13 replies to this topic

[bobnsandi]

Please excuse if this has been asked before. I've looked at all available posts & didn't see it if it is...

My hubby and I just sat for our FCC licenses this past Saturday. We successfully passed the Tech & General and are now awaiting our call signs. We are going to Ham Outlet in Phoenix tomorrow to buy a mobile & antenna for our toad. We'll put a pretty basic 2m/70cm set (Icom IC 208H?) in there with a magnetic roof mount dual band (Comet M-24?).

Our question is the coach. We have a 40' Itasca Ellipse, which is pretty much all fiberglass with the exception of the steel driver's cage. Would you experts share your experience with non ground plane antennas for fiberglass vehicles? We'd like to be able to use the radio while underway, so the ladder mount rigs probably wouldn't work for us.

Also, does anyone have any thoughts on a rig for the coach? We full-time, so the coach is our base station. We have HF privileges, but really don't know if we want to use them.

Lots of questions and we thank you for your patience with the "new kids"...

P.S. Will there be a gathering at Quartsite in 2012?

Bob & Sandi
Rover's Roost, Casa Grande, AZ

[HamRad]

Bob and Sandra, Congratulations on your tickets! I hope you enjoy the hobby as much as I have. I have no experience with fiberglass structures and antennas so cannot be of any assistance there. There will be a gathering of Hams at Q. It is usually held at mile 99 marker south of Q. I believe it is about 6 miles south. There are usually hundreds of Hams attending. Good luck and enjoy. Dennis, KA6TZP

[HamRad]

Dup posting. Sorry, Dennis

Edited by HamRad, 07 November 2011 - 02:11 PM.

[KU9L]

Congrats Bob & Sandi!

Each situation is unique, but a 1/4 or 5/8 wave antenna will require a ground plane to work decently. A 1/2 wave antenna does not need a metal ground-plane from the vehicle. My Larsen 5/8 wave on a magnetic mount worked really well on the roof of our truck, but in order to adapt to our Lance 1181 truck camper, which overhangs the roof, we had to go to a 1/2 wave through the windshield mount. I'd say it works 90% as good at the old 5/8 wave which had a very low angle of radiation. Sometimes in a canyon a 1/4 or 1/2 wave works better for getting out, but real world is sometimes a compromise. Does your Elispse have a drivers door? You can buy a mount that will work with the door to mount a half wave antenna from the door area. Google Larsen and download their catalog, Comet, & others are good too. I'm sure there are many motorhome users that can give you specific detailed instructions.

73,

Dave

[Mike Council]

Congratulations on the two new tickets! I won't ask about the scores, ha!

I've just started using a Shakespeare 393 with an air choke temporarily mounted on a fiberglass 5th wheel for 10 - 80 meters and it seems to work well enough so far. I use a HH for 2 & 70cm and find it does OK, not much traffic.

Good luck and I hope to hear you on the air soon. There is an RV/Ham Net at 7PM Central every evening on 7.265 if you want to join in.

73's,
Mike WU0G

[Don S.]

Mike,
Why are you using a choke on the 393?
How is it configured?
Don

[Roger K4RS]

Quartzfest will be held January 21st thru 28th 2012. Please come and join us. There will be lots of time to socialize and talk about radios / antennas.


More info can be found here:

http://quartzfest.or...p/main.php?home

73

[Mike Council]

Don, when I used the 393 the first time I got what I think was a lot of RF back down the feed line. Display on the IC700 didn't like it! I constructed the choke out of coax & a piece of 4" plastic pipe. It seems to work but I've got to get a meter on the antenna to see what's going on.
Mike

Attached Files

•  393 Choke.jpg   66.82K   12 downloads

[EvanandCarolyn]

Congrats, on the license.
I use the IC-208H and it's a good one. For the motorhome you could use a yaesu 857D with ATAS 120A or anything with a Tarheel.
W0AVN

Please excuse if this has been asked before. I've looked at all available posts & didn't see it if it is...

My hubby and I just sat for our FCC licenses this past Saturday. We successfully passed the Tech & General and are now awaiting our call signs. We are going to Ham Outlet in Phoenix tomorrow to buy a mobile & antenna for our toad. We'll put a pretty basic 2m/70cm set (Icom IC 208H?) in there with a magnetic roof mount dual band (Comet M-24?).

Our question is the coach. We have a 40' Itasca Ellipse, which is pretty much all fiberglass with the exception of the steel driver's cage. Would you experts share your experience with non ground plane antennas for fiberglass vehicles? We'd like to be able to use the radio while underway, so the ladder mount rigs probably wouldn't work for us.

