Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Thinking End Fed

BenMara said:
Center fed dipole fed with Ladder line to 4:1 and use autotuner on radio
Click to expand...

That's only going to work on certain bands with the right antenna and feedline length.

No one ever wants to do this because you can't buy it from mfj but make your own tuner. Roll some heavy gauge solid wire around a round form like PVC to make 2 identical coils. Then find a variable capacitor. Get yourself some clip leads and zip tie it to a piece of wood. This tuner will work better with ladder line fed antennas than most store bought tuners and doesn't cost much.

W4MMQ Tuner Schematic.jpg


Don't have room for a full size doublet? No problem. Build it out of 1/4 copper tubing, use havy gauge wire for the ladder line and antenna. Move the tuning capacitor to the input side of the coils to match a low impedance load.

Also notice that no balun is being used outside of it's design impedance the balun is on the input side where it's always around 50 ohms.
 
  • Like
Reactions: BenMara and fogdog
Im hoping to only use the auto tuner that comes in the 7300. Ive read some reviews of folks that use an end fed wirh there 7300's and they say it works.
I don't have any grand illusions about end fed antennas, but it looks like it would work ok.
I don't believe most people understand my property lay out, or they wouldn't be suggesting fan, cage, octopus, or any other type of antenna similar to these types. There is no way any of these types of antennas would survive up here. Does anybody have a antenna set up in the woods permanently that lasts more than one season ? I want to hear about that. I asked for suggestions , and thank you for that. I look at each design, and try to determine if it will work for me. Of course I want to hear that end fed antennas are good, because I personally believe for me it's the easiest best way to go. A verticle would be better, but the ones I see are way up in the price range. I would also have to build a mast for it, etc, etc, etc.
I am concerned about RFI in our house. I've had trouble with that before in dipole's I made. Lighting up the dinning room lights when I key up, and that kind of thing. I'm not totally into the wire, but a lot of folks use them. Being new to HF, and big HF antennas, I need your opinions. Thank you very much for your write ups, and please don't stop giving me sound ideas or resl world experiences with your antennas. I do look at each message.
 
fogdog said:
Is there a way to alleviate this. I used a rf balun, and low pass filter, and it worked. That was a center fed dipole though. Don't want RF in the shack or house.
Click to expand...

Centre fed and end fed are completely different animals altogether. Centre fed is driven at a low voltage high current point whereas end fed is driven at a low current high voltage point and is quite susceptible to having RF in the shack on anything that is not well grounded. It also depends on the exact impedance presented at the feedpoint which will vary over several different bands. Many EFHW installations are free from RF but many are also plagued with it. IMHO if running a halfwave make it a centre fed dipole.
 
  • Like
Reactions: Road Squawker and BJ radionut
BJ radionut said:
One other note in regards to EF's: Don't believe for second what MOST of the user's and producers say.
Yes they work, but without a suitable Counterpoise(and not 10-12 ft. of wire) and ground system at the balun…
What is the other Half of your Antenna? Your FEEDLINE!
No way around this!
All the Best
Gary
Click to expand...

And this is what tends to create RF in the shack as well as other issues.
 
Captain Kilowatt said:
Centre fed is driven at a low voltage high current point whereas end fed is driven at a low current high voltage point
Click to expand...

I know you're talking 1/2 wave center fed dipoles and this is true in that aspect. If the op ever gets into a doublet it may not be. Say an 80m doublet used on 40m. A pair of half wave wires in phase would have high voltage and low current at the feedpoint.

If he can hang a diople in the woods a doublet is not out of the question. He will even have gain on the higher frequencies. Way more pros than cons. If he was local and interested I'd help him build the tuner and show him how to use it.
 
  • Like
Reactions: Captain Kilowatt and BJ radionut
543_Dallas said:
I know you're talking 1/2 wave center fed dipoles and this is true in that aspect. If the op ever gets into a doublet it may not be. Say an 80m doublet used on 40m. A pair of half wave wires in phase would have high voltage and low current at the feedpoint.

If he can hang a diople in the woods a doublet is not out of the question. He will even have gain on the higher frequencies. Way more pros than cons. If he was local and interested I'd help him build the tuner and show him how to use it.
Click to expand...
Wish I was near.
 
Looking at your QTH, I would be inclined to set-up a fan dipole in those trees with a weight on the end to keep it tight but flex at the sametime. Flattop with a 1:1 balun, inverted V no balun.
I use a 58'/13' antenna straight into my KX2 with a height of about 12' at the highest point that works. Oh, I should say that this is on top of a mountain, so I have some good height of sorts.
 
  • Like
Reactions: fogdog

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Wildcat27:
    Hello I have a old school 2950 receives great on all modes and transmits great on AM but no transmit on SSB. Does anyone have any idea?
  • @ BJ radionut:
  • @ ButtFuzz:
    Good evening from Sunny Salem! What’s shaking?
  • dxBot:
    63Sprint has left the room.
  • dxBot:
    kennyjames 0151 has left the room.


      Top Bottom
      Back