You have asked for my data and I intend to write and post a report when the project is finished.....At my present pace this may take a week or two.
No hurries...at your convenience and when time allows. As I said...pure curiosity.
As to the (laughable) point made about it no longer being a Ramsey.....ya ok whatever floats the boat. But its only a matter of personal prospective on what it actually is no matter where it came from and no matter what is printed on the box and board I guess.
I suppose if I removed the 350 engine in my 68 Camaro and threw in a 67 Olds 440 engine and replaced the steering wheel with a 78 Pontiac Firebird steering wheel..the vehicle will no longer be a GM product. :/
OOOOOKKKKKKK.
RFB
Hum is caused by inadequate power supply filtering period. Aint got nothing to do with the box itself. That Ramsey has adequate RF bypassing along its B+ rail. A simple solution would have been to use a better power supply instead of ANY crappy wall buzzing wart adaptor.
Tear one apart and find out just how inadequate filtering there is in those pos's. There is a reason why some who began to use switching types worked and eleminated hum...because those are far better filtered at the output than those pos single diode underated filter cap wall warts.
Ever power those Ramsey's with a battery pack? Wonder why they dont produce any hum then? Go figure...DC..duh. Hmm how about plugging in that wall wart into an o-scope and see the wonderful display of up and down sine wave which would represent.....HUMMMMMM.
I would have expected a whole lot better than this!!! Maybe I am in the wrong place here. I yield the floor.
HUMMMDEDUMBDUMB
RFB
It is the nature of electronic scientists, which we are by such detailed interest in part 15 engineering, to carefully define each item.
Once definitions are set, a standard exists.
But not everyone follows the same standards. Take the human race, for example.
The Office of Electronic Technology (OET) is the testing laboratory for the FCC. And as such, OET Memorandum 63 was the results of tests authorized by Commissioners and administrators to provide evidence during a rules dispute. The dispute history involved transmitters used in Part 15 service that were "pre-manufactured" (not kits). The Antenna connectors were common use RF connectors for the antenna, and as such, the antenna could be replaced with anything connected to the transmitter output. The ruling dealt with a variety of manufacturers who had already secured certification and acceptance from the FCC. The ruling caused the manufacturers to re-certify their devices with a "semi-permanent" antenna that could be replaced with an exact replacement if lost, broken or damaged.
As an additional note: Part 15 transmitters are not certified in a FCC laboratory. They are certified in test facilities all over the world and the written reports and results are accepted by FCC staff. OET lab results are for the purpose of resolving argued issues (evidence) or confirming results of set standards (NRSC). Ramsey, Hamilton and other transmitter manufacturers "pre-built" units must be certified before they can go on the market. Kits on the other hand, only require "verification" which involves a letter of acceptance from the Commission (sometimes based on outside lab tests if requested on a case by case basis).
Kits are required, by the verification letter, to carry in the assembly instructions warnings involving operation which "may not" be in compliance with the rules. The notices I have read point to 15.209 and 15.219 with emphasis on compliant operation. However, in case law or administrative proceedings of the FCC. I am unaware of any rules or rulings forbidding the experimentation with a kit transmitter, as long as the operation of the transmitter does not interfere with licensed services.
Bottom line: It remains the ultimate responsibility of the person producing a signal with any Part 15 device to operate within compliance of the rules, administrative policies and rulings of the Commission. Please remember, rules can change as a a result of administrative hearing and proposed ruling making. So, don't make the mistake of making an interpretive judgment on the Part 15 rules without current court case law and administrative rulings. In many cases, it can take up to several years for the case law and rulings to make it into CFR 47. That is what attorneys get paid for. And in this case, they are worth their weight in gold.
At the end of the day after all the discussions and posturing, if someone hears your signal where they don't want to you'll be shut down even if you are 100% legal.
Is it really so cut and dry as that? I mean we got some legal positioning don't we?
Scary thought.
That was a very enlightening post Marshall.
Of course they always are to me when you don't speak in greek. 🙂
There are only two FCC rules that apply to Part 15 transmitter users: 15.209 and 15.219. If you comply with one or the other, you are legal. It doesn’t matter if the heap of parts comprising your transmitter is manufactured-certified, manufactured-uncertified, kit-built, modified-kit-built, home-brew or anything else. You are free to transmit with whatever you want, as long as you can demonstrate compliance with the rules.
