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eHam Forums => Mobile Ham => Topic started by: KC8AHN on January 03, 2011, 07:07:58 PM



Title: HF mobile, which rig?
Post by: KC8AHN on January 03, 2011, 07:07:58 PM
I currently have a 2003 Mercury Sable but maybe getting something different soon.

I am wanting to put an HF mobile rig in the car, current production rigs leaves me with the IC7000, Kenwood TS480SAT or the Yaesu 857D. I went and looked at the 7000 today, the sales guy was all about selling that rig (which it is the most expensive of the 3) but I am wanting some real world thoughts. The only drawback (if you call it that) with the Kenwood is it does not have 2m/440 (I currently have a 7900R installed in the car that covers those bands).

I was just going to do Dstar but am thinking I can have more fun having an HF mobile rig, especailly since I make 3 trips a year to Memphis and sometimes Dallas from Columbus OH.


Title: RE: HF mobile, which rig?
Post by: N5MOA on January 03, 2011, 07:54:36 PM
My vote for a hf mobile rig is the TS-480. I don't care for 2m/440, so not having those bands was a plus for me.

I haven't used a Yaesu 857d, so I won't comment on it, but I have used a IC7000.

Receiver, control head layout, easy menu to navigate and transmit audio, the TS-480 wins. The DSP works well, and the NB does an excellent job on ignition noise if you have any.

I used a TS-480SAT in the house and in the pickup for a year, then left it in the house and put a TS-480HX in the pickup back in February. I don't need the tuner with my mobile antenna, and the extra 100w is nice to have.

I'm sure you will get other opinions, but imo, the TS-480 is very hard to beat for a hf mobile rig. The IC7000 didn't, and I doubt the 857D will either.

You will have to decide for yourself what you want. If there is anyone local to you using any of these, and you can ride along and try it, would be the best way to see for yourself. If the dealer you went to has all three setup (they should) to try would be good too.

Then you can ask the "which mobile antenna" question. :P

73, Tom
N5MOA


Title: RE: HF mobile, which rig?
Post by: AD4U on January 04, 2011, 05:38:42 AM
Any of the three rigs you mentioned will be good.  What will make or break your mobile station is the antenna.  

Generally a small, all band, mobile antena = relatively poor performance (IMO).

In a HF mobile setting the antenna and how and where it is mounted is (by far) the most important part.

Dick  AD4U


Title: RE: HF mobile, which rig?
Post by: W1ITT on January 04, 2011, 06:57:55 AM
Steve..
For me, one of the most important criteria is the ability to operate the rig by "Braille", that is without taking my eyes off the road.  Some of the newer rigs that necessitate scrolling down through menus, and making selections with soft keys don't make the cut.  I have an old Yaesu FT-900 that I can pretty much operate by feel, being able to change all the things I need to adjust while under way.  The quickest way to get our state legislatures to outlaw amateur mobile operation...along with cell phone talking and texting while in the driver's seat, would be to have a serious mishap due to driver inattention to the road. 
Whichever you choose, the rig needs to be securely mounted in a position such that when you do take a brief glance at it, you can get your eyes back to the road asap.  And as someone else already pointed out, the antenna is the overriding factor in your success.73
Norm W1ITT


Title: RE: HF mobile, which rig?
Post by: K0BG on January 04, 2011, 07:56:00 AM
Go to my web site, and read the Miniaturized Radios article.

You also might want to read my review of the IC-7000: http://www.eham.net/reviews/detail/5338


Title: RE: HF mobile, which rig?
Post by: KC8AHN on January 04, 2011, 03:22:50 PM
Lots of great feedback, and I actually read the review prior to seeing your post Alan, nice write up. The plan is to install a rig in the car and use Hamsticks. I know it is not the most efficient set up but I cannot put a huge bug catcher on my car and still get into my garage for one and for two my budget will now allow a nice screw driver.


Title: RE: HF mobile, which rig?
Post by: AD4U on January 04, 2011, 05:21:02 PM
Hamsticks will work.  I have a friend who thinks they are great.  If you want to operate 20 meters and have a better signal, take the 15 meter Hamstick, remove the stock whip, and add a longer whip to resonate the 15 meter Hamstick on 20 meters.  A MFJ antenna analyzer is a good tool to adjust the whip to the right length.  This is means less coil and more radiating antenna.  This will make for a very tall antenna.  If not the 15 meter Hamstick, try it with the 17 meter (18 Mhz Hamstick).  The same friend did it with the 15 meter Hamstick, and from 10 miles away I can consistantly see the difference on my S meter.  Just a little less coil and a little more antenna, often works wonders when running HF mobile.

