Is there a good "HF antennas/grounding for dummies" resource anywhere?

[raisindot]

Yes, yet another stupid question about antennas and grounding. Apologies in advance for my stupidity and for dredging up this old dog, but I've searched the Wiki, past posts, and googled all over the place and am still extremely confused by everything I read, since they all seem to offer very fine iteas that are so far beyond my limited understanding of electronics that my head is swimming.

Anyway, I am currently using a newbie indoor antenna consisting of shielded wire taped to my basement ceiling and going to my new Icom R-75 receiver. I would like to improve reception and lower the noise threshhold by trying an outdoor antenna, but I am concerned about grounding and potential static building.

I do understand the ground rod concept. I think I could drive an 10' ground rod into the ground as well as anyone. It's all the stuff about connecting wires and baluns and capacitors and shields 'n stuff that make my brain hurt.

So, I would like to try the outdoor antenna--and by this mean a simple longwire, because I don't want to deal with attaching dipoles and things to the side of my house. I want something I can string from the basement window to a tree and take down when I'm not using it.

Issues:

1. I would prefer not to drill holes through a wall or window of any kind, and was wondering whether anything exists that would allow me to feet a signal or ground wire under a window sill?

2. I've read all the descriptions of how to string and connect and all this, but I've never seen a good, simple visual diagram showing what each step of the process, especially connecting from a longwire antenna to a coaxial cable, and connecting whatever to a ground rod, looks like.

3. I'd love a very simple visual explanation of a ground system to provide basic protection from static and ground the radio, and what kind of things I would use to 'discharge' any static buildup.

4. In terms of grounding the radio itself, my radio is a long way from a cold water pipe--I'd have to string cables through the ceiling to get there--and would like to know whether the "attaching to the center screw on the outlet" is really a viable alternative for the radio.

5. Should one ground both the radio and the antenna to the same grounding rod (i.e., need to send two separate cables--coax for the antenna, whatever for the radio, and connect both to the ground rod?

Note I am not aiming for maximum lightning protection--I always disconnect all electronic from all power sources and antennas lines at the first hint of a storm anyway.

Note that I know nothing about electronics, and am not aiming for a whole house solution--just something I can set up for 'safer' general purpose, casual SW/utility monitoring in good weather.

If there is a good resource on the web--a site, or even a book--designed for people like me, a citation would be most appreciated. Again, apologies in advance for my stupidity.

Suzie

 

[lanbergld]

Suzie, I'm sorry but I am very curious. Why do you have that wire attached to a basement ceiling instead of on a window?

I used to have an IC-R75 -- a couple of them as matter of fact -- and they are superb receivers. I logged more longwave beacons on the R-75 than on all my other receivers combined. But my loops absolutely had to be attached to the window.

Larry Lanberg
Richmond VA

 

[ka3jjz]

I will leave the subject of grounding to the many others who have made extensive comments on this subject. However I will say that skimping on the grounding will, sooner or later, end up costing you more than if you did it right the first time. A whole house approach, from everything I've read, is the way to go. The center screw approach is not a particularly good RF ground - it's OK to prevent shock hazards, but that's the extent of it.

As to antennas - while there are several articles from the AMANDX site (and one or two from MT) which are pretty simple to follow (and they are linked in our wiki) the most dummy proof antenna there is, in my view, is the PAR EF SWL antenna. The website has a downloadable manual which has many tips as to how to mount and wire it. Widely available, and equally widely praised. If the 45 foot of flex weave (I think that's as long as the antenna is) isn't enough, you can replace it with more if you wish. However, that being said, it's always good practice to have a second antenna available - if one doesn't seem to bring in that elusive signal, perhaps a second antenna (of a different type) will. It's hard to recommend anything without knowing a bit more about the outdoor area you have - how big, how many trees, how far from your house (frankly the farther away the better - you will be able to escape the noise generated from various appliances from your home better with distance...) and so forth.

As to feeding the coax through a window, I'm certain that I've seen feed through tubes or similar - you could, for example, use a block of plexiglass to fill the space where the window is open, then use the feed throughs to bring the coax into the shack. I've seen a few hams do this, though I admit I've never tried it myself. It sounds reasonably simple, however. I'm sure there are other solutions I haven't thought of. 73 Mike

 

[SCPD]

Feedlines and grounding

Issues:

1. I would prefer not to drill holes through a wall or window of any kind, and was wondering whether anything exists that would allow me to feet a signal or ground wire under a window sill?

