HFU HF Underground
General Category => General Radio Discussion => Topic started by: Fansome on May 12, 2010, 2308 UTC
-
http://www.hard-core-dx.com/nordicdx/antenna/ground/ground2.html
-
Like anything discussing grounding and antennas thee seems to be good info and not so in here.
"I believe it has been mentioned that electrical codes require that all grounds be tied together with heavy guage wire."
"I'm no expert on electrical codes, and codes differ in different countries. However, I believe that any such requirement must refer only to grounds used for safety in an electric power distribution system: I do not believe this applies to RF grounds."
Actually it DOES refer to ALL grounds If one has a ground near the station and a ground at the service entrance, any induced voltage (nearby lightning,etc) will cause current to flow inside the structure, since what the source sees when there's two grounds is a voltage divider....which is what you do NOT want.
There's some good stuff in there, but think of portable radios running off batteries... and connected either to the whip or a dipole...there's no ground there and the system works fine...
Grounding may help, and it's well done it a good safety measure but I've not found it to be a major factor in real-world DXing.
-
There's some good stuff in there, but think of portable radios running off batteries... and connected either to the whip or a dipole...there's no ground there and the system works fine...
Indeed!
When I run my E5 (I only use the adapter when the batteries are charging) into my dipole, if I ground the coax shield (I have a proper balun at the antenna), the noise from appliances and CFL bulbs goes up.
Peace!
-
Grounding may help, and it's well done it a good safety measure but I've not found it to be a major factor in real-world DXing.
I am no expert on antennas, but my experience is that my ground is critical to my reception of pirate signals. My antenna is 75 m long wire, which starts 30 m form my house, and runs into the woods. It is fed to my house by coax which has the sheild grounded at both ends. (At my radio the ground wire is connected to both the antenna ground and the coax sheild.) Both ends of the coax shield are connected to 1.5 m copper rods driven into the ground.
I basically followed the guidelines in http://www.iw5edi.com/ham-radio/?low-noise-antenna-connection,45. (Except I still don't have a balun ... didn't have one when I set it up, and seems to work fine. Tried ordering toroids at the local electronic shop, but still waiting.)
My main point is that when the ground is working properly, my noise level seldom moves the s meter. When it is malfunctioning (including the ground drying out), the noise level jumps to s5-s7.
All I can say is ... works for me.
Cheers, Terry
-
Hello all, my first time posting in here. I am having a problem with my reception, and I hope that you all can give me some feedback and let me know what I should/can do.
First of all I am using a ICOM R71A, and I have a 70 Foot Long Wire atenna in my apartment attic. Seems like I get no reception below 7000, and I different cannot hear any priates even on 6925. I get all static.
My receiver and antenna are not grounded. Do you think that it would help if I ground them, and if so, what would be a good grounding while living in a apartment?
Thanks again, Steve...
-
Years ago had a setup much like yours, using a DX-440 and about 40 feet of wire in the attic. I used this product to tune the antenna:
http://www.mfjenterprises.com/Product.php?productid=MFJ-16010
It worked pretty well. I was never able to hear pirates with it, but I took that to be because I was on the west coast. I was certainly able to hear a lot of other stuff, such as broadcast stations, hams, utilities, and the like. I didn't do anything about grounding the radio.
-
Hello all, my first time posting in here. I am having a problem with my reception, and I hope that you all can give me some feedback and let me know what I should/can do.
First of all I am using a ICOM R71A, and I have a 70 Foot Long Wire atenna in my apartment attic. Seems like I get no reception below 7000, and I different cannot hear any priates even on 6925. I get all static.
My receiver and antenna are not grounded. Do you think that it would help if I ground them, and if so, what would be a good grounding while living in a apartment?
Thanks again, Steve...
Grounding may help your reception, but I don't think lack of a ground is the reason you are having such trouble receiving below 7000 khz.
If you're not even hearing broadcast stations on the 49 meter band, I don't think lack of a ground is the problem. If you're in the U.S., Cuba should at least come in on the 49 meter band.
As far as a ground goes, the easiest and quickest ground for your setup would be a ground "radial" -- basically a long piece of wire that's attached to the ground terminal on your radio; you could run it across the floor and see if it improves your reception. A wire like that will act as a ground.
-
Hello all, my first time posting in here. I am having a problem with my reception, and I hope that you all can give me some feedback and let me know what I should/can do.
First of all I am using a ICOM R71A, and I have a 70 Foot Long Wire atenna in my apartment attic. Seems like I get no reception below 7000, and I different cannot hear any priates even on 6925. I get all static.
My receiver and antenna are not grounded. Do you think that it would help if I ground them, and if so, what would be a good grounding while living in a apartment?
Thanks again, Steve...
I agree with the other posters, grounding is not going to solve a problem with no reception below 7 MHz.
First step - have you tried listening for some of the powerhouse signals? For example, WWCR on 6875, Cuba on 6000, etc? They should both put in extremely strong signals into NJ. You'll need to check their schedules to see when they are on. If you can't pick them up well, or at all, then I'd suspect a radio issue.
And indeed, as a fellow R71A owner... there is one issue that comes to mind. Many Icom radios, including the R71A, used trimmer caps in the VCO that fail over time. When they do, the PLL doesn't correctly work, and you lose reception in part of HF. From memory, the lower PLL covers about 0-8 MHz. So perhaps this is your problem? Check and see how it does on AM as well, it should certainly pick up AM stations any time of the day.
-
What wire gauge would you recommend and how long across the floor? Thanks Steve. Oh I do live in USA and I do receive Cuba with a problem.
-
RE: trying a ground 'radial':
For SW reception, practically any gauge of wire should do. You could use the same wire you used for the antenna.
For just receiving (i.e. not transmitting) the length of the ground radial isn't very critical.
Make it the same length as your antenna, or somewhere close. You could even loop it around the floor if needed.