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View Full Version : OK, I boxed myself in with a QRP transmitter-Directional Beam Antenna?



KK4AMI
02-19-2012, 09:15 AM
I got my TenTec Argonaut, but 20 Watts SSB ain't gettin' me far. I am going to try digital but I would like to keep SSB and AM viable. The linear RF amp is way in the future so right now I'm looking at the antenna. I (read that wife) doesn't want a tower and yagi in the yard, so I'm stuck with wires in the trees. So I was thinking Vee Beam dipole? I was thinking about a Horizontal Vee Beam. Is it feasible to run two dipoles one N-S and one E-W in a cross shape and connected by insulators in the middle. What I want to do is have 4 legs each about 70 foot long and fed in the middle by two 450 ohm ladder feed lines. Then by picking any two wires from the feed lines, I can have a choice of feeding a N-S 140 ft dipole, an E-W 140 foot dipole or a choice of 1 of 4 seventy foot, 90 degree horizontal vee beams with main lobes going Northeast,Southeast,Southwest, and Northwest and hopefully at least a 3db gain in those directions.

K7SGJ
02-19-2012, 10:39 AM
It's amazing what 20 watts or less will do. I used to use a Sears cb I converted to 10 and talked all over the world. Of course, the band was in much better shape. A good comprimise for you and the wife might be a vertical. I've been using a Hygain I've had forever, or so it seems. Since it lacks the 80 meter kit, I use a dipole for 160/80 with good results. At the moment, I am looking at either the Butternut or the Cushcraft mini 5 band mini beam. Although I have lots of room, I don't have lots of $$, and it wouldn't take much of a rotator to spin it. What ever you end up doing, good luck and have fun.

KK4AMI
02-19-2012, 11:17 AM
It's amazing what 20 watts or less will do. I used to use a Sears cb I converted to 10 and talked all over the world. Of course, the band was in much better shape. A good comprimise for you and the wife might be a vertical. I've been using a Hygain I've had forever, or so it seems. Since it lacks the 80 meter kit, I use a dipole for 160/80 with good results. At the moment, I am looking at either the Butternut or the Cushcraft mini 5 band mini beam. Although I have lots of room, I don't have lots of $$, and it wouldn't take much of a rotator to spin it. What ever you end up doing, good luck and have fun.

I do have a 102 foot doublet dipole up now, its pretty omni directional like your vertical. The Cushcraft mini beam is kinda expensive for me to. I have the giant trees and space, so I thought I could build the crossed dipoles and get some directionality to throw my meager 20 Watts around.

WX7P
02-19-2012, 11:33 AM
What's the wife's problem with a tower?

K7SGJ
02-19-2012, 11:39 AM
I do have a 102 foot doublet dipole up now, its pretty omni directional like your vertical. The Cushcraft mini beam is kinda expensive for me to. I have the giant trees and space, so I thought I could build the crossed dipoles and get some directionality to throw my meager 20 Watts around.


Well, wire is relatively cheap. I have miles of 16 awg THHN in the train out back that I've aquired over the years from garage sale and such. I've been using it to add radials to the vertical. I've also been thinking about an OCD or some other wire antennas, too. We have 5 acres to string it out on, but being in the desert, the tallest trees are only about 10 feet, and no help. The inverted vee I have now is strung from a 30' push up mast out to some Palo Verde trees. I guess ya gotta use what ya got. That's why the mini beam is looking good at the moment, if I can get a deal on one or find a used one.

KK4AMI
02-19-2012, 12:01 PM
What's the wife's problem with a tower?

Unsightly to her I guess. She doesn't want her view of the mountains blocked.

WX7P
02-19-2012, 12:13 PM
Unsightly to her I guess. She doesn't want her view of the mountains blocked.

Really. Put it on the other side of the house!

KJ3N
02-19-2012, 12:14 PM
I do have a 102 foot doublet dipole up now, its pretty omni directional like your vertical. The Cushcraft mini beam is kinda expensive for me to. I have the giant trees and space, so I thought I could build the crossed dipoles and get some directionality to throw my meager 20 Watts around.

The first question is, how high is the current antenna?

The second question is, will the new antennas be higher than the current one?

There's nothing wrong with QRP (which is actually 5 watts, if you want to be picky) if you have the right antenna system (http://forums.qrz.com/showthread.php?291382-Receiver-or-antenna&p=2214512#post2214512).

Propagation is the primary factor of success, but the antenna is a very close second.

KJ3N
02-19-2012, 12:16 PM
What's the wife's problem with a tower?
Unsightly to her I guess.

Same problem here, but a good number of 60+ foot trees helps a lot. ;)

K7SGJ
02-19-2012, 12:59 PM
Unsightly to her I guess. She doesn't want her view of the mountains blocked.


If you do it right, you can tell her it's the latest clothesline that utilizes solar energy for drying, and RF energy for for neutralization of bacteria and cooties.

NQ6U
02-19-2012, 01:12 PM
20 watts is fine for the digital modes. I've had QSOs over most of the world other than the extreme antipodes using PSK31 and wire dipole antennas. I'd suggest you try the SignaLink USB interface because most modern computers lack a RS-232 port. There are adapters available, but I've had some trouble with the drivers—always a problem with Windows.

KG4CGC
02-19-2012, 03:07 PM
Sell your Argonaut.
Buy a TS 570DG(S)
about $600 on the current market.

KK4AMI
02-19-2012, 04:13 PM
Really. Put it on the other side of the house!

