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I don’t want this to become an Initiative discussion. But several posts in other threads have talked about changing the rules for AM, and I’d like to weigh in on that.
If, and I repeat, if, the FCC can be persuaded to change the rules on AM (which is much more likely than on FM), then it would be far more beneficial to concentrate on loosening antenna and ground restrictions rather than on increasing power.
For one thing, it’s simpler. Simple is good.
And let’s look at the effect of changing AM input power to the final stage to 1 watt, as has been suggested. If antenna system restrictions stay the same, you’re still only looking at less than 5 milliwatts of output power due to antenna inefficiencies (and probably a lot less than that).
But if power restrictions stay the same, and the restrictions on antenna systems goes away, you would be looking at a lot more power output with full quarter wave antennas – probably on the order of 25-50 milliwatts (depending on feedline losses).
And think of all the fun broadcasters could have experimenting with loops (perfect for apartment dwellers and those that need stealth antennas) and other types of alternative antennas, antennas that cannot be used currently (at least legally) due to their electrical length.
The perception of the change is also a lot more positive. I would think at first glance that any increase in power would be viewed by licensed broadcasters very negatively; antenna changes (even though ultimately they may make more of a difference in range), not so much. And to the FCC, it would make enforcement a lot easier – they’d just have to worry about the transmitter, which, if certified and unmodified, is a no-brainer.
I could even see a reduction in power to the final stage of the transmitter, which might make the perception even more palatable (remember, it’s the output power that ultimately determines field strength and range, not input power).
Anyway, just my 2 cents on this issue.
Total posts : 45366It would be really nice of one could legally use an 8 Ft loop or some sort of antenna like that and even keep the power as is to the final. Its something I’ve thought about.
The more I see translators appearing on FM the more I think that AM could be something we could try and make change on a band that is not so crowded.
This is good stuff to look into and I do like the keep it simple rule as well. An ATU could be made for the transmitters that are already out if the rules were changed and antenna/ground was unrestricted. I can’t imagine 1/4 wave AM antennas unless they were in a loop form for most of us however those could prove very effective as apposed to a piece of wire.
Total posts : 45366Mister Artisan Radio wisely said simpler is better. For radio hobbyists dealing in milliwatts simplest might even be best.
Unrestricted antennas would restrict themselves because almost no hobbyists will ever try to erect a super tall vertical antenna for all the physical and legal difficulties (zoning restrictions) that would entail. We might be able to do 7-meters for the slight improvement that would bring.
Of course there’d be a few long ground leads here and there, but the increase in range this brings has been exaggerated and would contribute more to safety than to range.
For the sake of simplicity and without opening a can of initiatives I’d consider a small tweak in the power department… life would be much easier with 100 milliwatts output power… there’d be a lot less explaining to do.
Total posts : 45366CB said: “…life would be much easier with 100 milliwatts output power… there’d be a lot less explaining to do.”
I said: “I agree with your perspective.”
Total posts : 45366Note that final amplifier input power can be measured with cheap d-c meters.
Output power is a-c power in the radio frequency range which takes an expensive wattmeter to measure, as well as knowing the exact load impedance the transmitter is driving.
Few Part 15 AM users would be able to measure r-f output power with useful accuracy.
Total posts : 45366I did not know that.
Total posts : 45366Simplicity. What often appears simple, isn’t.
Rich broght up one factor.
Another is that simplicity can be relative. What is simple to, say, a Part 15 broadcaster, may not be so simple to the FCC. If you take a look at the FCC’s headaches in regulating and enforcing Part 15.219, it’s pretty much all revolves around interference and antenna systems (primarily with ground leads). We can’t really do much about the former in the rule making arena, but we can address the latter.
Remove antennas from the equation, and you’re left with the simple task of ensuring that input power to the final stage of the transmitter falls within the regulations. As I stated before, that’s a no-brainer for unmodified, certified transmitters.
We have to remember that the FCC really doesn’t care about hobbyists, other than to ensure that we don’t interfere with licensed services. If we can make their life easier, while at the same time making ours a little better, everyone wins.
This kind of change would require no licensing or separate service. You don’t have to worry about urban vs rural (and what is the definition of each). Hobbyists can easily determine if their systems are compliant – there are no shades of gray, and you don’t have to use silly terms in describing Part 15 installations such as ‘strictly legal’. And the FCC gets to do less work in the enforcement arena, focusing mainly on interference concerns.
[I also have to say that I disagree with the statement that the effect of long ground leads has been overstated. Legal Part 15 AM systems with good, outdoor antennas are typically seen to get around a mile or so range, both in my experience and in the literature. Virtually every system that gets above that, reported sometimes to be 3 miles and more (such as KENC), has been found to have used long ground leads. Doubling or tripling typical range I believe can be classified as having a significant impact.]
Total posts : 45366It’s amazing how much there is to say about so little.
I love part 15.
Total posts : 45366Increase range to 5miles on AM with powered increased to 500mw or 1w to achive this range also the antenna rules would need to change to. If range was inceased to 5mile I would setup a station IMHO 2 to 2.5 miles is not worth it I will stick to internet broadcasting.
Total posts : 45366Gentleman, so far this has been a civilized conversation, let’s just hope it stays that way!
Before I give any final conclusions here, I’d like to think through all the comments and suggestions made here as we go along.
But I will say, I like bits and pices of the ideas that have been put forth here so far, every bit, every word does fit well together with the other person’s statement.
I will say, I know me building an 800 foor AM broadcast tower would be purely impossible or even legal for that matter.
But it would be fun building any length tower just for experimentation purposes.
As for RF power levels. I have not been able to experiment with 1 watt on AM because, I have no current AM transmitter that exceeds whatever “nano whatever” this Chris Cuff C-Quam Stereo transmitter is putting out. I would like to be able to legally hook up a linear amplifier to it that increases the RF range to more then 10 feet on a 102″ whip, but until 1 watt or 5 watt linear amps are legal to use, I will hold off on such tests, but there is a 5 watt linear amplifier avaiable out there for the AM broadcast band I wouldn’t mind being able to test.
Bruce.
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