What about using a multiplexer chip to reduce the number of I/O lines needed. A bit old school but effective.

Sent from my iPhone

Hi Mike

I have a couple of ideas.

I received the rotary encoders today, and am having a similar issue as you. It seems for each detent my encoder is moved, the frequency jumps 2 units. If you are careful, there is an encoder position between the detent positions where you can tune to odd units. It's like the encoder outputs 2 pulses for every click.

What if the code where changed to move==2 and move==-2?

Also, one of my interests is restoring vintage radios. To align theses, it is helpful to have a modulated signal, as there is no bfo. Rather than build a modulated output stage, what about using clk1 for the main carrier output, and if you want modulation, have clk0 and clk2 track with clk1, but offset by say +/- 700 or 1000 hz. If these outputs were attenuated by 6 dB relative to clk1, and mixed, they would approximate a 100% AM modulated signal. I know from a spectral purity standpoint things will not be the greatest, as the raduino does not output a sine wave, but you would at least have a tone you could hear on a receiver without a bfo.

73
Brent

I like that as a way to add io pin via i2c.
It's a pre-programmed ARM-Cortex-M0 running at 48mhz,
and considerably more powerful than the ATMega328p on the Raduino's Nano.

Y-es! :)

Thanks guys...all understood..

It's just that I built one for my Bitx and it doesn't seem to work.
The voltage on the gate of the fet is going up and down in response to the audio level
but there seems to be little or no attenuation to the stronger signals....
Double checked and I made no mistakes..
Phil? G4JVF

Plus, basic theory: a FET is a specialised case of the Trans-Istor ('transfer-resistor'). We default the term Transistor to the BJT (Bipolar Junction Transistor), with its Resistance (E-C) controlled by the current E-B. The FET (Field-Effect Transistor) does that same job, but the control of the Resistance (S-D) is by Voltage S-G (generating the 'Field' in the device).

The signal (Audio IN) *is* that voltage. The FET will conduct or not depending on the gate voltage, and act as a resistor in the divider with the 10k series resistor from M1 to attenuate the output.

I've used the PCF8575 before. It's a 16 bit I/O its 8 bit cousin
(PCF8574) is used on many i2c lcd displays.

Vince.

--
Michigan VHF Corp.

Must be having a senior moment but how does this AGC circuit work when there
is no voltage on the drain of the FET ....

Phil? G4JVF

I glued strips of wood just below the lid, then set the plastic face on top of the wood. The extra pot without the knob is just the volume control.

I think this is the for $9 from walmart. Added a pic of the antenna auto transformer. Its a 150-43 core with 14ga wire. I could have used a smaller core but this one is light enough for now. The caps are 2 x 120pf 6000v in series. BTW you can use this antenna at low heights for nvis.

WalMart has the Shakespeare Wonderpole 20' collapsible rod for $30 ish. ?It works great for me! ?You'll need to figure out guying though.

If you want an end fed half wave, Sotabeams Pico Tuner is 10w rated and very simple to make, but single band. ?While you're ordering, pick up a couple wire winders and a guying ring (If I recall, the 22mm ring works great on the Wonderpole with a bit of electrical tape to bulk up the pole where you want the ring to sit)

If you want a dipole, you can leave the last section of the Wonderpole collapsed - You need the extra rigidity to support the extra weight of the coax.

I second the motion to just get out there. ?Don't let the perfect be the enemy of the good here - I guarantee your setup will change as you find out what you need in the field. ?Fastest way to learn is to just get out there.

Sent from my iPhone ww

Adafruit?just added another option:??Because it's a breakout board, it might be easier to use than a raw DIP chip.?

开云体育

I am in the process of adding the following features/mods:

• Multi-banding using the QRP-Labs relay boards (LPF and BPFs)? ?- Requires 5 digital I/O ports (or 10 if you want to drive relays directly from a port)

In the actual state of the project/sketch you don't have as much as 5 free ports, I will suggest for version 2 the use of a I2C I/O expansion board as we already has a I2C bus and the code must be easy to implement.

If this is the path I will use those I/O ports for Output only and in non time-critical outputs to make the delays at minimum.

Allard: I have some experience with using the Si5351 for VFO/BFO from another active project, just let me know when the v2 start to develop to contribute with ideas/code/tips/etc.

--

73 CO7WT, Pavel.

Ashhar,

I want to thank you for the work you are doing and I hope this renews interest in homebrewing ham radio equipment. I am going to build a uBITX and hope to inform you soon about my success.

Art
KB8HGW

Port expansion can be had for a few dollars:?. What about adding a second Nano? Would still be cheaper than upgrading to a SAMD board. Oh, and speaking of digital modes, I've experimented with AFSK decoding (for APRS) on a Nano and it's ADC is just fast enough :)