K7VZ
07-14-2010, 12:52 PM
http://www.eham.net/articles/24023
900 Watt Generator for Field Day
Great little Field Day Generator…Did I say it was Cheap!
By Mike Higgins, K6AER
It is getting time to get ready for field day. Every year the local hams ask me about field day generators. I guess this is because I have loaned them out from time to time. There are several approaches to the dilemma of emergency power. You can go Eco trendy and use solar cells or shuffle batteries back and forth but the best and most applicable means of power generation is a FOSSIL-FUEL GENERATOR.
For a large field day operation you can use a massive commercial unit (10-15 KW) or a large construction unit (7-10KW) and do a distribution system. Many want to use their own generators and many are just fine for smaller applications.
Issues to be aware of with portable generators are listed below. As always safety is of a concern.
Fuel and fire safety is a must with a fire extinguisher and fuel storage safe distance from the generator. The area should be mowed at least for a 20-foot diameter. Fuel must be stored in a separate area as well as the fire extinguisher in an accessible convenient place away from the generator area. NEVER REFUEL A GENERATOR WHEN IT IS RUNNING. Other considerations are placement for access, noise abatement, distribution of the feed cables and grounding if necessary. In the case of large generators I have used a couple of sheets of plywood set in a right angle to be a sound wall with good success.
Grounding is a difficult issue when using generators. For single-generator operation, powering a couple of station locations, I don’t see any benefit in grounding. Grounding the antenna feed for lightning is a much more sensible option with the possible cessation of operation during storms. That means disconnecting and sitting inside the car. With large distribution systems, grounding of the generator is best with at least an 8-foot ground rod and standard NEC procedures must be followed.
GFI systems generally don’t perform well in field operations due to long feed runs and ground loops with the various end locations. If your generator has a GFI you may have Ground Fault issues.
Many small generator units are the inverter type and although efficient and light they can create a large amount of inverter hash that raises your HF noise floor to an unacceptable level. A brushless generator is best.
While I have touched on salient issues with field day generators what I wanted to tell you field day hams who don’t have a small generator about a great little generator I have used around the farm for a couple of years. I just got a flyer that Harbor Freight is selling these units for $99 until the end of June. You can also buy these units under a different brand name at Northern Tool Supply.
My unit is imported by Harbor Freight under the Chicago Tools brand under part number 66619. The unit is rated 800 watts continuous and 900 watts max. It is brushless type of AC alternator. I bought the generator a couple years ago for the $109 plus tax and the extra two year warranty, which cost an additional $19.95.
The 2 cycle generator runs on regular pump gas with a gas/oil ratio mix of 40:1. You have to install the top handle which requires two 8mm screws and fill it up with the gas/oil mixture and we are ready to go. I turned on the ignition rocker switch, turned on the fuel petcock and pulled the starter cord. After two tries it started right up and purred along at 3600 RPM. No smoke and pretty quiet. I looked at the generator and wondered if it was up to the big test.
Plugged in my Fluke DVM with the built in scope and took a look at the waveform. Pure sine wave, no spikes at 123 VAC, very stable and holding around 61 Hz.
So far so good. Let see what she will do. I plugged in my trusty 1 HP weed whacker that draws 7.8 amps and pulled the trigger. The generator made a bit more noise and the weed whacker ran just fine. How much noise? I took readings and at ten feet and the idle noise was 78 dB A weighted. At 959 watts out the noise at ten feet was 81 dB A weighted. Noise level of 79 dBa is about the level of normal conversation outside. Not bad. Being your basic to-the-limit sort of guy I plugged in the room heater at 1100 watts and it still put out 121 VAC. Now mind you, I am up at 7000 feet here in Colorado where the air is thinner. The motor is rated at sea level at 2 HP.
I plugged in a 500-watt load, Halogen spot lamp, into the generator AC output and went into the shack to check RF noise. Switching to the 40 meter dipole 100 feet above the generator I noticed the 40 meters noise level was S2. Went out and turned off the generator and came back in to check the noise and it was still S2. No difference. Now in field day operation your antenna might be lower but it was very clean with 100 feet of separation.
The unit weighs about 45 lbs. with fuel. The tank holds one gallon. Construction is very nicely made (no doubt produced by slave labor somewhere at this low sale price) and has very good directions that even a new ham could figure out.
Bottom line is I would buy another one in a heart beat. This is perfect for field day and small portable emergency operations. Run time is 3.5 hours at 500 watts out. With less wattage draw the run times will increase. I have about 40 hours on my unit and use it around the farm for weed whacking and portable construction needs.
I almost forgot to add it came with a complete manual and parts listing for the generator. For those of you who turn up your nose at 2 cycle engines don’t forget most very large engines are two cycle including train and ship board engines. There is nothing wrong with a well run 2 cycle engine. They are very reliable when properly used. One last item, Harbor freight said for any reason over the next three years I could return the unit for another one if this one was unsatisfactory. How could I go wrong?
