Suggestions for a two-tone generator please ...

[KC9KEP]

Hello all!

I am still working on fabricating my home-brew
all-tune SSB exciter (ARRL 1961).

As I am doing this in the interest of learning, I will
want to use a two-tone generator to prove out
the operation of my exciter.

Can anyone suggest a suitable two-tone generator?

Maybe a simple QST design that you like, or some sort
of kit of parts, or maybe a software program that
will generate the test tones?

Thanks!

--Tom Nickel AKA KC9KEP

[KC9KEP]

Woops .. There was a typo in there.

I meant to say; "all TUBE" not "all TUNE" exciter.

[ON4WIX]

Hi Tom,

you might want to take a look at the Elecraft 2T-Gen mini module kit. Very easy to build, works perfectly and very inexpensive! See http://www.elecraft.com/mini_module_kits/mini_modules.htm for more info or here on Eham http://www.eham.net/reviews/detail/5648 for the reviews, including the usual nitpicks ;-)

73 es HNY
Glenn ON4WIX

[WB6THE]

A circuit called a 'TWIN-T" oscillator, one transistor, two caps
and two resistors. and I recall that the output is
very nearly a sine wave. You could build one for each
tone or maybe just switch RC values around. Any ARRL
handbook in the last 40 years should have the circuit
or find it on Google. Might cost $5.00 to make if you
don't have a junk box.

#########

[WA3SKN]

A telephone touch-tone pad generates two separate audio frequencies when you use it.  The phone type has about 0 dBm output.  And if you design around a VHF mic with internal pad the levels might be near what you need.

-Mike.

[N3OX]

I use DL4YHF's Spectrum Laboratory and my computer's soundcard to generate test tones...

http://www.qsl.net/dl4yhf/spectra1.html

I use it with a mixer and signal generator to do the testing too, like this:

http://www.astromag.co.uk/ssa/

[VK1OD]

Can anyone suggest a suitable two-tone generator?

I wrote some notes at Using audio spectrum analysis for end to end linearity testing of an SSB transmitter / receiver system and I thought I had linked a wav file of the test waveform... but I don't see a link. I will investigate and add a link if the file is online. I am in the process of moving house, and I just thismorning left the place where the file is if it is not online.

Anyway, the article should be of interest, it shows how to use a PC sound card and one of the audio spectrum analysis programs to measure IMD.

Owen

[G8JNJ]

Hi,

If you have a PC and soundcard take a look at T Cube -Two tone test software (free) by Alberto I2PHD.

http://www.weaksignals.com/

It can generate different tones and has an inbuilt audio spectrum analyser which can be connected a receiver audio output for analysis of your transmitted signal.

It also has an I/Q mode which  is useful for testing SDR radios.

Regards,

Martin - G8JNJ

www.g8jnj.webs.com

[KC9KEP]

Thank you all for the replies!  Many great ideas ..
I appreciate it!

73

--KC9KEP