Antenna solution for only bands 80-40-30m?

[KO6WB]

Yes, I was referring the common 1/2 wave dipole as an 80 meter antenna fed with coax.
Although he didn't mention it W5DXP has a web site full of antenna tips. One of his ideas that works very well is the use of varying lengths of ladder line to make an impedance match to the rig. There have been variations on this configuration and some worked and others were only good on a single band.
Making your antenna in a length that would not normally be resonat on any of the bands you want to work is an excellent antenna. You could then use the variable ladder line length as a matching method.
You can see the methods at this site; http://www.wadsworthsales.com/Pages/w5dxp.aspx.
There is another site that has the same information only it's in PDF format. I have that saved in my antenna ideas folder on my PC.
Hope this helps
73
Gary

[AD4J]

Forget about dipole lengths to avoid when feeding with ladder-line.

That's good advice, if you can vary the feed line length when you switch bands. If not, you can often find an antenna length / feed line length combination that gives reasonable SWR on multiple bands using just one feed line length. The modeling results I posted earlier in this thread were aimed at finding a single feed line length that would give SWRs on all 3 bands within the range of a transceiver's internal auto-tuner. If you can vary the feed line length, you can get very low SWR and dispense with the tuner. W5DXP has good information and a program for calculations on his web site.

Jim

[AE7F]

That's good advice, if you can vary the feed line length when you switch bands. If not, you can often find an antenna length / feed line length combination that gives reasonable SWR on multiple bands using just one feed line length. The modeling results I posted earlier in this thread were aimed at finding a single feed line length that would give SWRs on all 3 bands within the range of a transceiver's internal auto-tuner. If you can vary the feed line length, you can get very low SWR and dispense with the tuner. W5DXP has good information and a program for calculations on his web site.

Jim

Yes, for now, the idea is to use a single feedline and let the tuner handle the difference. I will take a look at the links posted. Thanks guys.

[N5MDT]

I used to sets of Unadilla traps to create a 30/40/80 dipole. The performance was acceptable but the traps are a little pricey if you ask me.

[N0AZZ]

I work those bands daily and quite well using a vertical, a 10-40m all bands beam and a 270' OCFD @ 55'. The 30m rotatible dipole on the beam/ 3 element 40m is best and second is the vertical on in most cases 30/40m no doubt a real killer on 80m in 3 yrs have DXCC and not worked at it. With a good radial field a vertical is an excellent performer I use an Hy Gain AV-18HT for 10-160m.

[N7GH]

If you have a 10:1 tuner and a spool of wire (about 20 dollars), just make a long wire. Here's an article with "best random wire lengths", the lengths in green are the new improved values: http://www.hamuniverse.com/randomwir...nalengths.html

I've tried it, and yes, it's easy and works great.

Hi everyone,

My Spiderbeam is doing just fine, covering bands 20-10m. However, I do miss 30 and 40m, and I do need 80m for local schedules.

There is a way to add 40m to the SB and I may just do this at some point. However, I would like to discuss other options and probably get opinions on what the rest of you would do for 80, 40, and 30m.

One option might be to add the 40m option to my SB and then make a separate 80m dipole and try to operate it harmonically on 30m. I don't have experience with this and am not sure about the details of this option. Ideally, I would need something that would work acceptably at around 3.8Mhz for local work and 10.1Mhz for DX.

I can't model it at the moment but what about starting with an inverted V dipole at ~139 feet long at about 20ft above average-to-good soil and using 300ohm twin lead feeder? Perhaps someone could tell me how this would perform at both frequencies. (I still have the 102ft G5RV, which I could modify by adding additional length).

Another option would be a fan dipole for 80/40/30 but this is a lot of wire and adding 30 may not work very well. Not real interested in all that more wire up in the air anyway.

A third option would be a jumpered dipole, which I'm not really interested in.

Another option would be an 80/40/30 trapped dipole. This is a possibility but I don't know many who have an 80/40/30 or 80/30 combo - most I see are usually 80/40. Anybody use a trapped 80/30m dipole?

I'm sure there are other options as well. Since I have the SB and it is a good 5-band antenna, I don't need something that covers other bands besides 80/40/30 or 80/30. I don't object to using a vertical, either.

What do you guys think?

[AE7F]

I work those bands daily and quite well using a vertical, a 10-40m all bands beam and a 270' OCFD @ 55'. The 30m rotatible dipole on the beam/ 3 element 40m is best and second is the vertical

What beam are you using for 10-40m?

on in most cases 30/40m no doubt a real killer on 80m in 3 yrs have DXCC and not worked at it.

I'm confused what you mean by the above statement. Are you saying you have achieved DXCC on 80m using your 3 element beam? Which antenna was used to achieve DXCC on 80m (I assume the OCF or tower)?

With a good radial field a vertical is an excellent performer I use an Hy Gain AV-18HT for 10-160m.

Looks like a nice tower/antenna, albeit pricey.

[AE7F]

If you don't mind, how much did you spend overall and how have the traps withstood the elements?

[4X1SO]

Check out the G7FEK antenna. Info here: www.g6hoq.com/documents/G7FEK%20Antenna.pdf