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Author Topic: 40 meter mobile antenna, recomedations?  (Read 9341 times)
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W6TOM
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« on: May 29, 2016, 10:36:04 PM »

 I would like to get a 40 meter mobile antenna for my Toyota pick up, I don't want to leave it on the truck permanently but to be able to easily install it in an emergency. There are lots of places out west where there is no cell coverage, 40 meters is usually open to some place so this would be my emergency fall back if I were to break down in a remote area, like driving Hwy 50 across Nevada.

 I've looked a bit online, the Diamond HF40CL Monoband Mobile Antenna for 40 meters looks like it might be just what I want. I have an aluminum lock box on my truck with an antenna mount, I'm thinking of using this. The Toyota has a composite (non metallic) bed, the lock box would be part of the ground plain and I will also run  1 inch braid to the cab and outside of the bed.

 I'm curious what some of you guys have done, the only mobile HF I have ever run was 10 meters.


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Carl WA1KPD
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« Reply #1 on: May 30, 2016, 08:28:24 AM »

I just did a trip around the perimeter of the Us and was very pleased with the performance of the 2 MFJ mono bans sticks (40 & 17) I used.  I also was pleased by the license plate mount they have.  However I drilled holes through the trunk and used SS bolts and nuts as well as a separate ground braid to the car.
Carl
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Carl

"Okay, gang are you ready to play radio? Are you ready to shuffle off the mortal coil of mediocrity? I am if you are." Shepherd
Todd, KA1KAQ
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« Reply #2 on: May 30, 2016, 10:57:25 AM »

WA2PJP and NE1S are a couple more fellows who have done a lot of mobiling. Worth sending each one a message for input as they don't check in too often online.

Carl, curious what you ran for a rig during your adventure - new rig or something like a G-76 perhaps? I think the older gear would be great if you didn't have to change frequency often and had an alternator that could handle a tube rig. The newer rigs are certainly more frequency-agile while driving down the road.
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W6TOM
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« Reply #3 on: May 30, 2016, 01:17:36 PM »

  I actually met NE1S at Nearfest last Fall, we had worked each other on AM earlier in the week and he mentioned that he was going to be there. He has an old Webster Bandspanner on the bumper of his 60's vintage Falcon which I took some pictures of. I had a few Ford products with that same drive train, my first car a 64 Comet and later a 65 Ford Econoline.
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WU2D
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« Reply #4 on: May 30, 2016, 01:19:42 PM »

Without going crazy, it is hard to beat the Hustler setup for mono-band. Not bad on 40M at all and the resonators are cheap at the festers, so buy a couple three. I like to do a shunt coil to ground on the bottom to reduce noise and improve the match.
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K4RT
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« Reply #5 on: May 30, 2016, 01:48:29 PM »

I used the Hustler mobile for several years for SSB & CW with an Icom 706 transceiver and mobile headset mic.  I attached the Hustler mount to a piece of steel about 1/4 inch thick and perhaps 2" x 6" that I had a machine shop drill a hole in to fit on my trailer hitch.  I attached the 40M resonator to the mast or the multi-band attachment that supports three resonators for the higher bands.  I have the hinged mast, which was necessary to lower the antenna to park in the garage.  That set up was a bit clunky, but it worked well, and at that time with sun spot numbers high, I could easily make transcontinental & DX contacts mobile.  On my mast I think the threads are brass and frequent changing of resonators damaged the threads, so I had to cut away a small slice of the outer aluminum at the top and rethread the brass, which worked.

The Hustler & attachments are not low profile.  I was returning home from New Jersey about 15 years ago with that set up and had just finished a CW QSO with a ham in Belgium when I was pulled over at dusk by a federal parkway cop in Maryland.  The officer, a young guy, walked up to my window and said in a friendly tone "What is that thing on the back of your car?"  I told him and then he saw my single lever CW paddle and he asked "What is that between the seats?"  I explained the set up and told him I just finished a Morse Code contact with Belgium, and he said "That's really cool." A couple more comments and then he said "Drive safely" and returned to his car and we both went on our way.
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W6TOM
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« Reply #6 on: May 30, 2016, 01:56:38 PM »

  I was never good at CW, running CW while mobile is the "vintage" texting while driving!!
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Carl WA1KPD
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« Reply #7 on: May 30, 2016, 03:40:51 PM »


Carl, curious what you ran for a rig during your adventure - new rig or something like a G-76 perhaps?

