Ok, RF stupid...

[KC2UGV]

Given the following:


http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=QRP-SERIES

http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=QAMP

I can build these in about an hour each, including warm up time on the soldering iron.

Isn't SSB just modulating the sidetone in an AM mode, using half the sideband?

I figure this is a stupid question, but I never claimed to be an RF expert here :lol: Hypothetically, can I take one of these kits, and mod into an SSB kit by modulating the side tone with voice?

[NQ6U]

When you say "sidetone", what exactly do you mean? To me, the sidetone is a sound a CW rig produces so you can hear what you're sending. I could be wrong about this.

[W5GA]

When you say "sidetone", what exactly do you mean? To me, the sidetone is a sound a CW rig produces so you can hear what you're sending. I could be wrong about this.
And you'd be correct. I think Corey meant sideband.

[PA5COR]

Without an Xtal filter and balanced modulator you won't have SSB.
You need to remove the carrier and one sideband to produce LSB or USB chosing the right sideband.
These kits just produce a carrier without modulation, you can simply add AM modulation with an audio amp and modulator to modulate the carrier in AM.

My first transceiver i made went from a 9 MHz Xtal filter and sideband oscillators, later i went for the 10.695 types because i had them.
Plessey had some nice ic's like the balanced modulator chip, and audio compressor chip, saving some discrete parts in building.

Most CB ssb transceivers have the right Xtal filter and modulator to use in them mostly 10.695.
Older ones can have 7.8 MHz or 9 MHz ones., for me always a good source for parts to build my projects as donor pcb's.

Using a varactor diode and some additional circuitry you can make FM also.
That way i made my all mode 2 meter rig and later the 70 cm rig.
Cheaper as buying a FT 225 RD in that time, which i did later buy 2nd hand.

With a good transceiver and my transverters could make 23 cm, and 50 MHz.
That were my first homebrew transceivers i made 30 years back, and they were checked by our version of the FCC and passed.
In that time i used a vfo with 8 to 8.5 MHz range switching in 4 banks of xtals to get 2 MHz range.
( 144 - 146 MHz as the 2 meter band is here)
Using a Xtal oven to keeep the transceiver from drifting, the VFO was locked with a Huff Puff vfo stabilizer, http://www.hanssummers.com/huffpuff.html developed by Klaas Spaargaren, PA0KSB ( s.k).

[WØTKX]

Those QRP rigs generate a single output frequency, with the possible exception of harmonics.

Generally, you mix a low power single transmit frequency with the audio to create sidebands, then filter out the carrier and unwanted sideband. This results in a narrow range of transmitted signal, following the modulation. Much like the mixing that occurs in a receiver... there are other methods with the advent of digital circuitry.

SSB transceivers sometimes generate CW by modulationg with a single audio tone.
Ditto PSK and RTTY, but usng two tones. Olivia etc uses a few tones.

Here's a pretty good link that describes various transmit methods... http://www.ve7zsa.net/technical/advsgtxt/c9trans_b1_r00.htm

Poking around in the signal generation stages of a rig with a scope is pretty enlightening. I didn't grok how receivers worked with IF stages and mixing as a kid till I did that... and then SSB circuits made a lot more sense.

[KC2UGV]

When you say "sidetone", what exactly do you mean? To me, the sidetone is a sound a CW rig produces so you can hear what you're sending. I could be wrong about this.

Ok, posted a bit late last night. I was supposed to say "carrier" in place of "sidetone". Basically, the CW kits produce a single carrier, and then you mix the voice modulation with the carrier produced by a CW rig to get AM modulation (Not SSB, which is apparently a whole 'nother can o' worms); right?


And you'd be correct. I think Corey meant sideband.

Yeah lol.

Thanks to everyone else. I think it's getting into my nugget :)

[N2CHX]

Ok, posted a bit late last night. I was supposed to say "carrier" in place of "sidetone". Basically, the CW kits produce a single carrier, and then you mix the voice modulation with the carrier produced by a CW rig to get AM modulation (Not SSB, which is apparently a whole 'nother can o' worms); right?



Yeah lol.

Thanks to everyone else. I think it's getting into my nugget :)

Think of it this way Corey.... When you mix two signals you get a sum and difference. So lets say you have a carrier frequency of 1.000 mHz. Modulate that with 1 kHz and you get signals at three frequencies: 1.001 mHz, 1.000 mHz and .999 mHz. Single sideband is achieved by filtering out the carrier frequency and either everything above it or everything below it before it enters the final PA stage of the transmitter. Filter out just the carrier frequency and you'll get double sideband.

SSB is efficient because no energy is wasted on amplifying the carrier and one sideband. All of the available energy is used to amplify one sideband, which is sufficient to transfer information in the form of audio. The audio is recovered by adding a carrier signal in the receiver and then rectifying the two signals after they are added together. The process requires very high Q, multi-stage (usually crystal) filters.

[KC2UGV]

Making more sense now...