My antenna broked... [Archive] - The Island Of Misfit Hams

KJ3N

07-04-2014, 01:19 PM

Looks like I'll need to string up a new one. Better off, as this current one was a fan dipole for 20/30M. Figure the next one will just be a dipole for 80M, and use the tuner.

Any idears for the next wire antenna design?

Plenty of ideas, but I'll need particulars.

What's the longest stretch of wire you can put up? How high can you get it?

What will be the feed line length, and what type of feed line? Coax? Ladder line?

Do you envision this being used on just 80?

W2NAP

07-04-2014, 02:27 PM

dont feel bad, my radio broked

KG4CGC

07-04-2014, 02:30 PM

20m dipole fed with a length of window line cut to 20m and fed with a balun and coax. It works on 80 through 10. Don't ask me why. Well, 80, 40, 20 and 10. I think it's the balun. I forgot if it's 3:1 or 1:1 or whatever. I built it 3 years ago.

The other antenna I built is for AMBCB and LW. Half of it is an 80m band heavy wire sloped up into the trees and grounded at the base. This wire connects to the outer shield. The other half is 460 feet of heavy wire zigzagged through the trees and connected through the center wire and not grounded.

KC2UGV

07-04-2014, 06:13 PM

Plenty of ideas, but I'll need particulars.

What's the longest stretch of wire you can put up? How high can you get it?

What will be the feed line length, and what type of feed line? Coax? Ladder line?

Do you envision this being used on just 80?

Well, I got a 120x60ft lot to work with, so whatever length would fit there.

I'll be feeding with coax, and I'd like to be able to work most bands, primarily 40, 20, and 30. I figure put a 80 meter dipole up, and i'd be able to tune up for most bands.

KJ3N

07-04-2014, 07:01 PM

Well, I got a 120x60ft lot to work with, so whatever length would fit there.

That doesn't tell me much. I'm looking for what you think you have in the way of supports and what's the distance between those supports. You also haven't given me a height to work with.

I'll be feeding with coax, and I'd like to be able to work most bands, primarily 40, 20, and 30. I figure put a 80 meter dipole up, and i'd be able to tune up for most bands.

If you try to feed an 80m dipole with coax, you're not working the other bands (especially 40m), tuner or no tuner. You might make the radio happy, but you'll lose close to 90% of your power in the coax because of the mismatch on 40m. An 80m dipole (which is roughly 130 feet long, BTW) on 40m gives an impedance mismatch of 100:1. It's "only" 48:1 on 30m, and 62:1 on 20m.

If you insist on using coax all the way to the feed point, you need to make a fan dipole, with separate legs for 80, 40, 30, and 20. The other option is to use traps in the dipole legs for the higher bands.

A standard G5RV is 102 feet long, would fit in the space allotted, and work OK on 80, 40, 30, and 20. You just have to get it at least 35 feet in the air, and keep the 300-ohm twin lead off the ground and away from metal objects.

KC2UGV

07-04-2014, 07:41 PM

Yeah, not much in the way of supports, other than my house an garage. However, I think I'll give the G5RV a try... Should be able to get it high enough, and it covers the bands I'm interested in...

KC2UGV

07-06-2014, 01:46 PM

Ok, so for more details: http://binged.it/1n5Etm1

That's a bird's eye view of my lot. After some more thinking, I think it's time to consider plunking at least a mast down. My thoughts are putting a 50ft mast up against the house (In the back), with an antenna of sorts there.

The twinlead thing got me curious too: I've only been using coax since it's running through the house. How painful is it to run twinlead through a house? It's wood/drywall construction, but aluminum siding, which initially turned me off of twinlead. Is it doable in this case?

NQ6U

07-06-2014, 02:24 PM

Those long, narrow lots remind me of how San Francisco was subdivided. I've been within a mile or so of your house, BTW, passing by on I-90.

KK4AMI

07-06-2014, 02:50 PM

I have a 102 ft doublet. I'm using ladder line to a Radioworks Remote Current Balun mounted on my eve. From there its a 10 ft length of RG-8x through my window frame and to my antenna tuner.

KK4AMI

07-06-2014, 02:52 PM

Those long, narrow lots remind me of how San Francisco was subdivided. I've been within a mile or so of your house, BTW, passing by on I-90.

