Figured I'd start a new thread. Before I ask my question, I must say that all of the hu-bub regarding Phil and Keith is interesting. People inflate and conflate their opinions about others as the wind blows. I have found Keith to be very responsive-at all times. Never had a problem getting a response to my queries.
Now, I am getting two Rangemasters and plan to link them as a cluster on one rooftop in a week's time. I will keep you all apprised of my station's progress, signal strength and the rest. Here's my question guys. How do these transmitters operate in the winter? Mine will be set up in a region of the country that certainly gets its fair share of snow. Would you advise housing the units in another weather proof box? They will be mounted 20 feet up on my office's rooftop.
They will perform just as any other 100mW unit will. It all really depends on your installation. Up on the roof is ok, just watch out for that ground lead length.
Having two units operating in close proximity to each other, linked or not will not increase your range. You should put one of the units at another location near the fringe reception point, then your range will extend further.
RFB
Well, one way to look at it is that two Rangemasters located in close proximity would produce the sum of their output powers. Field strength and therefore range would increase by the square root of 2, or 1.41. That may not be as good as what you would get by spacing them, but it is still significant enough to warrant two transmitters, if you have the money to spend.
Locating the transmitters on a roof will open you up to FCC scrutinization, ala the NOUO issued to a broadcaster who apparently had 4 Rangemasters on a roof.
I say, go for it. If you get an NOUO, just stop operating and tell that to the FCC. The case will be closed and you won't get any of the fine or imprisonment stuff that scares so many.
The Rangemaster will run just fine. Although I do live in Florida we do have temps in the 20's and it does get very windy in January and during hurricane season. We also lead the country in thunderstorms and lightning strikes. I have 2 rangemasters in different locations. One about 15 feet high and another on the roof of a building thats 50 feet high. They both run 24/7. The case is very durable and I have never experienced problems with the antenna mount or antenna. Hope this helps.
I call my question "educated" because I'm smart enough to ask it, but not smart enough to know the answer. Here it is...
Would the very best result come if the transmitters were spaced exactly one-wavelength apart (based on the frequency)?
"I say, go for it. If you get an NOUO, just stop operating and tell that to the FCC. The case will be closed and you won't get any of the fine or imprisonment stuff that scares so many."
A risky proposal. I am surprised that someone in your position would encourage this person to just "go for it".
Perhaps you might want to include a disclaimer in your post in case this person your suggesting throw themselves to the wolves decides to throw guilt by association in your direction.
Here is my suggestion to the new broadcaster. Follow good engineering practices, don't blatantly operate outside of the rules, and do some research into operations that did get popped for taking bad advice.
RFB
"Would the very best result come if the transmitters were spaced exactly one-wavelength apart (based on the frequency)?"
One wavelength distance on a frequency in the MW band would take up more room than what most have. And by that time, your units will be separated almost the same distance they would need to be if you simply strung them out to cover more range...at that point...what would be the point in "clustering" them???
RFB
I've never found weather to be the issue.
What IS the issue is the shortened days. Yesterday, as I drove out of my house at 6pm (with it getting dark), I lost my signal (which I normally can hear in the daytime up to a mile out) a few blocks away. Coming home, I was listening rather easily to a station from Manitoba (I'm in British Columbia, so that's about 1200 miles away) that operates on my frequency.
I sometimes wonder where my signal goes at night - is there somewhere a thousand miles away that it rolls into and they're going - what's that!?
And I double what RFB says - don't just go for it if the "it" isn't within the rules.
On my system...the AM CC system, the winter months wreak havoc on the MW band here. More noise and buzz saw junk, especially at night. The upper part of the band becomes saturated with stations. Fortunately 1670 still remains fairly clear overnight to continue operating. However the distance down the lines does get affected. This is probably caused by the moisture and/or ice and snow buildup on those lines, particularly the neutral, thus creating a rather large attenuator along the entire length of the line the signal travels on, which in my station's case is the neutral line, which is not insulated.
I do find that the emergency 3 meter setup works beautifully in the winter months. This is probably due to the already good ground conductivity here, my proximity to a river that flows through town, and add the rain/snow moisture factor into the whole mix, that creates a nice and very large ground "blanket" and that tiny 100mW stick kicks that signal out a good 2-3 miles. In the summer, it hits just under 1 mile on a dry day.
RFB
I do not have a Rangemaster and therefore have no data regarding this so this is only something to be aware of. Crystal oscillators drift with temperature and a 1.68 MHz oscillator I bench tested drifted 1 Hz per degree F. There are ways to compensate for temperature and it may well be that the oscillator in the Rangemaster is compensated for temperature.
I don't recall reading any comments about drift problems but this may be worth checking.
Neil
On a recent posting here on the site I recall reading about "Crystal Ovens," a means of keeping crystals at a constant temperature, which I am sure Neil was just referring to.
RFB, can't you just crank up the power on your CC to compensate for weakened conditions?
As for "buzz saw," a station at 1600 in between my two signals which are 1550 and 1680, has had the "buzz saw for a long time, of course we mean HD radio, digital radio, and in their case, with 5 kW, the analog signal was all but gone. It rarely tuned in properly. UNTIL a week ago they got smart and turned off the "Saw," and now their analog is zinging.
MOST of the stations here are SMART or BROKE and do not have "Buzz Saw." Only two remaining stations have it, and I hope they get around to throwing it in the dumpster.
"RFB, can't you just crank up the power on your CC to compensate for weakened conditions?"
No. For two main reasons.
1. It could cause exceeding the limit of 15uV/m @30m (93 feet from source at 1670Khz)
2. It would cause severe receiver saturation within that limit field and a bit beyond it as well.
The better choice is to change frequencies. I found the low portion of the band has less trouble with the ice/snow buildup on the lines and ground during the winter. When the CC system is operating on the low end of the band (630Khz or 640Khz), the emergency 3 meter system runs the 1670 frequency.
It works out because the 3 meter setup performs better on 1670 in the winter season than it does in the summer, and the CC system works better on 1670 in the summer than winter. And the frequencies of 630 and 640 work well in the opposite.
RFB
Thanks for the reply Phil. Great to hear from you, sir. Your calculations are correct and commensurate with my engineer's. Love this forum!
I have never experienced drift with either Rangemaster.
"Your calculations are correct and commensurate with my engineer's"
Lets hope their calculations conform to the calculations called for in the Part 15 rules.
Good luck!
RFB