Author Topic: Tool box mounted antennas  (Read 18500 times)

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ghrit

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Re: Tool box mounted antennas
« Reply #15 on: December 21, 2014, 05:56:39 PM »
Yes, the box will be opened as needed.  That's the plan, anyway, and should work with a tipover mount or QD at the base.  Will also need tipover for the garage.  Thinking ahead, I could see smacking the top of the cab if there wasn't a way to tilt the tenna.  (For once, planned that far ahead, even if not much further.)
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AD

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Re: Tool box mounted antennas
« Reply #16 on: December 21, 2014, 06:17:33 PM »
For what its worth, I would mount on the back side of the tool box near the top right or left corner.  Then the lid can open without screwing with the antenna.  You can protect the coax inside the tool box with a metal flashing so you dont have extra cable needed to open the lid.

Or use the back bed stake hole method in the article.  If you ise this method, the tool box lid is not an issue and you can then pull the whip fwd to tie it down to the front bumper to get in the garage or use as a NVIS antenna. Like this
« Last Edit: December 21, 2014, 06:19:34 PM by AD »
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ghrit

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Re: Tool box mounted antennas
« Reply #17 on: December 21, 2014, 06:51:42 PM »
For what its worth, I would mount on the back side of the tool box near the top right or left corner.  Then the lid can open without screwing with the antenna.  You can protect the coax inside the tool box with a metal flashing so you dont have extra cable needed to open the lid.
I see that option.  With the tool box opening hinged at the front, if I bring the coax in the front under the hinge, no excess is needed but will still need to be laid down or dismounted.  The back side of the box will also work, and as you say, it won''t interfere with anything.

Or use the back bed stake hole method in the article.  If you use this method, the tool box lid is not an issue and you can then pull the whip fwd to tie it down to the front bumper to get in the garage or use as a NVIS antenna. Like this

Also understood.  One thing I have yet to do is measure from the toolbox to the garage door when in and closed and see if that will limit the length of a whip.  (All I need to do is remember the tape measure and to do it.)  That will decide if there's to be a tipover mount or QD, since the pickup stays in the garage when not on the road.

Please keep the ideas coming, I need to be sure I can answer the questions and make my thinking pass logic before I start drilling holes and spending.  Thanx.
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AD

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Re: Tool box mounted antennas
« Reply #18 on: December 21, 2014, 07:26:30 PM »
What fun is that?  Just start drillin and find outs what work  :o
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spacecase0

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Re: Tool box mounted antennas
« Reply #19 on: December 21, 2014, 10:25:32 PM »
I mount antennas in the center middle of any metal item,
does your tool box have a section in the middle that does not move ?
anytime you put an antenna on the side of any metal item it ends up being directional, not that bad, but I find it annoying
if you have to fold down the antenna to open the tool box, then why not just put the antenna in the middle of the roof where it will work better and you only have to fold it down to drive in low clearance areas ?

Lamewolf

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Re: Tool box mounted antennas
« Reply #20 on: December 22, 2014, 06:30:19 AM »
Has anyone any experience with mounting a mobile antenna on an aluminum pickup toolbox?  Assume the tool box (mounted close to the front of the pickup box) is properly grounded to the pickup box.  Will the toolbox behave properly as a ground plane?  What problems are likely to pop up?


Thinking of a whip with spring mount for use with an hf transceiver and tuner.  Will probably trim a 102inch off the shelf whip for 10M, that's yet to be determined.

I would just make sure the box is well bonded to the truck bed and then run some bonding straps from the bed to the frame and from the body to the frame.  I would also add an auto tuner like the SG237 or Icom AH4 inside the box to go with the whip.  No need to cut the whip if you use the auto tuner at the feed point of the whip.  Both tuners mentioned should work 10 thru 80 meters with your whip, or you could use the Hamstick type antennas for the band of interest.

