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eHam Forums => MARS => Topic started by: GKYGRL on May 17, 2011, 07:39:26 AM



Title: MARS Mod on Kenwood TS-940S
Post by: GKYGRL on May 17, 2011, 07:39:26 AM
I am preparing to do a MARS Mod (I am AAR2NR/T) on my Kenwood TS-940S.  I am curious if anyone has this radio and has done the mod and had success.

I use the radio with a Butternut HF9V and will be curious to know if anyone has had success using the Butternuts (which in my case is very, harmonically tuned out of the box) to do MARS.  What, if any, mods did you need to do to the antenna?

Thank you   8)

Diana, W2NU (AAR2NR/T)


Title: RE: MARS Mod on Kenwood TS-940S
Post by: W3JKS on May 17, 2011, 08:46:58 AM
Welcome.   www.mods.dk is your friend.  You should find most radios' mods on that site.  8)

Most MARS communications is regional in nature and depends on the NVIS mode of propagation.  Vertical antennas are not effective for NVIS -- you want a dipole relatively close to the ground for most MARS work.

73 and welcome to MARS,

john W3JKS/AAT3BF/AAM3EDE/AAM3RE/AAA9SL/Diamond Flight 88


Title: RE: MARS Mod on Kenwood TS-940S
Post by: W3LK on May 17, 2011, 12:44:03 PM
I'm with John.

Speaking from a lot of experience with my HF6, it is not bad for long-haul MARS (over 500 miles) but a lousy antenna for in-state coverage, which most MARS communications is. Dipoles are much better for routine MARS use.

I know lots of folks don't like them, but I use a B&W Terminated Folded Dipole for 90 percent of my MARS communications. It is mounted with the center at 18 feet and the ends at 15 feet. I routinely cover all of New England, West into Ohio and Pennsylvania, South into Maryland, Virginia and West Virginia.

It's only when I am working into states in the deep south that I switch to the Butternut.


Lon - NNN0OOR / NNN0AS1 THREE (Former MDE SMD, Deputy SMD, Assistant For Net Operations)
Southern New England Navy-Marine Corps MARS
Proudly Serving Those Who Serve


Title: RE: MARS Mod on Kenwood TS-940S
Post by: GKYGRL on May 17, 2011, 08:57:31 PM
Hi John and Lon,  Thanks for the Welcome! ;D

Which model of folded dipole do you have Lon?

http://www.bwantennas.com/ama/fdipole.ama.htm (http://www.bwantennas.com/ama/fdipole.ama.htm)

What size do you find effective for MARS work - did you use the 65 footer or larger?

Is there a Vertical option for MARS work that you are aware of?  One of our guys mentioned a Comet model (???).  The Folded dipole looks reasonable but not sure about trees or install.  A vertical would be easier.

Thanks!

Diana


Title: RE: MARS Mod on Kenwood TS-940S
Post by: W3LK on May 18, 2011, 09:07:55 AM
I have the 90' B&W. The 65' is really too short for 4-5 mHz work.

As has been said, a vertical (any vertical) is a poor choice for MARS, and the reasons have been given - statewide MARS requires a very high takeoff angle (NVIS) and you can't get that with a vertical. As for the Comet (and the Diamond equivilent) they are dummy loads with a piece of aluminum tubing attached. Anything works better.

Pretty much, if you are going to work MARS, you need dipoles.



Title: RE: MARS Mod on Kenwood TS-940S
Post by: AC6EA on May 29, 2011, 06:58:59 PM
Wow, W3LK  thank you for you great information, It is great people like you that make the
NAVY-MARINE CORPS MARS Such a great program.
I agree with you in every aspect of your antenna prospective.
I use the td-160hp1000 and different dipoles for our state and region traffic nets, sometimes you need to have more then one.
again thank you sir for you outstanding service to Mars.



Steve Greathouse
NNN0KQE/NNN0GBN ONE OH.