Also, does anyone have any thoughts on a rig for the coach? We full-time, so the coach is our base station. We have HF privileges, but really don't know if we want to use them.

Lots of questions and we thank you for your patience with the "new kids"...

P.S. Will there be a gathering at Quartsite in 2012?

Bob & Sandi
Rover's Roost, Casa Grande, AZ

[bobnsandi]

Many thanks to all for your posts. We installed the Icom in the toad yesterday and made our first contacts through the local repeater. Don't think we made too many errors.

We had a long chat with the folks at Ham Radio Outlet and they have some recommendations about non-ground plane antennae that (they claim) will work on our fiberglass coach. We'll probably wait until after the first of the year before addressing the coach radio since we're not planning to move it until Quartzsite.

Again, thanks to all for the advice and kind wishes...

Sandi (KD0PYS)
& Bob (KD0PYT)

[CARiess]

If you are going to be working repeaters, the ant is not critical. I work repeaters with a handheld.

[bobnsandi]

If you are going to be working repeaters, the ant is not critical. I work repeaters with a handheld.

We've also been able to use the local repeater with a handheld. But here's our reason for going the amateur radio route.

We're planning to spend summer '12 in Alaska and find CB inappropriate. We'd like to be able to access 2M/70cm while underway in the coach. Since we also sat for (& passed) general at the same time we're considering adding HF capabilities for when we're parked (looking at the Icom IC 7000 or similar). The VHF/UHF antenna would be mounted so it can be used stationary or underway while the HF antenna would only be used while parked.

Does that sound logical? We're hoping to be in Quartzsite in January and will definitely drop by the Quartzfest setup to "pick brains".

Again, many thanks to all who took the time to share your experience and advice.

Bob & Sandi Swanson
SKP #101110

[Bill Baxter]

We're planning to spend summer '12 in Alaska and find CB inappropriate. You may not like the Childrens Band but it is IMHO a necessary addition. Running the Alaska Highway it is your best communication device except for 2M. 2M will communicate well but since the repeaters are linked you may be talking with an operator 200 miles away. CB will be close range for road conditions and accidents. There is a link on the Anchorage ham club website with details and coverage maps of the linked repeater system. So there is one CB and one 2M radio. Around the big cities CB is almost intolerable. However, it is a useful tool. Set the squelch high so that only those transmitting within a mile or so are heard. Of course you could add APRS with Kenwood D700 and having a messaging capability.
'

We'd like to be able to access 2M/70cm while underway in the coach. If you're going dual bander why not add the 220 for the tribander. A lot of areas are going 220. Maine for the last three years on the linked system.

Since we also sat for (& passed) general at the same time we're considering adding HF capabilities for when we're parked (looking at the Icom IC 7000 or similar). The VHF/UHF antenna would be mounted so it can be used stationary or underway while the HF antenna would only be used while parked.
I'm not commenting on HF since I haven't figured an antenna system.


73's de N1XRB

Bill

[Redbear]

Mike,
Why are you using a choke on the 393? . . .

Radio waves and electricity travel on the surface of metal - in coax, the signal is on the outside of the inner wire, and the inside of the metallic braid or foil.

On a fiberglass RV, the "ground" signal traveling on the inside of the braid may have nowhere useful to go, so it makes a U-turn and goes back down the outside of the braid to see what havoc it can cause. In the old metal-case days, that would be the outside of the rig and the mike, where it had been known to burn operators' lips. With a plastic case, it heads inside the radio.

A choke (wound coax or ferrite devices) discourages signals from traveling back down on the outside of the braid to your station. This will also cut down on interference to and from electronic devices in the vehicle, because the outside of the braid running through the vehicle is no longer a signal-carrying part of the antenna system.

Also, for 2 meters, I will confirm that the 1/2-wave end-fed "dipole" whip is correct when there is no ground plane. A tuned choke plus capacitor network inside the required "coil" connect to both the center and braid of the coax to "shoot" all the signal up the whip. A ground plane will also help this antenna a little, but it isn't required.

As KU9L stated, 1/4 wave and 5/8 wave whips require a ground plane. This is because with correct mounting, the signal on the braid shoots across the roof at the same time as the signal from the coax center shoots up the whip. Think of looking across a still lake at a pine tree on the opposite shoreline. You see one tree in the air pointing toward the sky, and there appears to be another one on the water pointing down. That's kind of how the sky sees the two "halves" of your 1/4 wave ground plane antenna system.

OK, Physics professors, don't trash me. I know it's all a lot more complex than that, but picturing it the way I described it helps visualize how antenna systems work. The vehicle roof is a part of the 1/4 wave antenna system, not just a support for the mount.

73 de N1YR