AlmostHandy
Member
Some of you may remember my very first homebrew antenna, which was a multi-band ground plane design. I had constructed it out of a UHF Chassis mount, and used 12 gauge solid copper wire (standard 15A Romex). It works really well, but because it's extremely flimsy, it must remain indoors. I really wanted to create an outdoor version of this antenna, and budget concerns forced me to hack this one together with less-than-optimal parts. The major difference, is the element material. I used coat hangers this time.
This antenna, like v1.0, is based on a UHF Chassis connector. (I swear to Joe Pesci, as soon as I get the right N connectors and that run of LMR, there will be a v3.0). Unlike the first one, I did not connect the radials directly to the connector. Instead, I used a 50mm(ish) square piece of PCB with a hole drilled in the middle. (TIP: Drill the hole before you cut the square bit off your stock. Trust me.) I soldered the connector to the PCB, leaving about 8mm of PCB exposed on all sides of the connector.
The radials. Oh jeez these were a PITA! I cut and straightened a bunch of hangers, and started to prep the tips for soldering. It was immediately apparent that my 30W Iron was not going to work. I switched to my 100/140W Gun and tried to tin one of the radials. After spending ten minutes and having very little success, I had an Idea. I used the Anvil of my vise and some deliberate, and well aimed blows with a hammer to flatten the end of the coat hanger about 35mm from the end up. It remained about 1mm thick, and spread out to about a 2.5mm wide face. After a light sanding, and a quick dip in the flux, they tinned up in seconds. I'm not sure why it suddenly worked better, maybe solder doesn't like round surfaces, or maybe the stress of the hammering allowed some sort of change. Either way, it worked great.
I arranged the radials on the PCB parallel to the sides of the connector, in a sort of a basket weave style.
The main elements are constructed similarly to v1.0, but tuned to 120/450/850 instead of 150/450/850. I had a but of trouble mounting the end of the hanger into the solder cup of the connector, as the hanger is twice the diameter of the solder cup. I mounted the end of the hanger in the vise, and used a rotary tool to mill the end to acceptable dimensions. I also used 3 square 4-40 nuts to collar the end of the hanger around the exposed tip of the solder cup. After tinning the hanger with the 100/140W gun, the 30W iron was sufficient to attach it to the connector.
A daub of silicone and a shot of black Plasti-Dip coating, and it was ready for it's "mast".
I needed to get this antenna off the ground. I don't have a "real" mast, so I dug around in the basement, and found bunch of 20mm tubing with one swaged end, designed so that one tube can fit into the next. It was apparently some sort of portable wardrobe or closet that had a vinyl covering. I used 5 of the straight sections, with one of the sections sunk completely into the ground next to the house. It's only about 10 feet tall, but that's tall enough to get it out of eye poking range.
It's fed with a feedline that Dr. Frankenstein would be proud of. The receiver end is a length of RG-6U, with a BNC male on one end and an F male on the other, both twist on connectors. The antenna end is a length of RG-59U, with an F male on one end and a UHF male on the other. The F connectors are met with a dual F female adapter.
Yeah, I know. Total crap, and if there was a transceiver on the end of this feedline, it would probably burst into flames just out of spite, but connected to my trusty Pro-97, it works fantastically. Even better than v1.0, which is to be expected since it's outdoors now.
Tuning the main element to 120 instead of 150 brings in the Airplanes much more clearly, and I can still hear the Highway Patrol.
And now, without further ado, I proudly present you with Version 2.0 of my Multi-Band Ground Plane Antenna.
This antenna, like v1.0, is based on a UHF Chassis connector. (I swear to Joe Pesci, as soon as I get the right N connectors and that run of LMR, there will be a v3.0). Unlike the first one, I did not connect the radials directly to the connector. Instead, I used a 50mm(ish) square piece of PCB with a hole drilled in the middle. (TIP: Drill the hole before you cut the square bit off your stock. Trust me.) I soldered the connector to the PCB, leaving about 8mm of PCB exposed on all sides of the connector.
The radials. Oh jeez these were a PITA! I cut and straightened a bunch of hangers, and started to prep the tips for soldering. It was immediately apparent that my 30W Iron was not going to work. I switched to my 100/140W Gun and tried to tin one of the radials. After spending ten minutes and having very little success, I had an Idea. I used the Anvil of my vise and some deliberate, and well aimed blows with a hammer to flatten the end of the coat hanger about 35mm from the end up. It remained about 1mm thick, and spread out to about a 2.5mm wide face. After a light sanding, and a quick dip in the flux, they tinned up in seconds. I'm not sure why it suddenly worked better, maybe solder doesn't like round surfaces, or maybe the stress of the hammering allowed some sort of change. Either way, it worked great.
I arranged the radials on the PCB parallel to the sides of the connector, in a sort of a basket weave style.
The main elements are constructed similarly to v1.0, but tuned to 120/450/850 instead of 150/450/850. I had a but of trouble mounting the end of the hanger into the solder cup of the connector, as the hanger is twice the diameter of the solder cup. I mounted the end of the hanger in the vise, and used a rotary tool to mill the end to acceptable dimensions. I also used 3 square 4-40 nuts to collar the end of the hanger around the exposed tip of the solder cup. After tinning the hanger with the 100/140W gun, the 30W iron was sufficient to attach it to the connector.
A daub of silicone and a shot of black Plasti-Dip coating, and it was ready for it's "mast".
I needed to get this antenna off the ground. I don't have a "real" mast, so I dug around in the basement, and found bunch of 20mm tubing with one swaged end, designed so that one tube can fit into the next. It was apparently some sort of portable wardrobe or closet that had a vinyl covering. I used 5 of the straight sections, with one of the sections sunk completely into the ground next to the house. It's only about 10 feet tall, but that's tall enough to get it out of eye poking range.
It's fed with a feedline that Dr. Frankenstein would be proud of. The receiver end is a length of RG-6U, with a BNC male on one end and an F male on the other, both twist on connectors. The antenna end is a length of RG-59U, with an F male on one end and a UHF male on the other. The F connectors are met with a dual F female adapter.
Yeah, I know. Total crap, and if there was a transceiver on the end of this feedline, it would probably burst into flames just out of spite, but connected to my trusty Pro-97, it works fantastically. Even better than v1.0, which is to be expected since it's outdoors now.
Tuning the main element to 120 instead of 150 brings in the Airplanes much more clearly, and I can still hear the Highway Patrol.
And now, without further ado, I proudly present you with Version 2.0 of my Multi-Band Ground Plane Antenna.
