Antenna Radials and top hats are a bit of a grey area for the FCC, with some agents counting it towards total lengths and others completely ignoring it.
Elevation is crucial to such low powered signals, anything blocking that antenna is going to attenuate it to some degree. You'd be surprised how much my signal jumps up in the wintertime because the trees drop all their leaves.
To Reply 181:
So elevation matters!
Not the elevation of the transmitter with its attached ~3m whip, but the fact that elevated systems need a longer conductor to a true r-f ground. Radiation from that longer conductor is responsible for the greater total radiation. The longer that conductor, the more the effect.
But, what I did not see was a measure to prevent RF from eminating from the ground lead (or did I miss that?) If a true earth ground existed, but was choked to prevent radiation, would the results be the same?
If r-f current is prevented from flowing on that long conductor to r-f ground, then the elevated transmitter and whip would radiate very little -- less than if the system was mounted a few inches above the earth and connected using no choke to a ground rod, or buried radials (other thing equal).
To Reply 182:
Elevation is crucial to such low powered signals, anything blocking that antenna is going to attenuate it to some degree. You'd be surprised how much my signal jumps up in the wintertime because the trees drop all their leaves.
A major part of this signal improvement is due to the moisture content of the earth, which often is greater in the winter, and improves earth conductivity. The improved conductivity reduces propagation losses for AM groundwaves.
Yeah, Craig. It powers on fine. No signal. The ATU was on internal. My bad.
Mark,
Your comment, "...you have to set the operation for wire antenna, not for the outdoor set up, and the light on the front goes OUT when tuned right."
Ahhh! Good point. Thank you. Also, the light goes OUT? Is that with NO audio? I saw that somewhere but cannot find where that is written now. The instructions are bare minimum. Also, the thing has been changed to version II. A freakin' 1/8th inch audio jack! Hate those! No more RCA.
Plus, there is no audio input level adjustment! That SUCKS! My Orban 424A Compressor/Limiter has no level out adjust. Oh! The instructions say to set the modulation control. There IS no freakin' modulation control! WTF did they do to this? Sheesh! Version II, eh?
OK. Gotta get a small mixer, cassette recorder or something to pad the Orban Comp/Limiter to a level acceptable to the SpitFire. I got ideas. This was not expected. Why would they remove the input gain? They think we run things with iPods, I guess...
Doug
The antenna has to be at internal....the light will go OFF when you adjust the cap and get the right spot, whether audio or not. The other switches have to be set to the frequency range that includes the one you want to be on.
Ya, you have to control audio level at source with this.
Main thing is do you get a silent carrier on the radio with no audio?
The one I had a long time ago had the RCA jacks. So the Orban is a compressor...no gain control to compensate for the reduction?
Try with something else to see if working, like an MP3 player into the 1/8 jack?
The older one didn't have a input level control either.
Mark
We'll try the "noisebox" directly plugged into it. And that trim cap! How many turns...is it just one complete turn? I have to use my thumbnail. I don't have a tuning tool. Oh yeah...the Earth Ground! We don't have one of those here.
I live on the upper floor of a four-plex built in 1854. There night be a cold water pipe...drat...they are all PVC. Maybe the copper heating pipes...I need a hose clamp...
What if I don't use an earth ground? I just wanna test this thing...
Doug
I meant to post this earlier.. but got distracted by work...go figure.
So, essentially, my hypothesis is correct. Increased elevation in regards to low power AM under strict Part 15 rules does not necessarily gain distance. The key is a radiating ground lead,which is not suggested because of out of compliance issues.
A near earth or 0 elevation system with proper ground will outperform an elevated Part 15 AM unless the ground lead is allowed radiate on the elevated installation.
We should include this in the new installation handbook for Part 15 stations...with the reasons discussed here. It might save some newcomers the trouble of learning, and yet them still make decisions on their installations.
I myself do not prefer the elevated mounting system I currently have. My ground is not effective...and should not be radiating based on my installation. My coverage is less than some that have posted here with near earth or 0 elevation installations. Wet weather makes my system really perform well. I am sure it is due to earth/ground potential changing.
It is a headache to do maintenance on the transmitter when on a roof. I am thinking about installing an elevator!!
As for landbased obstacles, I think we should collaborate on our findings and clarify what is known. Big buildings are of course a major obstacle.. especially close to the transmitter.
Thanks Rich for the clarification. Hopefully this discourse will help others... if I can be arrogant enough to assume that!
Buildings and trees for sure, possibly a car if its parked close enough. My transmitter is right next to the driveway and I haven't noticed any signal drop when the truck is parked there. The obstacles are more of a near-field problem and become irrelevant once you are far enough away. (Unless is huge concrete structures or poorly grounded powerlines)
I see the same thing. My house is about 1/2 mile straight line from the transmitter. The street is lined with trees. As I near the trees the signal drops.