Hey Todd,
I did the trip in the Acura TLX so I did not go AM. The bands were so bad that is would have been a real disappointment. But amazingly, even with the bad conditions I had daily scheds with K1VYU and worked him  in LA, TX,OK, NM NM AZ CA CO,MT, SD and ILL

I have a HB 40 mtr AM rig and a ME PR 6 I plan to put in the 50 GMC with a Bug Catcher I picked up at Nearfest one year.

I really liked my KJ7U 6-160 screwdriver, but I did not want that big a footprint on the car. THe hamsticks were low profile and easy to breakdown and put away. No "guy wires" needed either.
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Carl

"Okay, gang are you ready to play radio? Are you ready to shuffle off the mortal coil of mediocrity? I am if you are." Shepherd
W1ITT
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« Reply #8 on: May 30, 2016, 03:56:03 PM »

Putting low-band mobile antennas on modern vehicles is a sketch.  Having been involved with a 3-30 mhz mobile chirp sounder setup on a Ford F-150 (don't ask...) we found that things go to pot quickly below about 10 mhz.  It seems that no two parts on any modern vehicle are electrically connected, so braid and self-tapping sheet metal screws are the order of the day.  Our antenna was mounted on a toolbox similar to what you describe but, again, make sure that it is securely muckled to ground, and don't forget the frame itself.
My antenna of choice is the Hi-Q with the 4 inch motor adjustable coil, but I have been very happy in the past with the old Webster Bandspanner, and life got better when I started using a shunt matching inductor at the base.
That being said, and against all common sense, my friend Joe K1RQG (sk) occasionally used a cheap 75m Hamstick on a four-magnet mount on his Mercedes two-seater and I would talk him home from Michigan to Maine with no problems, except for staying awake.  As I recall, Joe ran an extra braid ground from the magnet mount to somewhere just inside the trunk lid, and he had a few other pieces of braid discretely connecting various parts of "Der Kompressor".  No doubt he would have been stronger with a better antenna but, for the price and the low windload, it makes sense to have a cheapo Hamstick tucked in just in case your "good" antenna breaks. Spend as much time on grounding as you do on anything else.
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« Reply #9 on: May 30, 2016, 04:59:04 PM »

To expand on what Witt says,  mobile hf on low bands isn't easy.   Add QRO and things get very interesting.

One thing people forget to bond is the tailpipe / muffler.   Add the fact they are grounded at one end,  and usually hung with isolation pads,  grommets,  etc.   Makes for a dandy parasitic element on the counterpoise.

Rewarding,  yes.   Easy,  not always.   

--Shane
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W2NBC
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« Reply #10 on: May 30, 2016, 06:13:56 PM »

Low band operation.. hmmm.. It all depends!

If you're driving your car that you care about.. well, less invasive is typical with grounding, drilling, etc.

IF however, you're driving your ANTENNA while travelling, then consider the WA1HLR Dog Log..

BIG signals from small cars  Grin


 


* dog-log.jpg (74.88 KB, 526x581 - viewed 486 times.)
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Carl WA1KPD
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« Reply #11 on: May 30, 2016, 06:22:56 PM »

Putting low-band mobile antennas on modern vehicles is a sketch.  Having been involved with a 3-30 mhz mobile chirp sounder setup on a Ford F-150 (don't ask..

