I did a little checking, and per memory (which is not so good) and search functions, I'm thinking it was something about calibration around line 2074. There may have been more changes, I'm not sure. Ted, I'm sure could clarify. Roy was working on his during that time as well, and may be running the modified sketch as well. I've seen the "Manhattan skyline" a few times in other pictures. I did notice in the picture of that I put up, that I was running the wrong dds module and using a home built conversion board.
In the process of all this, I now am using the correct 9850 module.

Thanks, Mike.

I was basing the 7v. on the old datasheet and p.1 of the SM datasheet.
I suspected 8v was right, but had no direction, even though I have built
MAR3 amplifiers before. I don't have any SM devices, but plenty of the
original ones. Now that I look, the MAR user guide lists bias resistors
later on in the pamphlet, but 9v is the closest one with 111 ohms resistance.
I suspect ~80 ohms is right for 8v.

Nonetheless, there is some discrepancy in the schematic...I would guess
that when the MAR3 is installed, that should load the circuit, and the
"5V(TP2)" will be more or less valid (?).

john
AD5YE

If you look at page three of the Mini Circuits data sheet for the MAR-3SM you will see a table listing values of series resistor for biasing the device with Vcc voltages up to 15 volts.
Mike
K5ESS

When I got mine finished I had the same issues. It's a power hog on the 9v batteries. The external supply is pretty clean but just in case I added one of those ChiCom DC-DC voltage regulators that are about 1" x 3/4" and adjustable. Scope shows very clean dc and the AA works great.

PJH, N7PXY

PDP before CPM/4004/8080 was around, front panel IPL to boot the paper tape reader, memory and diagnosis tests using machine code since you can't run code on a broken machine..
Now I play with a PI Zero W, BLE+WiFi+HDMI 1080 video+USB OTG running Linux kernel 4.9x, Windows 10 IOT $9 - NPX 50Mhz ARM processor, $0.85 -?

Sorry. The notations are "8V(TP2)" and "5V(TP1)".

In any event, both TP1 and TP2 are 8.23v on my board.

john
AD5YE

Jack --

On the "TFT LCD VFO (Rev-2)" schematic, U3 is listed as a 78L08.

It feeds R1 (82 ohm) and L1 (100 uH), and then connects to the MAR-3SM+.

According to the data sheets I have seen, the MAR3 should be operated at 5v,
and the maximum voltage for the device is listed at </= 7v.

But the 78L08 is feeding 8.23v to the MAR3 device on my board (I have installed just
the power sections and am checking these out).

Is this correct? I notice at the junction going to OUT2 you have a notation of "5VTP2"
which would make sense for the MAR3 if the VR was a 78L05, but up near C13 there is another
notation of "8V(TP2)".

What's up?

john
AD5YE

Is there enough volume with just the Arduino D6 driving the speaker?

hello friends,

R46 is ok, and mic has plenty of output ( I think its even close to 1Vpp or thereabouts) - i am using a radioshack dynamic mic which I added a preamp.
If I use the stock mic i only have about 1W if I shout, thats why I made a preamp for the current mic I am using so that I dont have to shout.

I will try Jerry's tip tomorrow after work and report back later.

Keep it coming guys! thanks a lot and 73!

Jonathan/DV2NAH?

'pre-script' to the above:

I'm pretty much deaf, and have to use headphones to avoid deafening the rest of the household (or whatever environment), ...

:)

Hi Dexter,

Even with the Pin 3 mod, and also when I added the second 2N2222 to include the Pin 1 mod with it, I was having pops that were getting quite painful for a "non-deaf" person (hihi). Everyone's attempts seem to be trying to get the audio from the LM386 to be gone as quickly as possible. As the LM386 by default is disconnected from power on TX, I am using the second 2N2222 to slam the power off the chip as fast as possible.

I don't know what improvements that Raj has made/suggested of which you speak. I am not a huge fan of this "reflector style" forum, and find it confusing to browse and find that which you are seeking. If you could point me to a post for my review, that would be most helpful.

