kit) of these boards in 2 different uBitx, and I don't think mine are working... On local nets I still get blasted by close by stations and struggle to hear distant ones, without twiddling the VOL...

I will watch this thread for replies.

Good luck, 73 Nick VK4PLN

Re: ND6T AGC S Meter Calibration

Ralph Mowery
 

The s-meter wire goes to the  pin at the hot end of C4  where the pins are.

Here is what I got, don't recall the frequency.  
.4 volts for 50 uV or -73 dbm
4 volts -40 dbm
3.9 volts -50 dbm
1.8 V -60
.55 V -70
.1 V -80

Using the following in the manager.
4,36,71,106,140,175,212,217

50 uV shows 3 bars on the meter
-63 dbm shows 6 bars
-57 dbm shows  +
-51  dbm shows ++

I was using an IFR 1200s and Fluke digital multimeter.  The s-meter pin was disconnected when doing the voltage measurments.

de ku4pt


On Mon, Jul 23, 2018 at 7:54 PM, Mark M <junquemaile@...> wrote:
I have Don's & Kees' AGC board in my uBitX and am trying to get the S meter function in Ian's firmware working. I've been using the S meter helper in the Manager to try to set some meaningful values but have not been terribly successful so far. It seems like only the strongest signals give a usable level, it shows either a very small value or about a 75 value with little variation in between, it's either S1 or S9+ with nothing in between.

I borrowed an Elecraft XG2 receiver test oscillator from a friend to try the calibration with known input levels (it puts out 1uV and 50uV signals on 80, 40, and 20M). Measuring the voltage on the AGC board at J1 I get the following (I hope this is readable):

Band   No Sig    1uV    50uV
 80      .4mV     1mV    1.6V
 40      .3mV     .5mV   1.7V
 20      .3mV     .7mV   1.6V

Are these values typical? I'm not 100% sure the board is working correctly anyway...it's my first attempt at surface mount assembly so I may have messed up something altho I don't see any obvious problems. The radio seems to work just fine otherwise and the receiver seems to have decent sensitivity, to my ear at least.

The S meter is certainly not essential but since it's there, I'd like to see if I can get it working.

Anyway, any advice/opinions/comments are appreciated.

Mark     AA7TA




Re: ND6T AGC S Meter Calibration

Ion Petroianu, VA3NOI
 

Mark,
If you do not require calibration to a standard I would suggest you set your lowest value (mine is set to 2) and your highest value (you measured S9 at 50 uV in that gives you 1.6 V) at one third of 254 (82 to 85) and select one of the samples. I liked sample 3 and my highest value is set to 80.
The software will calculate intermediate values for you.
Encode and write to uBitx.
73,
--
Ion

VA3NOI

Re: ND6T AGC S Meter Calibration

Jack, W8TEE
 

Are we rearranging the deck furniture on the Titanic here? How important is it to provide an S meter reading down to the last dB of the log scale? I recently worked a contest running 80W and I was a 5-9 EVERYWHERE on the planet! If someone asks, I'll give an S meter reading that comes off my rig's S meter, but I have no clue how accurate it is. Is a 59 from me the same as the 57 report from someone else? I don't know. If I listen to signals on my BITX and compare its S meter reading to my commercial rig and they are the same at 59, I think that's good enough for most of us. If you're doing antenna or some other performance-related research for an article or something, I can see the need for a more precise measurement. But for day-to-day QSO's, a quick calibration against my commercial rig is probably good enough.

Jack, W8TEE

On Monday, July 23, 2018, 9:01:03 PM EDT, Ion Petroianu, VA3NOI <ion.petroianu@...> wrote:


Mark,
If you do not require calibration to a standard I would suggest you set your lowest value (mine is set to 2) and your highest value (you measured S9 at 50 uV in that gives you 1.6 V) at one third of 254 (82 to 85) and select one of the samples. I liked sample 3 and my highest value is set to 80.
The software will calculate intermediate values for you.
Encode and write to uBitx.
73,
--
Ion

VA3NOI

Re: ND6T AGC S Meter Calibration

Jerry Gaffke
 

S-meter readings won't mean much until we all standardize our antennas.
Officially, an S-meter measures the signal power going into the radio.
But of course, all the cool radios have one so the uBitx wants one too.

