I’ve written before about establishing a VHF FM station at your home (VHF FM Station At Home). Recently, Stu WØSTU wrote a fabulous article about choosing and installing a VHF/UHF antenna (Considering a VHF/UHF Antenna for Your Home?) In this Shack Talk article, I will share a few installation tips that I have learned over the years.
For this article, I am going to focus on doing a basic VHF FM installation, nothing too fancy, just trying to get a better signal into the air on 146 and 440 MHz. Some of these tips may be helpful for other types of radio installations.
Stick the Antenna In The Attic
First, let’s recognize that all antennas are a compromise between size, cost and performance. Putting a VHF antenna in the attic will reduce its performance, especially when there is snow on the roof, but it might be a reasonable way to go. In the attic, the antenna is not visible, it is not exposed to weather and it can be installed without climbing onto your roof. Some radio hams have an attic antenna as a backup to their main antenna on the roof.
Hide Stuff In The Closet
One of the challenges you may encounter is getting the coaxial cable up into the attic. You can always just punch a hole through the drywall ceiling and run the cable through. However, you might not like the look of a coaxial cable hanging down from the ceiling. One trick I’ve used is to punch the hole in the top of a closet where it’s not visible. Then snake the cable underneath the closet door and over to the transceiver.
Avoid Insulated Walls
You may decide to run the cable through the walls of your house. Your typical wood frame construction with drywall sheathing is not too difficult to work with. You can route cables through the walls and install electrical boxes in the location that you bring the cable out. Most exterior walls have insulation in them, which makes cable routing much more difficult, so stay away from them if you can.
Use Your Furnace Ducts
If you have forced-air heat in your house, then you have furnace ducts running to every room of your house. You can route a coaxial cable through these ducts to get from room to room. You can either loosen the grate to make room for the cable or slip it right through the grate.
RG-8X Gets Past the Tight Spots
RG-8X cable (sometimes called “mini 8”) is about ¼ inch in diameter, so it can be routed through much smaller openings that the “full size” RG-8 type cable. It is only slightly bigger than the RG-58 cable and has better performance. Loss is about 5.4 dB per 100 feet at 200 MHz. Don’t use it for long runs at VHF but it should work for runs up to 25 feet.
Use White Coaxial Cable
Most of the coaxial cable available has a black outer insulator, but you can find RG-8X cable with a white outer coating. For many indoor installations, white will blend into the décor better than black cable. The image on the right shows examples of RG-8X cable with black and white coating.
Leave Off The Connector When Installing the Cable
Antenna connectors are always bigger than the cable they are attached to. Leave the connector off when you are routing the cable, so that any holes you drill can be as small as possible. Install the connector after you get the cable in place. (Yes, this means you need to work on your connector attachment skills or get another ham to help.)
Use A Remote Control Head
Many modern mobile-base transceivers offer detachable control heads that allow the bulk of the radio’s case and the associated power supply to be tucked away out of sight. This can go a long way to keeping spouses happy with ham radio! If you wish to install a VHF radio in your home in a common living area such as the kitchen, living room, or den, a small radio control head discreetly attached to an attractive anchor may help maintain RF harmony in your home.
A friend of mine has a small control head attached to a heavy glass vase on a display/bookshelf near his favorite cushy chair, with the power supply and transceiver “box” hidden on a lower shelf behind the chair. The microphone is hung similarly out of sight, but within reach and using an extended cord. Use your imagination on how you can integrate such a radio into your house.
Don’t Forget the Power Supply
When planning your home station’s location, transmission line routing, and other factors, don’t forget that you’ll typically need a power supply to convert your home’s 120 VAC to the 13.8 VDC used by most transceivers. Be sure to select a power supply appropriate to your transmitting power needs, and note that many power supplies may have a footprint larger than the radio they are powering!
Let The Air Flow
Radios and power supplies generate heat that must be shed, and they will often use active air cooling – a fan pulling air through the chassis and across the electronic components to keep them cool. Even if your radio doesn’t use a fan, it will need some airflow to keep it cool. Be sure that your selected location allows for proper air flow so that your new station doesn’t overheat in the first QSO! And over time watch out for dust or debris clogging up the ventilation ports.
I hope you find these ideas useful. Every radio installation is unique, so use your imagination to come with other ways to route cables, place antennas and install radios.
73, Bob KØNR