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eHam Forums => Antennas and Towers and more => Topic started by: AK4SK on April 22, 2013, 11:35:24 AM



Title: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: AK4SK on April 22, 2013, 11:35:24 AM
I'd like to make go at the world of VHF SSB. My understanding is that horizontally polarized antennas are best for this (let me know if this is not correct). That being said I'm looking for an antenna design (or pair of antennas that I can stack) that is suited for VHF SSB on both the 2 and 6 meters bands.

73,
AK4SK


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: G7MRV on April 22, 2013, 01:56:22 PM
Yes, you are correct, you ideally want to be using horizontal polarisation for SSB work, as this is the accepted standard. If you use vertical, be aware that the cross polarisation will put you around 20dB down.

Also, unless you use an omnidirectional horizontal antenna, such as a halo, you will need a rotator.

That said, my 6m beam (3 el) is on a fixed bearing towards europe, which works fine for me being in the UK

I cant help with a combined design, but for very simple and very effective antennas to build, take a look at DK7ZB's webiste http://www.qsl.net/dk7zb/start1.htm (http://www.qsl.net/dk7zb/start1.htm) My portable 2m beams are to his designs, and they are very forgiving. Also, Martin is very helpful if you need to adjust the design a bit to suit the materials you have


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: AK4SK on April 23, 2013, 08:44:33 AM
Thanks for the info and the link. I'd like an omnidirectional antenna to start with just to see what is going on at first.


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: G7MRV on April 23, 2013, 02:17:28 PM
A halo will give you easy horizontal polarisation just to have a look around with. Onmidirectional but no gain, but its incredibly easy to build one.

Once you start using SSB on 2m or 6m, you will soon want a beam!


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: KG6WLS on April 23, 2013, 03:14:55 PM
Here's something that has been around the block a few times here on eHam. Built a bunch of these sometime back from the link provided here.

http://www.eham.net/articles/4319

Always fun to build ur own. Yep! A beam is better. ;D

73 de KG6WLS


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: AK4SK on April 24, 2013, 06:26:28 AM
Great! Thanks for the link.


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: AF5CC on April 24, 2013, 12:52:55 PM
MFJ makes a dualband 6m/2m antenna. On 6m it functions and a rotatable dipole.  On 2m it is stacked 5/8 waves, which will give a little gain.  It costs $60 or so new. 

John AF5CC


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: AK4SK on April 25, 2013, 10:37:50 AM
MFJ makes a dualband 6m/2m antenna. On 6m it functions and a rotatable dipole.  On 2m it is stacked 5/8 waves, which will give a little gain.  It costs $60 or so new. 

John AF5CC

Thanks, I'll take a look at that.


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: KD8TZC on April 25, 2013, 10:48:30 AM
Just get some wire and make a fan dipole.  Quick and simple and I bet you already have the wire at home.  You will need about 3' 3" for the 2Meter band (cut in half for each quarter wave), and 9' 5" for the 6M band (also cut in half).  If you want to get fancy, you can always get a 1:1 balun to attach your coax and wire all together but that isn't even needed.


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: AK4SK on April 25, 2013, 10:59:13 AM
Just get some wire and make a fan dipole.  Quick and simple and I bet you already have the wire at home.  You will need about 3' 3" for the 2Meter band (cut in half for each quarter wave), and 9' 5" for the 6M band (also cut in half).  If you want to get fancy, you can always get a 1:1 balun to attach your coax and wire all together but that isn't even needed.

I think I just might try this first!


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: WA8ZYT on April 25, 2013, 11:34:09 AM
Don't screw around with mediocre antennas on 6 and 2 or you will be disappointed. I recommend at least a 5 elements on 6 and a 9 element for 2 meters, such as the M2, or Innov 9 element LFA.

You won't hear jack with a dipole on either band.


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: KD8TZC on April 25, 2013, 12:49:56 PM
You won't hear jack with a dipole on either band.
I beg to differ... you can hear just about anything with a coat hanger...been there and done that with scanners and other items.  Not ideal, but they work.

I use a 10M dipole and have listened with it on 40M and have heard Afghanistan at night (listening to CW).  I have also worked voice with the Canary Islands and also Brazil on my 10M dipole.  It may not be as cool as a some of the multi-element antenna's but they get the job done and are simple enough to make and experiment with.  That's what HAM radio is all about anyhow.

John


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: AF5CC on April 25, 2013, 07:57:35 PM
You won't hear jack with a dipole on either band.

That is pretty true for 2m, but not for 6m.  I have gotten VUCC on 6m with an indoor dipole and  worked Puerto Rico and Costa Rica with a mag mount mobile whip on 6m. During a good Es opening on 6 you can work a lot with a dipole.  It isn't going to outperform a yagi, but it can still be a lot of fun!

