mobile antenna to base !

[StrangeBrew]

At the price Eagle1com is asking it would probably be worthwhile to grab one or two just to chuck in the junk box, they look like handy little gadgets to have on hand.

 

[Riverman]

I see countless videos of hams using the Buddistick Antenna in their back yard or a park and making unlimited DX contacts. It is basically a steel whip and a single wire counterpoise usually tied off to a small bush or stake. Most are running less than 5 watts.

Why then wouldn't a lowly CB'r such as myself have similar success with a 103" steel whip and a single wire for counterpoise on a short tripod in my backyard? Is propagation that much better on 10, 15, 20 and other HF frequencies than it is on 11 meters? What am I missing?

I will likely look like a fool when I read the responses so I'll apologize beforehand.

 

[M0GVZ]

Why then wouldn't a lowly CB'r such as myself have similar success with a 103" steel whip and a single wire for counterpoise on a short tripod in my backyard? Is propagation that much better on 10, 15, 20 and other HF frequencies than it is on 11 meters? What am I missing?

The higher probability the other station at the other end has a very good antenna installation and better radios with less internal noise.

Add to that far fewer people running dirty amps splattering over 30kHz or more, radios with far better selectivity and fewer music players and mic keyers and the chances are dramatically improved.

 

[Riverman]

The higher probability the other station at the other end has a very good antenna installation and better radios with less internal noise.

Add to that far fewer people running dirty amps splattering over 30kHz or more, radios with far better selectivity and fewer music players and mic keyers and the chances are dramatically improved.

That's a nice way of saying hams have more success with DX because:

a. The equipment is better
b. The operators are better behaved.

Add the two together and one greatly improves his/her chances of making DX contacts.

I'll buy that.

I think I'll go dig out my Technician Class study guide.

 

[binrat]

I see countless videos of hams using the Buddistick Antenna in their back yard or a park and making unlimited DX contacts. It is basically a steel whip and a single wire counterpoise usually tied off to a small bush or stake. Most are running less than 5 watts.

Why then wouldn't a lowly CB'r such as myself have similar success with a 103" steel whip and a single wire for counterpoise on a short tripod in my backyard? Is propagation that much better on 10, 15, 20 and other HF frequencies than it is on 11 meters? What am I missing?

I will likely look like a fool when I read the responses so I'll apologize beforehand.

Why not try?? But I would run 3-4 counterpoise wires instead of 1.
I have had a Buddipole that always worked better for me as a vertical mount 6-8' off of the ground with a few counterpoises than as a dipole.

 

[Riverman]

Why not try?? But I would run 3-4 counterpoise wires instead of 1.
I have had a Buddipole that always worked better for me as a vertical mount 6-8' off of the ground with a few counterpoises than as a dipole.

I tell you, binrat, all the worries over antenna height, angle of radials/impedance, ground loss, high take-off angles and everything else are enough to drive a guy to drinkin'. I think M0GVZ makes some good points about the difference between say, 20 meters, and 11 meters. And one day (maybe pretty soon) I will probably make the jump.

In the meantime, instead of a steel whip and some wire I think I'll just go ahead and get a six-element beam and mount it horizontally on my 4' camera tripod in the back yard (I really want a Moonraker but would need a taller tripod). Then set up my lawn chair, pour some iced tea, run an extension cord to my Cobra 85, quit worryin' and enjoy life. I won't need a rotor for the beam, I'll just turn it manually. If that doesn't work, I'll get a radio with SSB. That should do it for sure!

 

[hotrod]

I tell you, binrat, all the worries over antenna height, angle of radials/impedance, ground loss, high take-off angles and everything else are enough to drive a guy to drinkin'. I think M0GVZ makes some good points about the difference between say, 20 meters, and 11 meters. And one day (maybe pretty soon) I will probably make the jump.

