Gray-Hoverman UHF Antenna

My rented house in Kulai (now Kulaijaya), Johor, Malaysia do not have an outdoor antenna. For local tv channels reception using indoor antenna, it is good since the transmitters are on a mountain nearby. I want to receive good analog tv signals from down south Singapore as well as from Riau, Indonesia which I estimated some 80 to 100 km away.

Since the ball had started rolling in constructing antennas (previously for my wireless client and the access point), I began to search for a good high gain UHF antenna. After a while, my attention was immediately focused on a little known, at least to me, Gray-Hoverman antenna. Interesting comments and feedbacks. What made me attracted to this design was the high gain plateau that covered most of the channels I’m interested in. Without much hesitant, I began on planning although I felt that this antenna was a bit on the hard side to construct.

Gray-Hoverman Dimensions

more details here.

Having had the diagram in hand, I figured about doing it my way based on those projects done by others. Once done, I laid down the plan. The reflectors would come from aluminium tubes salvaged from scrap antennas although some were of different diameters. Frame would be constructed from domestic pvc water piping tubes, T joints and tube holders. The radiator elements would be a 6mm diameter copper tube. I then listed down what were the items needed to be bought, the amount required and the length.

In constructing the antenna, first thing I did was the frame, then the reflectors, followed by cutting and bending the radiator elements. After attaching the radiator elements in place, I placed 4 short pieces and 2 long pieces of pvc plastic wiring conduit that had the sides cut off to hold them in place.

Here’s the rest of the construction pics at certain stages.

Update 13 Jan 2011

Actually I had a different idea for attaching the reflector elements, but I don’t have with me a tube that will fit in the reflectors nicely. What I had was a tube with internal diameter bigger than the external diameter of the reflector. So I cut it and riveted the reflectors to it. Also I did cut a small V groove on the flat side of the tube holder so that the reflectors will stay fixed and not to slide out.

Update 15 August 2013

I have constructed a GH10n3 Gray Hoverman which can be viewed here.

My First Serious Antenna Construction

I had done constructing antennas albeit in a makeshift way and the results were never satisfying. I was never serious about it until recently. I had an access point which was some fifty metres away at another house and I was getting weak signals. That was the turning point, I decided to build a good high gain antenna.

It goes without saying that the first step was to do a research. After all the searchings and readings, I set my mind on the biquad antenna. It was simple, easily construct and did not have many parts plus I had the parts readily available. Suffice to say that the construction was not exactly according to the specifications given that parts were practically from scraps.

The main radiator element came from the field coil winding of a car alternator. Aluminium plate encasing a pc floppy drive was flattened and used as reflector, and an RF(?) panel connector to connect them together.

After spending some times cutting, filing, drilling and bending, the result was as in picture #1. On the downside, I had to connect a RF to BNC female connector at the back of the antenna. Another potential loss, this was not good. I improved it further by constructing another design. This time the antenna was directly connected to the RG58 cable at one end and a female BNC at the other end while being encased inside a tube. I knew that the BNC was not up to par but it’s almost there and cheaper. Furthermore my situation was not that very critical that every improvement matters. I ended up making two antennas this way with slight variations.

There was improvement in signals but still there was interference. The transmitting and receiving angles of the biquad were quite broad. I wanted to narrow it down. In the end I ended up with a narrow, almost line of sight, high gain 21 elements yagi at both ends, the access point and my client.

In retrospect, signals are best amplified immediately after the antenna and not after the loss incurred by the cable. This means that I need to spend away with a usb dongle that can be attached to the client antenna almost immediately. Then, instead of RG58, I just need a longer usb cable. I will not be doing this on the access point side because of the cost involved and the hassle of putting up the access point router and POE device to power it plus the need to protect it from the weather.

Anyway, here are the pics.