I didn't complicate the above statement by including the rules concerning spurious emissions because most any basic transmitter design will comply.
No published NOUO, NAV, or NAL documents have ever contained information about the transmitter. Violations are based solely on field strength measurements (15.209) or visible characteristics of the antenna/ground installation (15.219).
The question of legality of certified, uncertified, kits, or home-brew doesn’t require a lot of discussion, simply because the rules place final responsibility on the user for assuring compliant operation.
There is the possibility the FCC may elect to inspect your transmitter if your field strength appears to be too high for a 15.219 installation (after they observe your compliant 3-meter antenna/ground). You simply need to demonstrate that the input power to your final RF stage is 100mW or less, or shut down your 100W pirate transmitter!
There is prevailing urban legend and propaganda saying you are risking fine and imprisonment unless you use a certified transmitter. This propaganda is spread by manufacturers of certified transmitters to protect their business interests and justify the $15,000 or more they spent for certification. In fact, the rules for certification ONLY apply to the manufacturers of assembled transmitters, and have no bearing on the legality of use.
Relax. Think happy thoughts!
There is prevailing urban legend and propaganda saying you are risking fine and imprisonment unless you use a certified transmitter. This propaganda is spread by manufacturers of certified transmitters to protect their business interests and justify the $15,000 or more they spent for certification.
Phil, that's no urban myth. A majority of Part15 broadcasters are in fact fugitives of the FCC. They're all hiding out here at part15.us and being protected by the political pull this site possesses.. Why do you think everyone hangs out here?
But seriously I never heard that one. It's also surprising that getting a transmitter certified is a minimum of $15k. Sounds kind of extreme, I would have assumed maybe a few thousand.
But that explains why there's so few certified transmitters.
for bringing clarity to the issue.
Neil
Do not forget about 15.21
Then refer to your user/assembly/supplement info on website stuff.
One in particular, right off the Ramsey site...link here:
http://www.ramseyelectronics.com/resource/default.asp?page=fcc
..about 2/3 the way down.
Is it printed in the AM 25 manual...no. Is the info on the Ramsey link above viable to be considered as supplemental info to printed manuals for ALL their Part 15 stuff?....YES. (and it does say at the top of that webpage...AM/FM kits.
Third entry..
*Do not modify your kit in any way.
Hmm...
Anyway its up to each of us to operate within the rules. Modify your kits anyway you see fit, bring them into spec, or take them out, it's your move to stay within the lines of the road, or venture outside of them.
BTW...replacing R32 and 33 with a slightly higher value would have resolved your concern about that thing putting out more than 100mW.
What about your SSTran...out of the box, its 120mW. Not exactly 100mW is it.
Hmmm....might wanna modify that one too so its in compliance.
Not trying to be disrespectful to anyone or anything..but our operations are not just limited to 15.209, 15.219 or 15.221. Our operations fall under the ENTIRE Part 15 section. The 209, 219 and 221 are just specifics to only a part of the whole 15 section. Pay more attention to the entire rules and not just that tiny segment of the frequency chart to which your TX falls in per frequency of operation and so forth.
Anyway...
On with the show!
RFB
My SSTrans, both of them, show a power level of 96mW to the final stage. Perhaps that value can change with fluctuations in the electric power service, which is known to fluctuate to the degree that electric clocks will drift slow and fast over a period of time.
Perhaps that value can change with fluctuations in the electric power service, which is known to fluctuate to the degree that electric clocks will drift slow and fast over a period of time.
For a old electric clocks that ran on the geared down AC motor, ya that would occur since there was no form of rpm regulation in those things, plus add the fact that yesteryear the power generators and sub stations did not have the accurate 60 cycle regulation systems as they do today, and is why a majority of the modern era clocks sync up with that 60 cycle power for accurate track of time, as well as some referencing a time standard like the atomic clock down there in Ft. Collins. Co.
