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Author Topic: What is best type of Antenna for Mars Frequencies?  (Read 23165 times)

KC9CIL

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What is best type of Antenna for Mars Frequencies?
« on: November 18, 2003, 03:31:35 AM »

Hello.  Now that I've vented in the other topic.  Let me ask this question before I go out and purchase exactly the wrong type of antenna for Mars use.  Could someone tell me which antennas give the best performance on both the amatuer bands and the Mars Frequencies.  I've been looking at Log Periodic antennas, but the larger ones for 80 and 160 meter are just too big for my location.  I could stretch the limits with a 10 to 40 meter LP, but that still leaves some frequencies not covered.  

Thanks
Curt
KC9CIL
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KC5FM

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What is best type of Antenna for Mars Frequencies?
« Reply #1 on: November 18, 2003, 08:38:42 AM »

The antennas you are using now would probably do fine for MARS channels.

Most MARS operations fall close to our present hambands, i.e. just outside 75, 60, 40, 30, 20 meters, etc.

Personally, I would not advise someone to buy anything more, until after their training period is over.

Lloyd Colston      Mayes County CEM
Pryor, OK USA      http://www.geocities.com/mccem
   When Danger comes, it is too late to plan.
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N3ZKP

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What is best type of Antenna for Mars Frequencies?
« Reply #2 on: November 18, 2003, 11:51:05 AM »

Curt,

Do you have any HF antenna now?  There are lots of folks using G5RV-type dipoles for MARS. Ther perform as well or as poorly for MARS as they do for multi-band ham use.

The best antenna is one cut for a specific frequency but unless you have lots of room for multiple dipoles that's probably not a good option. :)

Personally, I have two antennas I use for MARS - a dipole cut for the 60m ham band and my Butternut vertical. With an external antenna matcher it works all the MARS frequencies just fine.

Except under unusual circumstances, you are only going to be needing three or four frequencies, and as Lloyd said, these are mostly just above and below the regular ham bands and any decent multi-band ham antenna can be used with an antenna matcher.

Welcome Aboard!

Lon
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KC9CIL

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What is best type of Antenna for Mars Frequencies?
« Reply #3 on: November 18, 2003, 01:47:06 PM »

I have a Gap Titan (10-80 meters)still in the box and a Barker & Williamson BWD90 (1.8-30 Mhz still in the box.  I'm  planning to purchase a beam to put on the US Tower HDX55 I'm picking up tomorrow (Wednesday).   I'm considering a Mosley Pro 67-C (10-40 meters) or a Hygain LP1010A (10-40 meters).  I have a tuner that is supposed to handle anything including tuning up a piece of random length wire. Would the Gap vertical and/or B&W folded dipole be adequate
Thanks for your input.
Curt
KC9CIL



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KC5FM

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What is best type of Antenna for Mars Frequencies?
« Reply #4 on: November 18, 2003, 04:43:13 PM »

Since you have the antenna tuner, either the dipole or the vertical will do nicely.

Personally, I use a 125-foot wire and antenna tuner for all my HF operations.

It's a personal choice, therefore, about the antenna.  There's some who think verticals are best and some who use dipoles.

Part of the consideration will be your neighbors, etc.

Let me know how more I can help

Lloyd Colston    Mayes County Emergency Management
Pryor, OK  USA    http://www.geocities.com/mccem
   Vigilance is the keystone of preparedness

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KC9CIL

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What is best type of Antenna for Mars Frequencies?
« Reply #5 on: November 18, 2003, 05:56:38 PM »

Thanks for the feedback.  I still am undecided about which beam, but I'm glad to know that it is acceptable to just have a verticle or dipole with out significant gain on the frequencies.

Curt
KC9CIL
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K3VW

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What is best type of Antenna for Mars Frequencies?
« Reply #6 on: November 20, 2003, 08:51:50 AM »

The easiest, cheapest and best antenna to use on the ham & Mars frequecies is a center fed, 125' each side, dipole, fed with open wire line to an antenna tuner. Height is not a concern, as long as it high enough to clear folks walking under it. Write down the antenna tuner numbers for all frequencies on a "cheat" sheet. Have fun and welcome aboard!
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K3VW

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What is best type of Antenna for Mars Frequencies?
« Reply #7 on: November 20, 2003, 08:52:25 AM »

The easiest, cheapest and best antenna to use on the ham & Mars frequecies is a center fed, 125' each side, dipole, fed with open wire line to an antenna tuner. Height is not a concern, as long as it high enough to clear folks walking under it. Write down the antenna tuner numbers for all frequencies on a "cheat" sheet. Have fun and welcome aboard!
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N3ZKP

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What is best type of Antenna for Mars Frequencies?
« Reply #8 on: November 21, 2003, 10:43:21 AM »

Curt,

Unless you are doing specific point-to-point communications, any beam is pretty useless for MARS. In a normal net you will be talking to stations from several directions in the same net. Trust me, there will NOT be time to rotate the beam. :)

Another consideration, very few MARS nets are routinely operated in the frequency range that the beams operate in except 40m.

The broadband B&W is widely used, but the results vary all over the place. My only suggestion is to try it and see what happens in your own situation.

My first choice would be the vertical, but then again, that's what I use so I am somewhat prejudiced. :)

Lon
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NC3Z

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What is best type of Antenna for Mars Frequencies?
« Reply #9 on: November 23, 2003, 12:26:00 PM »

Most of the regional or state nets will be in the 3-8Mhz range, so you would need a big LP!

