New 13.560mhz station almost ready!

You might be interested in this thread: http://www.part15.us/node/2870 and this one also: http://www.part15.us/node/3006

Keep up informed of your station progress.

Neil

Welcome Ron Kocher to 13.560 !!!!

Great to know you have joined the crowd here at 13.560, Ron.

Radio8Z, who just sent an earlier post, and PhilB, the inventor of the AMT5000 newest AM transmitter, contributed to the building of my transmitter which has been on the air for several months at 13.560.

I am on the air about 12-hours a day, so when I go off I can listen for you and any other "neighbors" here on the 21-meter band.

Where did your circuit design come from?

"I can only guess how much power it will take to get the 15,000uv/m at 30m"

It wont be 1.2 watts, somewhat lower. BTW, its 10,000uV/m @30m (15.225), and 30uV/m @30m (15.209).

If you cannot locate a suitable meter to check for legal field strength, you might check with a local radio shop and see if one of their guys might help you out to measure this. They usually have adequate equipment to do this. May not be a fancy Potomac, but their IFR's or Moto's most likely will be more than accurate enough for this measurement.

Or an even simpler method is to go out to 30 meters from your antenna and your signal should just barely be above the noise floor level, and further from that point it should steadily dive into the noise floor.

RFB

RFB you have an outdated power level for 13.560.....

FCC 15.225 Revised Oct. 1, 2009
(a) The field strength of any emissions within the band 13.553 - 13.567 mHz shall not exceed 15,848 microvolts/meter @ 30 meters.

Also, somewhere in the Big Talker thread, PhilB did some simulations for 3-types of antenna systems and came up with the general guideline that input power to the final to meet FCC field strength limits will be around 5 mW.

PhilB's post is titled "ANTENNAS AND FILTER TALK."

Ahh indeed. I referenced the wrong paper! ACK! YOUR FIRED! :p

I have too many reference books and papers. Time to clean the file cabinet!

But your leaving out 209 which is still the same I believe. I asked the field agent while he was here about a month ago doing an inspection about the double field strength rules on certain frequencies and which one do they actually use for measuring legal levels.

209 was his answer. Perhaps they look at that mostly because when they get a complaint, its usually over interference. They use that to measure out of band emissions.

RFB

"input power to the final to meet FCC field strength limits will be around 5 mW."

That much eh! Sounds about right. And is why I do not run a 13.560 station. The general public does not listen to that band.

Just a side comment regarding these certain bands of Part 15.

To us radio freaks and geeks, its worthwhile and fun to mess with these uncommon radio bands. But to the general public..the audience...they do not have any idea this 13.56Mhz and other bands exist simply because common radios available to the general public..unless they are specialty radios, do not receive these bands. Quite often the average joe or jane may actually have a radio that can pick up SW or LW, and probably have never flipped that band selector switch over to them except maybe once when checking out their new radio for the first time and heard nothing but static...so their radios stay on the AM dial or the FM dial.

Im not sure how many Part 15 operators here are running a station just for their own personal fun or uses, or are actually serious about being a low power broadcaster trying to reach a real audience and serving the community. I am the latter, though I do have fun with it, I take it very seriously and there are only two main places where that listening public will be.

The AM dial or the FM dial. The other bands might as well not even exist, and to the general public..they don't.

I wont count satellite radio as there is no Part 15 satellite radio to begin with.

But even though it is fun to *art around with these other bands, its really pointless from the prospective of serving the community. A heads up campaign would need to be done first to familiarize the general public of these bands. And boy would it have to be one heck of a sales pitch too. Why would anyone want to give up their excellent wide band hi-fi sounding music on their FM radio to listen to narrow bandwidth voice transmissions to the likes of a telephone?

They wont. Even avid AM band listeners barely tolerate the silly 5khz bandwidth there. Going further beyond that, even 3 or 2khz is pushing your luck that you would collect any significant number in listeners. And if you do..it would be us radio freaks and geeks who have spent decades tuning our ear drums to compensate for that tin can sound and can tolerate it even with a plethora of static noise behind it.

Now..back to the warm milky sound of AM C-QUAM in all its wide bandwidth glory! :p

RFB

It is true that broadcasting at 13.560 or 162 for that matter is an exercise in "self service."

