Well, we worked with this for two days. We tried grounding it three different ways. I had an engineer helping me who tuned the transmitter.
But I am not even getting a good 1/2 mile.
Something must be wrong and I don't know what it could be.
I've got three 8' ground rods and the antenna is on top of a 35' building. I'm doing some audio processing to boost the signal.
But the range is poor.
I suppose I will be getting back to Hamilton for advice, but maybe somebody has some insights as to what could be wrong.
BC Man... What is the ground conductivity in your specific area? Your engineer friend should be able to find that out for you.
In the US, it ranges from 0.5 to 30 millimhos. (Seawater is 5000.) That will have a direct effect upon your range. I live in a 15 to 30 millimhos area. 0.5 is terrible.
BC: << I've got three 8' ground rods and the antenna is on top of a 35' building. I'm doing some audio processing to boost the signal. >>
Are the wires to those three rods close together? If so, they will act nearly as just one wire (mutual inductance from inter-coupling) and thus defeat the purpose for having three.
Too, the wires to those ground rods could look like -- to the FCC -- as 30+ foot extensions (counterpoise) to your antenna system.
Good luck,
Bill in SE Texas
http://members.aol.com/K5BY/Index.htm
The ground wire runs down to one rod, and the rods are connected in series. There's just one ground wire to the first ground rod.
I am in Oregon which is probably similar to California. I know of at least one part 15 operation getting a good mile or more in California.
BC Man: << I am in Oregon which is probably similar to California. I know of at least one part 15 operation getting a good mile or more in California. >>
Ah so... Well, according to the FCC map at...
http://www.fcc.gov/mb/audio/m3/index.html
...Oregon has mostly a ground conductivity of 4 millimhos (not good), with an 8 spot at the northern border and a 5-er at the southern border. Whereas, California has lots of 8 area and even a 15 in a couple of places.
If you have just a 35-foot wire going to one or more ground rods, I don't believe you have a ground or even a counterpoise (because of the attachment to the ground rods). It appears to be an RF choke to me, i.e., a nothing to RF.
There's a young lady in the Boston area who has an SSTRAN and a loaded antenna she built. She was trying to find a good ground on the roof of a 45 story building. (I wish she'd contact me and give me a status report. Her email address is in my down computer.)
I suggested connecting wires to all the metal encased devices on the roof -- the heating, ventilation, and a/c (HVAC) units. And then tack down the wires with blobs of roofing tar.
For either of you, maybe connecting to an a.c. ground up there would work. That ground radiates all over the building and could probably do the trick. Connect to the socket where your Rangemaster's wall wart connects.
Good luck,
Bill in SE Texas
http://members.aol.com/K5BY/Index.htm
Here's some photos of my installation.
I did try grounding to the pipes on the roof and also to a ground wire from the telephone company, with no improvement.
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Note: There are a couple of inches between the horizontal wire going across the top of the building and my ground wire. They do not touch, although we did try hooking them together with no improvement.
Also, we did try unhooking my ground wire from the hook on the side of the wall, and running it fairly straight down from the transmitter, which did not help. We of course retuned the transmitter with every change we made.
The grey pipe is a plastic conduit pipe. I ran the ground wire through that so that nobody would be able to pull on the wire. I intend to solder the ground wires to the ground rods if/when this becomes a permanent set-up.
I'm waiting to hear from Mr. Hamiltion with his suggestions.
A very interesting layout, BC Man. Thanks for posting all of those photos. I look forward to when I can post photos of my station.
With that long of a run of cable, have you checked to make sure the supply voltage at the transmitter is what it should be? I assume, though, that you get the proper "RF" voltage reading when you have it properly tuned.
I'm afraid that your range limitation may be due to your area's ground, i.e., soil, conductivity. For FM-ers, the quality of the soil only affects "reflectability." For AM-ers, it affects the range of the "ground wave," which carries the signal during daylight hours.
Now, for a given ground conductivity, the range increases as the frequency goes down. But the bandwidth goes down, too, for a given antenna size. A lower frequency of operation may require adding pre-emphasis to the highs in the audio, especially for music. With that long of an audio run to your transmitter, you probably already have to do that some, because the cable will have more and more affect (attenuation) on the high frequency end of audio.
Good luck,
Bill in SE Texas
http://members.aol.com/K5BY/Index.htm
Thanks for you comments, Bill.
The run from my transmitter to audio source is not very long, though. Only about 20 to 25 feet.
Contact me where are you in Oregon..Nice setup
I'm down in Grants Pass.
Thanks for the compliment, but I am very unhappy about the situation right now. 100 yards of a good signal is not what I had in mind when I went to this expense.
Hopefully we can fix this..
I was wondering...is there a way I can help..
Jerry
Jerry,
Do you have your own Part 15 set-up? Do you use a Hamilton transmitter? What kind of range do you get?
Say, BC Man...
Have you considered running the pipe mast on the outside of the building, all the way down to the ground, and then grounding the transmitter about where it mounts on the pipe mast? The mast will then be your ground conductor or, to the FCC, your (elevated) ground.
To secure the upper part of the mast, just use a goose neck arrangement over the parapet and down to the existing upper support.
Then put a ground rod at the base of the mast and connect the two.
You should also consider putting a jumper wire across each pipe joint, to assure a good electrical connection at the joints. See my Transmitter and Antenna Mounting Details at:
http://members.aol.com/K5BY/Index.htm
Bill in SE Texas