Groundplane?

[Byron Kinnaman]

Thanks all for encouragement. I don't really think the exam will be a problem. All the technical stuff is easy. I've got ARRL license book and never bothered to even read the technial stuff. Most of what I have to remember is band vs frequency stuff, some operation conventions, and a bit FCC rules. I've been taking the online tests at eham.net. Usually miss one or two questions. The other thing going for me is it's multiple guess type.

I'll let you all know what happens.

[Byron Kinnaman]

Good Luck & God Bless Byron!

If you'd like to do some tune-up practice tests, go to www.QRZ.com and have at 'em. They give you multiple-guess questions straight out of the real question pool, keep a running tally score, and give instant correct answers on any you miss. All online in your browser. You do it enough times you'll pass Tech, General, or Extra easy.

Also, if you have any questions, I'll be happy to "Elmer". Just drop me a message, anytime.

'73 ConwayBob KI4HEE

With just a bit more study I could probably pass the General test. But at this time I'm only interesting in the high frequency stuff. Mostly handheld.

Thanks for the offer the "Elmer". If I fail the exam I might need it.

73

x7xxx

[Bob H]

With just a bit more study I could probably pass the General test. But at this time I'm only interesting in the high frequency stuff. Mostly handheld.

Thanks for the offer the "Elmer". If I fail the exam I might need it.

73

x7xxx

You threw me with the "high frequency stuff"...sorry, I figgered out you're talking about 6M, 2M, 440, ect. Cool. But work on doing General anyway...

Here's what you do... goto QRZ.com and take the Tech test...if you can do 80% no problem, start doing the General test too...do it a few times, then do a Tech test again, as a tune up. Keep doing the General test and the Tech test. Don't spend a lot of time at this, just make a game of it...keep trying to top your personal best. In a week, you'll be aceing both, I gauarantee it.

Here's the reason I'm telling you this... I'm a VE, a volunteer examiner. When you pass the Tech test, you're welcome to take the General test immediately. If you pass that, you can take the Extra exam. You pay a proctors fee before you test, but as long as you pass, you can take as many tests as you want. At our last session we had two guys walk in with no license and walk out as Extra Class Operators.

Go to QRZ.com...start practicing NOW.

ConwayBob

PS, get you're Tech ticket and download echolink, I'll be happy to work a sked with you over the net anytime. Get your General and I'll work you over any band that's open.

[Bob H]

Getting back to the topic at hand, Per, in your case most car antennas do use the car body as a "groundplane" or more accurately as a "counterpose". In some cases, coax antenna shielding that's grounded at the radio acts as the other "half" of the antenna. I don't know about fiberglass bodied cars like the Corvette but there is at least some "ground" involved, the car frame, door posts, ect., to act as counterpose. If you are using a car antenna, try to mount it to any metal part of the trailer or get a ground wire to where you have it mounted.

A easier solution is a cheap dipole antenna which dosen't require a counterpose.
A dipole antenna like this or this should do the trick.

Incidentally, fiberglass is "invisible" to most radio waves. A fiberglass "whip" Antenna is usually just a wire running inside a fiberglass tube or a bit of wire glued the length of a fiberglass rod. What I'm getting at is if you strung a dipole from floor to ceiling say inside your closet, or along the length of a cupboard or overhead bin, you'll in effect have turned your Fiberglass Trailer into a fiberglass dipole antenna that can sleep 4!

I'll see you on the radio,
ConwayBob

[Ed Harris]

Getting back to the topic at hand, Per, in your case most car antennas do use the car body as a "groundplane" or more accurately as a "counterpose". In some cases, coax antenna shielding that's grounded at the radio acts as the other "half" of the antenna. I don't know about fiberglass bodied cars like the Corvette but there is at least some "ground" involved, the car frame, door posts, ect., to act as counterpose. If you are using a car antenna, try to mount it to any metal part of the trailer or get a ground wire to where you have it mounted.

A easier solution is a cheap dipole antenna which dosen't require a counterpose.
A dipole antenna like this or this should do the trick.

Incidentally, fiberglass is "invisible" to most radio waves. A fiberglass "whip" Antenna is usually just a wire running inside a fiberglass tube or a bit of wire glued the length of a fiberglass rod. What I'm getting at is if you strung a dipole from floor to ceiling say inside your closet, or along the length of a cupboard or overhead bin, you'll in effect have turned your Fiberglass Trailer into a fiberglass dipole antenna that can sleep 4!

I'll see you on the radio,
ConwayBob

The only issue with this is the Reflectix insulation between the Rat Fur and the Fiberglass I would think.
I have used inside antenna' in my eggs so far but the newer Scamp is challenged because of the Reflectix it seems.
It truly insulates including R.F.

