Home › Forums › Transmitter Talk › Procaster Transmitter Tuning
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- April 8, 2011 at 12:46 pm #7716
Hello Guys…I have a question here. The Procaster Manual states that
the Procaster has to be tuned only after its installed in the finalHello Guys…I have a question here. The Procaster Manual states that
the Procaster has to be tuned only after its installed in the final
position or the tuning will not be accurate. We plan on installing our
transmitter at 40 feet. My question here….can this thing be accurately
tuned before we raise it to the final height…and if so..how will it
effect the output?Jack63
April 8, 2011 at 4:16 pm #21555radio8z
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Total posts : 45366Hello Jack,
Unfortunately the answer to your question is no.
The Procaster and most other transmitters which use an inductor in series with the antenna radiating element need to be tuned after they are mechanically installed. The reason for this is the inductor is used to cancel the capacitive reactance of the antenna system and this reactance is highly dependent on the electrical environment surrounding the system. Even the presence of a person’s body near the transmitter or antenna during tuning can cause errors and the usual practice is to tune per instructions and back away when checking the readings. This is tricky on a tower mount but it can be done.
Pre-tuning can and probably will result in less than optimum radiated signal strength to the point where range is greatly reduced.
Also, be advised that elevated installation of a part 15 AM transmitter may not pass FCC inspection if inspection is performed. The issue is the ground lead length. Search this site for “KENC” for quite a bit of information about this.
Mounting the transmitter at ground level above buried radials is generally considered a method to avoid these problems.
Neil
April 8, 2011 at 4:35 pm #21557kc8gpd
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Total posts : 45366i heard there was a 1 meter leeway in the height issue due to these transmitters being tested and passed at that height during the certification process.
i believe 3-4 ft above the ground was not an issue with most inspectors.
April 8, 2011 at 4:48 pm #21559RichPowers
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Total posts : 45366If I’m correct, height is not actually an issue in itself. The real issue is the radiating ground wire. If you recall with KENC, his transmitter mounted above the football stadium did pass inspection and was allowed to continue transmitting as long as he did not connect the ground.
I also seem to recall something about grounding to the metal on the the top inside of a chimney passed inspection since it did not radiate.. this is why in my own situation, I suspect that grounding to the 6″ of plumbing pipe sticking out of the flat roof would equally be acceptable.
April 8, 2011 at 4:55 pm #21560radio8z
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Total posts : 45366I didn’t intend to instigate a renewed discussion on the ground lead issue with my reply to Jack, rather just to refer him to some information on the topic.
Anyone interested can search this site on the subject and repeating what has already been said and speculation about what an inspection will bring is just going to clutter this thread and not solve anything.
Could we please defer to what has already been posted on the subject in other threads and keep this discussion on the subject of Jack’s question?
Neil
April 8, 2011 at 4:58 pm #21562Jack63
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Total posts : 45366Hey, Neil…
Thanks, dude. I wasn’t sure if I could tune this thing prior to
installation. Again, thanks for the information.Jack63
April 8, 2011 at 5:02 pm #21563radio8z
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Total posts : 45366Jack,
Glad to be of assistance. Hope my answer explained things well.
Let us know when you are on the air and how things work out.
Neil
April 8, 2011 at 5:19 pm #21565RichPowers
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Total posts : 45366Also concerning elevated installations; I had emailed that Talking billboard company guy a few weeks ago (recently discussed here) and asked if the business was now obsolete (since all the articles and publications and videos concerning it listed there are years old).
He told me no it is not obsolete but going strong.
I haven’t conversed with him further, but assume the billboard installs must all be elevated installations as well.And then there’s the matter of the Procaster and Rangemaster installation directions which both seem to defy the KENC situation
It’s all so mind boggling sometimes.I have to agree that evidence certainly does seem to indicate that legality of such an installation is based on the inspecting agents opinion and attitude… and perhaps the way you interact with that inspecting agent.
There does, after all, appear an underlining feel in the story of KENC that he kind of pissed the inspecting agent off.
Unfortunately, when it comes right down to it, there is too much speculation, and not enough clear hard facts on exactly what is what when it comes to Part15
Just don’t seem fair.
Waaaaah!April 8, 2011 at 5:24 pm #21566RichPowers
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Total posts : 45366Could we please defer to what has already been posted on the subject in other threads and keep this discussion on the subject of Jack’s question?
Sorry about that, Yes, you’re right Neil. Didn’t mean to confuse the matter.
(I was typing my last post before your reply came in)April 8, 2011 at 10:09 pm #21569mram1500
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Total posts : 45366It all seems to boil down to whether or not someone objects to the presence of your signal rather than compliance with the FCC rules.
There’s really not a hill of beans difference between 1/4 mile and 2 miles of coverage area. Yeah we all want the 2 miles. But your installation could be 100% compliant with the rules and still be shut down if the right person complains.
KENC was “caught” not because he was heard but because of his visibility, a newspaper article I believe read by a Field Inspector the story goes.
As for radiating grounds, if your signal increases with your ground connection is it because the ground wire is radiating or because it has reduced ground losses and increased antenna efficiency?