But running a large scale model railroad, another giant hobby for professionals, serves no passengers nor freight transportation.

Even on Part 15 AM or FM, is the best signal truly fulfilled if 2 listeners are tuned in? Are they paying attention? Is it somehow noble to provide sound for them? Is the broadcast wasted when no one tunes in?

All of life's questions can only be answered by philosophers, and three of them said the following...

Albert Camus said, "Life is absurd, but death also is absurd."

Arthur Schopenhauer said, "Unhappiness is the norm, happiness is the exception."

Carl Blare said, "How much you got without it?"

Well the new guy is confused...but that's nothing new!

RFB says "at 30 meters from the antenna, your signal should just barely be above the noise floor." Gadzooks! Could it be that bad? 15,000 microvolts/meter would be 15 millivolts/meter, and on the AM broadcast band, that would be a hell of a signal! (In AM broadcast, I believe 5 millivolts and over is "local", 2 is "grade B", and they don't call it a "fringe" signal until it's .05 or below. (or, 50 microvolts/meter or below.)

I just can't imagine a 15mv (15,000uv) signal being just barely above the noise floor. (Unless I had a doctor's diathermy machine operating next store on 13,560, creating that noise floor! Is that what you meant?

Plus, I've read elsewhere in the Pt. 15-us pages, of another operator "overloading all the front ends in my house" with only 5 or 10 milliwatts loaded into a dipole.

At least one other operator reported being able to listen to his signal for several blocks down the road with just a portable SW radio.

How could such varying reports both be indicitive of the same signal strength? Has anyone actually measured their signal on a good meter? Obviously I need some more advice. Thanks guys! Ron

My transmitter at 13.560 is feeding a half-wave dipole but the antenna is hung indoors across three rooms and so the outdoor coverage is sharply reduced, although it does go all over the neighborhood.

I wanted to put a shortwave radio in the car for better tests, but besides the fact that I can't find one, Bruce Dog Radio Studio 2 says cars put very heavy noise on shortwave.

In the winter months I'm trying to put an out door antenna to really test the system.

Carl - A signal that "can be heard all around the neighborhood" is more like I would expect at the FCC's maximum allowed radiation level. So at 30 meters from your antenna, I bet it sounds pretty good, eh?

Thanks for that report! BTW most editions of the Radio Amateur's Handbook have a chapter on mobile operations, and if I remember correctly, there are some pretty good tips about getting rid of noise on and near 20 meters. But you're right....first we need to find a SW radio that will go in a car!

Thanks again for your help. I'm going FS meter hunting! Ron

Keep in mind that field inspectors do not use typical radio receivers with beefed up sensitivity to conduct field strength measurements. IE..the "what you hear" off the radio is not necessarily what you will "read" on a calibrated field strength meter.

"But you're right....first we need to find a SW radio that will go in a car!"

As I pointed out....where is the majority of the public listening to radio on the spectrum....even if its just round the hood?

The AM broadcast band or the FM broadcast band.

Maybe this could be an opportunity for the Part 15 TX kit makers....market a converter kit so that the 99.99999 percent majority of common AM and FM radios in vehicles can tune in the 13.560 frequency, like those old style FM radio adapter units that plugged in between the AM radio and its antenna in cars.

RFB

Interesting thing about signals at these frequecies is their propagation characteristics.

Many years ago as a new Ham operator, I was working 40 meters (7140 kHz.) I heard a CQ, a bit weak but readable.

I answered and we exchanged info and I found this person to be just a couple miles away. Why such a weak signal to each other and yet we both work stations hundreds of miles from us? Proagation due to the ionosphere bounce.

So, that signal you hear around the neighborhood just might be heard around the world. I have done this with less than 1 watt.

"Interesting thing about signals at these frequecies is their propagation characteristics."

Yes propagation can be surprising on these bands. QRP is about a regular thing in HAM radio as is firing up the legal limit amp.

But QRP'ing is a throw of the Dabbo Dice, or interpreted for those unfamiliar with that table game of the future, a gamble. If conditions are just right, that little signal just might catch a good tail wind and get a little assistance. And just like a good sailboat, the sails and wind and the seas must all be coordinating to create these optimum conditions for that sailboat to move across a large distance.