ghrit

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Re: Tool box mounted antennas
« Reply #21 on: December 22, 2014, 06:46:47 AM »
I mount antennas in the center middle of any metal item,
does your tool box have a section in the middle that does not move ?
anytime you put an antenna on the side of any metal item it ends up being directional, not that bad, but I find it annoying
if you have to fold down the antenna to open the tool box, then why not just put the antenna in the middle of the roof where it will work better and you only have to fold it down to drive in low clearance areas ?
No fixed flat spot, the box is hinged full width.  As it is, there's only limited clearance with the garage door (a tad under 7-1/2 feet), so the center of the roof is problematic as well as no great wish to put a hole up there.  Folding will be needed regardless of mount location and type, a nuisance but necessary.
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BTPost

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Re: Tool box mounted antennas
« Reply #22 on: December 22, 2014, 02:35:05 PM »
The real question is: Will this be an HF, or VHF/UHF Antenna? If HF, that is a whole different BallGame, from a VHF/UHF Antenna. VHF/UHF really needs to be on the top of the Cab, so that it is't shaded by the Cab, itself, and that helps keep the Radiation Pattern close to Omni-Directional, which in Mobile Comms is a good thing.  If it is an HF Antenna then there are other considerations that take precedent. Understand that the Antenna Pattern of an HF Mobile Antenna will NOT be uniform, or even recognizable, in many cases, due to the Marginal RF Ground, available in a Mobile Installation. The Higher the Frequency of Operation, the Better the Efficiency of the Antenna, and RF Ground. Ghrit, if you are planning to use the TS-480, then you might look at mounting the Radio Portion, inside the Tool Carrier, and make a very short Antenna Lead, to whatever you decide to use as an Antenna, thru the side of the Tool Carrier, to the Antenna Mount. This allows the Internal Tuner, the Maximum flexibility, in tuning the Antenna, with the least amount of External Capacitive Coupling to the RF Ground, provided by the Carrier, Truck Bed, & Frame. You also will need to make the Hole thru the Carrier Wall at lease 1.5" in diameter, and use a Non-Conductive Material to Bring the Antenna Wire, out. If you just dill a small Hole, to do this, you get WAY TO MUCH coupling to the RF Ground and it is like taking a 2" FireHose with 50 PSI of Pressure, and putting a 1000# Weight on the Hose.  Just how much water would you expect to get out the Far end? External Capacitive Coupling is the KILLER, in Mobile Antenna Systems. there is a Reason that the HF Antennas on those Hummers, pictured are sitting on 3" ThruMount Insulators....  Then you just run the Power Cables and ControlHead Cables up to the Cab, and Hook them up. Use Good Grounding between the Carrier, and the Truck Bed, and between the Truck Bed and Frame. I like to use the Braid, stripped for a section of RG-213U, Flattened, with a Bead of Solder, running the length, and then sprayed with a heavy Coating of Clear Acrylic Lacquer. Make at least TWO Bonds, One at each end of the Carrier and at least two Bonds between the Bed and the Frame. I will be building such an Installation in Momma's Toyota 4X4 Extended Cab Pickup, this next spring, to put HF Mobile in it. I have an SEA1612B AutoTuner to mount in the Bed which can feed whatever HF Antenna I can come up with. This means I can run Regular RG58A/U coax between the Radio on Tuner, and not worry about how it is router thru the Cab Wall. I am thinking of using, either the TS-450 I have, or getting a TS480 like yours. If I go the 480 route, I will mount it on the Back Wall of the Cab, along with the TM-D710A VHF/UHF Mobile, and mount both Control Heads, under the Dash on the Passenger side. Then bring #8 Power Wires from a spare Battery, mounted next to the AutoTuner, in the Bed, that is charged off the 120 Amp Alternator on the engine, thru a 150Amp Solenoid that is controlled by a switch in the Cab. No Dead Batteries for this Old Boy.....Passenger side Controls, because it IS Momma's Truck, and SHE is the Driver when we are together.... I am Comms and Navigator...
Bruce in alaska AL7AQ

ghrit

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Re: Tool box mounted antennas
« Reply #23 on: December 22, 2014, 03:30:28 PM »
As of today, the whip will have to be no longer than 85 or so inches, or will have to come off in the garage, so some more thinking/research for ready made antennas is in the works.   (See, AD?  I can remember tape measures.)