Aren't those types of houses called "shotgun" style because of the long center hallways.

n2ize

07-06-2014, 04:23 PM

20m dipole fed with a length of window line cut to 20m and fed with a balun and coax. It works on 80 through 10. Don't ask me why. Well, 80, 40, 20 and 10. I think it's the balun. I forgot if it's 3:1 or 1:1 or whatever. I built it 3 years ago.

It will work and the radio will tune but it won;t be very efficient and a lot of energy will be lost in the balun. best method is to cut the antenna for the lowest band you will use and run balanced line right into the shack and match it to the radio via a balun-less link coupled tuner. When I first got on the air I used the coax from the transmitter, into a balun and then to the balanced line to the antenna. It worked reasonably welkl on 75 meters until one day in the middle of a transmission I heard a pop and the transmitter went out of tune. When I looked at the balun it was quite hot and part of the plastic case had melted open where the windings in the balun burned out.. Apparently a lot of my power was being converted into heat. Luckily I got hold of a 300 watt Matchbox and ran the balanced line into the tuner. What a world of difference. Big improvement in signal on all bands from 80 thru 10 and it ran cool, even when I pushed full legal AM power through it.

WØTKX

07-06-2014, 05:36 PM

^^^ correcto-mundo!

KJ3N

07-06-2014, 06:37 PM

Ok, so for more details: http://binged.it/1n5Etm1

Does anyone like trees in that neighborhood? Barely any to be found.

That's a bird's eye view of my lot. After some more thinking, I think it's time to consider plunking at least a mast down. My thoughts are putting a 50ft mast up against the house (In the back), with an antenna of sorts there.

Fifty feet is a decent height. Should do well on 75/80.

The twinlead thing got me curious too: I've only been using coax since it's running through the house. How painful is it to run twinlead through a house? It's wood/drywall construction, but aluminum siding, which initially turned me off of twinlead. Is it doable in this case?

Depends on what you'll wind up running next to, if you try that. Twin lead / ladder line doesn't like to be near anything that has metal in it. That includes internal AC wiring, duct work, and plumbing. 300-ohm twin lead can probably tolerate metal within 4 inches of it. 450-ohm ladder line likes to see a distance of at least 6 inches.

N2CHX

07-06-2014, 06:48 PM

You know what works really well for me? My vertical with top-loading. Works a lot better than any dipole I've ever tried and takes up practically no space.

KG4CGC

07-06-2014, 07:05 PM

It will work and the radio will tune but it won;t be very efficient and a lot of energy will be lost in the balun. best method is to cut the antenna for the lowest band you will use and run balanced line right into the shack and match it to the radio via a balun-less link coupled tuner. When I first got on the air I used the coax from the transmitter, into a balun and then to the balanced line to the antenna. It worked reasonably welkl on 75 meters until one day in the middle of a transmission I heard a pop and the transmitter went out of tune. When I looked at the balun it was quite hot and part of the plastic case had melted open where the windings in the balun burned out.. Apparently a lot of my power was being converted into heat. Luckily I got hold of a 300 watt Matchbox and ran the balanced line into the tuner. What a world of difference. Big improvement in signal on all bands from 80 thru 10 and it ran cool, even when I pushed full legal AM power through it.

I talked to Poland on 40m.

K7SGJ

07-06-2014, 07:18 PM

You know what works really well for me? My vertical with top-loading. Works a lot better than any dipole I've ever tried and takes up practically no space.

For an economical station, I have to admit, a vertical is hard to beat. I have an old 6BTV I'm still using, and it works quite well. It has also survived some pretty nasty winds out here.

WØTKX

07-06-2014, 07:21 PM

The orientation of the lot is an issue for the dipole thing, tho an inverted vee would work on the lower bands it's cut for.

NQ6U

07-06-2014, 07:22 PM

The heck with all that. Just build an isotropic radiator and be done with it.

K7SGJ

07-06-2014, 07:23 PM

The orientation of the lot is an issue for the dipole thing, tho an inverted vee would work on the lower bands it's cut for.

True enough. It's nice being able to switch between the Vee and Vertical. Especially during times of high QRN.

n2ize

07-06-2014, 08:49 PM

I talked to Poland on 40m.

Yes, it does work. It gave me a respectable signal as well. But I was still losing a considerable amount of power as heat. When the balun eventually burned out and I went to a link coupled tuner the signal wend from very good to great because much less of my power was heating up the windings in the balun. In a pinch however it will work reasonably well. However, a good tuner is superior.

