Installing an Ham 80=>2M transceiver

[JJH3rd]

I've noticed that several forum contributors are Ham radio operators and want to ask them for some words of wisdom before I re-invent the mobile Ham shack.

I have an Icon 706MKIIG that I have used in my pickup truck and I want to install it in the MH. That sounds simple enough, but I could use some hints and sage advise about powering the rig, grounding it and the cabling and mounting of vertical antennas. I anticipate operating the station only when parked.

Any help would be appreciated.

[wa8yxm]

Well.. for starters you need to decide where you are going to put it.. I got lucky with my rig in that where I decided to put it was.. Well, horzontially about 3 feet from the main 12 volt distribution panel (80 amp board 20 amp rig) so I only needed to add about a foot to the factory 12 volt leads to install my TS-2000.

Antennas (And cable routing) Again, this affects where you put it... In my case I was able to run them easily.. Down, through the floor (I could have run via the plumbing passages) and to the rear where I mounted a 2-meter J pole, a six meter quarter wave, and a Kenwood Auto Tuner (KAT-1, Marine grade version of the no longer made KAT-300, electronically identical)

I put a "Vent" (like a stove vent) in the wall and gluing the flapper shut put in bulkhead connectors for other antennas.. Very flexible install.

70cm (an ngp design) went on the roof.

The antenna is the fun part.. You now what i use for 2 and 70cm.. For other bands I have a collection of options.

The KAT-1 is designed to work with a long wire... I have a 100' long wire I toss over tree limbs or run to a 16' painter's pole off in the distance.. (In installed a hook at the roofline to hold the RV's end) I can put this 25 feet or more up in a tree very easily (Hand tossed weight)

I have shorter wires, I have a vintage 4 band trap vertical which the KAT will take down to 80 meters.. I have a "Goat Rail" along the roof. However truthfully it does nto work very well (it is 1/2 inch copper tubing)

QST has an interesting article in the October (I think, current in any case) edition on loop antennas. I'm considering.

[TXiceman]

I used a Little Tarheel II ( 6 to 80m) and made my own tilt mount on top of the trailer. The closest power was at my 12 VDC distribution center. My problem is the RF from the Progressive Dynamics power converter. After talking to PD, they said it was most likely 7 to 13.5 mHz. Well it does tare up 20 and 40m pretty good. His solution was a Faraday Cage around the converter. Guess I need to work on that this weekend.

Ken

[JJH3rd]

I plan to use the rig only when parked, so does it really matter if I use the 12V system or the 120V through a power supply? Would using 120V & power supply remove any problems that the Xantrex Freedom 458 converter/charger might create?

[Dmreese1]

Hi J.J.,

I run a couple of Yaesu's in my 05 Tropical with the Xantrex inverter charger system. Using 120V while connected to shore power, I have never had any interference or noise issues. I have not tried to run off the inverter as I also do my operating while parked.

I run a portable Trans World Antenna TW-2010 that I can put up in 5 minutes or so. It is a 10 thru 30m multiband.

I also have a Butternut HF6V that I deploy with 16 tape measure radials as a ground plane. This is a 23ft antenna that is good thru 80M.

For Vhf/Uhf I have an Arrow aluminum dual band J Pole mounted on a hinge on the roof. I raise it to operate and lower it when driving. The antenna connection is run thru a junction box on the roof down thru the top of the coach into the entertainment area. I routed the coax down to the drivers side console. I also have a second coax on the roof junction box which is near the front of the coach, this gets a Miracle Antenna MMD 17M that I use as a sloper up to a 25 foot fiberglass mast on the rear ladder.

On 50M, I use a Moxon on a 30ft mast that I aim manually.

To get antenna wires and ground into the coach I use a bulkhead connector board that fits in my small slide window.



Duane K3AL

[Dmreese1]

A few pictures from K3AL

[wa8yxm]

RE Progressive Dynamics and RFI.. Strange thing is ... I don't hear it (I have a PDI 9180 with charge wizard)... Still have not figured out why.. Like the Faraday cage idea though.