Have a safe Field Day.
900 Watt Generator for Field Day
Great little Field Day Generator…Did I say it was Cheap!
By Mike Higgins, K6AER
It is getting time to get ready for field day. Every year the local hams ask me about field day generators. I guess this is because I have loaned them out from time to time. There are several approaches to the dilemma of emergency power. You can go Eco trendy and use solar cells or shuffle batteries back and forth but the best and most applicable means of power generation is a FOSSIL-FUEL GENERATOR.
For a large field day operation you can use a massive commercial unit (10-15 KW) or a large construction unit (7-10KW) and do a distribution system. Many want to use their own generators and many are just fine for smaller applications.
Issues to be aware of with portable generators are listed below. As always safety is of a concern.
Fuel and fire safety is a must with a fire extinguisher and fuel storage safe distance from the generator. The area should be mowed at least for a 20-foot diameter. Fuel must be stored in a separate area as well as the fire extinguisher in an accessible convenient place away from the generator area. NEVER REFUEL A GENERATOR WHEN IT IS RUNNING. Other considerations are placement for access, noise abatement, distribution of the feed cables and grounding if necessary. In the case of large generators I have used a couple of sheets of plywood set in a right angle to be a sound wall with good success.
Grounding is a difficult issue when using generators. For single-generator operation, powering a couple of station locations, I don’t see any benefit in grounding. Grounding the antenna feed for lightning is a much more sensible option with the possible cessation of operation during storms. That means disconnecting and sitting inside the car. With large distribution systems, grounding of the generator is best with at least an 8-foot ground rod and standard NEC procedures must be followed.
GFI systems generally don’t perform well in field operations due to long feed runs and ground loops with the various end locations. If your generator has a GFI you may have Ground Fault issues.
Many small generator units are the inverter type and although efficient and light they can create a large amount of inverter hash that raises your HF noise floor to an unacceptable level. A brushless generator is best.
While I have touched on salient issues with field day generators what I wanted to tell you field day hams who don’t have a small generator about a great little generator I have used around the farm for a couple of years. I just got a flyer that Harbor Freight is selling these units for $99 until the end of June. You can also buy these units under a different brand name at Northern Tool Supply.
My unit is imported by Harbor Freight under the Chicago Tools brand under part number 66619. The unit is rated 800 watts continuous and 900 watts max. It is brushless type of AC alternator. I bought the generator a couple years ago for the $109 plus tax and the extra two year warranty, which cost an additional $19.95.
The 2 cycle generator runs on regular pump gas with a gas/oil ratio mix of 40:1. You have to install the top handle which requires two 8mm screws and fill it up with the gas/oil mixture and we are ready to go. I turned on the ignition rocker switch, turned on the fuel petcock and pulled the starter cord. After two tries it started right up and purred along at 3600 RPM. No smoke and pretty quiet. I looked at the generator and wondered if it was up to the big test.
Plugged in my Fluke DVM with the built in scope and took a look at the waveform. Pure sine wave, no spikes at 123 VAC, very stable and holding around 61 Hz.
So far so good. Let see what she will do. I plugged in my trusty 1 HP weed whacker that draws 7.8 amps and pulled the trigger. The generator made a bit more noise and the weed whacker ran just fine. How much noise? I took readings and at ten feet and the idle noise was 78 dB A weighted. At 959 watts out the noise at ten feet was 81 dB A weighted. Noise level of 79 dBa is about the level of normal conversation outside. Not bad. Being your basic to-the-limit sort of guy I plugged in the room heater at 1100 watts and it still put out 121 VAC. Now mind you, I am up at 7000 feet here in Colorado where the air is thinner. The motor is rated at sea level at 2 HP.
I plugged in a 500-watt load, Halogen spot lamp, into the generator AC output and went into the shack to check RF noise. Switching to the 40 meter dipole 100 feet above the generator I noticed the 40 meters noise level was S2. Went out and turned off the generator and came back in to check the noise and it was still S2. No difference. Now in field day operation your antenna might be lower but it was very clean with 100 feet of separation.
The unit weighs about 45 lbs. with fuel. The tank holds one gallon. Construction is very nicely made (no doubt produced by slave labor somewhere at this low sale price) and has very good directions that even a new ham could figure out.
Bottom line is I would buy another one in a heart beat. This is perfect for field day and small portable emergency operations. Run time is 3.5 hours at 500 watts out. With less wattage draw the run times will increase. I have about 40 hours on my unit and use it around the farm for weed whacking and portable construction needs.
I almost forgot to add it came with a complete manual and parts listing for the generator. For those of you who turn up your nose at 2 cycle engines don’t forget most very large engines are two cycle including train and ship board engines. There is nothing wrong with a well run 2 cycle engine. They are very reliable when properly used. One last item, Harbor freight said for any reason over the next three years I could return the unit for another one if this one was unsatisfactory. How could I go wrong?
Have a safe Field Day.