Suzie

Cut a piece of wood that you can fit between the window and the window sill, and then lower the window on top of it. (like putting a window a/c in). Then drill all the holes you want in the piece of wood to get outside.

Now, to learn all about grounding, I want you to poke around this site for a while:

PolyPhaser and Transtector - Surge Protection Specialists

There's a link called "Grounding" on the bottom left. Then click on Support on the top of page that takes you to, then click on Technical Notes. Read all that, then come back here if you have any more questions.

 

[W6KRU]

If the OP wants to run a long wire out of a window to a tree, what is to be grounded? Information about grounding towers and masts does not apply.

 

[BuffaloJustice]

Does a single wire build up much static in the first place? I know large multi element antennas mounted on large towers build up quite a bit but I wouldn't think a single wire would. If the wire is only up when in use lightning wouldn't be an issue either, except for the actual building wiring already mentioned.

 

[Viking1]

Get a piece of 1/4 inch plexiglass from lowe's, buy some barrel connectors, drill holes, mount barrel connectors through holes, wrap outer edge of plexiglass with weatherstrip, place in window sill, close window on it, screw a deck screw through the windows to keep them from opening.

 

[Viking1]

Now for the antenna, this is how it's done the right way.



for the insulators take 2 small pieces of pvc pipe, drill holes through each ends, run your antenna between them, strip, loop through the insulator, twist the wire back over itself and solder each end, one one side twist another piece of wire with the end stripped off to the solder joint you just made and solder again, this lead goes to the balun (red side), then tie "paracord" or other long lasting low profile rope to each end and hang one end from the eve of the house and the other from a distant tree (the higher the better) Take another piece of antenna wire and run between the 9:1 balun and the ground rod. (this will bleed off static)

Anything less than a 8ft ground rod is a waste of time and money and the shorter path to ground from the balun the better.

Antenna is for RX only.

The 9:1 balun is important as it matches the high impedance of the wire to the 50 ohm input of the radio, it greatly reduces static and noise and the ground side of the balun bleeds off static to ground.

9:1 RX balun
build it or get one of these
Shortwave/Ham Radio 9:1 UNUN Antenna "Balun"Transformer - eBay (item 230326175765 end time Feb-23-09 21:50:23 PST)

 

[Viking1]

1. I would prefer not to drill holes through a wall or window of any kind, and was wondering whether anything exists that would allow me to feet a signal or ground wire under a window sill?

2. I've read all the descriptions of how to string and connect and all this, but I've never seen a good, simple visual diagram showing what each step of the process, especially connecting from a longwire antenna to a coaxial cable, and connecting whatever to a ground rod, looks like.

3. I'd love a very simple visual explanation of a ground system to provide basic protection from static and ground the radio, and what kind of things I would use to 'discharge' any static buildup.

4. In terms of grounding the radio itself, my radio is a long way from a cold water pipe--I'd have to string cables through the ceiling to get there--and would like to know whether the "attaching to the center screw on the outlet" is really a viable alternative for the radio.

5. Should one ground both the radio and the antenna to the same grounding rod (i.e., need to send two separate cables--coax for the antenna, whatever for the radio, and connect both to the ground rod?

Note I am not aiming for maximum lightning protection--I always disconnect all electronic from all power sources and antennas lines at the first hint of a storm anyway.

Note that I know nothing about electronics, and am not aiming for a whole house solution--just something I can set up for 'safer' general purpose, casual SW/utility monitoring in good weather.

If there is a good resource on the web--a site, or even a book--designed for people like me, a citation would be most appreciated. Again, apologies in advance for my stupidity.

1. see my above post about the window pass through.
2. Do NOT use the ground off the electrical outlet!!!! the impedance is too high.
3. Anyone telling you to use anything less than a 8ft copper clad ground rod is a clueless idiot
4. Don't just slam your coax in the window, it squashes the cable and changes the impedance.


further explanation.