KG4CGC

07-06-2014, 09:07 PM

Yes, it does work. It gave me a respectable signal as well. But I was still losing a considerable amount of power as heat. When the balun eventually burned out and I went to a link coupled tuner the signal wend from very good to great because much less of my power was heating up the windings in the balun. In a pinch however it will work reasonably well. However, a good tuner is superior.

I usually save my antron for 10m but sometimes it works better on 10 depending on conditions.
I've run window line straight from the tuner but honestly, it's a bad idea here unless I have the tuner right up at the window to minimize the amount of line radiating indoors.

KC2UGV

07-07-2014, 07:06 AM

N2ADV

07-07-2014, 08:03 AM

OK, so now, after more looking, verticals have peaked my interest as well. To be honest, I care most about 40/20/30, any other bands are gravy. But, verticals seem to be a good idea, due to their takeoff angles. I've been hitting a limit with my distance, farthest I've reached is Texas westward, and Italy eastward. Figure maybe a vertical would be helpful here.
I put in a Hustler 6BTV with the 12 and 17 meter add-ons. It's ground mounted with 34 wire radials in the grass. It has been a crap-ton of fun. My farthest is Indonesia with 2.5 watts.

KC2UGV

07-07-2014, 08:22 AM

I put in a Hustler 6BTV with the 12 and 17 meter add-ons. It's ground mounted with 34 wire radials in the grass. It has been a crap-ton of fun. My farthest is Indonesia with 2.5 watts.

That's actually the antenna that caught my eye, and got me reading up on verticals. I've been using a dipole since I've started the hobby, maybe it's time to change things up a bit.

K7SGJ

07-07-2014, 08:24 AM

That's actually the antenna that caught my eye, and got me reading up on verticals. I've been using a dipole since I've started the hobby, maybe it's time to change things up a bit.

Don't change, augment.

I've been toying with the idea of adding the 12/17 kit as well.

KJ3N

07-07-2014, 09:24 AM

Don't change, augment.

This.

There's a reason I have 6 HF wire antennas.

K7SGJ

07-07-2014, 09:32 AM

This.

There's a reason I have 6 HF wire antennas.

As it should be. In this hobby, more is better.

KG4CGC

07-07-2014, 10:02 AM

As it should be. In this hobby, more is better.

Ah, really? Tell me, do you like gladiator movies?

K7SGJ

07-07-2014, 10:11 AM

Ah, really? Tell me, do you like gladiator movies?

Why yes, yes I do. I like Roman bath house, too.

KG4CGC

07-07-2014, 10:16 AM

When Bob comes a callin' ................

n2ize

07-07-2014, 12:55 PM

I usually save my antron for 10m but sometimes it works better on 10 depending on conditions.
I've run window line straight from the tuner but honestly, it's a bad idea here unless I have the tuner right up at the window to minimize the amount of line radiating indoors.

Yes, I know it can be problematic if the ladder line runs very close to other electronics. In my case I keep the tuner very close to the point where the ladder line enters the shack. When the ladder line used to come in through the attic I had it coming through the ceiling in a closet and I kept the tuner on the top shelf of the closet. When everything is properly tuned you should get very little stray RF in the shack, particularly with a balun-less link coupled type.

Funny thing was that the day before my balun burned out a station I was speaking with mentioned that I will probably eventually burn out my balun. bear in mind also I was running AM at a full 100 watts carrier so as long as I had the transmitter keyed the balun was constantly getting hotter and hotter. The big advantage of the tuner was a much more efficient energy transfer and no power wasted in heating the balun. But, for the short time I ran it I did put out a respectable signal and, if I were running only SSB or CW the balun may not have burned out at all. The AM signal was rough on the balun, particularly during long transmissions during roundtable QSO's.

KK4AMI

07-07-2014, 05:31 PM

OK, so now, after more looking, verticals have peaked my interest as well. To be honest, I care most about 40/20/30, any other bands are gravy. But, verticals seem to be a good idea, due to their takeoff angles. I've been hitting a limit with my distance, farthest I've reached is Texas westward, and Italy eastward. Figure maybe a vertical would be helpful here.

If your going to run low power stuff there are some great Hex Beam antennas (up to six bands). I was looking at those because they are light on a mast, nearly invisible and look fairly easy to build with wire, insulators and fiberglass poles.