An S-Meter using the diode detector of the AGC board will not have much range.
Given the two 1n4148 diode drops involved and 5v max into the Nano, I'd expect a range of under 3 S-Units.
At 6dB per S-unit, that's a voltage ratio of   10**(3*6/20) = 7.94.  
Use a log amp like the AD8307 if you really want an S-meter. 

Jerry, KE7ER


On Mon, Jul 23, 2018 at 06:10 PM, Jack Purdum wrote:
Are we rearranging the deck furniture on the Titanic here? How important is it to provide an S meter reading down to the last dB of the log scale? I recently worked a contest running 80W and I was a 5-9 EVERYWHERE on the planet! If someone asks, I'll give an S meter reading that comes off my rig's S meter, but I have no clue how accurate it is. Is a 59 from me the same as the 57 report from someone else? I don't know. If I listen to signals on my BITX and compare its S meter reading to my commercial rig and they are the same at 59, I think that's good enough for most of us. If you're doing antenna or some other performance-related research for an article or something, I can see the need for a more precise measurement. But for day-to-day QSO's, a quick calibration against my commercial rig is probably good enough.
 

Re: ND6T AGC S Meter Calibration

Mark M
 

Guys...I understand that S meters are mostly subjective and it's certainly not a necessity but everything else works so well and the capability is there so why not try to get it to work? I'm not looking for mil-spec accuracy, I was just wondering if what I see is typical or if it indicates a problem somewhere in the AGC board. I don't think I've ever had a qrp rig with an S meter so it's kind of icing on the cake.

And like Jack, I've noticed that for some reason, during contests they all seem to indicate S9. ;)

Anyway, thanks for the inputs...

Mark AA7TA

Re: #ubitx #ubitx-help Not able to set up extension switches using CEC firmware #ubitx #ubitx-help

Tom, wb6b
 

As an experiment, what is the analog reading when no button is pressed, and when the function button of the encoder is pressed? It should change from a high value to a very low value. Looks like, for this to work, the software must be configured to cleverly take advantage the ability that the processor's internal pull-up resistors can be enabled on analog inputs as well as digital inputs. The pull-ups vary significantly, but are around 30K ohms. If this is not a bug in the CEC code, or unusually high internal pull-up values, the low values would suggest the external resistors are lower values than expected.  

Tom, wb6b

Re: ND6T AGC S Meter Calibration

Jack, W8TEE
 

Mark:

I think you missed my point. I think all of us agree with you and what you're saying. Indeed, many of the S meter implementations are really Vu meters, not S meters, which is kinda my point: The µBITX is such a fun rig, does an "accurate" S meter actually augment the enjoyment we should get from it? To me, the answer is: "No!" It's nice to have an S meter, but I think we all know it's both subjective and relative and neither of those factors should detract from the fun. So, if you don't have an S meter, use your ears. If you do have one that works through the audio chain, use that. If yours work through the IF chain, good for you, but you're still going to give me a 59 during the next contest...aren't you? Who cares...as long as you can hear me!

Jack, W8TEE

On Monday, July 23, 2018, 11:11:51 PM EDT, Mark M <junquemaile@...> wrote:


Guys...I understand that S meters are mostly subjective and it's
certainly not a necessity but everything else works so well and the
capability is there so why not try to get it to work? I'm not looking
for mil-spec accuracy, I was just wondering if what I see is typical or
if it indicates a problem somewhere in the AGC board. I don't think I've
ever had a qrp rig with an S meter so it's kind of icing on the cake.

And like Jack, I've noticed that for some reason, during contests they
all seem to indicate S9.  ;)

Anyway, thanks for the inputs...

Mark  AA7TA



Re: #ubitx #ubitx-help Not able to set up extension switches using CEC firmware #ubitx #ubitx-help

Jack, W8TEE
 

It may even be more complicated in some cases. Using the statement:

pinMode(myPin, INPUT_PULLUP);

activates the Arduino's internal pullup resistors. Their purpose is little more than making sure the pin doesn't float. Some encoders, like the KY-040, has small pullup resistors on the small circuit board that comes as part of the encoder. Some encoders don't have those pullups. If you're unsure about your encoder, run some of the example sketches that come with the library you are using. Their behavior should make it pretty clear where your encoder stands.