Though I do not partake in that particular end of the hobby anymore simply because there is better means of communication today and quite less expensive and far more reliable, I used to be HAM operator too back in the day when the spectrum was filled with the "Electronic Iron Curtain" where even with the best of the best optimum conditions, QRP'ing was not such an easy game to play as it is today.

It was fun and quite impressive to see that little "HAM in a tuna can" transmitter make contact hundreds of miles away..even if only for a duration long enough to exchange call letters and maybe catch a few more words of excitement with the other operator till the reaper of fading propagation death comes along and severs that delicate link.

Done quite a bit of QRP'ing myself with one and two transistor homebrew CW units. There was also some SSB contacts made at the micro-flea level.

Good thing time was spent prior to all that becoming used to hearing weak signals and decrypting them through all the static spikes and woosh wash phasing in and out of these QRP contacts and making good copy of their transmissions.

I think us radio freaks and geeks can decrypt a 100 key sequence per nanosecond of code buried in noise that would drive away the rest of the world in a fraction of that time.

But in a tin can shell, we are talking about a special type of radio operation and communication using methods only trained enthusiasts know about, or would even be willing to spend much more time than a nanosecond putting their ear right up to the speaker or blasting the volume loud enough to shatter glass or drive the XYL crazy to throwing an iron skillet at your head just for that chance to add another QSL card to the wall of shame or fame.

We are talking about a form of radio communication that is not found in the average joe or jane's stereo entertainment center, or portable sitting on the end table next to the reading lamp, or even so much as the radio stuffed into that strong looking plastic dash board.

I am sure most have seen the video posted by a member who demonstrated the coverage of their AMT3K and 3 meter system. It shows two kinds of radios...a common portable, and a vehicle equipped with standard equipment entertainment apparatuses, which was a simple matter of starting the car, pushing a couple of buttons on the dash and tuning in what that vehicles stock radio was capable of tuning in.

I did not see any LW or SW or MW band selector on that radio, or the hand held portable.

And although this hobby has been around for more decades than all of us here are of age, there still has yet to be ANY common "stock" radio, be it for the table top or plastic dash board with the ability to tune in these specialty bands.

I am not saying give it up or your wasting time or your efforts are futile. I am simply trying to say that as far as the intent and purpose of Part 15 low power BROADCASTING, this 20 meter band, and the others are POINTLESS and USELESS and NONEXISTENT to the target audience....the every day joe and jane tuning a standard AM and FM radio, regardless if that audience is comprised of the "hood" 2 or 3, or 15 or 50 within a 3 mile radius. It is still where that bigger number of audience is and will be...the AM broadcast and FM broadcast band.

Keep on QRP'in and hope that impossible contact is made and that little QSL card from a land far away is sent.

But the bottom line is...QRP'ing is NOT broadcasting in any sense or meaning or interpretation of the word.

This forum is mostly about broadcasting to the general public. Adds on both left and right clearly help identify that aspect of this type of radio operation we enjoy. The general public's first impression when visiting this site for the first time is NOT hinting to HAM in a tin can or QRP'ing across the world on the flea wings of millivolts per meter.

Perhaps these occasional threads that pop up now and then discussing the tin can HAM band radio might encourage curiosity of a future radio operator. Perhaps this forum could use a section about that type of radio operation so that there is a place for everything and everything in its proper place...might help avoid confusion or prevent giving someone false impressions.

Let me ask you something mram...when you made those QRP contacts with this less than 1 watt tin can transmitter, what kind of receiver were you using, on what kind of antenna system and how high was that antenna system and how much gain did it have and bandwidth selectivity and any notch filtering capability in that not so common receiver?

I doubt the portable hand held radio or in-dash stock car radio is going to have such an elaborate set of special equipment around.

Have fun anyway!

RFB

i never run more than 100 watts on any band. i got into qrp out of necessity from never being blessed with home ownership and having to hide my gear from neighbors and landlords.

now i've come to enjoy the challenge of seeing how far my signal goes with peanut power and neutered antenna setups.