Dick  AD4U


Title: RE: HF mobile, which rig?
Post by: KC8AHN on January 04, 2011, 05:25:12 PM
Hamsticks will work.  I have a friend who thinks they are great.  If you want to operate 20 meters and have a better signal, take the 15 meter Hamstick, remove the stock whip, and add a longer whip to resonate the 15 meter Hamstick on 20 meters.  A MFJ antenna analyzer is a good tool to adjust the whip to the right length.  This is means less coil and more radiating antenna.  This will make for a very tall antenna.  If not the 15 meter Hamstick, try it with the 17 meter (18 Mhz Hamstick).  The same friend did it with the 15 meter Hamstick, and from 10 miles away I can consistantly see the difference on my S meter.  Just a little more antenna, often works wonders when running HF mobile.

Dick  AD4U

I will be sure to note that. The two bands I operate the most are 20/40. I have tried the others from time to time, but find myself mainly on those two. I do some traveling, as I said, I go to Memphis and/or Dallas a few times a year (my ex-wife remarried and moved to TX and she has two of my kids) so I want not only something reliable but something that I can check into nets and such on. Sure, cell phones are great, when they work. Lucky for me I never have been outside cell phone range, but I am sure there could be a time when radio will be the winning method of comms for me. Thanks for the feedback.


Title: RE: HF mobile, which rig?
Post by: K0BG on January 04, 2011, 06:41:05 PM
Just remember, even if you elongate a 15 meter hamstick to operate on 20 meters, you're still nearly 20 dB under a decent, full-sized screwdriver.


Title: RE: HF mobile, which rig?
Post by: KH6AQ on January 04, 2011, 07:29:09 PM
A 20 meter hamstick can perform nearly as well as a screwdriver antenna of the same length.

Let's model the 7.5', 14 MHz Hamstick over perfect GND. It is essentially a center-loaded monopole. The radiation resistance is 10 ohms. The loading coil is 10 uH and with a Q of 100 has a loss resistance of 9 ohms. The antenna efficiency is 53%. Now let's say the loading coil Q is only 40 as some claim. The loading coil loss resistance is 23 ohms and the antenna efficiency is 30%.

Now let's model a 7.5' screwdriver having a coil Q of 300. The radiation resistance is also 10 ohms and the coil loss resistance is 3 ohms. The efficiency is 77%. The difference at 14 MHz between the screwdriver and the coil-Q-of-40 Hamstick is 4 dB. For the coil-Q-of-100 Hamstick the difference is 1.6 dB.

Move these antennas onto a vehicle and the difference can be greater or less than model above. Mounted on the roof the difference becomes less. Mounted on the bumper the difference may be greater.

Where the antenna is mounted on a vehicle can be more important than the antenna itself. Mount the mobile antenna on the roof and the real antenna becomes a vertical dipole consisting of the mobile antenna and the vehicle body. Radiation resistance is maximized; this is the best situation.

Mount the antenna on the bumper and you have a U-shaped dipole with magnetic field cancellation. Radiation resistance is minimized; this is the less desirable situation.  


Title: RE: HF mobile, which rig?
Post by: W3LK on January 04, 2011, 07:52:03 PM
Lots of great feedback, and I actually read the review prior to seeing your post Alan, nice write up. The plan is to install a rig in the car and use Hamsticks. I know it is not the most efficient set up but I cannot put a huge bug catcher on my car and still get into my garage for one and for two my budget will now allow a nice screw driver.

I have a High Sierra 1800 on my Windstar. There is a fold-over between the top of the coil and the whip. I simply fold it over when entering the garage. Resting at the 20m position, this places the whip (in a horizontal position) about five inches below the top of the vehicle.

Having gone the HamStick route, I came to the conclusion it's great for one-band operation on 20, 17, 15, 12 and 10. For 40m, a HamStick is better than nothing, but not much. For 80m they are essentially useless. For multiband use, they are a royal PITB.

A photo of my installation is in Alan's photo gallery.



