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I am working my way towards being able to do radio alignments, learning along the way. Last night I learned just how touchy the adjustment is in my frequency counter as I spent 3 hours aligning it to WWV. The week before I made a high impedance active probe recalling how my galaxy hated that 10x probe. With my oscilloscope capable of various measurements like SINAD and owning a decent spectrum analyzer, I am almost there. The one thing I still need is a signal generator. I have a cheap signal generator from ebay that goes up to 60MHz, but it does not have modulation and it's signal cannot go low enough for what I need without 100dB worth of attenuators hanging off it.

I do not need to build anything extravagant, in fact, if it is centered on 27.205MHz with the ability to shift up and down 1kHz and modulate for AM work, I would be happy. I do not need it to function at 10MHz, 200MHz or anything else. The part that worries me is getting down to -130dBm as I assume that will take a lot of shielding and various stages of attenuation.

My original thought was a common base colpitts oscillator followed by a buffer amp with the modulation signal fed into the emitter of the buffer stage and maybe a low pass filter at the output. The only good transistors I have are some 3904's, BF998's and KSP10's from mouser, the rest of what I have are fakes from amazon and parts salvaged from old radios. Any suggestions or advice (other than "just buy one") would be appreciated!

Thanks!

<blockquote data-quote="brandon7861" data-source="post: 781928" data-attributes="member: 53724">I am working my way towards being able to do radio alignments, learning along the way. Last night I learned just how touchy the adjustment is in my frequency counter as I spent 3 hours aligning it to WWV. The week before I made a high impedance active probe recalling how my galaxy hated that 10x probe. With my oscilloscope capable of various measurements like SINAD and owning a decent spectrum analyzer, I am almost there. The one thing I still need is a signal generator. I have a cheap signal generator from ebay that goes up to 60MHz, but it does not have modulation and it&#039;s signal cannot go low enough for what I need without 100dB worth of attenuators hanging off it.I do not need to build anything extravagant, in fact, if it is centered on 27.205MHz with the ability to shift up and down 1kHz and modulate for AM work, I would be happy. I do not need it to function at 10MHz, 200MHz or anything else. The part that worries me is getting down to -130dBm as I assume that will take a lot of shielding and various stages of attenuation.My original thought was a common base colpitts oscillator followed by a buffer amp with the modulation signal fed into the emitter of the buffer stage and maybe a low pass filter at the output.&nbsp; The only good transistors I have are some 3904&#039;s, BF998&#039;s and KSP10&#039;s from mouser, the rest of what I have are fakes from amazon and parts salvaged from old radios.&nbsp; Any suggestions or advice (other than &quot;just buy one&quot;) would be appreciated!Thanks!</blockquote>

[QUOTE="brandon7861, post: 781928, member: 53724"] I am working my way towards being able to do radio alignments, learning along the way. Last night I learned just how touchy the adjustment is in my frequency counter as I spent 3 hours aligning it to WWV. The week before I made a high impedance active probe recalling how my galaxy hated that 10x probe. With my oscilloscope capable of various measurements like SINAD and owning a decent spectrum analyzer, I am almost there. The one thing I still need is a signal generator. I have a cheap signal generator from ebay that goes up to 60MHz, but it does not have modulation and it's signal cannot go low enough for what I need without 100dB worth of attenuators hanging off it. I do not need to build anything extravagant, in fact, if it is centered on 27.205MHz with the ability to shift up and down 1kHz and modulate for AM work, I would be happy. I do not need it to function at 10MHz, 200MHz or anything else. The part that worries me is getting down to -130dBm as I assume that will take a lot of shielding and various stages of attenuation. My original thought was a common base colpitts oscillator followed by a buffer amp with the modulation signal fed into the emitter of the buffer stage and maybe a low pass filter at the output. The only good transistors I have are some 3904's, BF998's and KSP10's from mouser, the rest of what I have are fakes from amazon and parts salvaged from old radios. Any suggestions or advice (other than "just buy one") would be appreciated! Thanks! [/QUOTE]

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