BT, as stated, it's hf, and yes, it'll be the TS480.  At present, the TS would be mounted in the cab, and the autotuner would (or could) be in the toolbox, as it will stay in the truck when the radio comes inhouse to be the base station (unplug power and coax and take it away.)  The TS came with a mount for exactly that purpose, and I have a notion to screw it into the bottom of the jump seat behind the driver's perch; that way the seat can be used if I'm cursed with too many passengers.  Control head will come up front, quite possibly in a coffee cup mount insert or gooseneck to a seat mounting bolt.  Putting the radio itself in the tool box is a non starter because the mic plugs into the radio, not the control head.  (Might be the only dumb part of the Kenwood design, lotsa cable, just not enough to reach from the cargo area to the driver's seat.)

So far as uniformity of the radiation pattern goes, I expect a bit of directional sensitivity in the fore and aft directions if centered on the side to side centerline of the vehicle, and there's not a lot can be done with that from a practical standpoint.

To rf grounding then:  What say you about dragging a ground strap on the road?  I've heard mixed reviews about that working or not for radio.  And yes, the tool box will be grounded via strap to the cargo box and the frame, somehow.

VHF and UHF will be served, as they are now. rather well by a mag mount top center of the cab.  I hook the h/t to that whisker and lead the coax thru the door seals, not going to become permanent, just portable.

Initially, power will be from the car battery, knowing full well the risk of running it down and giving me fits starting, so will be parking where I can use gravity to bump it.  (Manual tranny, daddy didn't raise no dummies in that area.)  Eventually, a portable gennie of the Honda 1000 flavor/size will get added to the loadout.  (They have a 12 volt outlet, but I'll probably use a normal 110V type power supply under those conditions.)
There are two kinds of ships.  Submarines and targets.
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BTPost

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Re: Tool box mounted antennas
« Reply #24 on: December 23, 2014, 02:10:49 PM »
Ghrit.... I wasn't aware that the TS-480 had the Antenna tuner as a Remote Box, separate from the Radio, itself.....(will have to look into that) I was under the assumption that it was part of the Radio Chassis, as it is with all their other HF Radios. With that new Knowledge, Your solution is definitely the way to go... Yea, Kenwood made a critical Design Flaw, in NOT having the Mic Audio coming from the Control Head. It is the same on ALL their Remote-able ControlHead Radios, and it sucks... I am used to the SEA Systems (SEA 322, 330, 225, 235) used in their Remote ControlHead HF Radios, where the Audio both TX & RX is done in the Control Head, the Radio Chassis, itself, does RF Stuff, and the AutoTuner is a separate Box, altogether. Been thinking about how to integrate the TM-D710 and a TS-480, into a common Tx/RX Audio Setup, (think aircraft installation) with a common Mic and Speaker, and a Mic Selector Switch near the Control Heads.... I guess one could just buy a B-2000, and have everything in One BOX, but I already have the TM-D710a, and it's AvMAP6, ready to go into the Truck, and the SEA1612B AutoTuner, so just getting a used TS-480 would make sense, NOW. I can sell the TS-450 to help finance the TS-480.

Dragging a Ground Strap is useless for RF Ground purposes, but will allow any Static Buildup to dissipate from the Fame, if it should buildup. Mostly that was a Lightning Issue fix, from Bygone Eras....
« Last Edit: December 23, 2014, 02:13:27 PM by BTPost »
Bruce in alaska AL7AQ

ghrit

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Re: Tool box mounted antennas
« Reply #25 on: December 23, 2014, 03:09:40 PM »
Ghrit.... I wasn't aware that the TS-480 had the Antenna tuner as a Remote Box, separate from the Radio, itself.....(will have to look into that) I was under the assumption that it was part of the Radio Chassis, as it is with all their other HF Radios. With that new Knowledge, Your solution is definitely the way to go...

