The AM Forum

Hello All,

 I'm looking for the 'voices of experience' as I begin to design my first serious antenna installation here in my new home. I have a lot that is about 130' x 125', on a major street. The neighbor on one side is fenced off for the most part, and there is a strip of town conservation land that seperates me from the other neighbor. Abutting my backyard is a HUGE parcel of conservation land, going back a mile - very beautiful.

 I have a couple of 25-35 foot trees in one corner of the lot, and a couple of the same at the far corner (up by the street). Alas, nothing very tall.

 First, I'd like to run an unterminated Beverage antenna running NE from the house, leading back to a matching transformer, then leading into the basement shack through a hardline (thanks to WGBH!).

 Next, I'd like to hang up an end-fed zepp, the half-wl wire running between my two sets of 'medium height' tree. The balanced line would be fed into a balun, with another hardline leading back into the shack.

Q: I KNOW that the best thing to do is to hang a dipole, high. Just can't do it here, yet. Anybody running on an end fed? Comments or suggestions?

Q: Anybody running a Beverage? How's performance with the end unterminated?

Thanks


David Goncalves
W1EUJ

David,

I recommend that you bury some coax back into the conservation land, and put up a dipole behind the tree line.

Bil W1AC

Not yet.

Dave Goncalves

Dave,
I ran an end fed for a number of years when I was a kid. The RF in the shack drove me crazy. How about a Vee. A balanced antenna will keep RF out of the shack much better than an end fed. I'm in the same boat at new qth but the wire is getting pretty brown. Almost time to ask my neighbor if I can use their tree. This would give me a VEE with 100 degree angle 125 feet on a side facing SW across the Rocky Neck salt marsh

I successfully use 600 ohm feeder with a "tuned stub" and virtually eliminated
all RF in the shack. This is with a center fed antenna tho...
Check out this site...(it takes a while to load) but is a good online
calculator for tuned stubs...http://www.smeter.net/feeding/stubtune.php
I use all kinds of "made for studio" audio gear in my audio chain of one station.
Absolutely no RF into it!
With a "random" length of open wire, man I had more RF in the shack than outside I
bet....
A 1/4 or 1/2 wave end fed is a FB antenna, if you can't do a center fed one IMHO...
Vri 73 Steve 8TOW

An end-fed if properly installed will work just about as good as any other antenna but in order to do so  you MUST............................................

1. Install a good ground system at the feedpoint.
2. Put the tuna / transmatch, or matching network right at the feedpoint and then run your coax to
    the shack from there. (This is extreemly important!)
3. Build, buy, beg, borrow or steal a tuna capable of feeding a voltage fed antenna at the
    power level you want to run.

If you cannot meet those requirements dont even think about running an end fed. Like Frank (GFZ) said you will have terrible "RF in the shack" problems. I used to run an end fed years ago because like you it was easier (at least I thought) to do with my back yard. I had RF dripping out of the cieling lights!! I finally said the hell with it and went balanced, all problems gone, end of story!!

There are a few guys out there that are using end feds and put out a good signal with them. But........................I guarentee you, they have done their homework to get them right!!

                                                                          the Slab Bacon

...try a horizontal loop...feed it with 600 ohm ladder line, to ur tuner...tim...sk..

On 160 meters here, I use an end-fed half wave.  It starts at my pole barn where there is a 30 foot mast.  It runs out to a tree at the back corner of the property, so where the far insulator is, that height is about 55 feet.  I have been amazed at the good signal reports I get, considering the relatively low height.  The barn is about 35 yards from the house.

A single #14 stranded wire comes down from the near end of the wire to my tuner inside the pole barn on the wall.  The tuner is a parallel resonant tank with a tap near the bottom of the coil for 50 Ohm coax feed.  The antenna wire connects to the top of the coil.  The 50 Ohm coax runs to the house/shack.  The tuner is manually tuned.  The tuner connects to 2 ground rods below the tuner, no other ground system at all.  But the coax, just under the grass, does happen to run in the exact opposite direction as the antenna wire, probably acting as a counterpoise.  There probably is a very small amount of current coming back on the coax to start with, but coax in the dirt probably gets some additional choke effects.  No r.f in the shack at all.

