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My experience of using the Yaesu VX-8r as a mobile

Moleculo

Ham Radio Nerd
Apr 14, 2002
9,194
1,674
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There isn't any rocket science involved with using an HT for a mobile rig, but I thought I would share some photos and some of my recent experience of using the Yaesu VX-8r as a replacement to a permanent mobile rig.

First, a little background: The vehicle being used is my RV. I decided against installing a permanent VHF/UHF rig in the RV because it would just not be used often enough to justify the expense, IMO. With the built-in APRS functionality, the Yaesu VX-8r makes a good choice if you would like others to be able to track your location while on the road. This was also a consideration for me since I frequently take the RV out into the desert for hunting trips during the season. The wife and family don't go, so this way they can track me if they desire (and assuming I can make it into a digipeater!)

I picked up a Lido Mount at the Dayton Hamvention this year - they had a sweet deal going on. Here is a pic of the mount on the window of the RV:

moleculo-albums-rv-station-pics-picture977-lido-mount-used-yaesu-vx-8r-belt-clip.jpg


This particular Lido mount has a reversable face. If your radio has a standard belt clip, you just clip on with the face oriented as pictured. If you have a swivel belt clip, you flip the mount face up and use it oriented the other way. Lido makes a bunch of different mount faces for whatever application you need.

Here's a pic of the VX-8r mounted on the Lido mount:

moleculo-albums-rv-station-pics-picture975-yaesu-vx-8r-lido-mount-visible.jpg


You can see that I've attached the external antenna and the hand help mic. The mic clips on the visor perfectly out of the way in the RV, making it easy to hear the speaker, yet easily accessible. The GPS unit (not pictured) is in the hand mic. Even with the RV cab overhang, the GPS is still sensitive enough that it worked perfectly, even tucked up on the visor against the roof.

Here is the front view as I'm sitting in the driver seat:

moleculo-albums-rv-station-pics-picture974-yaesu-vx-8r-rv-mobile-screen-fairly-readable.jpg


The radio is in dual 2 meter mode - VFO A is on 146.52, VFO B is on 144.390 for APRS tracking. One problem with using the VX-8r in this manner is that the screen can be a little difficult to see. While driving, an RV can be a little bouncy. There is a bit of flex with this particular Lido mount, causing the radio to bounce around just a little. This doesn't really hurt anything, but it does make it a bit challenging to read the screen when it's in dual VFO mode. If I put it into single VFO mode with the large letters, it was easy to see.

The original plan for the RV was to use a spare 2m/440 antenna that I have, mounted on an adjustable Diamond groove mount on the hood. The hood of the RV is the only place where there is any sheet metal. Unfortunately, the hood has a huge lip on it's edge so the Diamond groove mount did not work and had to be returned. For now, I just stuck a little 2m/440 antenna with a rare earth magmount on the top of the corner panel. I'm not sure what the hood on this RV is made of, but it's not sheet metal (maybe aluminum?) because the magnet would stick where I originally wanted it. You can see in this pic how it ended up getting mounted. It leans a little funny, but it's not that big of a deal

moleculo-albums-rv-station-pics-picture976-view-yaesu-vx-8r-outside-tiny-2m-440-antenna-rv-sheet-metal.jpg


One nice thing about the VX-8r is that it uses a standard external speaker 1/8" stereo jack. I ran a regular speaker cable to the AUX input on the stereo in the dash and was able to use the cab speakers to hear the radio. The passengers got a little tired of it after a while, so I ended up going back to just having the sound output to the hand speaker/mic over head. One word of caution with using the external speaker - When I also plugged in the cigarette lighter charger to the HT while the external speaker cable was plugged in, I got a mean ground loop hum through the speakers. I'm sure that would have been broadcast as well, if I didn't unplug it. So if you plan on using the charger, don't create a ground loop!

