Ham Radio

[roadhogs]

What is the best way to mount an HF antenna to my Signature? There seems to be no metal for a ground plane or protection from radiation into the coach.

[texnet]

There have been several threads on this with lots of different solutions, from running radials once you get there to using a tilt up mount on top of the coach to using a tow hitch bracket. I have not mounted screwdriver yet but will before the year is out but don't have a plan of attack yet!

[wa8yxm]

If you mount on the hitch adapter or extend a frame rail out a bit (Depending on your coach) you have the frame of the coach as ground plane.

nothing between you and antenna though.

Or, there are several "Field day" designs you might use,, These are designed to basically be stomped into the ground

[deSanford]

I use an HF Shakespear HF Marine antenna on the roof with a smart tuner for all bands 10-160 meters. deSanford

[TXiceman]

You might want to post this in the Ham Radio forum and get more exposure under Hobbies, Passions and Pastimes.
CB & Ham Radio - iRV2 Forums

73s
Ken

[Robi.1014]

Most of our Monaco coach roofs are made from aluminum sheets (right?), attached to the rig's aluminum frame....all grounded via the shore-power cable. For a roof-mounted antenna, that should provide reasonable ground plane and radiation barrier....maybe?

[wa8yxm]

Some good suggestions... Note that a quarter wave on 75/80 meters is what 62.5 feet long give or take a bit. Not many rigs have 60 feet of roof. Actually you need twice that, and if at all possible twice more at right angles crossing in the middle)

[bigdale]

I use hamstiks mounted on the ladder and grounded to the trailer hitch frame...works for me

[texnet]

Quote:

Originally Posted by Robi.1014 Most of our Monaco coach roofs are made from aluminum sheets (right)

My roof is fiberglass.... but the frame is huge so it will make for a great groundplane.

[SKYMASTER]

Quote:

Originally Posted by deSanford I use an HF Shakespear HF Marine antenna on the roof with a smart tuner for all bands 10-160 meters. deSanford

Curious which particular model of the Shakespear HF Marine antenna you're using, and perhaps you could attach some photos of your installation. I see they make a 23' unit and a 28' unit, with several models and/or variations.

On most of their mounts they say that a secondary support has to be utilized 5' or so above the base. Are you side-mounting to the coach, or roof mounting with a hinged fold-down set-up?

Thanks.

John

[spike45]

Quote:

Originally Posted by roadhogs What is the best way to mount an HF antenna to my Signature? There seems to be no metal for a ground plane or protection from radiation into the coach.

While I personally do not use an Eliminator Screwdriver antenna (W9GAS), I do know that Dave (KA8KIP) has his product available for mounting on his motorhome with an extra long mast tube. Check out Dave's web site:

Services

[deSanford]

I'm on the road now John. I will see if I can post some pictures of the mount. The antenna is raised by pressing a button inside the motorhome. The "satilite jack" has built in stops for up and down. It works as a long wire antenna when I'm going down the road with it horizontal and when it is up (when I'm parked) as a vertical. I keep it down when traveling as it would hit the bridges otherwise. deSanford

[spike45]

I have studied this set of webpages many times. And they do get updated frequently.
KØBG.COM

Alan Applegate covers a lot of subjects with experience and knowledge. I highly recommend the left column subject, "Antenna Mounts".

While I was formerly content to run a Hustler resonator set mounted to the pickup truck bed, my signal reports did not improve until I started connecting large pieces of the truck together with flat braid (not wire). Here is a list of connections I made to improve the RF ground plane:

• I have the truck bed connected to frame in 4 places
• Tailgate to bed, two places
• truck bed to cab, two places
• cab to frame, 2 places
• hood to cab, 2 places
• each front fender to cab, 1 each
• extra strap from engine to truck frame
• ground braid strap from back of TS440SAT through cab floor
• from cab floor underside to transmission
• from transmission to exhaust system
• rear exhaust system to frame
• rear axle housing to frame

The only parts I have not added braid to are the doors. It should be done though.

Formerly, without this RF ground network, my ground losses were really high in comparison to the already low radiation efficiency of mobile antennas. Consequently, my signal reports were meager. Now, with the HiQ 4/60 screwdriver Hi-Q Amateur Radio Products - Antennas signal reports are vastly improved except for the really crummy band conditions today (8/3/11).

Simple whip antennas such as the old stand-by, 102 inch CB whip with a tuner such as the SGC or similar do work but not as well as having an antenna that is actually tuned to the frequency of your choice. Even those whips have A frequency that they will be tuned for (fractional wave length) 10 meters would be close. The difference between "works" and good signal reports will be better seen in some type of screw driver antenna where you can tailor the coil to cause the radiation efficiency to increase relative to your ground network.

As a Service Control Operator on the MidCars Net, 7.258, MidCars Amateur Radio Service 7.258 KHz I hear from all the mobile antennas that check in on my shifts. There are quite a number of simple Hamstick types that work fairly well especially if they have the whip tuned for the upper end of 40m. Lower down the 40m band they are not so great even though the tuner provides a good match. These fixed length antennas are very compromised and the Shakespeare is just a bigger version!

Also take a look at the Cap Hat section of K0BG.com site. The Cap hat does make a difference as it allows for a shorter antenna that radiates like a much taller antenna. You can see a larger picture of my mobile station at QRZ.COM Callsign W9GAS

73 de Gary
W9GAS