Title: RE: HF mobile, which rig?
Post by: K0BG on January 05, 2011, 06:26:25 AM
Dave, while sitting down in front of EZNEC, it's easy to come up with the "oh it's just 4 dB down" scenario. Next time you have time, read the results of the last 3905 Group's Antenna Shootout.


Title: RE: HF mobile, which rig?
Post by: KE5DFK on January 05, 2011, 10:32:41 AM
I'm with what N5MOA said.

I have the TS-480HX in my Jeep with a home brew antenna from a QST article.

What does the 480 give you, a HUGE display, a great HF receiver as N5MOA stated, the NB is awesome, on my Jeep I go from an S7 without to an S3 with the NB.  A built in tuner or 200w out of the box.  Big buttons are a plus.  Like others I did not care about UHF/VHF I wanted a dedicated HF radio. 

For me the 857 has buttons where I put my fingers to turn the dial and the display is WAY TO SMALL for mobile, layered menus.  The 706 S/N ratio was way to high.  The 7000 more money than I wanted to spend.  None of the above will give me an auto tuner or 200w out of the box. 

The 480 is very intuitive to operate, 10mts and I was up an running after opening the box, the menu system is very well setup, the menu is single option no layered menu here.  The manual is great.  If you want to do digital mode no fancy interface is needed.  The optos are built in, connect the DIN to the sound card and ready to go.  I used the DIN to mic/spkr cable from Buxcomm.

For the money as a PURE HF the TX-480? is hard to beat.  You don't see a lot of TS-480s on ebay or anywhere else, there is a reason for that.  They are keepers.

Good luck and make your decision on what works best for you and your intended use.

Carlos
KE5DFK



Title: RE: HF mobile, which rig?
Post by: KH6AQ on January 05, 2011, 12:34:39 PM
Alan,

I could not base a buying decision or base an engineering decision on data obtained in an amateur antenna shootout; amateurs using amateur equipment and amateur measurement techniques give amateur results - and aren't the 3905 antenna shootout tests conducted at 7 MHz? We're talking 14 MHz here.

I can and do base engineering decisions on simulation backed up by paper-and-pencil reality checks. It's what I do for a living.

Amateurs should be able to base their buying decisions on solid data and analysis and not on an amateur antenna shoot out conducted on the wrong band. Bad data = bad decisions. 

Reality check
To say that the signal from a 20 meter Hamstick is 20 dB down from a screwdriver antenna is to say the Hamstick has 1/100 the radiation efficiency. If the screwdriver has 100% efficiency the screwdriver has 1% efficiency. That means the loss resistance of the Hamstick is 100X the radiation resistance. But as shown the ground mounted simulation the radiation resistance of a 20 meter Hamstick 10 ohms. To have 1% efficiency the loss resistance would need to be 1000 ohms. If it were the input impedance would be 1010 ohms, but it isn't. Under the conditions stated a 20 meter Hamstick cannot be 20 dB down from a 7.5' screwdriver.

Simulation shows the Hamstick loading reactance being about 1000 ohms. Given a loading coil Q of 40 (I measure Q = 100 ohms in situ, which is what counts) the loss resistance is 25 ohms. Ground mounted over a perfect ground plane all we have is radiation resistance of 10 ohms and loss resistance of 25 ohms. The input impedance is about 35 ohms and the radiation efficiency is 10/35 = 29%. This is a point of reference. It will vary with the mobile installation and can be higher or less than 29%.



Title: RE: HF mobile, which rig?
Post by: K0BG on January 05, 2011, 12:40:32 PM
Carlos, you're correct. For the money it is hard to beat an Hx. However, if you have to use the noise to quell the level as you've done, perhaps you need to do a little more noise abatement.

I do know that the older I6 Jeeps make a lot of RFI, especially ones with plug wires. This said, I believe an unNB level of S7 can be improved with a little work.

Have you done any bonding?


Title: RE: HF mobile, which rig?
Post by: KC8AHN on January 05, 2011, 04:08:30 PM
Lots of things to consider here. Again, i must consider that I am on a budget (most of us are, I am just getting back to work after being off for 2 months due to an injury) and am just wanting something reliable.

When I make my trips down south, I want to be able to check into some of the nets on 40 if it is open (Specifically SouthCars since I will be in the south and maybe the Nightwatch net if I am out in the evening). I like 20 for longer range and DX, and I understand I should not expect to work DX with a hamstick set up). I may use the rig as well in my home. Currently I have the FT450, I do not have anything to compare it to, but it seems hard to beat, except it is too big for mobile use.


