Tim,
Thanks. I am well aware of all that.Thouight I was clear that this was just a temporary setup to get familiar with the system. I apologize if I wasn't more clear on these points.I already have an external enclosure ready to house the transmitter and mount it to the base of the antenna, be it the 102" whip or the ISOTRON 200b, OR YET SOMETHING ELSE. With the current 1700 ft. range I am currently getting with my experimental setup, my signal won't even cross my property line, which is one reason this temp setup is just that, temporary and unacceptable. I already do have 2 other masts (these are aluminum) on my deck which are already grounded. One mast (10 foot) supports my Davis Vantage Pro 2 weather station, the other, a 20 ft aluminum mast supports my GODAR-USA DXR-1000 antenna which is used for DX SW and AM-BCB reception. So I can reach either of these grounds with a very short ground lead, should I choose to do that.My other option,and probably the best one, is to install the radial system in the ground in my back lot and ground mount the antenna.right on it. Since the hill is high up, the antenna will still be as high as if I mounted it on the 25' mast on my 2nd floor deck.
Jim
... I already do have 2 other masts (these are aluminum) on my deck which are already grounded. ... So I can reach either of these grounds with a very short ground lead, should I choose to do that. ...
Jim: Unfortunately the top of such masts will not provide an r-f ground even if the bottom of those masts is attached to a very good r-f ground buried in the earth.
So no matter how short is the "ground lead" conductor from the elevated transmitter to the top of that mast, the entire, exposed height of the mast will carry r-f current, and become part of the radiating antenna system of that transmitter.
Below is an analysis of this situation.
Additionally, from a legal standpoint, the FCC will count your mast as part of the ground lead.
If you put your transmitter on top of a metal mast, and connect the ground lug on the transmitter to the top of that mast, your ground lead is now the 6" wire from the transmitter to the mast, added to the length of the mast. So if you have a 30 foot metal mast, you now have a 30' 6" ground lead. There have been NOUO from the FCC issued to several who have had mast mounted transmitters, and those who have had them mounted to other metal structures. All the metal between the transmitter and the Earth is counted as ground lead.
I have an elevated installation, however my transmitter is mounted to a 3 foot piece of PVC pipe which is mounted to the side of my wood house. I have no ground lead connected. It is certainly not idea, but fortunately I live in the boonies where there are only two other solid AM stations, and very little noise floor, so I can be heard over a mile during the day. I can't really do a ground mounted transmitter -- it would be under several feet of snow 6 months out of the year!
TIB
"If you put your transmitter on top of a metal mast, and connect the ground lug on the transmitter to the top of that mast, your ground lead is now the 6" wire from the transmitter to the mast, added to the length of the mast...There have been NOUO from the FCC issued to several who have had mast mounted transmitters, and those who have had them mounted to other metal structures. All the metal between the transmitter and the Earth is counted as ground lead."
Which absolutely sucks, with additional expletives added. The RangeMaster, I believe was designed to broadcast exactly in that fashion! Then old Keith got the notice...big dent in that idea! Oh well, the thing still is a blowtorch...
Right. ANYTHING to kill the chance of a decent signal at 100mw! For 40+ years I broadcast at 100,000 watts on a full service FM. I was on 5 and 10 thousand watt AMs as well. For the FCC to squash my little 100mw because of the (hyphenated expletive) ground lead? Hell, why bother?
And everyone wonders why there are so many Pirates...it's this kind of rule! Don't break the Law, but I will damn well complain about it! Does anyone agree with me, or do I need to go elsewhere?
Doug
To reach your target area with a part 15 AM system you must locate the transmitter and antenna at the target location.
Getting the audio to the transmitter could be done in any number of ways, which would be an entire second scientific project we can talk about.