Not in the front yard, that's a definite no-no!

KK4AMI
02-19-2012, 04:14 PM
20 watts is fine for the digital modes. I've had QSOs over most of the world other than the extreme antipodes using PSK31 and wire dipole antennas. I'd suggest you try the SignaLink USB interface because most modern computers lack a RS-232 port. There are adapters available, but I've had some trouble with the drivers—always a problem with Windows.

I'm using an old IBM T23 with xubuntu, no issues with RS-232 ports :)

KK4AMI
02-19-2012, 04:16 PM
The first question is, how high is the current antenna?

The second question is, will the new antennas be higher than the current one?

There's nothing wrong with QRP (which is actually 5 watts, if you want to be picky) if you have the right antenna system (http://forums.qrz.com/showthread.php?291382-Receiver-or-antenna&p=2214512#post2214512).

Propagation is the primary factor of success, but the antenna is a very close second.

I have giant oak trees all around the property. My current dipole is about 35 to 40 ft up. The trees are around 60 to 80 feet tall.

KJ3N
02-19-2012, 04:35 PM
I have giant oak trees all around the property. My current dipole is about 35 to 40 ft up. The trees are around 60 to 80 feet tall.

Then, before you spend time and energy on another antenna, get the current one up to that height. Be sure to get it set up as a flat-top, not an inverted vee. Also make sure that the wire runs as close to N/S as possible. You may find that your 20 watts now works much better.

If the antennas you proposed to put up are not going to be any higher than the current 102-footer, I wouldn't expect much improvement in your situation.

NQ6U
02-19-2012, 05:03 PM
I'm using an old IBM T23 with xubuntu, no issues with RS-232 ports :)

In that case, you can probably homebrew your own interface. If you've got a couple of old POTS modems around the joint, cannibalize them for the 600:600 audio transformers; the rest is just common stuff that even Radio Shack still sells.

KA9MOT
02-22-2012, 01:58 PM
If I had allot of room and more than 1 tall tree, I'd put up a Full Wave Loop. As large and as high as I could. Put a 4:1 balun at the feedpoint, feed that with coax. You'll need a tuner. My buddy KA9NRT has a loop cut for 40M and that thing has always amazed me. Check it out ----> http://n1su.com/loop.html

I've been seriously contemplating a 20M Delta loop here. My yard is big enough for a fullwave loop on 80M but I don't have any supports :( (Only 1 tall tree).

I have a homebrew Sound Card Interface around here somewhere...... If I can find it, you can have it.

WØTKX
02-22-2012, 02:28 PM
Well, if you decide to sell the Argonaut... :whistle:

KK4AMI
02-22-2012, 05:15 PM
If I had allot of room and more than 1 tall tree, I'd put up a Full Wave Loop. As large and as high as I could. Put a 4:1 balun at the feedpoint, feed that with coax. You'll need a tuner. My buddy KA9NRT has a loop cut for 40M and that thing has always amazed me. Check it out ----> http://n1su.com/loop.html

I've been seriously contemplating a 20M Delta loop here. My yard is big enough for a fullwave loop on 80M but I don't have any supports :( (Only 1 tall tree).

I have a homebrew Sound Card Interface around here somewhere...... If I can find it, you can have it.

The full wave loop is omni directional right? If I had 100 to 1000 Watts I'd be game. Since my little Argonaut only has 20 max, I need to throw it around carefully. That is why I was thinking about a directional horizontal Vee dipole. One pointed in each of the cardinal directions. I think I can get 3 dB gain that way.

Thank you very much for the offer of the Sound Card interface. I have that covered already. Now I'm trying to figure out what computer control software and PSK-31 software I want.

KK4AMI
02-22-2012, 05:19 PM
Well, if you decide to sell the Argonaut... :whistle:

I love that little thing. The receiver is excellent. I've made a couple of contacts into New York on 60 meters. My favorite is listening to AM broadcast, KDKA in Pittsburgh. My ol' hometown. That digital filter just opens way up and AM radio sounds so good. It sure puts the R-71A to shame.

KJ3N
02-22-2012, 07:06 PM
The full wave loop is omni directional right?

Only at its base frequency, and sometimes not even then, depending on where on the loop you feed it. Anywhere else above the base frequency, all bets are off.

I use a full-sized 40m loop not only on 40m, but also on 20m. On 20m, it produces a 4-leaf clover pattern with about 7dbi gain within those lobes. The same goes for my 80m dipole. On 20m, I get another 4-leaf clover pattern from it with about 9dbi gain within those lobes. Properly oriented, these 2 antennas compliment each other quite well. Each fills in the gaps of the other.

BTW, even a loop has gain. It's just that, depending on height, most of it goes straight up (at the base frequency), which is usually not what you want to work DX. A 40m loop has about 6dbi of gain, but you're not going to work a lot of DX if that gain is going straight up.

WØTKX
02-23-2012, 12:00 AM
When I had my last loop up, all five support points were done with nylon pulleys. This let me tweak the feedpoint position around so one of the lobes on 17 made EU stations LOUD. I left it there. Seemed OK "lobe wise" on 15. Hell I even used it on 6. "Random" as I fit it to the space available, 430' of wire. Worked really well on 75-30 meters. 160 was meh. About 45-50' up, a little droopy to allow for high winds whipping the trees around.

I plan to deploy a loop again soon, this one can be larger, with support trees 60-70' high.