Title: RE: HF mobile, which rig?
Post by: AD4U on January 05, 2011, 05:44:19 PM
Just remember, even if you elongate a 15 meter hamstick to operate on 20 meters, you're still nearly 20 dB under a decent, full-sized screwdriver.


I wonder if even a dummy load is 20dB down from a screwdriver.  I do not use Hamsticks because I think there are better alternatives.  I use the original big ugly Texas Bug Catcher.  What I was trying to present is that you can improve the performance of Hamsticks by doing as I suggested.  It still probably won't make a Hamstick top dog on the mobile venue by a long shot, but it does improve its performance.

Dick  AD4U


Title: RE: HF mobile, which rig?
Post by: N5MOA on January 05, 2011, 06:19:33 PM

and I understand I should not expect to work DX with a hamstick set up).

You can work some dx with a hamstick, I don't think anyone suggested you wouldn't.

If they did, they are mistaken.

Hamsticks aren't the worst antenna around, they just aren't anywhere near the top of the list. At least not my list. :P

After getting your radio setup, and operating with a hamstick for awhile, you may find it does all you want to do mobile. If not, there are other antennas that do, imo, a better job you can upgrade to.

As others have mentioned, the antenna install is the most important part of operating mobile.

A hamstick, properly installed, will most likely function better than the latest greatest whiz bang screwdriver or bug catcher installed improperly.

73, Tom
N5MOA

 


Title: RE: HF mobile, which rig?
Post by: K5LXP on January 06, 2011, 06:10:10 AM
I proudly operate one of the poorest HF mobile antennas there is, the ATAS100.  It "works", and so do hamsticks.  It all depends on your expectations.

For me, it's just a diversion while driving, not a contest flamethrower.  I spend probably 80% of the time just listening.  In the past two months I've driven about 5000 miles on trips to TX and WI, and had a lot of fun with this sucky antenna.  Worked a couple dozen zones during CQWW (even JA's on 40M), contacts with MIDCARS, and general QSO's and special event contacts on 20 and 17M.  This past trip over Christmas I had fun in the Rookie Roundup and SKN in addition to numerous CW and SSB skeds with the folks back home while enroute, and a bonus QSO with eHam notable WB2WIK on 40M CW.  You don't need to be busting pileups to have fun with HF mobile.

The only problem I would have with hamsticks isn't so much the performance but the issue of being stuck on one band.  During any given trip it's inevitable that you'll have the "wrong" antenna on the car and you'll either have to stop at the side of the road or wait until the next gas stop or whatever to switch antennas.  I would recommend buying/homebrewing a hustler-type "spider" setup with two or three resonantors on it for the bands you think you'll be on the most, say 40 and 20.  Screwdrivers aren't necessarily all about performance (though it can be nice) but convenience as well.  Swapping coils and masts all the time gets old.

You need to start somewhere though, so get the rig installed, do your chassis bonding and as you gain experience you can optimize your antenna setup to a system that works for your style of operating.


Mark K5LXP
Albuquerque, NM


Title: RE: HF mobile, which rig?
Post by: K0BG on January 06, 2011, 06:42:59 AM
As Mark alludes to, you can make contacts with a lousy antenna; millions of amateurs have been doing that since day one! You just have to decide which is best for you.

I use a Scorpion 680, which I believe is the best made of all of the remotely tuned antennas. I suspect its average coil Q is equal to, or better than, any other commercially made antenna. It sports a cap hat few mobile ops would tolerate. There are remedies applied to control common mode. The vehicle SLI, and remote battery are both BCI size 34 AGMs, supported by a 130 amp, continuous alternator. And, I use an amplifier.

I often hear or read where other mobile operators have an S6 or higher noise level, and are forced to use the NB 24/7 as it were. I have essentially zero QRN from the vehicle itself, because I've spent the time and money to make it so.

So what are you after? As I said, that is your decision.


Title: RE: HF mobile, which rig?
Post by: KC8AHN on January 06, 2011, 05:14:47 PM
Thank you all for the replies. I beleive I mentioned but may not have, this is just for fun, something to do while I drive the many miles up and down the interstate, maybe to keep me more awake, maybe to just have come "company" on the long road trips. I have a 2m/440 in the car that was near useless when I made my trips last year, I do not want to deal with that again. I am not looking for a contest mobile station, just something fun.