And not without risk.A friend of mine who is well experienced, technically astute and meticulous, was putting a replacement 100 watt hf xcvr in his car. Keyed it up and the airbags blew.  What was different between the rigs is unknown.
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Carl

"Okay, gang are you ready to play radio? Are you ready to shuffle off the mortal coil of mediocrity? I am if you are." Shepherd
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« Reply #12 on: May 30, 2016, 06:49:26 PM »


   I wonder when the BTV MLA-C mobile 80/40m Magnetic Loop Antenna will be available? A MLA will be a different beast entirely, and the vertical polarization component will be good for NVIS communication.

http://www.btv.cz/en/upcoming-news

Jim
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W6TOM
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« Reply #13 on: May 30, 2016, 06:51:00 PM »

 Before I retired from the local power company last year one of my jobs was to support our construction crews radio needs. The linemen used a frequency for talk around in the 150 band, one 40 foot line truck with a two man bucket had a issue. When the truck was running or ignition key in the accessory position, the radio had bad interference. With some help from the Fleet Electronic Specialist we were able to trace it to on of the airbag sensors. That was the end of that, we could do no more due to it being a safety issue and the manufacturer had gone out of business.

 We were cautioned not to run antenna coax parallel to wire runs as those runs might have  been airbag control or engine control lines. I never heard of anyone setting off airbags but we were cautioned about the possibility. I did hear about RF getting into engine computers causing issues, key radio and vehicle parks itself!

 Doesn't say much for a manufacturer of large trucks used by the utility industry that didn't consider that the end user just might want to install a radio?? DOH!!! Some of the guys had 100 watt 150 Mhz radios, they needed to talk point to point and not all places have cell coverage.


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K4RT
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« Reply #14 on: May 30, 2016, 07:37:38 PM »

  I was never good at CW, running CW while mobile is the "vintage" texting while driving!!

Tom, It depends on the station configuration & operator. I never had to take my eyes off the road while operating any mode. But you raise a good point.

In regard to ground, even then 15 years ago some mobile operators were reporting problems with chassis bonding.  I grounded to the car frame and had no such problems, but apparently others have.  Also, in my case RF caused no problems with the vehicle systems.  However, the car's A/C generated RFI to the receiver on some bands.

The lowest band I have operated while mobile is 40M.  Certainly, operating mobile HF on the low bands is a compromise, but give it a try.  Should be fun.
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Dave K6XYZ
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« Reply #15 on: May 30, 2016, 08:10:33 PM »

I would like to get a 40 meter mobile antenna for my Toyota pick up, I don't want to leave it on the truck permanently but to be able to easily install it in an emergency. There are lots of places out west where there is no cell coverage, 40 meters is usually open to some place so this would be my emergency fall back if I were to break down in a remote area, like driving Hwy 50 across Nevada.

 I've looked a bit online, the Diamond HF40CL Monoband Mobile Antenna for 40 meters looks like it might be just what I want. I have an aluminum lock box on my truck with an antenna mount, I'm thinking of using this. The Toyota has a composite (non metallic) bed, the lock box would be part of the ground plain and I will also run  1 inch braid to the cab and outside of the bed.

 I'm curious what some of you guys have done, the only mobile HF I have ever run was 10 meters.

TOM....WU2D is correct.
I used the Hustler Super coils....the larger much more efficient coils with their break-over mast and a quick disconnect to remove the whole thing off the mount in a couple of seconds.

I had previously used a Master Mobile 40mtr coil and a base loading coil about 1 1/2" OD with a tap for 40mtrs.
This worked quite well and I traveled all over the USA with this setup...monoband.

later...I changed to Hustler and started operating several bands including 80, 40, 20 & 15....all with Super coils except 80 and no base coil.
I was wondering how well it was going to work without the base coil but all bands worked quite well without it.
However....Swan and perhaps another company made a switchable tapped base coil that I had considered using.
Not sure if anything like that is mfgd today but if you look around you will likely find one of them.

edit...actually, the 'base' coil is not a loading coil....I think the proper term is 'matching' coil.
This coil has only a few turns and serves to 'match' the coax to the base impedance of the stick...connect the coax to the tap on the coil.
I'm not an antenna expert so someone straighten me out....all I know is that it worked bitchen!

Dave
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« Reply #16 on: June 02, 2016, 10:54:05 AM »

Hustler isn't a bad solution, especially for 40 meters and up. I've read several places that the high power coils are less efficient than the low power ones if you don't need the extra power capability, because of the stray capacitance of the larger end caps on the coil.

