Date   
Re: SB II #112 nearly done / searching the last building mistakes

Don, ND6T
 

I'm glad that you're getting back to health!
Yes, looks like you found another anomaly in voltage chart. The odd gate condition (Q2) is probably an artifact of the probing. But do check the DC resistance to ground and insure that it is close to zero ohms (a check of the connections through L1). The drain of Q23 should pull down slightly during transmit because of the ohmic losses of the supply chain. The photos of the signals seem like they might be OK but the frequency response of the probe and 'scope make it look cleaner than I would expect. Also, it would be more instructive if the voltage range (or estimated peak-to-peak voltage) was included. I assume that you were measuring with a 50 ohm load right at the BNC (not more than a few cm distant)? May I also assume that you are using a X10 probe? What voltage is your supply? What current is being drawn while transmitting a CW carrier? This would give us an idea of what power is being presented at the output load and the efficiency of the transmitter. What band are you on?
From what I can see, it appears to be working a bit at least.
73, Don

Re: SB II #112 nearly done / searching the last building mistakes

Sascha Bohnet | DL5SMB
 

Sorry for the really late reply. I had been sick and was really busy getting well again (you know what they say about the "man flu").

The TX led does light, if I switch to transmitting and I am using a electret capsule. But to try to rule out microphone problems, I use CW for testing.

I have an oscilloscope and tried to get an understanding of what might be wrong, but was not really successful.

But first again to the voltage chart, where I noticed some other thing in TX mode:

The Drain of Q2 should be 2,4 Volt  i think (instead of 5 Volt) , like the Base of Q1, right? The source of Q2 is 5 Volts.
I think there is a mixup in the chart, probably due to the pinout of the MMBF4416.

However i noticed that if i try to measure the voltage of the Gate of G2, this transistors seems to simply turn on and my power supply
needs to limit the current. Is this a usual behaviour?

I know that this is a special amplifier, but I wonder if simply applying the measurement tip, should trigger this. Seems a bit odd.


Now to the oscilloscope
First thing to check should be the final I think.

The voltage of the Drain of Q23 is 13,27 Volt in RX and 13,17 Volt in TX (both Voltages taken with the multimeter).
What is curious is, that the voltage seems to drop while transmitting. In the chart it seems to increase.

This is the picture of the signal at the Gate Q23. 
and this at the Drain Q23

So it looks at least as if the Mosfet is amplifying. However after the second toroid (L9) the signal gets attenuated again
It looks like this at the BNC jack

L9 seems to be okay, I desoldered it and checked its inductance which is as it should be (I don't remember the value anymore, i calculated it and compared).

Any ideas what might be wrong?

73 Sascha




AD9850 DDS based Antenna Tuner Adjustment Aid

Kurt Loken <kurt.loken@...>
 

Hello All,

Does anyone happen to have a BOM of the parts for KD1JV’s AD9850 DDS based Antenna Tuner Adjustment Aid? I’m going to build it and need to procure some of the components.

Thanks,

Kurt-AE6UJ

Re: It's all gone quiet on ATS V5

David Perry <bumbledp@...>
 

Well I guess  like Edison and his light bulbs,  apocryphal or not, now you know another way that doesn't work...

Chin up Steve 

David G4YVM 

Re: SB II #112 nearly done / searching the last building mistakes

Don, ND6T
 

You are correct about the voltage on Q3 collector. It's being fed constantly through T1, R12, L10, and F1.
The chart shows 5 V on the drain, not the gate. That voltage is wrong since it is being supplied through the PTT port of the controller which, in turn, is supplied by 3.3 volts. Therefore it should measure 3.3 volts. That same line feeds the PTT and key connections through R52 so you should also get 3.3 volts on those terminals in the initial idle condition.

The gate should measure at nearly open, perhaps 40 millivolts or so if anything. When the PTT (or key) is closed that will measure about half a volt without audio.

No, the note is cogent. The voltage on the gate will change with audio level or state of the VOX_EN bus.

When you close the key or press the push-to-talk button on the microphone does the TX (D3) indicator light? What are you using for a microphone?