For the ground at the entrance, I measured across my window and went to Lowes and had them cut me a piece of plexiglass 1/4 in thick a bit longer than I really needed so I could adjust it for best fit then I ordered oversize nuts for the barrel connectors from "wireman.com" along with 25ft of 2in copper flashing. I screwed the copper flashing across the plexiglass carefully using small screws then carefully drilled the holes for the 3 inch barrel connectors. (go slow and take your time) Then place the barrel connectors through the plexi securing them with the oversize barrel nuts making sure that the nuts securely contact the copper flashing on the outside. Then add a bit of lock-tite to the nuts to keep them from becoming loose. At the point to ground I screwed another piece of copper flashing to the one going across pointing down @ 90 degrees with 4 small screws then ran a brass screw with washers and nuts on each end to make the ground attachment for my equipment inside the shack. )everything to ONE ground) Then wrap the plexiglass in weatherstripping and install in the window and using fish tank silicone seal along the edges of the nuts and flashing to keep water out. For security, run a 3 inch screw through the windows so it cannot be opened or closed. Now drive in a 8 ft ground rod outside the window (wait till after it rains, much easier) Using 2 stainless steel pipe clamps (auto parts store) secure the copper flashing to the copper ground rod as tight as you can get it. Next get a propane or mapp gas torch and heat the hell out of the top of the ground rod and using ROSIN CORE electrical solder flow it between the copper flashing and the ground rod ensuring a good electrical connection. (heat the work, not the solder)

This will give you the pass through, seal out the outside weather and insects, ground the antennas properly at the shack entrance, give static a easy path to earth and give you a point to ground your equipment to as well. (everything goes to ONE common ground)

look at my post above and if you use the 9:1 balun (recommended) seal it up real good with the silicone and mount it just outside the window. The red side goes to the antenna and the black side connects directly to the ground rod. (run the end of the bare wire through the pipe clamps and solder to the ground rod)

(excuse the mess, I haven't finished everything yet)

I've rambled enough, you get the idea, I'm off to bed.

 

[James04TJ]

While the previous post is good, remember a couple things... First the ground rod that your are installing near the entrance panel must be bonded to the service entrance ground (and any other grounds). Second, you do not want to use solder to make connections between ground system components (use bolt on fasteners or exothermic welding). Finally, your entrance bulkhead should contain lightning arrestors but you must ground the shield of the coax prior to those protectors.

If you click the technical papers link on Polyphasers website as previously noted, they have a paper for amateur radio applications that does a good job explaining grounding and bonding for the hobbiest.

 

[raisindot]

As to antennas - while there are several articles from the AMANDX site (and one or two from MT) which are pretty simple to follow (and they are linked in our wiki) the most dummy proof antenna there is, in my view, is the PAR EF SWL antenna. The website has a downloadable manual which has many tips as to how to mount and wire it. Widely available, and equally widely praised. If the 45 foot of flex weave (I think that's as long as the antenna is) isn't enough, you can replace it with more if you wish. However, that being said, it's always good practice to have a second antenna available - if one doesn't seem to bring in that elusive signal, perhaps a second antenna (of a different type) will. It's hard to recommend anything without knowing a bit more about the outdoor area you have - how big, how many trees, how far from your house (frankly the farther away the better - you will be able to escape the noise generated from various appliances from your home better with distance...) and so forth.

Thank you for the recommendation. It looks like the PAR is a good choice.

I've looked at the manual, and find the ground information nearly incomprehensible. It says.

"How to configure the grounding. This will vary from location to location. The 9:1 binocular core
transformer has both the primary and secondary ground leads brought out to 10-32 stainless studs.
See Fig. 2. Default is with these two connections (#1-#2) shorted and attached to an RF ground close
to the matchbox . This connection may also be left ungrounded and then grounded at the receiver.
However, this connection may result in noise pick up on the shield of the coax. Depending on the
efficacy of the receiver ground, more noise may be present with this connection, and the outer shield
may also act as part of the antenna. Alternatively, the shorting connection may be removed and the
antenna side grounded at the antenna (#2), the receiver side (#1) may then be grounded back at the
receiver location, or left ungrounded– whichever results in less man made noise pick up . The
thought here is that noise generated in the home (dimmers, fluorescent lights etc) can be conducted
along the coax to the antenna."