I have had good luck with the B&W 90, although I did lengthen it to 135' based on some tests done by L.B. Cebik (http://www.cebik.com/wbfd.html) to enhance the 4Mhz performance.

With this antenna and 100W I have had good luck as NCS on our Region nets covering from the Wash DC area up through New England and out to Michigan.

However a resonant dipole will work better at a discreet frequency but falls off quickly past it's resonance compared to the B&W.

Another good option is a horizontal loop with a good ATU.
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N2CKH

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What is best type of Antenna for Mars Frequencies?
« Reply #10 on: November 25, 2003, 05:16:19 PM »


Hello All,

As an ex-Navy MARS and current Army MARS operator, when assisting new members I have always found that
a low to the ground mounted random wire, inverted V
or dipole to work well depending on your surroundings.

However, what works BEST from my experience for the
4-30Mhz range is a 135 foot wire span dipole drooped
between a dipole/inverted V with the center at about 20-25 feet above ground level using 450 ohm ladder line to a 9:1 balun to coax into the building.

My current installations at both my residence and my clubs MARS station using this design, I make use of
a 9:1 W2FMI model 9:1-HB450 ferrite core balun transformer and 12 gauge steel core copper 450 ohm
ladder line wire with a heavy duty center  insulator/support and reinforced connections to handle the New Jersey winters. A ground connection from the balun body along with the polyphaser lightening arrestor is taken to an 8 foot copper clad ground rod 9 feet below the balun at the rear of the building.

At my residence, where the entire antenna and feed line
is in the clear, the antenna never goes abovea 2.5:1 VSWR from 3-30Mhz and has multiple points, many within our Amateur bands where the VSWR is less than 1.8:1,
at the club station, where the antenna is near a standard bob wire military fence, the VSWR is similiar in that it is never over 3.1:1, however it never goes
below 2.1:1 except at 20 meters where it is 1.7:1

The performance of the antenna is superior to any thing available for comparison, to include resonant
dipoles, inverted V, G5RV and Carolina Windom antennae.

Sincerely,

/s/ Steve Hajducek, N2CKH/AAR2EY (ex-NNN0WWL)





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KB9ZB

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What is best type of Antenna for Mars Frequencies?
« Reply #11 on: December 13, 2003, 12:17:36 AM »

you are right on the money with the g5 resisior. variable ( g5rv)  i have had the besy luck with the folded dipole, runs very well on all the ham bands and mars fequencies. the best part is that it is almost always tuned for what every frequency i want, the 2 mhz is tight but other than that you don't need to tune up much to get it on the money.
also it will take a kw without any problem works great up to 3 kw based on my mars ops in japan and deago.
ron
nnn0vag
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KG4RUL

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What is best type of Antenna for Mars Frequencies?
« Reply #12 on: December 13, 2003, 01:59:07 AM »

Because of CC&R restrictions, I am currently operating using a Force 12 Flagpole Antenna.  I regularly check into 80 and 40 meter nets using this minimal antenna setup and 100 watts.

Dennis - KG4RUL
NNN0FAE
NNN0GBS FIFTEEN
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K3UOD

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What is best type of Antenna for Mars Frequencies?
« Reply #13 on: December 13, 2003, 04:42:27 AM »

I'm not in MARS, but I've had excellent luck with the B&W folded dipole (90' version) on frequencies above 7 MHz.  On 75M it is about 6 dB down from a 135' dipole.  For operations under 500 miles, I wouldn't worry about that 6 dB. Mine is one that the local National Guard threw away because it had high VSWR.  I discovered that the balun was full of water.  I shook out as much water as I could and hung it in the sun for a few days then put it up and tried it.  It worked fine.  Moral: be sure to mount it so the balun hangs with the drain hole on the bottom.  I've been considering re-building it as a 135 footer.  You will find many bad reviews in the web on the B&W.  Mostly from people who have never tried one.  I recommend ignoring them.

My present antenna is a home brew 135' off-center fed dipole.  It is just a 4:1 balun with 45' of wire on one side and 90' on the other.

It has SWR below 2:1 on 80/75, 40, 20, and the lower half of 10.  With a tuner it will also work on 60M.  At the time I was building it I was planning to get active on MARS again so I measured the SWR at various MARS frequencies.  None were higher than 2.5:1.  With a tuner, I can work any band except 30 and 15.  I use a seperate antenna for them.  Total cost of balun, wire, and end insulators less than $20 at RF Connections.
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K6IXF

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What is best type of Antenna for Mars Frequencies?
« Reply #14 on: December 28, 2003, 11:57:18 PM »

Hi: Under the category of for what it's worth department, I use an export model SG-2020 (Rel 1.12) and a B&W 65 footer. My back fence is wooden and the antenna is stretched out along it below the top, The bottom of the antenna is probably 2 or 3 feet off the ground. (C,C and Rs, etc.) I can work 95% of the net stations with 20 watts here in Northern California. I have also used my MARS modified 746PRO and on occasion, the extra power helps.

There is some good information about NVIS antennas (like the way I am using the B&W) on Yahoo Groups/NVIS which in turn has links to closely associated web sites on Army radios and Tactical links. There is also a digram and link to instructions for a simple NVIS antenna.

This is AAR9ZC/Barry
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