With this setup and 5 watts, I was able to chat with quite a few stations along the way. Almost all were home stations, but there were a few mobiles also. 5-10 miles of range seemed to work pretty consistently, with much farther distances to base stations with good antennas. I have a little 35 watt VHF amplifier that I may try to hook up and rest on the dash somewhere. One good thing about RV's is that they tend to have a big dash that you can put to use. I would really like to figure out a way to mount a real antenna on the hood, but this just may not be very feasible.

When I got home, I pulled up my station on Login - Google Maps APRS and found that I was much more successful at being tracked by the digitpeater even with this little cheap external antenna than with the stock duckie. I expected that, but the difference it made really was remarkable.

So there you have it - hand held Yaesu VX-8r HT turned into a mobile.

Cost without radio
Lido mount - $25
2m/400 magmount antenna - $12
Radio Car charger - $27
 

Very cool. If you end up integrating an external amplifier I would definitely like to hear about it. Curious about the other antenna you wanted to put on there, what one was it? And if you do decide for another antenna what one will it be, are you interested in the 6m capability or just 2m & 70cm, or consider maybe buying into an a 10m-70cm capable antenna for HF incase you get a beefy radio later? (got my general today, so now I'm wondering)

http://universal-radio.com/catalog/hamantm.html


How are you going powering the radio too with the nasty ground-loop thing? I am thinking of getting the EDC-6 (8r power cable minus the cig) and dropping the 8r right into the cd-41 cradle charger.

I ask because I like your plan. What you say is true about getting a dedicated mobil rig, kinda expensive, and hard to justify after all other money spent on the 8r. My group has a Kenwood D-710 (totally totally awesome, and extremely extremely easy to use) that is in a tool box with a battery, battery tender, and a mag mount antenna. It interfaces with a computer pretty slick, we have a MacBook with XASTIR and couldn't be more pleased with how it works. But spending just a little more (<$100) on power, mount, and antenna like you said gives you pretty much the same capabilities if you've already made the initial 8r investment.

Awesome work too. The whole setup is clean. Don't worry about the antenna poking out the side either, bigger and more protruding the better. I am waiting for the ham plates for my car, then I need an antenna. I'll take a picture of it when I nice ol' big goofy antenna and the plates on there. I might even put a pirate flag at the top of it...

I think that the links that get copied from aprs.fi use cookies or some history info because when I send others the links to my IGated packets (and vice-versa) I always end up putting their call back into the search box.
 
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Curious about the other antenna you wanted to put on there, what one was it?

It was a Comet SBB-5. It's a spare that I already have, so I was just trying to make use of it. The problem on a class C RV is that the bunk that hangs over the cab limits the height of the antenna you can use unless you can get it mounted farther out on the hood. The groove mount for the hood would have solved this problem if I had been able to get it to work.

How are you going powering the radio too with the nasty ground-loop thing?

For a day trip, you probably don't really need to power it - the battery will last long enough. However, I wanted to see how it worked with the Yaesu cigarette charger, which is what I was using. I only get the ground loop when I also attach the speaker cable to the radio. This would be easy to solve if I cared enough to do it, but in reality I probably would never have a reason to have both cables attached at the same time. I was just experimenting with the possibilities.
 
Glue a fat (steel) washer under the hood where you want the antenna, checking first if you mag-mount is strong enough to hold of course.
 
Since I had all of the necessary parts laying around, I got industrious late yesterday and decided to hook up a Power Plus HL-35V 35 watt 2 meter amplifier that I picked up for cheap at a swap meet a while back. This little amplifier also has a GaAsFET pre-amp built in, and is made by Tokyo Hi-Power.

I used my bench top disc sander and ground the too-big, round head screws on the underneath side to be flat, so that the amp would sit more flush on a piece of velcro. I found that I had a spare cigarette plug power adapter from radio shack in the junk drawer, so I extended the power cables and wired it up. I had a SMA to SO-239 cable already and found that I had all the other necessary connectors to get the amp hooked up to the mag mount antenna.