What I don't get it is how I would actually ground the antenna using the inputs. Where would I attach the twisted weave antenna? How do I make the connection between the grounding rod and the matchbox? Why would I choose to ground the receiver only and not the antenna? Could I ground both the antenna and the receiver using the two grounding inputs on this thing? Could I just "screw in" the coax cable to the matchbox and run that straight to the receiver, or should I run one end of the coax into some kind of "protection thing" and run the other end out to the receiver?

Again, sorry for my ignorance. I understand the concept, but not the implementation.

Suzie

 

[raisindot]

Suzie, I'm sorry but I am very curious. Why do you have that wire attached to a basement ceiling instead of on a window?

I used to have an IC-R75 -- a couple of them as matter of fact -- and they are superb receivers. I logged more longwave beacons on the R-75 than on all my other receivers combined. But my loops absolutely had to be attached to the window.

Larry Lanberg
Richmond VA

Well, mainly because I'm an idiot and read somewhere that these kinds of ceiling antennas worked well.

When you say "attached to the window" do you mean on the inside of the window (i.e., on the sides between the window sill and the screen/storm windows?) or do you mean outside on the window frame? I'd consider moving the whole thing to an inside window loop as a first step if this might work better.

Suzie

 

[raisindot]

1. see my above post about the window pass through.
2. Do NOT use the ground off the electrical outlet!!!! the impedance is too high.
3. Anyone telling you to use anything less than a 8ft copper clad ground rod is a clueless idiot
4. Don't just slam your coax in the window, it squashes the cable and changes the impedance.

Sorry, but this just made me laugh my a** off. I'm sure it works extremely well and looks incredibly impressive technologically, but I think the neighbors would tar and feather me if they had to look at anything like that hanging out the window.

Suzie

 

[Viking1]

While the previous post is good, remember a couple things... First the ground rod that your are installing near the entrance panel must be bonded to the service entrance ground (and any other grounds). Second, you do not want to use solder to make connections between ground system components (use bolt on fasteners or exothermic welding). Finally, your entrance bulkhead should contain lightning arrestors but you must ground the shield of the coax prior to those protectors.

If you click the technical papers link on Polyphasers website as previously noted, they have a paper for amateur radio applications that does a good job explaining grounding and bonding for the hobbiest.

1. Forgot to add the service entrance thing,Yes that is correct, it was 4am. Mine is clamped about 6 inches underground and run underground to the other 4 ground rods at the corners of the house and tied into the panel ground along the way. Also, there isn't anything wrong with flowing solder over the connections to ensure the impedence is low as long as you have a good solid connection to begin with, it can only make it better. (see the two stainless clamps holding the flashing to the ground rod)


Polyphasers aren't necessary if you're disconnecting when not in use.

 

[Viking1]

Sorry, but this just made me laugh my a** off. I'm sure it works extremely well and looks incredibly impressive technologically, but I think the neighbors would tar and feather me if they had to look at anything like that hanging out the window.

Suzie

That room doesn't really face anything, and my nearest neighbor would need binoculars to see it.

 

[ka3jjz]

Thank you for the recommendation. It looks like the PAR is a good choice.

I've looked at the manual, and find the ground information nearly incomprehensible. It says.

"How to configure the grounding. This will vary from location to location. The 9:1 binocular core
transformer has both the primary and secondary ground leads brought out to 10-32 stainless studs.
See Fig. 2. Default is with these two connections (#1-#2) shorted and attached to an RF ground close
to the matchbox . This connection may also be left ungrounded and then grounded at the receiver.
However, this connection may result in noise pick up on the shield of the coax. Depending on the
efficacy of the receiver ground, more noise may be present with this connection, and the outer shield
may also act as part of the antenna. Alternatively, the shorting connection may be removed and the
antenna side grounded at the antenna (#2), the receiver side (#1) may then be grounded back at the
receiver location, or left ungrounded– whichever results in less man made noise pick up . The
thought here is that noise generated in the home (dimmers, fluorescent lights etc) can be conducted
along the coax to the antenna."

What I don't get it is how I would actually ground the antenna using the inputs. Where would I attach the twisted weave antenna? How do I make the connection between the grounding rod and the matchbox? Why would I choose to ground the receiver only and not the antenna? Could I ground both the antenna and the receiver using the two grounding inputs on this thing? Could I just "screw in" the coax cable to the matchbox and run that straight to the receiver, or should I run one end of the coax into some kind of "protection thing" and run the other end out to the receiver?

