We decided our first effort would be to set up a 6m ground plane antenna on a mast mounted on top our chimney. 6m is a wonderful band offering DX possibilities along with access to local repeaters.
For this project we would need:
- 6m ground plane antenna
- Chimney mast mounting kit
- Standard 1.5 inch x 5 foot antenna mast
- Low-loss 50-ohm coaxial cable (we use Bury-FLEX 1.1 dB of attenuation /100 FT at 50 Mhz)
- UHF connectors
- 8-foot copper clad steel ground rod
- Lightning arrestor (we use ICE coaxial lightning/EMP suppressors)
- Soldering iron
- Electrical tape
- Self-sealing silicone rubber tape
- Rope and bucket
- Crescent wrench
- Leather work gloves
- Pair of HT's (optional)
PartsIn days gone past, items such as chimney mast mount and masts were commonly available in local hardware or electronics stores serving the needs of customers with TV antennas. We went shopping in local area stores and found none had chimney mast mounts or even 5 foot antenna masts; though, they did have an 8-foot ground rod. The ubiquity of cable TV seems to have reduced the need for TV antennas. Thankfully, these items are still available through Internet retailers.
We ordered a Ronard chimney mast mounting kit and Winegard 5 foot mast and they arrived quickly. The Winegard mast was more substantial than expected. The mast was 18 gauge steel tubing without any visible seem. The Ronard chimney mast mounting kit included stainless steel straps and heavy duty hardware. The chimney mast mounting kit included very basic instructions for setting up the straps.
We had picked up an older 6m ground plane antenna brand new in the box at a ham fest several years ago for $20.00. We had used this antenna with a 18 foot painters pole for an easy-to-setup ARRL Field Day antenna. We used our MFJ-269 antenna analyzer to cut the antenna centered around the SSB DX calling frequency of 50.125 Mhz (see 6m band plan below).
We also had a lightning suppressor, electrical tape, self-sealing silicone tape, coaxial cable, UHF connectors, and the tools already available in our shack.
Safety FirstAmateur radio is generally a very safe activity. There are potential risks to consider and take the necessary precautions. Among these is coming in contact with high voltages and currents, falling from heights, and having something fall on you. Our motto is, "safety first" and this mindset helps us avoid accidents.
Installation PreparationThe first step was call the local utilities and request them to identify buried cables and gas lines. They came out within a few days and marked everything clearly with spray paint and flags.
We next surveyed the work areas looking for hazards. It is critical before starting to make sure that any new antenna installation cannot come in contact with overhead wires or buried utilities. We confirmed that no hazards were present.
We assembled all the parts and tools at the base of the chimney and enlisted a helper. This job could be done by one man; however, two hams are better than one. It is considerably safer to work with a helper since ladders and heights are involved.
We also brought out a pair of 2m HT's to aid with communication between the roof-top work and the ground-work. This is so much effective than yelling back-and-forth at the top of your lungs and being misunderstood. We are hams after all. There is typically a fair amount of wind noise up on a roof that can interfere with being heard without the aid of a radio. This helped avoid a comedy exchange, "I said, send up a WRENCH not go sit on the BENCH!!!" or "What was that? Did you say, GO! or NO!?"
Installing the Chimney Mast MountThe Ronard chimney mast mount included directions for fastening the stainless steel strap to the strapping clip. However, no other directions were provided. The mount itself is a fairly simple device and perhaps assembly is self evident. Installation is another matter. Installing the mount took a bit of trial-and-error to get it right. Here are a few things we learned:
- Wear leather gloves when handling the stainless steel strap. The strapping is razor sharp. We didn't think to bring gloves to the roof top and by the time the installation was complete our hands had a dozen or so nicks.
- Pre-bend the strapping into shape before placing around the chimney. The strapping wants to return to its coiled shape unless you counter this with new bends. It is much easier to handle the strap when it is in the approximate shape of the chimney than if it is in the approximate shape of a tightly wound coil.
- Wire cutters won't cut stainless steel strap. Perhaps there is a better tool? We didn't discover this until we were on the roof so we ended up using metal fatigue to break the strapping in the desired place.
- Prepare the strap and strapping clips on the ground. If we had it to do over again we would pre-cut the strap to the desired length and pre-install the strapping clips all on the ground. This would avoid the possibility of losing one of the small clips on or over the side of the roof. It would also be easier and provide more convenient access to tools in the workshop.
- We kept our hands free while climbing the ladder and roof and used a rope and bucket to hoist up parts and tools from the ground. Here is our helper made the biggest contribution.