Typically I leave on my trips between 5-7am, arrive in Memphis (if that is my final destination) around 3-5pm. My first trip last year did not have me leaving until after 1pm and I made Memphis by midnight. I may go into Dallas directly which is about a 19 houir trip, gotta have some company along for that.


Title: RE: HF mobile, which rig?
Post by: K0BG on January 06, 2011, 05:27:47 PM
I can relate to that. When I started operating mobile back in 1972, I was traveling nearly 75,000 miles a year, over 7 states. A couple of years later, and it was 100,000 miles, over 12 states. Although there were a lot of auto-patches back then, 2 meters got boring rather quickly, especially when you were 100 miles from the nearest repeater. As a result, 20 meters was the place to be. By 1977, the sun spot numbers were so good, 6 meters was open 24/7. An old HyGain loop, and a Gonset, you could work WAS in about a week if you were active enough.

It was about this time, I discovered that an average mobile setup was just that—average. If you really wanted to compete in the DX chase, you needed to work CW, and you needed a large antenna, and lots of PEP.

If your needs are less, then go for it. But don't chastise someone for wanting more.


Title: RE: HF mobile, which rig?
Post by: KC8AHN on January 06, 2011, 05:31:30 PM
K0BG, you wont find me chastising anyone. I commend those like you with great set up's, and the resourses you provide are top notch as well.

I would love a top notch set up in my car (heck, even in my shack) but my budget will not allow for it. Being a single parent (I am primary parent for one of my kids) and paying child support, I just do not have much extra income so I must do with what I can.


Title: RE: HF mobile, which rig?
Post by: AD4U on January 07, 2011, 06:03:55 AM
Between Christmas and New Years, I drove my "little truck" 450 miles from SC to Va Beach to visit my two grandchildren.  Since I was driving alone, I operated HF mobile much of the 7 hour trip to pass the time.  

In my "big truck" a Ford F-250 diesel, I run the original big ugly Texas Bug Catcher, an ICOM 7000, and a 600 watt Metron Amp.  IMO this set up puts out a very respectable and competitive mobile signal, equal to most.

In my "little truck" I use a Yaesu FT-100D barefoot and the Hustler 54 inch mast and several different Hustler resonators.  During the trip I operated 40 meters exclusively.  My 40 meter antenna consists of a 30 meter Hustler resonator with a LONG whip to make it work on 40 meters.  Again (IMO) more antenna and less coil = a better mobile signal.

Even though the Newtronics Hustler antennas are not very highly thought of by some, I am completely satisfied with the results.  I had a number of stations on 40 meters comment that I was so strong (compared to other signals on the band - moblie and fixed station) they did not believe that I was actually mobile.

I know that band conditions play a very important part in mobile success, but it just goes to show that even less than optimum mobile antennas can still radiate a decent signal and you can have fun doing it.

Dick  AD4U

PS:  Although I have never done a side-by-side comparison between the "set-up" in the "big truck" VS the "little truck", I feel the 600 watts and the Texas Bug Catcher in the big truck would be consistantly around 2-3 S units stronger than the 100 watts and the Hustler antenna set up in the little truck.


Title: RE: HF mobile, which rig?
Post by: K5LXP on January 07, 2011, 07:30:47 AM
KC8AHN, you have have your cake and eat it too.  You can start out with economical hamsticks or Hustler coils and then in the mean time, build someting that offers better performance and more convienience.  You can build masts and high Q resonators using home improvement store materials very inexpensively, or even free if you have the materials on hand.  You can even build a decent performing screwdriver antenna if you like.  Here's a site with plans that are pretty easy to follow:

<http://www.mobilescrewdriverantenna.com/index.html>

You could build one of these for less than the cost of a couple of hamsticks if you're resourceful.

I respect Alan's position of optimizing performance.  Like most things though there is a point of diminishing return vs your level of expectation.  Like you, it's just a diversion while driving for me and most often just listening to CW, a net, or a shortwave station is sufficient.  Any QSO is fun, doesn't matter if I'm 599 or 539.

I think more important than anguishing over details and having the "best" right out of the chute is to start with something, anything.  Once you gain experience you can build on your success and make changes and improvements over time which is fun, challenging and rewarding. 


