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Portable antenna with gain
- Thread starter northern35s
- Start date
![DSCF2056[1].jpg](/data/attachments/10/10880-c2d6c5524f87db305ed644b18031e8dc.jpg)
We may joke about the performance of the Antron 99 but put one on a pole and walk it out about 20 feet into the waterline of that picture and I'll put money on it working more DX than anything you could set up easily on the beach. I'd even take one Antron over the salt water rather than two phased verticals on the beach. All the problems with CMC and a high take off angle completely disappear when you place the Antron over this near infinite ground plane and it can rival the performance of many land mounted Yagi's.
I've spent a lot of days / hours searching for the ideal location for portable, mobile and backpack operations, and believe me when I say I would wear waders and stand in the sea if it made that much difference, however I noticed no appreciable difference between my 1/4WL antenna being over water (waders on) or near the water. The Fresnel zone anecdotally appears to be the major component responsible for the enhanced gain and low angle take off.
Why isn't it portablesomething that is lightweight, can be carried in a rucksack, and takes me 10 minutes to erect, I'd call that pretty much portable, it's hardly permanent. I can take my backpack gear onto the beach and erect the antenna at the waters edge, even if I keep the gear very lightweight, one rig at 5-10W maximum, one LiPo battery, and I'll still have a good signal the other side of the World. I can pack it all away when done and still have room for sandwiches and a flask of coffee in my rucksack.
You must also remember why I'm building a 10m version, it's simply to test the theory, my main goal is 20m, that's bigger, more expensive, more to handle, if my early attempts with a 10m version pay off then I'll have a go at the 20m version.
The reason why here in the CB section and not the ham section, well the fact it's currently a 10m version and very little scaling required for an 11m version. Wouldn't you like almost amplifier like gain just for the sake of carrying a second lightweight pole rather than one? I know a chap who goes hill-topping in his car with a drive on mount, 20' pole and 2 element 11m yagi, I know people who do the same with 3 and 4 element yagis, are they portable or not? Certainly not backpack postable!
If I want single element performance I can do that with my car, my bicycle or my backpack. I often drive my car with a 13' antenna attached, so I'm not worried about driving with big antennas, I've also spent a king's ransom on what is possibly the best mobile antenna money can buy, I've modified my car's tailgate to take the weight and forces associated with installing such an antenna, I'm not afraid of a little effort to maximise results, plus I like to make shit, it's something to do and I can learn from it
The thrill of making it through a pile up, to a station the other side of the World, with minimalist equipment is fantastic, see for yourself:
80W, 1/4WL antenna and romped through an EU pile up to Australia long path, some 14,232 miles between us :w00t:
https://www.youtube.com/watch?v=9R5UDAnXFLA
imo any beam isnt really portable. not saying it cant be done. but if it were me id have
a99/imax type of antenna and/or a sirio d27 for flatside. ONLY because easy up easy down
if a storm came along you would be able to disassemble a a99/imax much faster than
ANY beam. and lighter .facts dont lie
You have no idea what the antenna weighs, I can tell you now that the antenna, and it's support poles, are lighter than an A99, how do I know? I have an A99 here for testing.
Now that is a fact!
You're welcome to your opinion, and you've shared it with us, however I don't share the same. I would however be interested to hear of your experience whilst operating portable with your A99
As a kid, I spent enough weekends going out on my parents boat with the Antron 99 stuffed into the fishing rod holder that I can assure you just placing the coax in the salt water produces enough coupling effect to that ground plane that it makes a measurable increase in received signals on an S-meter.
Did you align the base of the antenna so it was close to the water line? Where you on HF? Did you make an attempt to replace the portable antennas ground plane with the water by making any connection to it through a mast or coax in the water. My post was not an opinion, it was the results of being shocked by the biggest increase in gain I had even seen using a location with no elevation.
Later I found out I could get the same increase without the coax in the water if I attached a short jumper wire from the side of the CB to the side of the HF high seas marine radio. Well over an S-unit increase because the marine HF rig was grounded to a gold plated block under the boats waterline. I'm surprised you're unaware of the notable increase in gain salt water provides at HF but then again so was until I measured it.
There is a place on the highway here that crosses a tidal salt marsh with a bridge over the tidal inlet. I can hear and see a difference in signal strength as I cross the narrow marsh/inlet. It is only about 1/8 mile long but signals get stronger especially when crossing the bridge. It is noticeable on HF and REALLY noticeable on the AM broadcast band.
I'm not, and neither is my experience just opinion. I use it to my advantage everytime I get out by the water, it's one of the main reasons why I can work stations 16,000 miles away with 500mW. It's the reason why some of the big Australian contest stations hear me better on their upper antenna (lowest lobe, lowest arrival angle) than their lower antennas (higher arrival angle).
I can see the results of walking away from from the waterline on signal reports, both received and transmitted, it has a significant effect.
I don't use radials or counterpoise wires dragging behind me, I use a technique called ground tuning, where tunable series L/C networks are used to maximise ground current in the small backpack frame, but the details of that are worth their own seperate thread
I will however put your theory to the test, by using a trailing counterpoise wire and walk out into the water, and I'll be sure to record the results for all posterity. In the meantime if you want to see what I get up to with my backpack, search my username 'northern35s' or callsign 'G7DIE' on youtube, you might find some of them interesting.
Looks good, I've seen a few people using this configuration beam and there's no questioning their efficacy. Maybe a project for me sometime down the line.
The problem is I've got more projects than I've got time, QRO mobile is a big project for this year as I need to complete this to a professional and reliable standard, I can't afford to spend time mothering it when it's done. A large second battery and ALS500M amplifier, in the already small trunk of my car, is going to take some planning
You have no idea what the antenna weighs, I can tell you now that the antenna, and it's support poles, are lighter than an A99, how do I know? I have an A99 here for testing.
Now that is a fact!
You're welcome to your opinion, and you've shared it with us, however I don't share the same. I would however be interested to hear of your experience whilst operating portable with your A99
long before i able to have a base setup. my mobile had a 148 side mic with a 102 whip
id drive to the highest hill i knew of in my very small town . once there i assembled
my a99 and mounted it to a 5 foot pole then slid it thru my trailer hitch hole [took ball off]
now this wasnt the most effiencent antenna or setup. but at 16 and coulnt have a real
base setup this worked real good.i was talking with locals on ssb up too 60 miles away
couldnt quite do this with just the 102. the whole setup time couldnt have been more than
3 or 4 minites. best of all it was tuned perfectly so no time at all on tuning either
In the absence of an infinite copper ground plane, salt water is the closest thing and will concentrate more of the pattern on the horizon.
I don't use radials or counterpoise wires dragging behind me, I use a technique called ground tuning, where tunable series L/C networks are used to maximise ground current in the small backpack frame, but the details of that are worth their own seperate thread
This is the same principle MFJ capitalized on when they adapted their antenna tuners for ground applications and tuning the counterpoise for resonance at the operating frequency. I'm curious to see if this type of counterpoise tuner could be used as an advantage to maximize current flow into the body of water? The only problem might be the size of this ground plane could be outside the tuning window of the device.
If you have the time, I hope you check it out. The short jumper between the HF SEA 222 radio on our boat and the CB eventually got a switch installed to connect the gold plated grounding block to the CB. For years I used it like a small linear and receive pre amp when the ground block was connected to the CB. Actually making the electrical ground connection to the body of water seemed to make a larger increase than just having the antenna located above the water.
PS: I took your advice and checked out some of the places you have worked DX from. All I can say is nice work and interesting vehicles to operate from.