In the meantime, instead of a steel whip and some wire I think I'll just go ahead and get a six-element beam and mount it horizontally on my 4' camera tripod in the back yard (I really want a Moonraker but would need a taller tripod). Then set up my lawn chair, pour some iced tea, run an extension cord to my Cobra 85, quit worryin' and enjoy life. I won't need a rotor for the beam, I'll just turn it manually. If that doesn't work, I'll get a radio with SSB. That should do it for sure!

now thats agood idea

 

[Rick330man]

I took my hub-based Starduster copy down a few months ago and just put it back up last week. I'm using three of the stainless steel Radio Shack 102" whips as my ground plane radials. They were purchased when Radio Shack was blowing them out. There's an old Radio Shack 102" fiberglass whip serving as the vertical radiator on top of a stainless steel Workman heavy duty 4" spring. My coax it about 54'. There are two 27' sections of RG8X.

It works. My SWR is about 1.33 on channel 40 and up to 1.57 on channel 1. It is nice not to have to worry about a coil.

For portable, I have a portable mount that I hook up a 102" inch whip to. I'll run a single 105" copper wire for a counter-poise. It works pretty well.

 

[Riverman]

With the coax hanging straight down, the feedpoint impedence of a horizontal half-wave wire dipole is around 75 ohms I believe. If two mobile antennas such as Firestiks are used instead of wire, does the impedence remain about the same or is it higher?

 

[The DB]

Actually, with most coils it drops, unless there is something else in play, such as the coil being tapped... I am not sure if there is something in the Firestik that changes that, a friend has a Firestik with an additional ground wire sticking out. although he never hooked it up and his antenna works fine...

If you are going to use two Firestiks in a dipole arrangement, people have successfully done that before.


The DB

 

[Riverman]

DB, I have made and used such an antenna but always wondered and never knew what the impedence was as I don't own an analyzer.

 

[The DB]

Using modeling as an example, a full length center fed dipole mounted one wavelength above earth I get a feed point impedance of a hair above 72 ohms at resonance. Making both sides five feet long instead of tuning to a resonant length, and using an inductor on both legs (not quite the same as making an actual coil, but same principle) at resonance I now get 27.7 ohms. That can change based on the inductor's design, and where on the antenna it is placed.

Inductors on the antenna lower R, but in a mobile environment, other factors raise R.

I know of people who have used Firestik antennas successfully in a dipole configuration before, I don't know what readings they reported offhand, SWR or otherwise, I would have to look said situations up and see if they reported such things.


The DB

 

[Riverman]

My thought was since mobile fiberglass antennas such as the Firestick are rated at 50 ohms, using two for the legs of a dipole would result in a feedpoint impedance of either 50 ohms, or 100 ohms (since there are two).

Since hams have been using hamstick dipoles for ages I figured this has been discussed many times and a foregone conclusion has been reached.

 

[scout943]

Been using one for the past 15 years works just fine ,i use heavy duty chicken wire fencing for the ground plane about a two foot square piece ,its been up in the rain wind and snow with no problems 1; 5 swr .

 

[Marconi]

Hey guys, if 2 - 1/4 wavelength ss whips or 2 - 1/4 wavelength wires were setup as a dipole and it shows in the image below...a match of <>72 ohms @ <>0 ohms of reactance at the feed point, then why then would a resonant Firestik a 1/4 wave coil of wire on a former...not show to be similar at <>72 ohms at resonance too?

Dipole with two resonant wires that happen to be 104.21" long with .625" inch diameter of aluminum at 36' feet in this example,





I can't support my thinking with a model and I have not tested the idea in the real world using a FS, but it doesn't jive for me. IMO both antennas with a 1/4 wave whip or a 1/4 wave helix coil are nothing more that a 1/4 wavelength radiator regardless of construction.

On post #204 above #71 gets it right IMO, but then he questions his thinking. I think his first thought is correct.

DB are you saying you added a loading coil to shorten the legs to each side of a dipole and you saw 27 ohms of resistance at resonance in that setup?

Are we to believe that because these two distinctively different 1/4 wave radiators over a good predictable (not a mobile) ground plane are not interchangeable?

DB, you may be telling us this was a real world experience you had where you saw 27 ohms on a dipole, I'm not sure, but I would like to see this model if you did it using 4Nec2.

A simple resonant 1/4 wave helix for 11 meters takes too many wires for me to model in my version of Eznec, or I would build the idea and not ask it of you. Sorry!