I've used those, hamsticks, and a variety of screwdriver antennas for the last 20 years with generally good results. Grounding and bonding is definitely an issue, and you can see the difference in various vehicles. And larger bodies, station wagons and vans, have always worked better for me. Haven't tried any pickup trucks.

On 40 meters and up, most of the antennas except the wander lead things seem to work reasonably well, even with a mag mount on the higher bands. I usually run a strap or braid to a grounding point to augment the capacitance through the magnets. The best magnet mount was one I made with a square foot of aluminum held flat against the car roof by 4 big magnets attached to two pieces of wood that ran over the top. Added a box for a ball mount, and a switch for matching caps and it worked great with a TenTec Argosy on 40 and up!

I went to matching coils at the base, and have been very happy with them through the last decade. For one thing, they reduce the static from rain and other sources. I used to get a rising screetch and zap while driving in the rain that would repeat. With the shunt coil to ground, that's gone. And the match on the low bands is much better with the screwdrivers. If you have an efficient antenna on 40 or 80, and yes that's a bit of an oxymoron, the impedance at the base will be low, 10-25 ohms. The shunt coil helps transform that. My current 5 inch pirhana Hi-Q has a nice null on 75 meters with about 9 turns of #14 about 1 inch in diameter. I find I usually have to compromise between the best match on 75 or 40. I usually match it for 75 meters, and accept a little higher level on 40. On 20 and up the coil mostly looks like an RF choke and doesn't impact much. To get a good match on 160, and I've made some contacts there, I'll need to put in a second coil and relay to switch it in when I'm on that band.

Mobile cw is fun. I do it pretty much only on the long superslab. RT81, 88, etc. I've used a couple of different paddles. The best was a squeeze style made from a couple of pieces of spring stock that you squeezed and it flattened and made contact with a screw head. A picture of one designed to hold in the hand is attached. I had it zip  tied to the back end of the emergency brake handle out of the way of using it, but in a good spot for where my hand lays while driving. Works pretty well.

Current rig is an FT857 with a turbo tuner. Plans for a mobile amp. Have used Alinco DX70 with good success, and an Icom 706 as well.
 
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73 de Kevin, WB2EMS
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« Reply #17 on: June 02, 2016, 02:43:23 PM »

KE0G dollar special.

In the older ARRL manuals.

Describes a shunt coil at the base of the vertical


--Shane
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« Reply #18 on: June 02, 2016, 04:06:00 PM »

Realized I didn't attach the picture. Mine is made with a u shaped metal channel, some insulating tape under the springs, and can be adjusted for a nice feel while being cheap and fairly rugged.


* squeeze paddle.jpg (64.23 KB, 736x552 - viewed 386 times.)
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73 de Kevin, WB2EMS
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« Reply #19 on: June 02, 2016, 07:32:03 PM »

http://www.k0bg.com
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« Reply #20 on: June 06, 2016, 10:45:40 AM »

K0BG.com is a great site with a lot of useful information.
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73 de Kevin, WB2EMS
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« Reply #21 on: June 18, 2016, 10:41:37 AM »

I always take an Elecraft KX-3 (15 Watts) and the KPA-100 (100 Watt amp) with me and the antenna I use is an Diamond HV-7A.  This antenna is rated for 120 Watts HF and 200 Watts VHF/UHF.  I bought it originally for my Yaesu FT-8900 mobile radio but use it mostly with my KX-3.  I just took it with me to Europe, broke it down and had it in my backpack.  It is a bit heavy at the base.  The coils can be changed for 10, 15, 17, 20, and 40 meters and the coils are small and easy to pack.  I have found that to works very well with the vehicle as the ground plane.  When portable, I use the ground plane wires from a super antenna, for some reason this works well for me.

I also have a Hi-Q antenna but it requires tuning for all areas of the bands while the HV-7A is much easier and quicker to setup and no moving parts or power requirements.

I have not tried a Hustler antenna.
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