I didn't post this yesterday, but it was one of those days..
I had noticed the live stream had dropped, and when I came into the office, the stream encoder laptop had shutdown due to overheating. The internal fan had failed. In all fairness, it was noisy so I should not be surprised.
I moved the stream encoding back to the primary program source laptop. It is very easy since RadioDJ has an encoding plugin. But I noticed a stutter during track changes. I had not rebooted in several weeks, so I knew it was time.
Of course during all this, I am slammed with an unusual amount of work related activity. I also notice that I have stream listeners logged in.
I kill off as many unnecessary processes as I can. It helps.. The stuttering is not gone, but is much better.
About 6:00 last nite I get a chance to switch the audio ZaraStudio and reboot... 30 minutes later after all the usual updates that Windows loves to share with us. I am back on line with the primary program source laptop.
I should have parts tomorrow to repair the stream encoding laptop..
Today things seem to be calm!
You don't need a ground for it to work.....it's not how many turns to tune, the cap just goes through it's range and keeps turning. Just find the spot where the LED goes out. It works similar to the other AM transmitters.
Use the cold water pipe where you turn the water on or off under the sink and if PVC the 3rd earth ground plug in the wall socket.
Mark
I think based on me being legally Blind I won’t be placing any transmitters way on a roof. The closest thing I’d do is a room up in the air but really a ground install makes things a lot easier. If I need to retune the antenna or clean it from snow its a lot easier to do this on the ground. About the height as a DirecTV satellite dish from the ground.
Since Deltaville, VA is relatively close to water it may benefit me if I could find someone who would put the transmitter near the marina. The moisture of the soil would make a good ground and would cover Taylor’s restaurant but may not cover the Deltaville Market and of course Top China or the gas station/7 11. So that was why I thought about the church.
Now only if the Landlord would let me use that shed across the way from me to put up an AM station. My FM signal could go to a Radio in the shed. From the Radio I could go to the AM Transmitter. Or just put the antenna on the ground and run the wires to the Transmitter or if I had the Procaster run the studio module inside the shed. A 8-10 foot ground rod would be easy. Actually the antenna would have to be in front of the shed to be away from the trees. That may be a problem because you’d see the antenna right from the road and I’m sure the company may not like that however if they didn’t care it would make for a great clearing and my signal would coer the range I want with a simple 100mW AM station.
Not to keep bringing this up but if we got rid of the ground/antenna rule for AM we’d have our range and we could probably keep the 100 mW rule.
I've been Internet broadcasting since 2008. You should have 8-16 GB RAM, 64 bit OS, a quad core CPU running at least 2 Ghz or very close to it then you can surf the net and still run RADIO SOFTWARE.
I think its a better idea to have radio related computers do exactly one function. The On Air would be strictly for automation, the streaming computer strictly for streaming, etc. BSI Sends out Dell Optiplex computers with 4GB ram and Windows 7 for use with their Autiomation software. 8GB or more would certainly be pretty stable. I've had ZaraRadio run on a 512mb machine without any issues, I wish I would've tested it on 256!
I've heard that Zara runs on just about anything. I've tested it on Windows 98 and it seemed to work fine.
That stutter generally occurs when the software playing your programming needs CPU cycles, and it doesn't get them (if you're using Windows, it isn't a great multi-tasking system, UNIX or Linux is much better).
One way to solve that problem is to raise the priority of your automation software (in Windows to Above Normal). Unfortunately, Windows doesn't remember that setting the next time you reboot, so you either have to keep resetting it manually, or find software that will remember (such as PRIO for Windows - I know it works for older versions of the OS, not so sure about later ones).
I certainly believe in that concept also. That is one of the things I have been doing. Most of the equipment I have left over from other projects. CPU allocation looks good on all of them, usually it is at less than 30 percent..
On the laptop that generates programming. It was network related, keep in mind that it had been a month since the last reboot...windows just generally needs that. The CPU cycles looked good even with the stuttering, but there was a problem I am guessing with some of the virtual interrupts.
I may convert to linux, I used to use it for many projects when I was still doing IT work. But, it is easier to grab a windows OS for business applications and not have to do extra training...so I have windows.
I have been eyeballing those cheap Dell Optiplex systems. I intend to order one for another project.
ZaraRadio seems to run on almost anything, and it is stable, I use it as my standby for program source software.
RadioDJ is also stable, but it requires SQL to handle the media links and settings. That does up the requirements some, but the versatility is great. I am still learning things..