Installing the 6m Ground Plane AntennaAttaching the mast and ground plane antenna was the easiest part of the installation.
- Build the antenna on the ground. The antenna has 5 main parts that needed to be assembled. Once assembled the antenna is light and somewhat bulky. We choose to build the antenna on the ground for ease and safety.
- Hoist up tools to the roof with the aid of a bucket and a line. Communicate with the helper on the ground with an HT. Make sure the helper stands well away from the roof line or where anything could fall.
- Hoist the mast from the ground to the roof with a line. We passed the line through the mast from one end to the other. We tied a wooden dowel to the rope at the end of the mast and hoisted it up. This kept the mast in the same orientation as the line and made it very easy.
- Hoist the antenna from the ground to the roof with a line. We tied the rope to the bottom of the antenna and also at the top. This allowed for an easy hoist in a vertical orientation to the roof.
- Hoist the coaxial cable from the ground to the roof with a line. We tied the rope to the coaxial cable and hoisted it up with ease. Take care there are no twists in the coax that could turn into a kink (bad for coax) while hoisting.
- Seal the coaxial connection. Some people prefer coax seal. We prefer applying a couple of tight layers of good quality electrical tape followed by a wrapping with self-sealing silicone tape. This will prevent water intrusion and corrosion.
- Secure the coax to the mast with electrical tape or cable ties. This prevents the coaxial cable from bouncing around against the mast in high winds. Provides some strain relief as well.
|6m Ground Plane Vertical Antenna Close Up|
Installing RF Grounding SystemWe used a step ladder to stand on to drive the 8ft ground rod with a 8 pound hammer. This made it easy to keep the hammer on-target as it went into the ground. We switched to a larger sledge to drive the last foot or so.
We attached an ICE suppressor bracket with 2 ICE lightning suppressors mounted to the top of the ground round. One lightning suppressor for use on 6m and the other for an HF antenna.
We placed the lightning suppressor and cabling within an enclosure to provide some protection from the elements.
|Lightening arrestor system|
First 6m QSOWe connected the cabling to our Kenwood TS-480SAT and powered up. We had a local Pittsburgh 6m repeater already programmed into memory (51.740 Mhz with a PL tone of 100.00 Hz) so we dialed it up and found a group of hams in a ragchew. So far so good on receive. We were wondering if the antenna would tune up and transmit? We hit, "tune" and sure enough it tuned immediately. This was a good sign that everything was in order. We waited for a pause and then transmitted giving our call. One of the hams came back immediately acknowledging our call and inviting us into the group. Voila! 6m ground plane vertical antenna project success!
|6m Ground Plane Antenna mounted on chimney|
Since our first QSO, we have enjoined joining into the Pittsburgh 6m repeater net and finding a few other local 6m repeaters we can reach. We are also eagerly awaiting a 6m opening when we can give 6m DX a workout with the new antenna and make progress toward our ARRL 6m DXCC award.
The 6m band is the "magic band" and has something to offer everyone - from DX'ing, repeaters, ragchew, CW, digital, ...
ARRL 6 Meter Band Plan, 50.0-54.0 MHz 50.000-50.100 CW and beacons
50.060-50.080 Automatically controlled beacons
50.100-50.600 SSB 50.125 SSB DX calling frequency 50.200 SSB domestic calling frequency (Note: Suggest QSY up for local & down for long-distance QSOs)
50.600-51.000 Experimental and special modes 50.700 RTTY calling frequency
50.800-50.980 Radio Control (R/C) channels, 10 channels spaced 20 kHz apart (new)
51.000-51.100 Pacific DX window
51.000-52.000 Newly authorized FM repeater allocation
51.100-52.000 FM simplex
52.000-52.050 Pacific DX window
52.000-53.000 FM repeater and simplex
53.000-54.000 Present radio control (R/C) channels, 10 channels spaced 100 kHz apart
Shortwave ReceptionAn unexpected side benefit was the antenna's receive capabilities. While tuning around HF we discovered the antenna performed nicely as a shortwave receive antenna. We were surprised how well it received shortwave stations. We attribute the quiet performance to having a good RF ground and installing the antenna above the roof line. In the past, we have always used horizontal wire antennas (i.e. long wire, dipole, and fan-dipoles) for shortwave reception. This antenna has given us a new appreciation for a VHF vertical for shortwave reception. This is also something to keep in mind when in an emergency situation - a VHF antenna is an asset for both VHF and HF reception.
The NJ2X Kindle Edition is now available.
© Michael W. Maher and NJ2X.COM, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Michael W. Maher and NJ2X.COM with appropriate and specific direction to the original content.