So all in all, a well-implemented end-fed half wave, I think.  If I want to change frequency, though, I have to make a trip to the barn with a piece of coax and the MFJ-259B.  The system is stable and actually I can just dial the tuning cap. position to numbers that are logged.

I run a similar setup to Tom with an inverted L. I have a motorized tuner in my bulkhead which is fed by coax across the basement from my shack. The inverted L starts at the bulkhead, goes up 50 feet and then out to the woods. This is convenient but not ideal.

I do not have RF in the shack or RFI on 160M but I do get into some silly touch lamps when I am "tuning" on the higher bands.

This antenna would be a lot quieter on RX if ran underground coax and I started the Inverted L in the woods! I do this on my beverage which of course, works great. 

Mike WU2D

On 40 meters an inverted vee works very good at 30ft. My coax-fed field day 40meter vee has been up at 25 feet for 15 years. The 80 meter vee ain't a whole lot higher.

Anybody have experiences with a ~ 120 - 140 ft doublet at 35 - 40 feet, running to a balanced tuner? I think, after removing my mental limitation on not using roof-top equipment, I could manage that, with the coax running to the shack in the basement. I can run that open line from the center of the doublet to a short pole on the roof, which can feed the line back down to the garage.

I'm not sure on the inverted L, as that'll depend on good grounding, as it is a marconi type antenna - won't it? The particular corner where I can setup the feedthrough into the house, there isn't very much land to lay out wire.

Up till now, I have not heard anything good about the inverted V. I'd consider it, but I don't have a good center support around, just a couple of good, high trees for end supports. I suppose that I could do a regular V, with the center support on the house roof, and the ends up in the two trees, but what would that get me that a straight dipole/doublet or end fed zepp would not?

Mr. K1JJ, where are you?

Dave Goncalves
W1EUJ

Dave I have never had good luck with an inverted Vee close to the ground. A center fed dipole would have a higher average height.
Use open wire line and it will work  on all bands.
Search on W4RNL Cebik and read a dozen times

Brett/N2DTS is doing this, up in New Joisey.  Ladder line from a Dipole for x-amount of feet, then it changes to Coax to be fed out of the back of a tuner.  Seems to work fairly well.

I say, Dave, if you've got room enough for a 75m inverted Vee, you've got room enough for a full-size 75m Delta Loop.  All you need at the apex is a 60' push-up mast.  I would also feed the antenna at the apex, and tie the ends 25~35 feet with the trees on opposite corners of the lot.

After 50' (or more) of 450-ohm ladder line, if you need to, connect that to coax, and bring it into the shack and use your tuner on it.  You'll have lots more wire up there to generate a signal with, and all of that feed-line to keep the reactance out of the line with.

I ran an inverted Vee on 40M at my house when I was a kid. We were on a small town lot and it roughly followed the roofline. Real simple #14 wire and RG-58. It worked pretty good on the third harmonic for DX on 15M Novice band and of course I drew an OO comment or two.

It was a great performing antenna. I hooked single transistor and single peanut tube transmitters and all manner of silly things up to it and it really got out.

I even converted it to that crazy MIT bazooka design from the 72 Handbook with the shorted coax and the open wire feeds and that worked too and was broad on 40 and quiet for noise. 

Mike WU2D

Thanks all for the recommendations and experience. I havn't made my mind up yet, but one action item is clear. I need to find out exactly how high I can those ends. I'm estimating here (triangulation), but I MUST get a fishing line up there in a strong fork and physically measure that height.

I'm glad my medical-tubing slingshot is in good shape.

Dave Goncalves
W1EUJ

A 35 foot center fed dipole will work better than anything  close to the ground.