Again, sorry for my ignorance. I understand the concept, but not the implementation.

Suzie

I'm afraid I don't have the antenna, so I can't answer this directly. However Dale at PAR has built a reputation on taking the time to answer questions, and if you research his antennas on the EHam website, you'll find that what I just said is backed up by everyone who asks. If no one answers here, ask him - chances are he will be willing to answer any and all of your questions. 73 Mike

 

[lanbergld]

Well, mainly because I'm an idiot and read somewhere that these kinds of ceiling antennas worked well.

You're not an idiot! This is what makes it a hobby after all -- trying different things. I've also heard that ceiling antennas, door antennas, floor antennas etc. work for certain people. Not for me. Mine has to be right on the window. Not near the window, not below the window & not above it. But right ON it. I go all over the world like this. I couldn't receive otherwise.

It makes no difference whether its on the inside of the window or on the outside. The outside isn't any better, let's put it that way. I use plastic suction cups hooks to hold the wire or loop directly on the window glass.

About your grounding and noise. Please try this simple experiment.

Take a short length of wire. Just three or four feet. Strip both ends to bare -- just at the ends. Put one end into your (+) spring terminal. Let other end stretch out, toward your window or wherever. Tune around & listen to the noise. THEN, without changing anything else, put the other bare end -- the free end you had stretched out -- and insert this into your (-) spring terminal. Tell me if your noise disappears or reduces substantially. It should.

Larry Lanberg
Richmond VA

 

[raisindot]

About your grounding and noise. Please try this simple experiment.

Take a short length of wire. Just three or four feet. Strip both ends to bare -- just at the ends. Put one end into your (+) spring terminal. Let other end stretch out, toward your window or wherever. Tune around & listen to the noise. THEN, without changing anything else, put the other bare end -- the free end you had stretched out -- and insert this into your (-) spring terminal. Tell me if your noise disappears or reduces substantially. It should.

Larry Lanberg
Richmond VA

Can I assume that by + spring terminal you're referring to the ground terminal and - spring terminal you're referring to the 500 ohm antenna connector? Just want to make sure, since these aren't marked with plus/minus on the back of my R-75.

Suzie

 

[Bill1]

Window Pass-Through

In case you are looking for an off-the-shelf solution for passing coax, wire, etc. through a window, here's one I use:

http://www.mfjenterprises.com/pictures/MFJ-4602.jpg

Saw it at the Dayton Hamvention last year and brought one home. I only put it in the window when I am going to be operating for a time, and then remove it. This solves the unsightliness issue, and reduces the risk of someone trying to use it as an entry point (unless they want to break in while I'm right there in the shack ).

This panel works well. It comes with weatherstripping and air leakage when it is installed is minimal.

Once the ground un-freezes, I will drive a ground rod and make a tie point available for the panel when it is in use. I realize this isn't an optimal solution, but in mapping out the installation (with I.C.E. lightning arrestors, etc.) I discovered a previous owner of our home, or someone, had clipped the service entrance ground so we have lived for 11 years with no service ground. I discovered the clipped end of the wire has been painted over a few times, even by me before I realized what it was!

Anything will be an improvement over that...

 

[James04TJ]

1. Forgot to add the service entrance thing,Yes that is correct, it was 4am. Mine is clamped about 6 inches underground and run underground to the other 4 ground rods at the corners of the house and tied into the panel ground along the way. Also, there isn't anything wrong with flowing solder over the connections to ensure the impedence is low as long as you have a good solid connection to begin with, it can only make it better. (see the two stainless clamps holding the flashing to the ground rod)


Polyphasers aren't necessary if you're disconnecting when not in use.

I missed the mechanical connection on the ground, you are 100% correct that it certainly does not hurt to augment the mechanical connection with solder.

As for disconnecting the equipment, the only word of caution would be exactly where you are disconnecting. If you are disconnecting from a bulkhead that terminates inside the structure you still run the risk of fire due to arcing from a current that makes its way down the center conductor. For around $100 for a good polyphaser I look at it at very cheap insurance compared to a possible fire loss.