Here's a pic of both the amp and the view from the dash

moleculo-albums-rv-station-pics-picture980-power-plus-2-meter-35-watt-amplifier.jpg


moleculo-albums-rv-station-pics-picture981-picture-dash-yaesu-vx-8r-2-meter-amplifier.jpg


I tried it with a meter and found that 5 watt input gave right at 35 watts output. Since it was around the time of the afternoon commute here in SoCal, there were plenty of folks on 146.52. With this set up I was able to make contacts at quite a good distance. Of course, from my location at my house on the hill, I had the elevation in my favor, so I'll have to see how well this does on the road.

The pre-amp probably makes as big of a difference on the RX as the 35 watts does on the TX. When I turn the pre-amp on, signals that barely showed S1 on the HT's meter went to an S5. One station I talked to who was on a base about 35 miles away had an S5 reading on the meter, and it went to an S9+ with the pre-amp. The preamp in this little thing works very well...no distortion, just a good strong signal boost.

Now that I've got the amp wired up, I'm thinking up ways I can use it with a battery and a camera bag to make a portable satellite station. That sounds like it could be my next fun project :)
 
Not sure if this was changed, so it may be illegal in Californica to have anything stuck to the windshield...

But looks like a nice setup, and that little VHF amp would be quite handy.
 
Yeah, it's illegal in CA, which is one reason why i wanted it down in the corner. However, I always see tons of people on the freeway with a GPS right smack in the middle of the windshield and noone bothers them.
 
Since I just bought a GPS, I had to actually look this up. It seems OK, if attached to the lower corners of the windshield:

Driver side: no more than 5 inches from bottom and side.
Passenger side: no more than 7 inches from bottom and side.

SB1567 - California: Electronic Devices, Motor Vehicle Recovery Corporation, Consumer

Since it is specific to GPS, and your unit is GPS capable, perhaps that would be OK. Also, there is an exclusion:

(11) An electronic communication device affixed to the center
uppermost portion of the interior of a windshield within an area
that is not greater than 5 inches square, if the device provides either
of the following:
(A) The capability for enforcement facilities of the Department
of the California Highway Patrol to communicate with a vehicle
equipped with the device.

And since you can receive PFR...
 
Mole,

Very nicely done.

The 8R keeps looking like a better and better radio. Especially with a sub-$100 amp that'll get you 35w.

Great write up.
 
Be very careful....considerate of anything that isn't really well fastened up on the dash or in general lying around loose inside a vehicle.

I've seen some incredible things done with the energy of some relatively lightweight projectiles in vehicle collisions.

It's something most of us don't think about...and with luck won't be reminded of. I wasn't aware of it at all until I was an EMT for several years.
 
...One word of caution with using the external speaker - When I also plugged in the cigarette lighter charger to the HT while the external speaker cable was plugged in, I got a mean ground loop hum through the speakers. I'm sure that would have been broadcast as well, if I didn't unplug it. So if you plan on using the charger, don't create a ground loop!

Moleculo, I was using my VX-8R this morning with earphones and the cigar lighter cable, and noticed no hum at all, and the people I talked to were saying I was loud and clear. Is this something specific to amplified external speakers? FWIW, I was using earplugs from my iPod, and the lighter adapter was the one with the noise filter E-DC-5B.\\

73,

KF5CKB
 
One word of caution with using the external speaker - When I also plugged in the cigarette lighter charger to the HT while the external speaker cable was plugged in, I got a mean ground loop hum through the speakers. I'm sure that would have been broadcast as well, if I didn't unplug it. So if you plan on using the charger, don't create a ground loop!

I just caught this. Can you actually transmit with the HT plugged into the cigarette lighter? I know that if the HT is plugged into the wall, it will turn off when I transmit.
 
You won't cause a ground loop by just using headphones with the cig lighter charger. The ground loop happened when you plug it into the line in on your car stereo and also the cig lighter. That's because there are now multiple paths to the vehicle's ground from the radio.
 

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