As to today's stuff electronically, voltage regulators on the DC side of things should take care of any fluctuations well enough to avoid wild swings in these transmitters. Only exception there would be if the final is running on B+ that is not regulated. That is a whole different story.
I am wondering now if at the time you performed this measurement on that 25 that you were using un-regulated power wall wart's making that thing swing wildly on the B+ which would cause that to obviously go outside of reasonable range of 100mW. That final in those are not fed by any voltage regulation, but right off the main B+ rail from the power connector. Ya there is a filter cap there, but that don't regulate nothing in the way of voltage being fed to that final.
I believe that thing can operate between 9V and 12V. And using the junk wall warts which are totally unregulated and improperly filtered and produce a "pulsed" like DC voltage source, would certainly make them run at more than 100mW for sure. Even a .3 volt pulse on a 9VDC rail will be enough to make them run a bit hotter..as well as cause all that hum garbage.
I remember when I got my 25 unit and powered it up the first time with that supplied power adapter. Inside of 10 seconds I unplugged that adapter and tossed it right into the junk pile and hooked that 25 up to a very well regulated and properly filtered bench power supply with 12 volts and the thing performed beautifully. As to the 100mW thing, changed out r32 and r33 with higher value resistors and was said and done. Worked like a champ, never did any further mods....didn't need to.
RFB
A majority of Part15 broadcasters are in fact fugitives of the FCC. They're all hiding out here at part15.us and being protected by the political pull this site possesses.
Political pull? Fugitives?
If there were fugitives, interpreted as less than honest radio operators hanging out here I doubt they would be hanging out here because of political pull or "protection" as you put it. You think for one second a pirate operator gives a hoot about political pull or protection when they are outright violating the law to begin with, and know it too, all the while having them antennas out for all to see and easily spotted and found with the FCCs direction finding tools that tag and bag within seconds?
Not saying they are not here, but I seriously doubt they hang out here for protection! That's quite laughable. Its like saying a gangster or murderer wont buy a gun and use it unless they are members of the National Rifle Association and attend their annual meetings!
Made my day with that one....now I'm in a good mood again! LOL!!
RFB
RFBurns information about the 60Hz power line frequency being better regulated than in the past was interesting to hear, because my last education on that topic was many years ago.
But I think voltage still varies a lot on power lines because of conditions that probably never will be brought under perfect control: because of line length, varying electrical loads, the quality of house wiring, and so on.
The clocks were driven more by Hertz, but I think the SSTran output voltage is entirely a matter of voltage. So I would be more accurate to specify that AC voltage fluctuations probably cause the transmitter output power to vary.
And the other factor, probably, is the DC regulation (or lack thereof), as mentioned by RFB.
My SSTRAN final DC input power is 93 mW. If more than 100 mW is measured then a review of the measurement method might be appropriate. The SSTRAN does provide internal voltage regulation so extreme variations in the voltage from the wall wart can only reduce the power.
RFB wrote:
"I am wondering now if at the time you performed this measurement on that 25 that you were using un-regulated power wall wart's making that thing swing wildly on the B+ which would cause that to obviously go outside of reasonable range of 100mW. That final in those are not fed by any voltage regulation, but right off the main B+ rail from the power connector. Ya there is a filter cap there, but that don't regulate nothing in the way of voltage being fed to that final."
I don't know if you are addressing me or not but I will respond. The AM-25 has no voltage regulation of the main DC rail which supplies the audio section and the final amplifier. (There is a "poor man's zener" regulating the PLL section at about 7 volts.) The final Q point and hence the final input power will, as you stated, vary with changes in the supply voltage. Recognizing this, I modified mine to include a LM317 regulator set to 12 volts. The external supply has sufficient voltage such that there is no drop out with the 12 volt regulator, thus my measurements were made with a confirmed constant 12 volts into the AM-25.
The final power input is set by the DC bias applied to the audio circuit, set by R23 and this establishes the power. R33 and R34 can be changed but it is easier to set the power with R23. Changing R33 and R34 will still require adjustment of R23 so I left them as they are. As I previously posted, a shunt across R20 brings the R23 adjustment range down so a voltage of 3.3 volts at the R34 test point can be achieved which results in 100 mW final input on my unit.
Neil