Colin, I'm not sure why you're having trouble understanding this, the capacitance is there no matter if the row is used or not.

The capacitance decreases with each neighboring row that is vacant because they're in series, but it's still there. Any circuit over 10-20mhz or so if moved to a project board would have to be retuned. I have heard of many people setting up oscillators on a breadboard that they get to work just like they wanted to and when they move them to point to point or strip board and they don't work anymore because they fail to acount for it.

Anyone that has used a microcontroller or cmos logic gates and left lines floating knows this because the capacitance is high enough that any nearby floating gates will follow the nearest signal line they can find like a sick little puppy.

Inductance is an issue as well though I've never seen any static numbers for what kind of inductances there actually are.

Basically anything over 10mhz you want to work reliably in a real circuit should probably be wire wrapped or point to point soldered, unless you're fine with it working only on the breadboard.

You could chop off the regulator and the additional RF power stage, but it wouldn't be as stable (frequency drift) and wouldn't have the same range (Output power):

Originally Posted by colin55

I have sold over 100,000 kits and the audio is so good that you cannot tell if someone is talking in the next room or the sound is coming from an FM radio.

No.
Your FM transmitters do not have pre-emphasis (treble frequencies boost) like FM radio stations use. So your FM transmitters will sound muffled on an ordinary FM radio because all FM radios have de-emphasis (treble frequencies cut) and therefore your transmitters will sound bad with no treble frequencies like an AM radio or like a stereo with its treble tone control turned all the way down.

My FM transmitter sounds perfect because it has pre-emphasis.

Post audio received on your respective devices record them in .wav format with NO alterations of any kind. A modern pop radio station will generally do. A good 30 seconds worth of audio, and since I don't know jack about FM radio design I'll judge the relative quality of the rendered audio. By ear and with through spectrum analysis. And Colin if you look at audioguru's board and think that's "not professional" Then you've got a serious problem! Would you care to post some live photo's of the last few boards you personally made so we know what a real professional is capable of?

Colin, my apologizes. I wasn't commenting about any portion of FM transmitter design. I simply want you to use a common FM receiver to record the audio from your transmitter. Post those .wav clips and I'll judge them, both with my own ear and from a spectrum analyzer, and post my results. For best results you should feed your FM transmitter with hi-fi audio, or better yet, white noise.

Originally Posted by colin55

You have absolutley no idea what you are talking about.
An FM station through one of my bugs sounds exactly like the radio station coming from the radio.

It does not and please stop arguing.
FM radios in your country have de-emphasis that cuts 3.2kHz to -3dB, 6.4khz to -6dB and 12.8kHz to -12dB. 15khz is reduced more.
The 22k collector resistor in the mic preamp transistor of your Wasp transmitter is bypassed with 1nF which cuts 7.3kHz another -3dB and steepens the high frequencies cutoff slope. It will sound very muffled on an FM radio.

My FM transmitter has pre-emphasis to cancel the de-emphasis in FM radios. My mic preamp transistor has a 10k collector resistor that is bypassed with 470pf so it cuts frequencies above 34khz so that 15kHz sounds good.

My FM transmitter has a low-dropout voltage regulator so its frequency doesn't change like yours does when the battery voltage is running down.

Would you care to post clip audioguru? A local FM station will do, preferably a song I know so I can download an appropriate clip for comparison =)

It's the expense of getting the extra components, such as the regulator, and even the enamelled wire, that put even the original poster off building it. That's why I supply kits for everything I produce.
Alkaline batteries are very expensive and not needed for 30mA circuits.

Out of more than 100,00 kits, no-one has commented on the fact that the transmitter does not clarity, and returned a kit.
I have compared the output from a radio and from a bug and could not tell the difference and I have a new $15 hearing aid from China, so I can hear it very clearly now.

It looks good to me strip board and all I would love to use strip board but haven't found any one that sells it in the US. And I never had any luck with solder less bread boards and fm transmitter. I all ways had to solder them up on a cheap board you get from radio shack. I don't think that board would look better if it was on a pcb. Very nice work.

I don't use a 7805 voltage regulator that has a dropout voltage of 2V. I use a low-dropout regulator that has a dropout voltage typically 0.05V or 0.2V max at the low current it is used for. Then my oscillator frequency is stable until the 9V battery voltage drops below 5.2V.

Doesn't an FM radio sound exactly the same as an AM radio with your hearing aid?