A properly designed/installed counterpoise isn’t supposed to radiate. If that’s the case an increase in signal should be acceptable where the “ground wire” between the transmitter and the ground/counterpoise is short (read ground mounted transmitter) because you can pretty much guarantee the signal is going to increase when you reduce ground losses.
So, not to advocate purposely violating rules; relax- keep a low profile- do your thing and don’t irritate anyone with objectionable content or interference.
April 9, 2011 at 1:08 am #21571RichPowers
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Total posts : 45366There’s really not a hill of beans difference between 1/4 mile and 2 miles of coverage area.
…hmmm, O.K. Bob, if you say so!…
April 9, 2011 at 2:04 am #21572mram1500
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Total posts : 45366The point being that it’s not worth worrying about pushing the envelope to achieve a 2 mile coverage with the odds that there might be one person out there with a chip on their shoulder. Ya can’t be pushin’ to hard to get 2 miles.
And the odds of them hearing your signal, slim. At least in my case that’s the situation since I don’t advertise locally. I’m broadcasting for my own selfish curiosity and enjoyment. I’m a radio junkie!
So I’ll keep it to the 100 mW input and 3 meter antenna. And though the discussions go on ad nauseum about top hats and radials and elevated systems-I’m not gonna worry about it.
The FM Pirate Guy in town got busted several years ago. He was running 50 watts into a 5/8 wave ground plane at 30 feet, 24/7. You could hear him 10 miles away or more.
Why’d he get caught? The FCC just happen to be passing through town for a translator construction permit on the same frequency. What happened? He was told don’t be so obvious. Maybe just weekends and drop the power to a watt. They threatened to confiscate his equipment and then backed down. Instead, he handed over the transmitter as a good faith gesture and promised not to do it again, too soon.
April 9, 2011 at 3:00 am #21573RichPowers
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Total posts : 45366Bob, after that clarification, I follow what you’re saying.
The fact that I will be doing heavy local promotion of my station here has been a constant concern to me, but heavy promotion is necessary for the potential success of it.On one hand, I figure I’m not really competing with anybody.. but my first station years ago I called “WTYB” – because this island has an unofficial widely used logo (featuring a tie, a Y, and a bee) that’s on everything from koozies to bumper stickers..
But shortly after I built my website and began initial promotion of WTYB, a licensed Savannah FM station (WSIS I think) suddenly applied for these call letters and got it and started promoting themselves as “Tybee’s Radio Station” – even though there is absolutely nothing about them in any shape or form to do with Tybee even to this day..Now if it comes to happen – they are FM, and I am AM.. on what basis could they file a complaint that I would be causing some form of interference?
There are several things that have caused me to delay actually beginning broadcast at this time,I know it’s been months, but it’s coming -really! ..and it’s coming soon.
But first, I’m really trying to complete a formulation of a structured scheme for a wide array of local programming to fall nicely into.. (I’m having a hard time wording this).. I want this elaborate.. theme.. laid all out, and ready to accept a vast array of programming supplied and performed by the local clubs, organizations, and the city personnel themselves..OK – I’ll put it this way.. I don’t want it to start small, it is to start out running full force and complete.. It is to be strong from the moment it starts.
The whole thing worries me.
Reality is that Part15 does not have much of a leg to stand on.. it leans on crutches… But it still does stand, so there is a chance this can work.This island is it’s own little alienated place.
It is possible for this to work as a real thing.excuse my rambling
April 9, 2011 at 3:51 am #21574mram1500
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Total posts : 45366Rich, I must say I’m envious. You are going where most of us would like, to make a business venture in radio. It’s easy for me to say I don’t care if I’m the only one listening for my signal because I’m a tinkerer. I just want to see what works.
And though I go through the motions of “programming”, I haven’t changed it in ages. Of course that’s partly because of the “royalty” thing and it’s much easier to pick my “program” out of the static when it’s always the same.
Very curious how the FM station picked up on your theme. Your promotion worked all to well. Island Radio works, maybe a Margarita logo… I wish you the best and let’s hope the FM owner doesn’t feel his revenue is being interferred with.
You go guy! Throw it out there and see where it goes. Better to aim high and miss than aim low and hit.
April 9, 2011 at 4:12 am #21575Ken Norris
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Total posts : 45366“Unfortunately, when it comes right down to it, there is too much speculation, and not enough clear hard facts on exactly what is what when it comes to Part15”
We’ve been through this before, but perhaps it’s not such an obvious topic in the archives.
The the basic Title 47 regulations were written more than 3/4 century ago including Part 15. It was a vastly different time, compared to the crowded spectrum today, with digital wireless devices everywhere, in all kinds of bands.
Still, there are some similarities, and updates, which suggest that the regulations were (and are) written to accommodate changes in both technology and politics. Thus there are deliberate ambiguities which allow for interpretation by unelected officials in a given era to abide by the current climate.
It’s not much help, I know. We all wish the code was more black and white so we could more easily determine if we’re compliant or not in a given situation. But the ambiguities do allow for some slack on our side as well.
In spite of some things that we’ve experienced, I don’t think it’s helpful to look at an FCC agent as ‘the enemy’. Even an agent is subjected to the calamities of policy changes, probably much more than we know … powers and principalities, not people on the ground.
I think all we can do is try to be conscientious about how we build and operate our little micro-stations, then simply get on with it.
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