John AF5CC


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: WB2WIK on April 26, 2013, 09:57:39 AM
You won't hear jack with a dipole on either band.

That is pretty true for 2m, but not for 6m.  I have gotten VUCC on 6m with an indoor dipole and  worked Puerto Rico and Costa Rica with a mag mount mobile whip on 6m. During a good Es opening on 6 you can work a lot with a dipole.  It isn't going to outperform a yagi, but it can still be a lot of fun!

John AF5CC

I've been active on VHF weak signal modes for about 45 years and surely agree that when the 6m band is "open," a lot can be done with very little.

However, for the other 95% of the time when the band is not open, small antennas -- especially vertical ones -- typically yield a lot of "nothing heard here."

An interesting and somewhat eye-opening test which I've demonstrated hundreds of times is this one I run at home:

6m loop at 30 feet; Cushcraft Ringo vertical antenna at 30 feet; 7 element horizontally polarized beam on telescoping tower whose height I can change from about 28 feet to 65 feet by telescoping or nesting the tower.  All low-loss feedlines brought to a 4-position antenna switch, so antenna changes can be made in less than a second.

Tune around with the beam at 65 feet, and with various beam headings, I can hear six 6m beacons 24 hours a day, regardless of propagation.  (When the band's open, of course, there are many more in various directions depending on conditions at the moment.)  But those six vary in distance from about 60 miles to about 300 miles, and they're always readable.

Now, switch to the loop:  Two beacons can be heard, weakly, not nearly as well as with the beam.

Now, switch to the vertical:  One beacon can be heard, very weakly.

Works this way every single day.

The antennas all "work," but the beam's advantage is so obvious that many are astounded.

So, on an average day with no special conditions (no sporadic-E, no any kind of ionospheric propagation), just tropo, I can "work" stations in about a 300 mile radius (about 283,000 square mile area).  On the same average day, I can "work" stations in about a 60 mile radius using the loop (about 11,000 square mile area).  The difference in the number of stations that might be workable is a ratio of 283/11, or nearly 26 to one, in favor of the beam.

That's why if 6m is "pretty quiet" using the beam, it can sound "abolustely dead" with a loop. ;)

 


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: AK4SK on April 26, 2013, 01:02:52 PM
Thanks for all the other replies.

73,
Chris


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: KB1GMX on April 26, 2013, 03:25:33 PM
What WB2WIK said is painfully true.

Minimally a yagi on 6 even three elements or a moxon, for two I'd say not less than 6 elements.
unless your intent is local use out to maybe 30-50 miles.  Aslo even a dipole on 6 has to be rotated
as the pattern at 20FT is actually like the textbooks!

You only need maybe 6 feet between them (more is better) and at least 20ft more like 30+ feet up.
Without question larger and higher is better on both bands.

With 4 elements on 6 at 20W I"m good to about 120miles, at 200W 300 happens.  For 2M I use an
11 element and with 200W it's solidly good to 150+ and often much more.

Since Es season makes any old went noodle usable I often turn the power down to under 5W SSB
to work Europe to make it interesting.  More often though I need more power to be heard over
the pileup din.  Seriously when Es is in a good antenna makes weak ones into strong and also
gives me equal punch in the out going direction for those with tepid antennas.  Also when the Es
are weak or aurora it can make the differs between barely heard and acceptable copy.

I also have a square loop for 6M and a 6 element for 2M as auxiliary antennas for nets and the
difference is remarkable.

Allison


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: KQ6Q on April 26, 2013, 09:55:00 PM
What's best depends on your budget. Mine was/is limited - I had a 3 el 6m beam and a 14 el cross polarized on 2m, on a cheap TV rotator.
Didn't want to spend $400 on one rated for the load. Cheap rotator didn't point reliably, failed, replaced, repeat. we have santa ana winds out here in SoCalif, and I was lucky the whole stack didn't come down in 10 years. and with the beam pointing not reliably, I missed some contacts. Took down the beams and rotator, replaced with phased Omniangle Loops for 2m,and a single Omniangle loop for 6m. works great! Now I've finally worked some grids in Washington state that I could never hear before because of nulls on the beam.  I have no nulls, and the antennas are never pointed in the wrong direction!
I'm not going for VUCC, just like to make contacts in a contest when the band is open.

Fred, KQ6Q


Title: RE: Dual Band Antenna(s) for 2 meter and 6 meter SSB
Post by: AK4SK on April 29, 2013, 06:06:12 AM
My budget is a bit limited so that is certainly an issue. I'm not looking to get into VHF SSB full blown, I have other ham activities to keep me occupied most of the time. I'm mainly just looking to have the capability even if it is far from ideal.

Thanks again for all of the info and suggestions.

73,
Chris AK4SK