2 Meter SSB

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Michael:
Im going to try 2 meter SSB and i would like to know the distance of 2m SSB with a directional antenna putting out 50 watts?

Steve Katz:
As has been discussed right here dozens of times, this cannot be predicted because there are too many variables.

Working "range" on two meter SSB is dependant upon...

-Antenna height above ground (note 1)
-Antenna height above average terrain (note 1)
-Antenna height above near field obstacles (note 1)
-The actual path between station 1 and station 2, including elevation contours over that path
-Antenna gain (note 1)
-Transmission line loss (note 1)
-Transmitter power (note 1)
-Receiver sensitivity (note 1)

(Note 1: For both your station, and the station you're trying to contact.)

With 8 major variables greatly influencing the outcome, usually it's anybody's guess how far you'll be able to work.  If you operate from atop the highest mountain in your area and have a 100-mile horizon, chances are your average working radius with a decent, horizontally-polarized two meter beam and 50 Watts will be 300+ miles, 24/7, without any extraordinary propagation.

There's no truth to the silly rumor that 2 meter propagation is "line of sight."  That's ridiculous, and not even close to the truth.  However, your visible horizon does play a role in your working "range," and the longer it is, the better.  And in all cases, the higher your antenna is above ground, the greater your working range will be -- without exception.  This single factor is probably the largest contributor to "long range" success on VHF!

Obviously, for SSB, you want to use horizontal polarization.  The larger your antenna (beam) is, the more gain it will have, but the narrow its pattern will be.  Good for "DX," not so good for general tuning around to find activity.  You can end up with a very high-gain antenna that's so "sharp" you can only hear stations in one direction, and have enormous rejection everywhere else.  Again, great if you know who you're aiming at, and not so great if you don't.

Everything's a compromise, but after 39 years on two meters working "weak signals" ("DX" stations, so to speak), my impression is that antenna height is paramount; location is very important but often cannot be changed, so shoot for the height!  Then, feedline loss, antenna gain, and having your antenna as much "in the clear" (above all local obstacles) are all very important.  Transmitter power, receiver sensitivity and actual equipment used falls much farther down the list, and should only be optimized after the "antenna" factors are.

BTW, from my modest home station in Los Angeles, on two meter SSB my average "working range" is about 250 miles in most directions, most of the time, when contacting similarly-equipped stations.

WB2WIK/6


Michael:
Ok Thanks for the info and the antenna im looking at is a cushcraft 20 element i think with 11.1dbi gain. I have alot of trees beside my house which might be a problem so i am trying to find a big enough mast to get the antenna im buying above them.

Steve Katz:
Absolutely, positively get above those trees!

The CC 20 element 2m beam is really only a 10 element 2 meter beam in the horizontal plane, and another 10 element 2 meter beam in the vertical plane, so you can use it for both SSB and FM if you use both sets of elements.  It's not a *bad* antenna, but there are many available that are lighter and have less wind loading, with substantially more forward gain for use on 2 meter SSB (ignoring the FM stuff).

One example: The M2 model 2M9SSB.  It's only 9 elements, but it's on a 14-1/2' long boom (longer than the Cushcraft 20 element), and gain comes from *boom length*, not the number of elements.  It's also completely optimized for the SSB portion of the band, and it has substantially better performance for SSB work than the 20 element Cushcraft (sacrificing FM use).  Not only that, but it weighs less, so installing it up higher is easier!

Height is everything, until your antenna is up so high that it's absolutely the highest thing in your neighborhood and nothing is higher.  When you're at that level, then additional height will only gain you a bit longer horizon, with tropospheric propagation about 3x that improvement.  (For example, if your horizon is 10 miles with an antenna at 50 feet above ground and your antenna is already the highest thing in the neighborhood for several blocks around...increasing your antenna height so that your horizon becomes 12 miles will only gain you about 6 miles more in typical strong-signal working radius.  Not much.  But if your antenna at 50 feet high is blocked by trees or other obstacles, and increasing its height to 60 feet will get it above those obstacles, you can count on a tremendous improvement in working radius -- possibly the difference between working stations 50 miles away vs. working stations 200 miles away.  There *is* that much difference, once you get clear of everything.)

I remember an "Elmer" of mine, Neal Hubach W2KME of Springfield, NJ, who was a radio engineer with AT&T for many years and a very active ham, answering my question to him when I was a new ham and a kid: "On two meters, when do I know my beam is really high enough?"

Neal's answer: "When you're driving towards your house, and you're still a couple of miles away, and you look up, and the first thing you can see is your beam, before you see anything else in your neighborhood, it's high enough."

That's just about exactly right.

WB2WIK/6

Michael:
Alright Thanks for all the information im still looking for a big enough mast to get above those trees though.

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