I do have CAD capabilities, but my post was created by simply editing the graphic that Giancarlo has kindly posted.

Let's talk about remainder of your last paragraph for a moment. I am assuming the CW mod you speak of is part of Raj's improvements. If it is not, are you suggesting I create a resistive audio mixer to patch in the output from the CWcarrier pin from the Raduino (Pin D6, or P3-2)? I assume that would be much nicer sounding than the square wave sidetone generated directly from the Rad to the speaker output as per Allards diagrams.

In any case, I would appreciate Raj's improvements to be pointed out to me so I can review and maybe regroup (always looking to improve).

Best Regards,

Jonathan, N?JMS

开云体育

Hi Jonathan.

I'm pretty much deaf, but even then I've not needed full volume. Raj's improvements to quality could even lessen the need. Given that, I've not needed any more than the pin3 mod - and isn't pin 6 the Vcc supply to U1? Are you sure you're not messing with pin 7? or 2?

You seem to have the CAD usable, how about this? - CW sidetone is possible by resistor (1k or so?) from pin 3, with another from there off to the raduino pin giving the tone. Audio in from the Volume control wiper is then to the 2N2222 collector point. The 2N2222 clamps the Rx audio on PTT - it should be pretty much instantaneous, and any 'pop' there will be from the remnant Rx audio level. Those 2 resistors are then a voltage divider? feeding the sidetone. U1 is, of course, powered on Rx, and the CW mod will have it powered also on TX - I don't operate CW so I haven't explored this. ON PTT release there may be some 'pop' as U1 powers up - it will only take a few milliseconds, and we can delay the 'let-up' of the 2N2222's clamp by a small cap across the (10k) resistor feeding its base. T=CR so ~10 milliseconds per microfarad.
In short, I'm wondering if there is any real need for that second 2N2222?

Hopefully helpfully,
73 de ZL2DEX

Can't find the "SoftwareControl" group, Jack. [Where at, man, where at man, de-focus?] The aa project looks interesting ...
73

Raj, you're a gem! :) D18 and R111 were on my list, just hadn't got 'a round tuit'! Not at home at present, but will be doing the R112,114? mod - should be vastly better! Those with the 'super-cap' emitter-follower decoupling replacing R113 should do wonders ...

Vy 73 de ZL2DEX

I completed the AA a few months ago, and it has been working perfectly. I found that it really likes clean power, and plenty of it. A regular 9v battery would work for a few scans ?then the unit would go nuts. I would check the voltage on the battery and it would be low. The wall warts I checked were just a no go, so I ended up using 6 AA batteries in a holder. This corrected a cursor that would jump around when turning the encoder, and a "waggling" frequency, which gave an output like this into a 51 ohm resistor.





Once that was fixed, the unit would scan a resistor perfectly, but would not scan an antenna. That was because the unit was outputting the wrong frequency. "Ted" over at SoftwareControlledHamRadio made a change to Jack's code, and after loading it, the unit worked perfectly. This is the scan with all working.


My face did an exact duplicate of what was on the screen (smile), and it hasn't missed a beat since. I have really enjoyed having this tool on the bench, but I am planning to re-case, copying the case type and layout of "the guy with the wife and rabbit" working on the antenna. (So sorry I couldn't remember your name, so if you read this here, be sure and fix my memory). The new case is in hand, and I am in search of rechargeable batteries.?

Dumb question, but have you tried using a different electret mic element ?

I had initial low output problems with my Bitx40 using a cheap computer headset with an electret mic element.
I switched to a different headset and now I am getting full power out. It seems that some electret mic elements?
are more sensitive than others. ?I didn't see you mention anything about what you are using as a mic.

Cheers

Michael VE3WMB / VA2NB?

Everyone,

I have come up with a modification to Gian's circuit that makes the pop/click completely tolerable with headphones at full volume. Please see the attached modified schematic and report back with your results. The pop is still there, but does not tend to hurt the ears. I may get some crap for the layout/design, but I don't care. I am always open to friendly suggestions to make it better.



73

Jonathan, N?JMS