I got this from HB. Under Psrt 15 Transmitters, there is a thread discussing the RangeMaster at ground level and above groun d level. I am claiming FAIR USE here quoting him:
[Edit Notification Part15.us administrators have received notice from Bill DeFelice at HobbyBroadcaster that the copied post is copyrighted and that if the post is not removed a complaint will be filed under the DCMA with the site hosting provider, therefore it is gone but here's the link to the original post:
https://www.hobbybroadcaster.net/community/index.php?topic=728.msg32842#msg32842
end edit]
Basically your ground wire cannot be an antenna. Use engineering practices to prevent it from radiating; An interesting topic is that it seems to be OK with the FCC to use the Earth of the electric system for this connection. Note that the million or so talking house transmitters that are out there connect directly to the building earth ground, I assume this was approved in their certification?"
I am glad I ran across that post. I feel a bit differently now. I hope this develops discussion. It sure shines a light on some important issues...
Doug
Your turn.
Tim,
No problem I am well aware of the rules. When I set up my permanent installation the antenna will be ground mounted above the radials and still be just as elevated as if I had it on one of my 25 ft towers on my second floor deck, as my back lot is a good 40-50 ft higher than the ground level of the house.
Dugger, to keep things civil, "Fair Use" does not apply here. Attorney David L Amkraut, in an article for TheBookDesigner.com, says Fair Use consists of "limited and reasonable uses of copyright–protected work." Large copy-and-paste reprints from a source identified by the murky acronym "HB" does not qualify.
To keep things respectful and legal, the proper thing would have been to ask the author for permission to use excerpts, with links to the original piece. Luckily, actions like yours only cause friction and raw feelings between Part 15 groups on the Web. Elsewhere in real life, it can be cause for copyright infringement and assessed damages.
I've been in publishing for 28 years and can tell you that merely claiming "Fair Use!" does not make it so. Seek out the "Four Factor" test to see why. But more importantly, I'm sure you would not like seeing entire blocks of your own work appropriated without proper credit.
... When I set up my permanent installation the antenna will be ground mounted above the radials and still be just as elevated as if I had it on one of my 25 ft towers ...
Jim: Just to note that other things equal, the groundwave fields produced by "Part 15 AM" systems greatly depend on the r-f power they radiate -- not from their elevation above local terrain/AMSL.
An elevated tx+whip system using a 25-ft mast/conductor to connect to an r-f ground most likely will produce higher fields at the same given distances than a transmit+whip system installed at the same elevation AMSL, but using a much shorter conductor to connect to an equivalent r-f ground.
The reason for that is due to the added radiation from the 25-ft conductor from the tx to earth r-f ground, for the system installed at the higher elevation AMSL.
Darsen, you said:
"...the proper thing would have been to ask the author for permission to use excerpts, with links to the original piece."
Good grief. The man posts in a public forum. I gotta ask permission to quote him? Not a chance. I just will be more selective. Too much of this friction and raw feelings between Part 15 groups on the Web.
Oops! Now I'm quoting YOU! I'm done.
Doug
Mods:
Feel free to delete post #81 if there has been some "violation".
Doug
Jim you might want to invest in a rangemaster or procaster before you spend too much trying to get this system to work the way you want it.
I've been there and spent 3 or 4x what the Rangemaster goes for by trying to get the lower cost transmitters to get the same range. In the long run it might be cheaper to save up for the higher priced gear and get the coverage you want. I was dissapointed for several years until I bit the bullet and got a used Rangemaster.
Not saying good coverage isn't doable with your gear, in fact its very possible, just be prepared for a headache and some choice cursing as you work on it. (Which arguably can actually be very fun and educational)
Basically your ground wire cannot be an antenna.
This is incorrect. The rule is the combined length of your antenna, feedline and ground lead cannot exceed 3 meters. The FCC doesn't care much about the rest.
And when you want to know about what may or may not be included in a certification, look it up on the FCC web site!
TIB
Mighty,
Thanks very much for the suggestion. While I am happy with the SSTRAN AMT-5000, I am now also looking at the Procaster and the Rangemaster.
Jim