I had to log in to congratulate ya! It looks well done, and the kit itself looks better than I thought it would, more professional and digitally controlled. I'd been thinking it was just a step above the FM-25, just the 25 with a frequency display.
I'm enjoying your adventures in kit building as well, and really like that it also can be set for 75us, something that most built transmitters lack, and the audio is a little dull at 50. It made me go wow hearing 75 after getting used to 50, it added extra sparkle in the highs.
I like the swooping arc of the via holes in that one open board area, like the logo that certain shoes have, catch the wave.
It looks like you have expensive tastes in furniture too, Carl.
I know the 100B has a modulation meter and that would make nice of the 30B had it. Good to hear it compares with the C. Crane. Thanks for your information Carl.
The photo I took of the FM30b Panel Readout was out of focus so I'll have to try again, but it's right next to me here on the computer and I have GOOD news... it DOES have a means of observing modulation level! More about that in a second.
Nate Crime, that swirly area composed of holes in the circuit board is, according to the manual, an actual coil! Later tonight I'll look that up and quote the actual description.
O.K., with the panel set to "Volume" there is a visible volume level strip that can be "upped" or "downed," and what I didn't know earlier... there are symbols that appear based on level. When level is low a "-" (minus symbol) appears on the screen. When the volume is high enough to perk some audio a "g" flips on. When the audio clips/distorts a lower case "c" pops on. And when the transmitter is over-modulated an upper case "C" shows up, and it is time to back off.
And right over here, 10-feet 10-inches away on the desktop, the spectrum analyzer.
Having the tripod near the analyzer made the dBu jump up from 40 to 45.
Nice I don't see any spurs near the spike which is the actual frequency. That looks like a very clean TX. That is what we are looking for.
Great job...hope you have lots of use and enjoyment of this for a long time.
Mark
The radio programming of KDX Worldround Radio has launched a new Ramsey FM30B Transmitter for transmission at minimum radiated power from the Internet Building in the Center of North America.
The transmitter can be seen with the POWER department of the control panel showing an empty bar all the way across, showing absolute minimum power.
Much thanks to Mark, TheLegacy, Bruce MICRO1700, Neil Radio8Z and everyone who contributed ideas, helpful advice, and supportive feedback.
We are not finished and this thread will continue for awhile while we review and study everything about this transmitter.
Earlier today a remark was made about the rounding swirl of holes visible on the main circuit board, and this feature is called "the stub" and works in conjunction with the variable capacitor, actually an inductor coil that is the basis of the voltage controlled oscillator. The stub acts like a coil in the circuit and has a very predictable value, to paraphrase from the manual.
You may recall that I left the green LED out of the circuit and want to discuss it at greater length... it is not a power light as I thought, but a LOCK indicator! On tomorrow's schedule we'll discuss the green LED.
We haven't looked for spurious emissions or harmonics from the Ramsey FM30B, hold my place here and I'll look now... be right back...
Very good. Could find no trace of out-of-channel artifacts from the FM30B, and the 2nd harmonic at 170 MHz is so supressed that it is not showing on the spectrum analyzer, and only a scratchy trace of it can be heard via the ALINCO DJ-X3 Communications Receiver when the antenna is right at the transmitter antenna.
Great Work Carl,
Glad to hear the kit turned out fine.
Ramsey FM Transmitter kits really are worth the money not too hard to build.
Still enjoying my FM 25 B after all these years.
Great that there is very little to no spurs. That is one of my dreams to have a transmitter that is so clean I can relax and enjoy it without fear that it causes any sort of issue. I like the power display too easy for someone like me to see who is visually impaired. Thanks for the pics and the live coverage of the kit assembly. Hope this lasts for many years.
Keep The Faith.
All the good replies are printed out for me to show to the gals at the singles bar later. Oh wait, there's an ALPB Meeting tonight.
Today will be more tests with the FM30B, which has now been operating for 24-hours.
John WDCX earlier made the suggestion that the FM30B might sound better than a C.Crane FM, which I at first answered by saying they both sounded the same, but maybe there's more to say.
Both transmitters resemble the sound of licensed FM stations, and are either exactly alike or...
Maybe the FM30B sounds just slightly different from the C.Crane. I want to say that it sounds better, but that would be too subjective, as it may be that the 75 uS preemphasis on one is just a tad different than the other.
One place to look is a frequency response test run through each transmitter followed by a detailed report here.
Alright, it's a deal.
Now that the new Ramsey is part of day-to-day operation here at Worldround Radio, it teaches me this...
Having a read-out panel is just like professional radio, where we take meter readings and check to see whether the transmitter is currently on fire.
A well designed transmitter will have indicators of all kinds, like a viewing screen that says "NOT CURRENTLY ABLAZE."
With the FM30B we can check VOLUME to see how often we modulate from "-" to "g," which is good, and if we see a "c" or a "C" we know to back it off to avoid overmodulation.
With POWER combined with the nearby spectrum analyzer we know that the field strength is reduced to serve only the immediate campus, here at Immediate University, being sure to leave the surrounding residents "beyond the contour."
Today we'll start plotting and scheming to add meters and blinkers to all the other transmitters around here, even those not presently in use... they will indicate "NOT PRESENTLY IN USE."
This Review of the Ramsey FM30B from Radio Brandy is well done and matches exactly the experience I had building mine.
http://www.radiobrandy.com/RAMSEYFM30.html
Great review Carl. Just wish I could build such a transmitter. Love it.
One thing i would do different with the Ramsey FM25B is put RCA jacks on it.
That stereo headphone jack is flimsy. I have thought about changing mine to RCA.
Glad the transmitter is working well for you Carl.
Right Barry, I remember the stereo miniplug input on the FM25B, and then a 2nd miniplug for use as a pass-through, to power a speaker amplifier or something else.
I've been wondering what the minimum power level is for the FM30B. It's probably the same for the FM25B, I still have the manual for that... I'll check it later.
I've been running the FM30B at minimum power which turns out to be slightly less than the C.Crane FM2, because my needs don't require more power.
John WDCX wondered about the audio quality, and I've already said a few things about it, and I now report that it sure sounds like it has an Aphex Aural Exciter built in because of the life-like sizzle around the high frequencies. Makes musical instruments stand out.
I was going to take mine out for a drink later but it's happy just staying home.