Dragging a Ground Strap is useless for RF Ground purposes, but will allow any Static Buildup to dissipate from the Fame, if it should buildup. Mostly that was a Lightning Issue fix, from Bygone Eras....
The TS480 DOES have an on board auto tuner, but it is limited in range.  IIRC it starts cutting back on power at 3:1 and refuses entirely to transmit at (again, IIRC) if it sees 10:1.  My intent is to be able to use it with the external tuner on all bands that I can come close on.  For now, knowing that radiation efficiency goes straight down the tubes if the antenna is not itself close to resonant, it looks like I'll be researching mobile antennas that are practical (i.e., not all bands) rather than do it all at 1:1 and 100% efficient across the board.
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Tempstar

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Re: Tool box mounted antennas
« Reply #26 on: December 23, 2014, 09:57:49 PM »
I run a 480sat mobile with an Alpha Antenna vertical on a 95 Bronco with a mount I made (pics tomorrow if it stops raining). I have done no extra grounding. The Alpha actually does better than spec once mounted due to the capacitance of the vehicle. I'd put on the antenna, keep the feed line as short as possible, and go from there. Running braid from something that already has a mechanical attachment is a waste of good braid. You'll likely see coupling to the cab in front of the antenna which may help or hurt depending on the antenna design, and if you have to mount on the box I'd go as far rearward as possible. Being in the center of 18" of toolbox on 20' of truck isn't going to make a difference. The vehicle is too small to make an effective ground plane at HF freqs anyway. Oh yeah, DO grab about 5 ferrites for your size coax and put 'em below the antenna, keep the braid from radiating.

Just my observations.
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Tevin

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Re: Tool box mounted antennas
« Reply #27 on: December 25, 2014, 12:20:36 PM »
I run a 480sat mobile with an Alpha Antenna vertical on a 95 Bronco with a mount I made (pics tomorrow if it stops raining). I have done no extra grounding...Running braid from something that already has a mechanical attachment is a waste of good braid...and if you have to mount on the box I'd go as far rearward as possible. Being in the center of 18" of toolbox on 20' of truck isn't going to make a difference. The vehicle is too small to make an effective ground plane at HF freqs anyway. Oh yeah, DO grab about 5 ferrites for your size coax and put 'em below the antenna, keep the braid from radiating.

Tempstar does bring up a good point. Fussing over the location of a mobile antenna down to mere inches is overthinking things.

When I put up any antenna, mobile or otherwise, the first thing I do is set it up stock with no special considerations and see what I've got. You have to have some known base level of performance, otherwise you're just guessing. 90% of the time my new antenna works fine with no further action needed. I've never had to deal with capacitive coupling, or worry about the size of the hole messing up my RF, or insulated pass throughs.

I'm not saying these things are never an issue, I'm just saying you should not assume they are going to be an issue until they actually are. When you go into a project with the preordained mindset that all these (unconfirmed) technical difficulties exist, you start playing head games with yourself looking for "problems" that need fixing. The end result is either A) a setup that is way more complicated than it needs to be, or B) a setup that performs no better (and possibly worse) than if you had just left it alone in the first place.









ghrit

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Re: Tool box mounted antennas
« Reply #28 on: December 25, 2014, 10:00:30 PM »
Tempstar does bring up a good point. Fussing over the location of a mobile antenna down to mere inches is overthinking things.

When I put up any antenna, mobile or otherwise, the first thing I do is set it up stock with no special considerations and see what I've got. You have to have some known base level of performance, otherwise you're just guessing. 90% of the time my new antenna works fine with no further action needed. I've never had to deal with capacitive coupling, or worry about the size of the hole messing up my RF, or insulated pass throughs.

I'm not saying these things are never an issue, I'm just saying you should not assume they are going to be an issue until they actually are. When you go into a project with the preordained mindset that all these (unconfirmed) technical difficulties exist, you start playing head games with yourself looking for "problems" that need fixing. The end result is either A) a setup that is way more complicated than it needs to be, or B) a setup that performs no better (and possibly worse) than if you had just left it alone in the first place.
That is understood, and sorta the way I intend to go.  The key is for me to have a clue what the problems might be and have a (more or less) logical "plan" in place for potential problems.  Back in the day, we used to try to fix things by what we called "easter egging", meaning a trial solution by replacing or adjusting things) for problems with unknown causes.  Never liked that approach all that well because it meant we didn't know our gear well enough. But there were times when it was the only way to approach the problem.

And the chuckle:  The only reason for placing a mount within inches (or fractions thereof) is cosmetic.  Gotta LOOK good, even if it doesn't work ---
There are two kinds of ships.  Submarines and targets.
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