Now that you have concluded the voltage checks it might be the time to begin signal tracing. Do you have an oscilloscope? Or perhaps an audio amplifier for signal tracing? A signal injector of some sort? An oscilloscope is handy but not necessary since simple gear will get you through this sort of thing.

73, Don

Re: SB II #112 nearly done / searching the last building mistakes

Sascha Bohnet | DL5SMB
 

As I am working myself through the voltage chart now... might it be that not everything there is correct?

In the RX chart at Q20 I am measuring 3,3V instead of 5V Gate voltage - without a microphone connected. I see the refernce
about audio mic input level, but this seems just a bit weird.

Nevertheless the next big difference I noticed - at least compared with my rig - is that at Q3 Collector I am always measuring 13.2 Volt.
RX or TX. Is that right? If I am interpreting the schematics the right way, I think this is as it should be, or am I reading it wrong?

Re: It's all gone quiet on ATS V5

Jeff Logullo N0̸MII
 

Please add my name to this list which does not exist ;-)
--
Jeff N0̸MII

Re: It's all gone quiet on ATS V5

Steven Weber
 

 

On farther testing, the compander AGC is a bust. It’s got two problems. One, I can’t get the attack time fast enough. It takes 3-4 cycles for it to respond and that causes a heck of thump before it kicks in. Which is part of problem 2, it wants to try and make the output level 2 V p-p, even the noise. Oh well, it seemed like a good idea at the time…

 

So, back to the drawing board.  Diode clipping followed by the band pass filter sounds good. Instead of back to back silicon diodes for clipping, like on the MTR and original ATS rigs, I’ll use Shottkey  which will start to clip at a lower level. But that level is a bit low to use directly, so it will be followed by a ‘386 amp with a trimmer resistor under the front panel to set the maximum volume. That way various levels of hearing and headphone sensitivities can be accommodated. I think that’s a reasonable compromise.

 

Steve KD1JV

 

Re: It's all gone quiet on ATS V5

David Perry <bumbledp@...>
 

I know Steve doesn't "do" lists, but your (Scott) are absolutely right.  That first thread he started when he announced it is a sort of list of orders.  It would be nice if Steve used that to sell the first batch.  As I, and others have said, definitely in for me.

David G4YVM 

Re: It's all gone quiet on ATS V5

Scott Schillereff
 

Hi Steve,
With so much anticipation for your new rig, I suspect there will be more demand than supply.  Will this be first-come-first serve?  This may be disappointing to a lot of people who miss the notice (I suspect within hours you'll have your quota).  If you plan on a limited one-time production, have you considered some form of lottery to pick the lucky recipients of this little gem?  Just a thought.
73, Scott
VO1DR
St. John's, Newfoundland

Re: It's all gone quiet on ATS V5

David Perry <bumbledp@...>
 

Steve
That finished rig looks amazing.  Your workmanship is excellent.  I'm looking forward to  owning this beauty.

Best wishes Steve

David G4YVM 

Re: SB II #112 nearly done / searching the last building mistakes

Don, ND6T
 

Sascha,
It doesn't seem that it is that far off. The adjustment of the bias trimmer is very touchy. A very careful nudge should bring it up another 30 milliamps. As for the lack of modulation, that is something to trace down.
Congratulations on your progress! Yes, a wonderful rig! 73, Don

SB II #112 nearly done / searching the last building mistakes

Sascha Bohnet | DL5SMB
 

Hi everybody,

Though it took nearly a year now, I am finally almost done with my  SBI kit. Thanks you Steven for this really great ( or better small ) highly portable and multifunctional tranceiver.  I will use it a lot.

I first had some problems receiving anyhing but a rattling noise, but noticed only shortly after that I had wrongly turned X7 around 90 degrees. No wonder  After changing this the  RX worked immediately and I was happy.

The transmitter still has a problem, which I will try to pin down with the voltage chart shortly.

