blind spot?

[8valve]

here for another question
me and a friend were trying to talk to each other with CB,
nothing special at first but, we live about 80 miles apart
we thought it would be fun to have a connection from time to time with the radio

what we have done;
first the "local" principals
antenna as high as possible for a "line of sight" connection
that didnt work on all mode's am, fm, usb, lsb, cw
first at 4 then 35 and even with 100watts
ok, it is probarly to far for "local"

then according to dx principals
which worked fine for dx a wire dipole on about 3 meters high
same story on the mode's even with various power levels
it is probably to close for "dx"

the radio's and antenna's are good we have measured them as far as we could
for dx we worked some nice contacts
so everything works properly

so my question is;
how do we get past that "blind spot"?
its not the end off the world as we cant make it happen but we would like to make it happen from time to time

 

[Highlander_821]

Maybe backscatter mode could work. Get beams and point them both to the SE in the early morning right around sunrise. It won't always work, but I know several people in the midwest who used to do this.

I have had success talking about 110 miles, but only a couple of times. Both times it was late at night, and the band was REALLY quiet. The guy I was talking to had a moonraker 4 at 110 feet AGL, I had a 5/8 omni. Both of us were running about 150 watts SSB.

 

[9C1Driver]

You will have to look into running some kind of a beam antenna and then make sure you are on USB or LSB. I would think if you could each get your IMAX 2000 70+ feet up, run say 300 watts, and again be on USB or LSB it should work.

The other night I was mobile with a Wilson 5000 and Magnum 257HP. A guy I know was about 80 miles away on an Omni base antenna. I parked on the roof of a parking garage about 45 feet up and on 27.585 LSB we talked no problem.

 

[W5LZ]

The simple fact is that there's no sure way of doing it. You are right, you two are just the wrong distance apart for the circumstances. You might hit on an antenna combination that may work for you but don't count on it. You might change the time of day when you try, that can have as much affect as anything else will.
- 'Doc

 

[mechanic]

CB frequencies are not a good choice for this distance. I check into a net on 39 LSB and most times I cannot be heard. I live near several of the Great Lakes and at time there is thermal propagation or "ducting".
Best distance is 15 to 25 miles and power does not always help! Narrow modes work better with SSB good and CW better. Some of these modes are not allowed on CB!
I have done well with CW mode on ten meters at a distance of 75 miles but for some this is not to be had. Best answer is to use other frequencies but for that you will need to have your HAM license. **Jump_im** 75 meters will work very good for this distance especially in the morning or evening!

73 mechanic

 

[8valve]

sure i know that with ham it would be "easier"
but i dont have a license, equipment or the money to go out and buy a lot of stuff :headbang

our antenna's are mounted 6 meters (20ft +- )
while i can maybe get it higher with some kind of tower
my friend lives in a city so he is kind of limited in his antenna hight

did some measuring
ive got a dike on my property its about 13 feet higher then the rest of the land
what ive measured is that i would need about 65ft of additional cable tho feed it if i put it there
according to this calculator;
http://www.saarsham.net/coax.html

this is me "loss" now;

about 10% off the power
loss of dB: 0.431

then it would be;

about 35% off the power
loss of dB; 1.849

that would be an additional loss of 25% off the power and 1,4 dB loss
if i use the same rg58 cable (ive got nothing else on hand)

would the additional hight out weigh the cable loss?

 

[QROdx]

Are both of you using a directional horizontal (beam) antenna?
If not, what about a dipole mounted horizontally as high as you can possibly get it?

The reason I'm suggesting horizontal versus vertical is because it will better follow the curvature of the earth.
Also, having the directional capabilities and forward gain of a beam would help.

You wouldn't believe the height that each of you would need for true "line of sight" communications.

Not counting for obstructions, refraction or fresnel effects, at *2 meters / 6 feet* above sea level, the distance to the horizon is roughly 3 miles.

If each of you had a tower of *30 m / 100 feet* in height, the horizon is at a distance of roughly 12 miles.
A tower of *100 m /330 feet* in height, the horizon is at a distance of roughly 24 miles.

Like the old saying goes, "the higher you get your antenna the better".

I'll second some of the earlier comments, back scatter would be worth a try if you both have beams.
Your friend being in the city could also try pointing in a direction away from you to benefit from reflections toward you while you are pointed toward him.

SSB would also help, as well as a little "fire in the wire"
Good Luck

 

[8valve]

we both have a horizontal dipole on the roof of his house
and i also got a GPA (he is thinking of mounting one on the roof of his house to

as far as fire in the wire
150w ssb should be enough (thats as far as i can go)
and about 100w am/fm

 

[QROdx]

Two things come to mind that you could try.

1) Each of you turn your dipoles so that the broadsides face each other, basically "point" the antennas at each other.

2) If it's not too much trouble, you could hang a reflector wire behind the dipole.
You'll have a 2 element beam with no boom.
That's an old trick I used to do on 80m. I hung a wire 40 feet below the dipole and with some rope and a few pulleys I had a "steerable" dipole that really made a difference.

There's no real magic to it, just use a wire that's roughly 5% longer than the dipole.
Assuming you're doing this on 27MHz...
1/2 λ dipole @ 27.2MHz = 8'7" per side
Reflector @ 5% = 18' spaced 4' to 5' behind dipole, tweak as needed

 

[2RT307]

I would try a cell phone.

73,
RT307

 

[Eastside]

Your best chance would be both using beams on sideband.....I talk to stations in the surrounding states barefoot that my local stations on ground planes cannot even hear....best time is late at night when its real quiet

 

[8valve]

Two things come to mind that you could try.

1) Each of you turn your dipoles so that the broadsides face each other, basically "point" the antennas at each other.

2) If it's not too much trouble, you could hang a reflector wire behind the dipole.
You'll have a 2 element beam with no boom.
That's an old trick I used to do on 80m. I hung a wire 40 feet below the dipole and with some rope and a few pulleys I had a "steerable" dipole that really made a difference.

There's no real magic to it, just use a wire that's roughly 5% longer than the dipole.
Assuming you're doing this on 27MHz...
1/2 λ dipole @ 27.2MHz = 8'7" per side
Reflector @ 5% = 18' spaced 4' to 5' behind dipole, tweak as needed

i sort off understand it (not to much)
if you want could you paint it real simple?
google translate doesnt translate this technical stuff well


@ eastside;
we only can try it around those times because off work,
ill look further into a beam

 

[QROdx]

No problem.
Maybe this will help.

 

[8valve]

thank you,
im going to experiment with this when ive got the time,
just hanging a wire behind it, i should be able to make that

 

[wavrider]

thank you,
im going to experiment with this when ive got the time,
just hanging a wire behind it, i should be able to make that

Hang the wire about 65" behind the dipole.

You may have to re tune the dipole once you put the reflector behind it as it may change the impedance at the feed point.