Yagi antenna performance

I'm trying to improve Cell Phone (Sprint) reception in a remote location. I have an amplifier and can make, but not recieve, calls. I must mount my short magnetic antenna on the metal roof of a privy for the system to work, and then it only gets trhough at night.

I bought a Yagi antenna for cell phone use and have it mounted to PVC pipe about 35' above sea level (my camp is over water adjacent to the intercoastal canal).

There is NO improvement whatsoever. Should I ground the antenna (the privy is not grounded but does have metal roof)? Is there something else I can do?

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I don't think you need to ground the Yagi. However, you do need to point it to the closest / geographically "best" cell site. Yagi antennas are directional, where-as regular ones (such as your short mag mount), are omni-directional.

Basically, your short mag mount gets signal from anywhere, where the Yagi will ignore everywhere except where you point it.

Just out of curiosity, what brand amplifier are you running ?

I do have it pointed to direction of best reception. The problem is that a short magnetic antenna mounted on the metal roof of a privy (about 24 sqare feet) eight feet above sea level gives the same reception as the Yagi antenna mounted to PVC pipe forty feet above sea level.

The amplifier came from Wilson Electronics and gave me first-time ever reception from the camp. It won't connect during the day, however. I was thinking the Yagi would give me a stronger day-time signal.

Hmmmmmm, strange that the Yagi is giving you no more performance than the stubby mag-mount. Even with such a large ground plane, you'd think the Yagi would yield some better results.

Wilson does make the best stuff, I have a Wilson unit in my home (in the shadow of a mountain, barely any RF) and it works like a charm.

Maybe point the Yagi in different directions anyways ? See what happens ?

Try lowering the yagi down to the level (elevation) that the magnetic mount is at. If you are on network with Sprint, the frequency is 1900 Mhz, but if you are off network, you could be on the 850 Mhz spectrum.

Try the yagi at all elevations from the ground to well above the location of the magnetic antenna. On certain Sprint phones, you have the ability of accessing the field test screen which will display your signal in dB’s. This is far more accurate than the signal bars for aiming the yagi. It is also very useful in determining the cellular site when driving in your area in the event you can not see it from the yagi mounting location.

What you are experiencing has occurred in some cases. The design of the antennas that are located on the cellular sites (towers) have changed over the years to offer an increased amount of accuracy in the coverage spread. Some of the latest ones have servos on the hinge that allow the tower and drive engineers from the carriers to tweak the angle of the antenna to maximize the amount of coverage that each antenna transmits. This new design also creates a horizontal disc if you may that keeps the signal penetration at ground level where it is needed most. It is more effective in very flat topography as opposed to hilly but very functional in efficient transmission of signal.

With this being said, we have found that coverage at ground level is stronger than on the peak of a roof due to the carriers signal spread in the area. This is not the case in all situations, but something to keep in mind when doing the install. Try taking some readings at different levels from the ground to the fascia of your roof in an attempt to find the best location. You may also want to test the signal in a 360 degree area around your home. If there is an obstacle between your antenna mounting location and the cellular site, the coverage can be sacrificed. In our testing of antennas, we have found situations on vehicle roofs where the same antenna had a variance of 10 dB when moved in an area of only 6 feet.

Thanks for your informed reply. The installation site is a fishing camp over water.

The mag mount location is an outhouse about 10' over sea level. It has a metal roof. I get a 2 bar signal with the Wilson signal booster. The pointing direction is at a berm about 15' above sea level.

I bought the Yagi for two reasons: I can phone from in the camp; and I thought I'd get a stronger signal.

The Yagi mount location is on PVC pipe attached at the back of the camp. It is about 30' above sea level. I get the same 2 bar signal with the Wilson. The pointing direction is roughly the same as the mag. I'm 99% sure that it is above the berm. However the signal is no stronger.

How do you tell if the Sprint phone (Motorola C290) has "field test" capability?

I'm thinking of grounding the Yagi as it's pretty high up. I don't want lightning coming down the cable. I can put a copper rod in the sea bed and ground the Yagi to it. Do you think I'd get a better signal as well?

I could also lower the Yagi to near or at roof level (about 15' above seal level). At least I'd relieve the grounding concern and still be able to keep the booster in the house.

Do you have any other thoughts?

The key on the Magnetic antenna is to have it placed so the whip portion is vertical. You mention that it is aimed at the same location as the yagi so I am confused. The polarization is vertical on the cellular sites so it is imperative the that antenna placement is the same.

The C290 uses RF adapter model 359909. Are you using the direct connection amplifier connected to the phone or are you using a wireless repeater or SignalBoost unit?

What yagi antenna are you using? Do you know if you are on the Sprint network or if you are off network roaming?

The Motorola C290 does have the field test option. Here are the instructions on how to place your phone in to field test: Enter ##33284##. Enter Field Service Code, 040793 and press OK.

Signal strength is 3rd line down in from of MN/A or HN/A. Turn phone
off and on to exit.

The complete list of Cellular phone field test modes is available here: Cellular Field Test modes

Regarding the lightening suppression, we recommend using an inline lightening suppressor on all applications. This does not guarantee that the equipment will not be damaged in the event of a strike, but it does give some added protection. I would recommend doing this and grounding the U bolt on the yagi.

Again, I have to wonder if the Yagi is pointing in the correct location. Since the magnetic antenna is an omni-directional, and the Yagi is directional, it's plausible that the Yagi simply needs to be re-aligned.

Do you know exactly where the cell site is ? You say you're on a lake, I assume the cell site is on the other side ? Anything obstructing it ?

Didn't mean that mag is aimed. I did have a friend check "bars" as I rotated Yagi. Best we could do was 2 - same as mag.
I'm not sure about the amplifier. It connects to thae antenna and the phone and a 12 volt power source.
I'm on Sprint Roam at the location. The Yagi is for cell phones that's all I know.
I won't be back at site till Labor Day.

Which amp are you using, the 37dB, 50dB or 60dB ?

If the unit is connecting directly to the phone, it is not a repeater so you can disregard the question from Abom asking for the model number as the ones that he listed are repeaters. On the back of the unit the model number is the first 6 numbers of the serial number. If you are on “roam” in the area, I am 99% sure you are on an 850 Mhz carrier like Verizon.

The next time you travel to the location, try making a call to 611. If the carrier that you are roaming on has the customer care forwarding, Sprint will answer. If this occurs, try placing a call with some numbers transposed like 555-555-5555. This should give you an error message followed by a tag with the carrier’s name.

I would make sure you have a part number 951110 Yagi test adapter that will allow you to connect your phone directly to the Yagi. Key in the field test sequence and connect the RF adapter and do some slow pans with the yagi, making sure you power cycle the phone every 30 degrees for extra accuracy.

If it's simply a direct connect amplifier, will he not be better off with a wireless "repeater" solution then ?

Just wondering...

I don’t think I would move to a wireless solution at this point as there is still an issue with establishing a connection with the direct wire to wire connection. In areas were the coverage is extremely poor, an inline direct connected solution is going to be a better long term enhancement and far more reliable.