Also Bob,I found the BuddiPole used on QTH and just like the Fiberglass Here you have to be ready to pull the trigger the moment you see a used one because the next guy sure will.
I first saw them and met W3FF at Dayton a few years ago and the quality is very nice.
I also have a Super Antenna MP-! which works well and he makes a DiPole version of that also.
To me though the issues I have with both of them are the coils.The Budipole clip system seems very fragile and about to break at any time and the MP-1 "screwdriver" like coil is not much better.

They are unbeatable for portability though.

73
Ed

[Darwin Maring]

Having worked inside RF proff rooms off and on for many years (Many were walk in freezers with metal walls and brass/copper fingers around the doors) with all outside connections going through an extensive filter system we found this out.

At the North Dakota Stanley Mickleson Anti Ballistic Missile site we wanted to put a cable TV in the room so we drilled 1 hole small enough so a coax would just fit and after we drilled the hole and B4 we inserted the coax, we got the local radio station.

[Bob H]

I forgot about the reflectix insulation...my Scamp is pre-ratfur, reflectix sure would block things a bit. I've seen a Miami FL TV station use chickenwire built completely around the studio, to act like a faraday cage, worked real well too.

About the Buddi-pole...There was a guy selling a Buddi-pole at the Charleston SC Hamfest...wanting $300 bills for the complete set-up...I'm sure he got it too. I've seen Buddi-pole copycats for sale and homebrewed stuff using those big MFJ telescoping whips and home wrapped coils. Looks like a pretty cool project. Someday I'll win a lottery and get one of those MFJ antenna analyzers... there'll be no stopping me then.

Meanwhile, I throw my Carolina Windom wire antenna up between two trees to get out.

"73" ConwayBob

[Bob H]

"At the North Dakota Stanley Mickleson Anti Ballistic Missile site we wanted to put a cable TV in the room so we drilled 1 hole small enough so a coax would just fit and after we drilled the hole and B4 we inserted the coax, we got the local radio station."

That's so cool! It's amazing the magic of radio and how anything can serve as a antenna. Stories of people hearing radio signals coming from dentalwork are true too! The first place I owned was a mobile home parked close to the local Radio Station. One day I heard the local station clear as day coming out of my window air conditioner. Cool sounds comming out of a cool AC!

ConwayBob

[Byron Kinnaman]

Per,
Do you have a television antenna in that Burro. If so connect the TV antenna to the FM receiver or replace the auto antenna with rabbit ears or some other television antenna. FYI, FM radio frequencies are between Channel 6 and Channel 7, making TV antennas great FM broadcast antennas.

[Per Walthinsen]

Byron:

Yes, I have a Winegard Sensar amplified crank-up monster, and the wall antenna hookup for the TV is right by the stereo. I should try it. If it does the job can I put some kind of splitter on it to feed the stereo as well as the TV?

There is already some kind of a splitter on it internally, since there is a second TV antenna plug in front. Maybe I could reposition it right next to the original one.

Does this mean that I can junk the automotive antenna and glass over the hole, making the already sleek Burro even sleeker? (Always looking for weight reduction and less air drag. )

[Byron Kinnaman]

Per,

Try the tv antenna, if that works then ditch the auto antenna. I don't know of any reason why it wouldn't work with a splitter.

[Pete Dumbleton]

Keep in mind that a splitter will cut the signal by 3dB, or in half.

[Byron Kinnaman]

Keep in mind that a splitter will cut the signal by 3dB, or in half.

True if it's a passive splitter.

[Pete Dumbleton]

Good point! Have to admit that I have never knowingly encountered anything else but passive.

[Per Walthinsen]

An update: I already had a second antenna plug in the area, so I cobbled up a cable to feed the stereo from the Winegard. Not sure without opening it up whether it uses a splitter or not.

With the antenna resting flat on the roof the FM reception improved a lot. It went from strictly not listenable to superb. The TV reception seems to be unaffected. I listen to a local station, KBPS, which is relatively low powered, but now it comes in loud and clear. The old antenna is scheduled for demolition. Thanks, Byron!

[Byron Kinnaman]

An update: I already had a second antenna plug in the area, so I cobbled up a cable to feed the stereo from the Winegard. Not sure without opening it up whether it uses a splitter or not.

With the antenna resting flat on the roof the FM reception improved [b]a lot. It went from strictly [b]not listenable to superb. The TV reception seems to be unaffected. I listen to a local station, KBPS, which is relatively low powered, but now it comes in loud and clear. The old antenna is scheduled for demolition. Thanks, Byron!

Glad I could be some help.