Mark K5LXP
Albuquerque, NM


Title: RE: HF mobile, which rig?
Post by: AA4PB on January 07, 2011, 07:43:08 AM
I'd be willing to bet that a properly installed Hamstick is not 20dB down from a screwdriver on 20M (75M is a different story). If you were running S9 on a Hamstick, switching to a screwdriver would make you 20db/S9. In playing with Hamsticks, I don't see that much difference with a full sized 20M dipole.



Title: RE: HF mobile, which rig?
Post by: KC8AHN on January 09, 2011, 02:24:52 PM
Looks like I have an IC7000 coming. I found a deal that was too good to pass up so once the funds are here, I am buying this rig. I just need to get use to it here in the house before I take it to the car.


Title: RE: HF mobile, which rig?
Post by: WD5GWY on January 10, 2011, 02:03:10 PM
You will like the performance of the ICOM 7000. I have one and it
is a great radio. One thing to note, if it seems to be hotter than
some rigs you have used in the past, it is. But, unless you
are blocking air passage, and not allowing the internal cooling fan
to work properly, then you should have no problems. I was worried
about that and it turns out after doing some temp checks that it was
well within specs for operating temps.  (you can always put an external
fan directed over it (don't block the air path for the internal fan, that'll
create problems) and cool it even more.
  Once you get it set up the way you want it, you will not need to access
most of the menus very often.
Have fun.
james
WD5GWY
 


Title: RE: HF mobile, which rig?
Post by: KE5DFK on January 10, 2011, 02:35:46 PM
Carlos, you're correct. For the money it is hard to beat an Hx. However, if you have to use the noise to quell the level as you've done, perhaps you need to do a little more noise abatement.

I do know that the older I6 Jeeps make a lot of RFI, especially ones with plug wires. This said, I believe an unNB level of S7 can be improved with a little work.

Have you done any bonding?

Alan, whip me with a wet noddle no I have not bonded  :-[.  I have been on your site over and over again and read what I need to do but have not done it.  It is an I6 2001 Jeep no plug wires it has the rail system.  The only "grounding" I have done is to have separate 1 inch ground straps, one for the radio and one for the MFJ-993 auto tuner, both to the same bolt.  I did bond the doors, maybe the hood also.

Carlos
KE5DFK


Title: RE: HF mobile, which rig?
Post by: N4SXX on January 18, 2011, 05:51:07 PM
sorry I did not read if anyone made this suggestion SO   I run a nice set-up for me it has been in several autos it is the Icom 706Mk2G with a screwdriver antenna the rig has a detachable face which make mounting very discreet for me right now it is mounted behind the seat ( rig ) face in console antenna control also in console I am now driving a small pick-up and before this it was in a 1987 BMW 325is


Title: RE: HF mobile, which rig?
Post by: W2RI on January 19, 2011, 08:03:57 AM
The Icom 7000 is a great rig. As James mentioned, it can run hot, but it can show the internal temperature on the main display so you can keep an eye on it. Unless you're doing a digital mode at full power for a long time it shouldn't be an issue.

I'd recommend you join the Icom 7000 mailing list on Yahoo : http://groups.yahoo.com/group/ic7000/

Good DX !

-- Brian


Title: RE: HF mobile, which rig?
Post by: ZENKI on January 21, 2011, 01:22:54 PM
I would go with the TS480HX, the extra 3db is well worth it mobile. Try and improve your antenna system by 3db! Using a TS480HX you will  need to run at least a 1kw amplifier to notice the difference. I  have a 1KW mobile amplifier installed, now with the TS480HX I hardly turn it on!

As for the antennas. All these expensive screwdrivers are big heavy contraptions. They are all very expensive, you looking at investing 1000 dollars or more just in an antenna system. You also bolting on a massive heavy contraption to your vehicle just for the convenience of band changes.  If I was a serious low band mobile dxér I might consider using these big heavy  contraptions.
For 20 and 40 meter dxíng there are many choices that are as good. Even a properly installed Hamstick in the center of the  roof well grounded will just about be equal with these big heavy muscle antennas.

I personally did not think all that effort and heavy hardware was required. The way most people install their screwdriver antennas they are just wasting performance and money. My homebrew  helical antenna mounted in the center of the roof has beat many of these  "super space age and mil spec" screwdrivers in shootouts and pileups running barefoot. Because they are big heavy contraptions most people do not install them correctly. Its far easier doing a proper install job on a light antenna  than a big heavy one. Thats why most people  install these big screwdrivers poorly because they are big fat heavy contraptions.