Re Using 12 or 120 volt system... The radio is designed to operate off a 12 volt automotive system (13.6 volts nominal) So if your converter, like mine, is big enough to do the job (Mine can crank out around 1,000 watts if I ask it nicely (960) way more than a 100 watt transciver needs) Why haul a big heavy (even if it is a light weight switching type) power supply.. I mean that's one more piece of hardware and more pounds.. you don't need it.

I have two converters in this coach already.. (The other one does 1,200 watts at 12vdc or 100 amps) so even if the PDI goes Diodes Up.. I close two switches and I still have FULL POWER. (Xantrex Prosine 2.0 if you want to know what unit #2 is)

Speaking of the Prosine... One thing you DO NOT WANT in that rig is a MSW inverter.. That will tear up the bands, Epically the lower bands.

[tj4dirt]

If you plan on only using it only while parked it would make the wiring easier if you ran off a converter. I wired my 12v to a lug by the front tire, only about a 6' run in through the floorboard. My antenna is on the ladder and the cable run under the MH.

[wa8yxm]

By the way.. If you are putting it up in the driver's area.. Somewhere either under the dash or under the hood (if it's a gasser) there are a pair of brass bolts.. Nothing attached, they will usually be on the bottom of a fuse box... I know Chrysler and GM both do it this way on cars. and Workhorse on my motor home.

Directly connected to the positive cable from the main battery with the 2nd heaviest gauge wire in the vehicle (if not the heaviest) Most tranceivers will suck power from these just fine.

[wa7hra]

My station sets in a "drawer" on top of the dog house and under the dash. The "drawer" extends about six inches towards the rear of the coach and beyond the lip at the front of the dog house "cover". It is the same width as the DH. It is flush with the dash board. It pulls out and the cover is removable for access to the equipment. Your 706 would fit in the "drawer" which is made of 1/2 inch plywood and is stained to match the interior wood of the MH. All the external wireing except for the microphone cords pass through a hole in the left side of the "drawer".

My HF antenna is a 23 foot Shakespeare 390 marine antenna attached to the front lower corner of the slide out. The antenna and all the attaching hardware was purchased from West Marine which has stores in many cities. I have an AH-3 (the current model is AH-4) Icom antenna tuner bolted to the inside, exterior wall of the compartment directly behind the left front wheel. I manually run a jumper from the feed through on the wall to the base of the antenna. The antenna is fully assembled at all times and can be erected in less than a minute.

The station has an Icom 7000 HF radio and a Kenwood TM-D700 VHF/UHF radio. The antenna for the D700 is a simple dual bander. The two radios and all the station accessories are powered by a regulated power module connected to the house batteries which are solar charged. The regulator provides a constant 13.5 V minimum regardless of battery voltage. I do not use any 120V power supply.

Bob, wa7hra..........

[Bill WA6YBD]

I have an Icom-706 mounted in a console I built many years ago. I first built it for a Fleetwood Flair. Back then I use an Icom-730 and a Icom-27 (2mtr) and an Icom-37 (220MHz). I modified the console to fit the 706 after I purchased my 1995 Dolphin. Another modification was required for our 2005 Dolphin. see below. There are several circuit breakers for the various radios and accessories, switches to select antennas, amplifier band and to raise or lower the antenna.



Antennas:
For 2mtr/440 and 220MHz, I use 1/4 wave antennas mounted to a sq tubing several feet long, mounted on the roof. For a ground plane I used some sticky aluminum tape (normally used for sealing air handling ducts) attached to the sq tubing and stuck down to the roof. After tuning I painted over the tape with some white roof seal to help protect the tape. I ran the coax into the grey electrical box normally used for satellite, down behind the TV and down the corner post to the radios. sorry no pictures.

For HF I use a High Sierra antenna mounted to the ladder. When I am parked I add a section to the bottom of the antenna to extend the coil above the rig. I also use a 102" whip when parked. This has worked out the best for all parks. I have never had any complaints about wires in trees, etc. The bands I operate normally are 40 and 80 meters. I store the antenna and extension mast under the MH in some PVC tubing. I can remove the base extension and use a shorted whip if I want to operate while driving down the road.




