# Garage Door Opener Problem

Discussion in 'General Technical Questions and Answers' started by W3ICM, Feb 19, 2019.

1. ### WB5YUZHam MemberQRZ Page

How long is the connection from the ground buss to the earth ground? What does the earth ground consist of?

2. ### W3ICMHam MemberQRZ Page

Thank you for your interest in solving my problem.

The wire from the shack ground bus to ground rod #1 is 10 feet of #6 solid copper wire. It's straight. It is connected to ground rod # 1 that is an 8-ft copper clad rod driven vertically into the soil. The wire is solidly connected to the rod using TWO acorn-type connectors spaced about three inches apart. Thus there is a solid double connection there The earth ground at the moment consists of TWO 8-ft copper-clad rods driven vertically into the soil. They are about 18-feet apart, and are connected together with # 6 sold copper wire, buried 3-6 inches.

I have another "to be connected" rod driven into the soil, around 18 feet from each of the other two rods. They form a triangle. I will connect them all together when the weather gets better and I have time. Also, my spring or summer plan is to use # 6 solid copper wire to connect the earth ground rod # 1 or maybe rod # 2 to the earth grounds of the electric company and Verizon Fios grounds.

I did some research into grounding, and I read that multiple copper rods should be spaced apart at least twice the length of the rods, hence the 18-foot separation.

Please let me know if this ground system is adequate or inadequate. I am open to suggestions to improve.

3. ### KP4SXXML SubscriberQRZ Page

Your ground may not have any effect if its simple RF overload of the door opener.

WB5YUZ and KB4QAA like this.
4. ### N0TZUPlatinum SubscriberPlatinum SubscriberQRZ Page

If it were me, the first thing I would do is install capacitors across the two door button terminals and on the door sensor terminals of the motor unit, as others have suggested. The wires connected to those terminals are the most likely way that your signal is being introduced into the control electronics of the motor unit.

If that doesn't fix it, then the next thing would be to add ferrite chokes to those wires (while still retaining the capacitors), and also to the power cord of the opener. Multiple turns are much more effective (to the square of the number of turns) than adding more chokes.

5. ### WB5YUZHam MemberQRZ Page

Well, this could be part of the problem. Traditionally, you want an RF ground connection in 20m to be about eight feet long or shorter - the rule of thumb being, 1/8 wave or less.

However, yours is not that much longer than eight feet long, so it is not as likely to be the problem as it would be if it were, say, twelve feet long.

Try disconnecting the ground lead at the shack end and see if that helps. Remember, some of the most knowledgeable amateurs on this board do not have a separate "RF" ground for their shack - any RF grounding necessary is taken care of at the antenna.

One other question: does your G5RV have a good 1:1 current balun at the junction of the balanced-line and coax? Common mode currents on the outside of the coax shield are not unheard of with G5RVs when there is no balun at that point, especially when the balanced-line section does not hang straight down, perpendicular to the plane of the antenna.

6. ### KQ0JXML SubscriberQRZ Page

I put the .01 disc Cap across the terminals from the sensors - problem solved. Craftsman GDO.

7. ### K9STHPlatinum SubscriberVolunteer ModeratorPlatinum SubscriberQRZ Page

Having 10-feet of 6 gauge wire in your ground connection is not going to be a very good ground at 14 MHz. It will be OK for 40-meters and lower frequency bands. I am a firm believer in external grounds. However, the connecting wire has to be short and the shorter the better.

If you use copper, or aluminum, "flashing", the wider the better, you can achieve a good r.f. ground with longer runs. I have 8-inch flashing running along each level of my main console, connected together with another 8-inch wide flashing that runs down to floor level. Then, there is a section of 00 gauge wire, less than 12-inches through the wall to the first outside ground rod.

Twice the length of the ground rod spacing between rods is OK. Experimentation has shown that 2.4 times the length gives the optimum grounding.

For r.f. grounding (not for lightning protection), in most soil types, most of the effective grounding takes place in the first 4-feet to 5-feet of the rod. As such, 2-ground rods 5-feet long, spaced 12-feet apart, are almost twice as effective as a single 10-foot ground rod. Also, using a chemical ground rod, instead of a solid ground rod, usually increases the grounding by a considerable amount.

One can make 2-chemical ground rods out of a single 10-foot long piece of copper pipe. Details of this are at the following URL:

http://nebula.wsimg.com/efed167c324...50C433DB440D6B60D&disposition=0&alloworigin=1

After DRIVING the rods into the ground (12-feet apart), then fill with rock salt and water down the area around the rod. Wait a few days and then come back and "top off" the salt (it will have settled a fair amount). Then, every 6-months, or so, "top off" the salt again.

The sodium chloride will not hurt the environment and definitely increases the effective grounding of the rods.

Now, I don't think that your ground system has much, if anything, to do with your problem! The length of the connection between your garage opener equipment and the AC mains, to the switch(es) involved, etc., are almost certainly acting as antennas and the closer to a quarter-wave, or multiple of a quarter-wave, those lengths are, the higher the r.f. energy conducted into the apparatus is going to be.

Using bypass capacitors, located at the equipment, to ground from the various input lines, will often cure the problem. If the problem is not solved by capacitors, then ferrite is going to be needed. Also, it is possible that the 20-meter signal is overloading the r.f. receiver in the opener. That will require additional shielding of that particular circuit.

R.F. opening garage doors has been a problem for decades. There was a new subdivision built near a military base where every house had a garage door opener installed. The frequency required to operate the openers just happened to be within the frequency range of one of the radar systems used by the military. Soon after people moved into the subdivision, a new radar system was installed at the military base. Yes, this system just happened to be one of those that operated within the same frequency range as the garage door openers.

The garage doors, in the subdivision, were driven crazy. They were opening and closing, vibrating, etc. The developer tried to sue the military because of this. Of course, the garage doors operated under 47 CFR Part 15 rules and had to accept any, and all, interference that came their way. The developer had to lay out many thousands of dollars to replace all of the garage door openers in the subdivision.

There have been numerous cases where amateur radio, even "CB" radio, transmitters have caused problems with these openers. The opener owners had to turn off the openers, modify the openers, or replace the openers because the problems were caused by the openers and not by the transmitters turning the openers off and on.

Glen, K9STH

8. ### W3ICMHam MemberQRZ Page

No balun on the G5RV....just a standard G5FV the way it was purchased.

9. ### W3ICMHam MemberQRZ Page

'Thanks Glen....there was also a serious problem in some locations near military bases where the military went to a 380-399.9 MHz digital trunking land mobile communications system That's the same band as the garage door openers, and the openers had no selectivity. It created a mess. Many people complained to their congressman. Although the openers are Part 15 without any interference protection rights, the fact that many people complained to Congress was in effect, a de facto primary service, and some spectrum management was necessary.

10. ### WB5YUZHam MemberQRZ Page

In that case you can try installing one and see if it helps.

Varney, G5RV did not use a balun in the original design because they were a relatively new thing in the late '40s and not well understood. Many people who have had RFI problems with G5RVs have been able to mitigate or eliminate them by installing a good 1:1 current balun at the junction of the balanced line and coax, to eliminate common-mode currents on the outside of the coax shield.

An air-core "ugly" balun might help on 20m, but to obviate potential future problems on longer wavelengths it might be best to use on wound on a core.