I just homebrewed  the best center loaded antennas that work as well and better than most screwdrivers. I like 20 meters and 40 meters mobile and  have monoband  coils that work very well. I also  have a  homebrew helical wound antenna that when mounted on top of the roof performs as well as my mid mounted  12 foot long center loaded whip and works better than most screwdrivers.

The only screwdriver I would consider buying  or building would be  the one made by VE6AB as seen on K0BG's web page. This looks like a well engineered screwdriver that could be lighter that the 20 pound Scorpion which stings you in many ways.  I wish VE6AB would produce this antenna commercial and offer a Titanium version! When you drive on roads with no speed limits the last thing you need is a 20 pound antenna exerting lots of pressure on your expensive car, it would be even worst if the antenna broke its mount.  I have driven with my  light loaded coil antenna at well over 200Kph without any problems. Screwdriver antennas seem like a good idea for MAC trucks and Hummers!


Title: RE: HF mobile, which rig?
Post by: K0BG on January 21, 2011, 01:51:57 PM
The antenna you're referring to was made by Jerry Clement, VE6AB. I haven't ask him specifically about what it cost to make, but knowing how it was made is enough. I suspect if it were made commercially, you'd be paying in the neighborhood of $2,000. The bottom portion is spun closed, and not everyone has the equipment to do that sort of work. Probably the most unique part if the operating motor, which is a linear actuator, mounted outside the antenna itself.

As for the 3 dB from your antenna.... Actually that is quite easy to do on the average vehicle installation. While we all think our specific install is super special, the fact is, most aren't. I've seen screwdrivers installed where there was no motor lead choke to be seen, which makes you wonder about the rest of the install. The same goes for common mode chokes.

Another issue, universally overlooked, is the generated SNR; both transmit, and receive. It is easy to present a case wherein one dB increase in transmit power can make the difference between a QSO, and not. Reducing localized RFI is just as important, but is often overlooked as well.

It all boils down to just how far you're willing to go. If an ATAS mounted on a K400 is your cup of tea, that's great, but it isn't mine!


Title: RE: HF mobile, which rig?
Post by: W3LK on January 22, 2011, 12:37:01 PM
Screwdriver antennas seem like a good idea for MAC trucks and Hummers!


I drive neither; I drive an '03 Ford Windstar with a High Sierra HS-1800Pro on it and have no problems with anything. There's two photos of the installation on Alan's photo gallery. It's been on the vehicle since it was new, and on a similar Windstar for two years before that.

73,

Lon - W3LK
Naugatuck, Connecticut


Title: RE: HF mobile, which rig?
Post by: WZ3O on February 07, 2011, 01:15:34 PM
OK, time to "wade in" with my 2¢s..........

I own an IC-7000, great rig but a bit pricey for mobile....will do anything you ask, but is a compromise on 2M/440......

The Kenwood TS-480 (SAT/HX) another nice rig, had one liked it, a bit big regardless of separation capability?.....

The Yaesu FT857D with separation kit is, IMHO, the most "bang for the buck", with many convenient mounting options ("read" small spaces, etc). Also had one mobile, nice small package with tons of features on all bands... Decent HF, 2M, 440,etc.....Only needed one rig in mobile.....

OBTW, all but the 480 SAT need a tuner or resonant antenna........I'm sure you knew that....

And "YES", to paraphrase a Real Estate saying, "antenna, antenna, antenna"............& WELL GROUNDED!!!!!!!

Have fun, enjoy DX mobile, I do, it's cool...... ;)


Title: RE: HF mobile, which rig?
Post by: K0BG on February 12, 2011, 04:19:47 PM
Gee. I've been at this mobile thing for about 40 some years. In all of that time, I have never seen a grounded antenna that radiated! Oh! Oh! Sorry! Maybe I misunderstood.

Any antenna will operate properly without any ground whatsoever! If I take a rig out to field day, string up a vertical with elevated radials, power the radio with a battery, it will work very well. This said....

I have to assume you mean that the antenna in question has to have a ground plane under it. Oh! Oh! Maybe not!

What I think most people mean is, the mount (!!) must be grounded, even if it is attached to a trailer hitch! Well, even if it is, that in itself doesn't mean adding a ground wire from the mount, back to the frame of the vehicle is a direct replacement for an adequate ground plane under the antenna! Well, it isn't!