Amplifier:

I have a Metron 1000B amplifier that puts out about 600 watts mounted in the forward storage compartment. I have approximately 650 amps of battery power that powers the MH and radios.



A MH makes a great mobile QTH. The most important part of a mobile installation is the antenna and it's grounding. I'm sure you will have lots of fun once you get your antennas and radios installed.

73 ~ Bill WA6YBD

[Bill WA6YBD]

Hello again,
I left out some very important stuff. The most difficult and important part of any mobile installation is the antenna. For good results you need a good antenna. Not a Hustler, they are nothing more than a radiating dummy load. A lot of amateurs think just because they got a good match they are home free. The Hustler antenna loading coils are made from Nichrome wire. The coils end up having a very low Q. They may be broadband but that's due to a very low Q. The Q of the antenna is very important. The higher the better. A high Q antenna will require resonating (tuning) more often. This is a good thing and the main reason the screwdriver type antenna was invented by Don Johnson W6AAQ (SK). I have a signed copy of his book, 40 Years of HF Mobileering. This is the bible for HF mobile antennas and installations. Many people (companies) have copied his idea and many have improved the design but I must give credit where credit is due. Don Johnson the inventor of the screwdriver antenna.

With all that said a good high Q antenna on 80 meters will have an impedance of somewhere around 10 ohms. Because your radio is looking for a 50 ohm match you will need to transform the 10 ohm antenna up to 50. This website has some good general information about matching. Antenna Matching I built several UnUm transformers and they works great.







The next thing to consider is RF grounding right at the antenna. Very, very important. What I did was to run a piece of heavy braid from the antenna mount and matching transformer to the closest solid ground I could find. I removed the tail light assembly and tied the braid right to the metal frame of the MH.

Time spent on the antenna and ground will pay off in spades.
73 ~ Bill

[JJH3rd]

The PDF of the 05 National Dolphin brochure describes the tubular steel frame that surrounds the MH's living space as having all sorts of structural advantages. I'd like to know if it is part of the MH's electrical ground plane and if so how do I access it to make it part of the antenna. Or should I not include it at all or avoid it?

Also would it make any difference if I make use of a ground at the typical camp site, such as the water line (if it is a metal and not plastic pipe)?

BTW, Thanks OMs for the VERY good suggestions and comments.
73 JJ

[Bill WA6YBD]

There is no way to avoid using the metal frame of the motor home as part of the ground system. The frame is tied to both the 120 VAC electrical ground as well as the 12 VDC battery (-) system. As soon as you connect the radio(s) to the battery you are connected to the chassis metal frame and all common grounds in the motor home. This does not mean you have a good RF ground. The key is to use the frame as a GOOD RF ground. The large size of the motor home frame will act as a fairly large capacitor to couple energy from the coach to earth ground beneath the coach.
Connecting to a water pipe: As soon as you connect your AC power cord to shore power you are connected to a water pipe or some other local ground required by the local electrical codes. Even though you are "grounded electrically" it may not be a good RF ground. The best RF ground would be to spread radials out from the base of the antenna laying directly on the ground. Very difficult to do when rolling down the road. When I am dry camping I do not put out radials or run a wire to a water pipe that may be present. I seem to get good coupling to ground just using the metal frame of the motor home.
For good HF performance: (1) The loading coil of the antenna should be as far above the top of the motor home as possible. (2) The antenna should be as long as possible. (3) The loading coil should be as high Q as possible. (4) The longer the whip is on the top of the antenna the shorter the loading coil will be. Less loading coil means less power lost in the coil. (5) A good (low impedance) RF ground must be present at the base of the antenna. You should ground the shield end of the coax at the antenna base to the closest part of the motor home frame possible. In my case the base of my antenna is connected to an aluminum plate that is attached to my ladder. This may serve as a good structural support but it is not a good RF grounding mechanism. I use a short (2 foot) piece of 1" braid to go from the base of the antenna to the frame of the motor home. I removed the tail light lens behind the ladder and connected the braid to the metal frame of the motor home.
73 ~ Bill