ham radio

just a few questions about the feasibility of this

  • would it be possible to replace the crystal to achieve at least 200MHz to output to a DAC
  • gnuradio <-> arduino <-> ADC/DAC <-> antenna tuner?

im looking at using the arduino mega as a platform for a frequency counter, transciever, spectrum analyzer.

The maximum speed of the processor is 20MHz, so no, your overclocking wouldn't work

could you suggest a PIC that would?

edit: 20MHz is enough to go into the 17 meter band.

I can’t think of any microcontroller that would.
Try an ARM.

what about a frequency multiplier before the DAC?

moopthereckoner:
just a few questions about the feasibility of this

  • would it be possible to replace the crystal to achieve at least 200MHz to output to a DAC
  • gnuradio <-> arduino <-> ADC/DAC <-> antenna tuner?

im looking at using the arduino mega as a platform for a frequency counter, transciever, spectrum analyzer.

A better method is to use the arduino just for the user interface and to control special purpose chips and modules to do the actual RF stuff. I’m currently building a 40 meter CW QRP station using cheap Asian DDS modules and standalone Arduino for the display and control of the DDS chips. Been lots of fun so far, just need to find a cost effective metal case to house all the modules assembled so far.

DDS module for cheap: http://www.ebay.com/itm/270842833841?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Arduino software example for controlling such modules: http://www.theladderline.com/inexpensive-ad9850-dds-boards-ebay

Lefty WA6TKD

i-is there a way to hug you?

electronically and totally platonic of course!

moopthereckoner: i-is there a way to hug you?

electronically and totally platonic of course!

Your welcome. Ham radio and Arduino can be a great combination for DIY radio projects. DIY RF has always been a favorite area for me.

When you have a need to measure the signal level of a RF signal I've found the analog devices AD8307 to be a great chip to work with. It can directly measure RF signals up to 500 Mhz and directly measure from around -80 dbm to around +10 dbm, and with external attenuators wired in you could measure any power level your likely to require. The chip converts the power level to a simple 0-4.5 vdc measurement range suitable for directly wiring to an arduino analog input pin. The chip is a little costly, but still under $10 I think, but replaces a whole lot of individual parts that would be required to output a logarithmic power range of equivalent capabilities. http://www.analog.com/static/imported-files/data_sheets/AD8307.pdf

73

Lefty WA6TKD

i see that the AD series of DDS have a linux driver, can i simply wire a usb to the module and work from there?

this is just for a transmitter, I'm getting a kit for the reciever.

When you have a need to measure the signal level of a RF signal I've found the analog devices AD8307 to be a great chip to work with.

I was amazed at the specs on that.

I helped an Artist guy use it for an "Art Installation" (Which I never saw personally..) in which it detected very nearby CellPhone transmissions.

Then it started dripping blood (or something) from the ceiling.

Ain't Technology Wonderful. And how about those Logarithms??

I figured that one transmitter I was once responsible for had an output of +70 dbm 8)

moopthereckoner: i see that the AD series of DDS have a linux driver, can i simply wire a usb to the module and work from there?

this is just for a transmitter, I'm getting a kit for the reciever.

Wire a usb what to the DDS module? Just a usb connector, no. I guess I would look at the linux driver to see what type of device it is expecting to see on the usb buss. I know nothing of linux so can't help much.

Lefty

The breakout boards I see say:

  • Parallel and serial data input can be selected via a jumper cap

So with a typical USB-TTL interface, probably can talk to it.... as a serial device.

What application runs it is another story...

terryking228: The breakout boards I see say:

  • Parallel and serial data input can be selected via a jumper cap

So with a typical USB-TTL interface, probably can talk to it.... as a serial device.

What application runs it is another story...

No, the serial input is a SPI type with a data, clock, and enable input. Long data words are used. It could be bit banged I guess using serial control signals.

KT1F, Ross, has written a complete arduino application for talking to a AD9851 module via an Arduino: http://www.theladderline.com/node/10

And with a few changes the same sketch will work with the lower cost AD9850 module:

http://www.theladderline.com/inexpensive-ad9850-dds-boards-ebay

Lefty

Thanks, Lefty..

Glad I said 'probably' :~

Wish I had time to play with these... "Radios" these days is mindblowing to this pre-silicon guy...

I used to be on CW and RTTY with my Dad every week for years.. various generations of stuff from mechanical teletypes thru computers.

Now he's 99 and almost blind and so deaf that the only way I can communicate with him on the phone is to send him Morse and he talks back. Funny how that 5 baud nonsynchronous mode still works.

terryking228: Thanks, Lefty..

Glad I said 'probably' :~

Wish I had time to play with these... "Radios" these days is mindblowing to this pre-silicon guy...

I used to be on CW and RTTY with my Dad every week for years.. various generations of stuff from mechanical teletypes thru computers.

Now he's 99 and almost blind and so deaf that the only way I can communicate with him on the phone is to send him Morse and he talks back. Funny how that 5 baud nonsynchronous mode still works.

Well I am just getting back into ham radio after decades of inactivity. A lot has changed, they dropped the code learning requirement. However CW and RTTY are still popular modes but of course SSB is the most active. AM, FM and lots on newer digital modes are also used. The population of hams seems to be higher these days with the dropping of CW code requirements, but the radios seem awful expensive and do not track the trend of cheaper and cheaper electronics over time as the rest of the consumer and PC world enjoys. Must be a lack of scale of volumn production and possibly not enough competition.

I've got a lead on a local ham that said he is willing to sell me his old Kenwood TS-520s hybrid transciever for $100 ($200-300 less then resell value). That would be quite a score if it goes down as planned. It's a great old radio from the mid to late 70s where the chassis and panels were still made of heavy metal, real knobs a human can handle, no menus or digital displays. Just a pair of 6146Bs pumping out better then 100 watts of RF. It's a radio one can actually troubleshoot and repair if required rather then just sending off for expensive repairs. These old Kenwoods hybrids are quite popular still with those in the know, and plus they look very cool:

http://www.radiomuseum.org/r/trio_kenwo_ts_520_s.html

Lefty

I’ve got one too. Since 8th grade. Still works!