The real secret is very simple. It is the metal mass directly under the antenna, not what's along side, that counts!


Title: RE: HF mobile, which rig?
Post by: N6PG on February 19, 2011, 12:00:42 AM
I think you can't go wrong with any of those radios.  Whatever is the first "good" deal on the used boards might be a good decider.  I have the FT-857, and I'm very happy.  I would recommend the mic with the DTMF pad.

I agree that the antenna is very important, but don't let it distract you too much.  As someone else pointed out, many hams have been making contacts with inefficient antennas for a long time.

When I got my 857, the owner GAVE me his ATAS-120.  You can read the reviews to see how much people don't like it... but you know what... I mounted it up high on the car, gave the antenna mount a good ground, and I have talked to Japan, Indonesia, the Falklands... all on that "terrible" antenna.  The good news is that it's such a low profile antenna, that my wife doesn't mind it on her car.  It isn't an eyesore.  The 857 adjusts and tunes it automatically... and it does the job.  One antenna on the car for 40 meters to 440 Mhz!  I know you can't defy physics, so it isn't the best across all bands, but it certainly works.

BTW- The 857 only draws .5 amps on receive.  That's a lot less than the icom.  You can take the 857 camping and set it up with a buddipole antenna and one of their great power pack batteries and operate for a long time.

I think any setup will provide you lots of fun... but you will always be looking at other setups and wanting to change what you have!  Let us know what you end up with.
Enjoy.
73's
Scott


Title: RE: HF mobile, which rig?
Post by: AF6WI on February 19, 2011, 01:25:16 PM
As another has said, I don't think you can go wrong with the radios mentioned. I use a TS-480SAT, which sits on my desk at home when I'm not mobile, and which works fine when I'm out camping with the radio.

I use a Tarheel screwdriver. I find it puzzling to see it referred to as a heavy contraption, but to each his own.

My suggestion is to see if you can find a radio which gives you multiple uses. I use the TS-480 as my home radio, my on the road radio, and my camping radio, so I get more use out of it than just in the vehicle. The Tarheel works fine, although it's somewhat directional since the antenna is not mounted in the center of my roof. It's mounted in the back and points more towards the front, over the metal roof. I live in California, and I've used it on my vehicle to work stations on the East Coast (Rhode Island, Florida, for example), as well as points in between.

All radios and all antennas are compromises, so you have to find the compromises that work more nearly in your favor and that sacrifice things you care less about. The TS-480 is bigger, but it dissipates heat better. The screwdriver may not be as good on any particular band as a dipole cut for the band, but I just push a button in the cab to tune the antenna to a different band where I can reach out and talk with someone. I don't have to stop, get out, switch sticks, etc. That's a compromise I'm happy with, given that I can work stations all over the US from my vehicle.

I have the Tarheel Model 100, and it doesn't seem heavy to me, although it is of course heavier than a stick of whatever brand tuned to a specific band. I have no objection to those, but I'm happier changing bands from the cab on the roll if some particular band is crappy and another is hot - I just search while on the road. I've never thought of my Tarheel as a heavy contraption, but that's because I get my intended use from it. Others may not; your mileage will vary.

If I may suggest, stop thinking about it and go buy stuff. Get on the air and see what works for you and what works against you. Then you'll be here giving your advice. :->

Everyone tells you what works for them, and then assumes it will work just as well for you. That's sometimes not the case.


Title: RE: HF mobile, which rig?
Post by: K0BG on February 20, 2011, 07:26:36 AM
Quote
Everyone tells you what works for them, and then assumes it will work just as well for you. That's sometimes not the case.

I'd say it isn't the case 90% of the time. If you look at the specs for all of the late-model made-for-mobile transceivers, they're very close. What difference there is probably won't be noticed by the average operator. Where the difference really shows up is in the use of the radio. I personally find the FT857 a difficult radio to operate (yes, I have owned one). The IC7000 is a bit better as far as the menuing goes, but it too needs some improvement.

The same things can be said for antennas, and how they're mounted. Everybody seemingly brags about their low SWR, the DX they've worked, shootout results, and similar mundane references.

However, as alluded to in the quote, your seemingly identical install may indeed end up as nothing more than a static receiver! It is the classic example of effort vs. results, and too darn many just won't extend the requisite effort.