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Post by Deleted on Mar 14, 2017 17:12:22 GMT
Elevating your antenna is not necessary for Part 15 AM operation - it will give you a long ground wire which makes you non-compliant with the rules, and you likely can achieve better results with a ground mounted antenna. I know I did. Here is a link for a discussion about the most important aspect of an AM antenna system - the ground. www.part15.us/forum/part15-forums/general-discussion/am-ground-systems-and-propagationDecrease the ground resistance & you'll greatly increase the efficiency of your antenna. I'm on my phone, but will post re my experiences later.
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Post by Druid Hills Radio on Mar 14, 2017 17:14:34 GMT
Reply to Jim: The Talking House was certified with a remote antenna tuner. So in fact, the internal tuner was removed from the circuit and replaced with the "final stage" some distance away. So is there anything besides the ATU and antenna on that extension? It seems to me that if the transmitter is on the ground then his signal must still traverse that 300 ft. to get to the ATU and antenna. Thus I don't understand the difference in losses. Jim:The ATU becomes external as opposed to internal. The unit was certified with 100 feet of coax not 300 as some claim. The output impedance the Talking house would like to see is 50 ohms. The output impedance the Sstran would like to see is in the order of 800 ohms. So that being said, attaching a 50 piece of coax to and output that would like to see 800 ohms results in a huge mismatch. Also, when mismatches are high with coaxial cable the losses go up exponentially. Now that being said, even if the output was 50 ohms to 50 ohm cable, the 10 foot antenna at say 1610 kHz is anything but 50 ohms. Once again, huge mismatch = loss of radiated power.
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Post by Deleted on Mar 14, 2017 17:21:58 GMT
I suspect there are other reasons than Part 15 compliance that gave the individual 6 miles range with a Procaster.
Chez Radio used to supply 100 feet of shielded 4 conductor cable with the Procaster to hook up power & audio. In the early ones, they instructed the installer to connect the shield at the radio side to the negative power terminal (i.e., ground). That made a nice 100 foot long ground wire (how they got that through certification we may never know).
My point is that you need to know the installation specifics before claiming range. I too don't think it's likely that you can get 7 miles on a Part 15 compliant transmitter. 1-2 miles, maybe, again depending on installation parameters.
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Post by Druid Hills Radio on Mar 14, 2017 17:33:57 GMT
David said: Chez Radio used to supply 100 feet of shielded 4 conductor cable with the Procaster to hook up power & audio. In the early ones, they instructed the installer to connect the shield at the radio side to the negative power terminal (i.e., ground). That made a nice 100 foot long ground wire (how they got that through certification we may never know).John added: "If one looks at the test photos, the 100 foot cable was not part of the test. It does bring into play the "secret" 3 foot waver for the ground though. The transmitter is on a 1 meter high table with a ground wire attached to the ground plane below. Now that means that the total combined length of the antenna and ground exceeds 3 meters."
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Post by End80 on Mar 14, 2017 18:30:30 GMT
There is a fellow in Indianapolis claiming a 6 mile range. At least that is what he claims. I believe he is using a Pro-Caster. I have a hard time believing a 4 mile range could be legally achieved, particularly without a ground.. Maybe in some extreme circumstance, but I'd have to see it to believe Yes I know Henry, I'm very aware of all such claims, and it can be done with 100mw input, I have even easily exceeded 6 mile range with a part15 transmitter and a 100mw input.. So have others. But not with a 3 meter antenna system... So again, I have a hard time believing a 4 mile range could be legally achieved.
It might be -just barely a maybe- possible to LEGALY achieve a few miles radius under the best of conditions and most ideal of installations.
I do not have my head in the sand. Station8's proclamations is exactly the type of beliefs that sucked me into the part15 hobby to begin with over ten years ago, and it was a big disappointment when I, and many others realized it was nothing more than elaborate hype and misinformation... But it didn't make me abandon the part15 hobby, instead I accepted part15 capabilities for what they really are, and accepted what could really be done.
A more realistic objective under part15 would to hope for a 2 mile [emp]radius[emp], but even that can be tough.
It's quite simple to determine if a part15 AM operation is legal or not: Is the entire antenna and the ground length under 10 feet? Is the input power 100mw or less?
If it's not, then it is not part 15, and if it's not part 15, then it's not legal.
Neither I nor Station8 have our head in the sand.. but one of us are full of crap.
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Post by Druid Hills Radio on Mar 14, 2017 18:38:05 GMT
This station has a 50 foot radiating ground.
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Post by End80 on Mar 14, 2017 18:53:30 GMT
This station has a 50 foot radiating ground. That makes sense. How did you know?
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Post by Druid Hills Radio on Mar 14, 2017 19:17:00 GMT
This station has a 50 foot radiating ground. That makes sense. How did you know? He described it in the video. About 4 minutes into the video.
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Post by End80 on Mar 14, 2017 21:26:59 GMT
I guess I should have actually looked at the video, but thought I had seen them all before.. but this one I hadn't seen, WOW! I notice most of the comments posted on the video insisted the install was not legal, but one of them I got a kick out of:
"his setup is legal the grounding wire can be longer than ten feet, it is your grounding rod or lead that is at ground level can not exceed ten feet, the transmission line is where the transmitter is at ground level and the antenna is up at a higher level. the procaster transmitter is up at 55 feet as said in the video the antenna is connected to the transmitter. trust me... his setup is legal."
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Post by End80 on Mar 14, 2017 21:28:46 GMT
"Trust me.."
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Post by mark on Mar 14, 2017 23:21:20 GMT
Watching the video how can this be legal with a grounding wire from the stake in the ground up the pole to the transmitter with the antenna on the Procaster?
