Re: ND6T AGC S Meter Calibration
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
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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:
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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
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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
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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
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Re: [VK3 Event] Bring your Bitx/uBitx - Melbourne QRP by the Bay 28 July
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
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Re: uBITX HF transceiver and blue MBITX metal case.
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
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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
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Re: ND6T AGC S Meter Calibration
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.
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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.?
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Re: #ubitx #ubitx-help Not able to set up extension switches using CEC firmware
#ubitx
#ubitx-help
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
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Re: ND6T AGC S Meter Calibration
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 ?BITX 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
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Re: #ubitx #ubitx-help Not able to set up extension switches using CEC firmware
#ubitx
#ubitx-help
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
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Re: ND6T AGC S Meter Calibration
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
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Re: ND6T AGC S Meter Calibration
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
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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.
?
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Re: ND6T AGC S Meter Calibration
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
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Re: ND6T AGC S Meter Calibration
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
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Re: ND6T AGC S Meter Calibration
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
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Re: ND6T AGC S Meter Calibration
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
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ND6T AGC S Meter Calibration
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
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Re: #ubitx #ubitx-help Not able to set up extension switches using CEC firmware
#ubitx
#ubitx-help
I have the same difficulty with the iambic paddle setup.? I am only getting readings of 4 and 6 in the ADC.? I used metal film resistors, could this cause this kind of problem?
Dan, W2DLC
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Re: uBITX No Power Output all of a sudden
#ubitx
Board fab shops give their design rules, perhaps something like:
? ?minimum 10 mil drill size
? ?minimum 5 mil annular ring of copper pad around each drill hole
? ?minimum 6 mil trace width, minimum 6 mil spacing?
That's the rules for OSH-Park, where a mil is 1/1000'th of an inch
The minimum bid shops might be a bit more sloppy than OSH-Park.
I've seen boards where the drill job wasn't centered on the pads, to where
the edge of the hole was well beyond the edge of the pad.
In that case, you won't get as good a connection between layers through that via,
though even so it's probably good enough for our purposes in most cases..
Or could be that the plating process was rushed, and they didn't get enough material in there.
Generally speaking, you're best off backing off 10 or 20% from what a fab shop claims
they can do on a good day.
The via that failed was being asked to take 2 or 3 amps into the IRF510 drains.
That's asking a lot for one via.
Might be better to make it a 40 mil hole, has greater circumference, greater current capacity.
Though as someone has already suggested, the wimpy via does serve as a sort-of poorly spec-d fuse.
Jerry, KE7ER
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On Mon, Jul 23, 2018 at 02:00 PM, Clark Martin wrote:
Vias are frequently smaller than most component holes. ?I suspect the small size tends to prevent the plating solution from getting in thoroughly due to surface tension.?
?
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uBITX HF transceiver and blue MBITX metal case.
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
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Don, ND6T
Paul Galburt - K2AYZ
Ion Petroianu, VA3NOI
Nick VK4PP