Jack, W8TEE

On Monday, July 23, 2018, 11:33:52 PM EDT, Tom, wb6b <wb6b@...> wrote:


As an experiment, what is the analog reading when no button is pressed, and when the function button of the encoder is pressed? It should change from a high value to a very low value. Looks like, for this to work, the software must be configured to cleverly take advantage the ability that the processor's internal pull-up resistors can be enabled on analog inputs as well as digital inputs. The pull-ups vary significantly, but are around 30K ohms. If this is not a bug in the CEC code, or unusually high internal pull-up values, the low values would suggest the external resistors are lower values than expected.  

Tom, wb6b

Re: ND6T AGC S Meter Calibration

Jerry Gaffke
 

Correction to my previous post:
The dynamic range of this S-Meter will be greater than just the range of the diode detector,
since it is throttling back the RF gain control as the audio level rises.


On Mon, Jul 23, 2018 at 06:51 PM, Jerry Gaffke wrote:
An S-Meter using the diode detector of the AGC board will not have much range.
Given the two 1n4148 diode drops involved and 5v max into the Nano, I'd expect a range of under 3 S-Units.
At 6dB per S-unit, that's a voltage ratio of   10**(3*6/20) = 7.94.  
Use a log amp like the AD8307 if you really want an S-meter. 

Re: uBITX HF transceiver and blue MBITX metal case.

Bill Cromwell <wrcromwell@...>
 

Hi Ian,

My first wild guess about that 9-pin D sub is the old serial port rig control. Most of us have been forced to abandon that for USB but some of us still have radios with those. Hams who have radios with the old serial ports and computers without - or - radios with only USB ports and computers with only serial ports have to go out of their way with kludge adapters. If your station does not use that old-time infrastructure just ignore that D opening. Maybe yours has a different purpose. It's there if you can find use for it.

I have a radio that uses the D-shell connector for old style T-R switching from the computer. None of my computers have those any more. I installed a vox circuit for use with fldigi. The D-connector just sits there with no duties any more. I could buy an adapter to avoid building and mounting the vox unit. One more thing and it's cables to manage.

73,

Bill KU8H

On 07/23/2018 05:20 PM, Ian Reeve wrote:
At a recent Radio Rally in the UK I happened acrosss a unbuilt uBITX kit
and matching metal case.
The case is punched for a tx/rx bi-colour led and thanks to this group I
have found the wiring needed for this.
The case also comes with small pcb for the led,for the tuning
encoder,for the power and fuse assembly and for the three jack plugs,
mic/ptt,key and phones.

It also came with a Digital board that fixes to the rear of the case.
There is no information on this board or its wiring, it contains 2 jack
sockets, a USB and a 9pin D Sub.

Any help would be appreciated on the latter item.
Thankyou and 73 de Ian M0IDR
--
bark less - wag more

Re: [VK3 Event] Bring your Bitx/uBitx - Melbourne QRP by the Bay 28 July

John Veach
 

Got all excited.  Just finished my first uBitx and told the XYL we were heading for Melbourne this weekend.  Then I realized it wasn't Melbourne Florida!  A bit far

Re: PCB Artwork hint

Paul Galburt - K2AYZ
 

Hi, Clark,

Thanks for the feedback - I am now proud of my acceptance of the efficiency of the uncentered traces! 

I have been burned by the care needed to route traces for 100 MHz and Gig Ethernet traces, but that's another story.

Always something to learn.

73,

Paul K2AYZ

uBITX Increasing 28 Mhz output by changing C81 #ubitx-help

 

When Farhan released the new V4 boards, one of the advertised changes from V3 was a better distribution of output power across the bands,
realized by changing C81 near Q90 to 470pF.

I tried to replicate this change on my V3 board but the net result is about 1W out across all the bands with a supply voltage of just over 12V.
I noticed that in the V4 schematic R83 changed from 10 ohms to 2.2 Ohms so I made that change as well and it made little to no difference.

I also tried adjusting RV1 and it does make a slight difference but there is very little room for adjustment on this pot so the change is insignifcant. 

What am I missing ? 

I reverted back to the original components and I am back to about 5w out on 40m and 1W out on 10m with 12+V supply.

Cheers 

Michael VE3WMB

Re: PCB Artwork hint

Gordon Gibby
 

Robert: w0w, you taught me something!  I never understood why those were there!!!!!


On Jul 24, 2018, at 07:52, Paul Galburt - K2AYZ <galburt@...> wrote:

Hi, Clark,

Thanks for the feedback - I am now proud of my acceptance of the efficiency of the uncentered traces! 

I have been burned by the care needed to route traces for 100 MHz and Gig Ethernet traces, but that's another story.

Always something to learn.

73,

Paul K2AYZ

Re: ND6T AGC S Meter Calibration

Don, ND6T
 

Mark; Yes, those appear to be typical. The MOSFETs begin conduction at around a volt and a half.
I simply used a calibrated generator as a source to establish my S meter readings. Those values will differ slightly from unit to unit.
To those that have doubts about the attenuation I would advise making some measurements. At 3 volt bias there should be more than 50 dB attenuation at 7 MHz. Does the manual gain control work? If not, evaluate your RF grounding at the attenuator location for a start.
I agree, S meter readings are mostly ornamental. 73, Don

Re: [VK3 Event] Bring your Bitx/uBitx - Melbourne QRP by the Bay 28 July

Jay - WS4JM
 

What time UTC will you be on the air? It would be cool to connect with a Bitx "down under".

73 de Jay WS4JM

Re: Inexpensive eBay Amplifier Kits

Andrew Kasurak
 

Re: uBITX HF transceiver and blue MBITX metal case.

Jim Strohm
 

Bill Cromwell wrote:
"My first wild guess about that 9-pin D sub is the old serial port rig control. Most of us have been forced to abandon that for USB but some of us still have radios with those. Hams who have radios with the old serial ports and computers without - or - radios with only USB ports and computers with only serial ports have to go out of their way with kludge adapters. If your station does not use that old-time infrastructure just ignore that D opening. Maybe yours has a different purpose. It's there if you can find use for it.

I have a radio that uses the D-shell connector for old style T-R switching from the computer. None of my computers have those any more. I installed a vox circuit for use with fldigi. The D-connector just sits there with no duties any more. I could buy an adapter to avoid building and mounting the vox unit. One more thing and it's cables to manage."

In my last field of professional endeavor (product documentation for microcontrollers and industrial equipment) a lot of the "next to new" equipment like endpoint sensors and plasma generators used proprietary, one-off serial interfaces at baud rates from the last millennium.  Documenting them and getting them to work was always a challenge.  Once I had to translate two plasma generator manuals from Japanese using google language tools just so our apps and field engineers could get the plasma generators talking to our controllers -- WITHOUT any support from our field office in Japan.  That project failed, but not on my account.

These serial interfaces should have been deprecated more than a decade ago when USB started to come on the market.  Considering that today you can get a USB-capable Arduino or Raspberry Pi microcontroller board that speaks USB for far less than $100, there's absolutely no reason for manufacturers to keep using outdated proprietary serial interfaces -- we HAVE a standard serial interface, and it's called USB.

Still, this industrial equipment lasts a long time.  I have a few as-new plasma generators with serial interfaces that are nearly old enough to vote.  Any surplus stuff I get nowadays that has a serial interface, the first thing I do is rip out the interface, because I'll never get documentation or software for it, even if I can translate from Japanese or even Mandarin with google language tools.

Eventually I'll get around to learning how to interface one of the aforementioned micro boards to this stuff.   Meantime?  If it's DB-9, DB-25, RS232?  JUNK IT!

Off my soap box...

73
Jim N6OTQ

Re: Mike element

Ken Held KF7DUR
 

Jerry

I have 3 or 4 of the Baofeng mics from different sources, as well as a variety of mic elements.  When I was trying to get them to sound good on the Baofeng radio I concluded that the housing caused them to sound bad. The mics sounded good out of the housing but got muffled when the housing was closed up.
The Baofeng mics did have a hole over the element, I even drilled it out a bit to see if that would help the sound quality. I never did get the mics to sound good.
The -24dB element I used for my uBitX mic is the larger size element but it fits snugly in the housing. I think that may take care of the sound quality issue I had.