That's a whole lot more than 3 meters total antenna and ground wire. So his results couldn't be typical with a "legal" install
Mark
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Post by End80 on Mar 14, 2017 23:51:20 GMT
Of course not.. The above was a quote from one of the comments to the video. I wasn't saying that! I was just amused at the ridiculously of it.
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Post by Deleted on Mar 15, 2017 1:34:10 GMT
Even though most of my experience has been with BETS-1 FM here in Canada (it makes more sense here than AM),I've experimented a lot with AM over the years. I've used Talking Houses and Talking Signs with both wire antennas and the ATU, an AMT3000, a ProCaster (which I still have) and a Rangemaster.
I've found that, by far, the most significant factor in increasing range is the effectiveness of your ground. So much so, that even non compliant antenna systems don't necessarily operate as effectively as a legal system with a great ground.
When I was running Artisan Radio on Bowen Island (which is largely a big rock sticking up out of the ocean, i.e., a pretty poor ground, probably almost as bad as the desert), I installed a Rangemaster at my home, about 25 feet in the air and ran a long ground wire down to a metal stake. This was in a semi-rural area, so pretty quiet electrically, and I could only get 1/4 to 1/2 mile (in one direction) range at best, to an excellent car radio. Installing radials made little difference.
When I moved to Pitt Meadows (which is located on the shores of the Fraser River, in a floodplain, i.e., a pretty effective ground), I installed that same Rangemaster, tuned in exactly the same manner (100 mw to the final stage) at ground level. I pounded a metal stake about 4 feet into the earth, and ran the ground wire (very short, about a foot in length) to it, with no radials. I was located in an older subdivision, surrounded by some fields, but it was much more active electrically than the location on Bowen (not comparable to a strictly urban setting, but still more measurable interference than Bowen). With that setup, I easily could hear my signal out to a mile with the same car radio (I could also hear static, but the programming was clearly listenable) and out to about 2 miles in one direction (with a very weak signal, still audible above the noise but not really listenable). I could even hear the signal about 3/4 mile away (by the window, on the 2nd story of a house) on a Sony portable blaster (very weak, but still there).
The only +ve difference for Pitt Meadows between the 2 locations - much better soil conductivity. In every other aspect, the Bowen location had it beat (higher, long ground wire, no electrical interference, etc.).
The discussion that I linked to earlier from Part15.us looked at how much a better ground increased the efficiency of a monopole antenna. Under ideal conditions, a Part 15 antenna maybe has around 5% efficiency (with a perfect ground, i.e., sea water). Under poorer, more typical ground conditions, the efficiency is well under 1%. With differences in efficiency of between 1 to 50x or more, it's easy to see why Part 15 broadcasters get such a wide range of results from seemingly similar conditions, even with identical transmitters.
In the case of that guy who got 7 miles, I haven't yet looked at the video. But I think it's safe to assume that he would have also gotten decent results if he had a truly legal setup. If his ground was as ineffective as mine on Bowen Island, there's no way he would have gotten 7 miles, even with the long radiating ground wire. Although, I also wonder if he attached the shield of the audio cable to ground in the transmitter, as I discussed previously - that might actually create an inverted V (with the audio cable shield and the ground wire being the 2 legs, in which case a good ground is not essential).
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Post by End80 on Mar 15, 2017 3:16:47 GMT
I really need to try the ground install even though its a terrible spot for it. I think I mentioned my only option is surround on three sides by buildings, with the fourth side partially obstructed by a storage trailer, a huge old tree, and a LP gas tank! Plus it happens to be an area where people cut through when leaving the bars at 3am. So I'm not crazy about that spot.
As for the install in the video, it's a 55 foot pole supported by numerous guy wires, and the transmitter is at the very top with a ground wire running all the way down the pole.. So it's essentially a 65 foot antenna. The video is 6 years old, but a quick Google search indicates it's still in operation and there is no record of a NOUO for it.
Incidentally, in the last six years there have only been 20 NOUOs for AM (and literary many thousands for FM), But of the 20 for AM, most of them involved the same people, and with that considered it brings that count down to exactly 10 citations since 2010. The majority of those have occurred in Washington and New York, but also a few in Arizona, Minnesota, and California, and then just one in Michigan, and only one in Illinois... Point being, that AM has not been of particular enforcement concern. The most likely reason for this lays in the fact that enforcement is complaint driven, and since most part15 installs (even the non compliant) usually have less than a 3 mile radius of range, so who's going to complain?
I'm pretty sure a fair amount of part15 broadcasters tend to bend the rules a tad, based just on the pictures I've seen on some of their websites, but rarely do I see something so extremely blatant illegal as the one shown in the video.. it's actually the most illegal install I ever seen, but I guess it pales in comparison to KENC's on the water tower many years ago! Personally, I'd rather be legal than illegal for the sake of another mile range, additional transmitters can extend range legally, but of course it's easier said then done unless your using different frequencies.
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Post by station8 on Mar 15, 2017 16:27:15 GMT
Hi : This is for end 80 and other people with the same mentality !!!
Calling me crap before you say that about someone you better know them personally first !
It must be nice for end 80 to get away calling me crap but if I call someone that people want me kicked off is this not Fair NOPE this is what I call kissing butt to the right people ! ! End 80 you have no clue what my background of experience is at all !!!
I don't know you well and you don't know me well !
The next time you call out because you say I don't know what I'm doing or talking about
I will take you and others out to the wood shed and kick your ass for lying !!
Now take that and think about what you did !!
Station 8
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