With the bias poti turned fully Acc , the current is only 120m  during transmitting. If I adjust it , I can turn it up quickly, but that does not solve the problem. Somewhere 30 mA are missing, I could imagine in the driver stage or so. I will measure  power tomorrow, when I got more time - the MOD LED does not flicker either, whatever position the mod poti is

I hope I will have sorted it out soon - I will report in again:-)

Sascha

Re: It's all gone quiet on ATS V5

Steven Weber
 

No, because there are five connections needed. Reset, Serial in, Serial out, serial clock and ground.

 

A place to plug in a standard 10 pin ISP header is built onto the board, so connecting up a programmer is not a problem. You just need a programmer.

 

Steve KD1JV

 

I know it's a bit of a kludgy hack, but could you hook up the ISP pins on the ATMega328 to the 3.5mm jacks?  I'm not sure if those pins are otherwise occupied or if they could safely be shared, or maybe you could program it through the 3.5mm jacks and then cut a couple of traces.  Anyway, just a thought.

Cheers,
John VA7JBE

 

Re: It's all gone quiet on ATS V5

John VA7JBE
 

I know it's a bit of a kludgy hack, but could you hook up the ISP pins on the ATMega328 to the 3.5mm jacks?  I'm not sure if those pins are otherwise occupied or if they could safely be shared, or maybe you could program it through the 3.5mm jacks and then cut a couple of traces.  Anyway, just a thought.

Cheers,
John VA7JBE

Re: It's all gone quiet on ATS V5

Steven Weber
 

Because otherwise you’d need to program it. Which isn’t all that hard to do and many of you can, but for others it would require getting a programmer like the Olimex AVR-ISP-V2 or similar. And you need to be able to program the fuse bits.

 

Steve KD1JV

 

 

Why is there a need to program the chip before soldering to the board?

73

Simon
VK3ELH 

 

Re: It's all gone quiet on ATS V5

Kelly Jack
 

Why is there a need to program the chip before soldering to the board?

73

Simon
VK3ELH 

Re: It's all gone quiet on ATS V5

poikaa3
 

   I just purchased a new box of Altoids and passed out as many as I could! Now I have an empty box for the build!

73 Rod W8GRI

Re: It's all gone quiet on ATS V5

Joseph Trombino, Jr
 

Howdy Steve.

Haven’t been following this rig as closely as I should have so regret the following dumb question.

Will the new rig be single-band for, say, 40M?

Many thanks for any info.

Looks like another winner!!!

73, Joe W2KJ

On Jan 18, 2020, at 10:23 AM, Steven Weber <steve.kd1jv@...> wrote:

Here’s a few more pictures. I haven’t tested the RF deck yet. Yesterday I was focused on getting it built and doing the mechanical aspects to make sure it all fit in the tin. Which I’m happy to say it does.

Now I got to figure out how to program the processor without mounting to the board first. And start on the documentation – that’s the hard part.

Steve KD1JV

Assembled in tin:
<B34874B245AB4C7A98E70FD026739FB0.jpg>

The T/R RF deck mounted to bottom of tin.
<DE65CA13DEDB453F9BC58C21EEA4C853.jpg>

Bottom of T/R board
<8875424B95624CEFA094EA85F02A44D0.jpg>

Bottom of display/controller board:
<53D1418661EF4ADEA50A57997CC3F1F6.jpg>

Re: It's all gone quiet on ATS V5

Lincoln Thormahlen
 

That's really cool looking! Thanks for sharing, Steve!

Lincoln

N9IN

On Saturday, January 18, 2020, 10:23:34 AM EST, Steven Weber <steve.kd1jv@...> wrote:


Here’s a few more pictures. I haven’t tested the RF deck yet. Yesterday I was focused on getting it built and doing the mechanical aspects to make sure it all fit in the tin. Which I’m happy to say it does.

 

Now I got to figure out how to program the processor without mounting to the board first. And start on the documentation – that’s the hard part.

 

Steve KD1JV

 

Assembled in tin:

 

The T/R RF deck mounted to bottom of tin.

 

Bottom of T/R board

 

Bottom of display/controller board: