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Author Topic: HF mobile, which rig?  (Read 9529 times)
KC8AHN
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Posts: 108




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« 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.
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N5MOA
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« Reply #1 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. Tongue

73, Tom
N5MOA
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AD4U
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Posts: 2153




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« Reply #2 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
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W1ITT
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Posts: 145




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« Reply #3 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
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K0BG
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« Reply #4 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
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KC8AHN
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Posts: 108




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« Reply #5 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.
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AD4U
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« Reply #6 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
« Last Edit: January 04, 2011, 05:23:23 PM by DICK WHETSTONE » Logged
KC8AHN
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Posts: 108




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« Reply #7 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.
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K0BG
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« Reply #8 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.
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WX7G
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Posts: 5922




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« Reply #9 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.  
« Last Edit: January 04, 2011, 08:12:23 PM by DAVE CUTHBERT » Logged
W3LK
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« Reply #10 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.

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K0BG
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« Reply #11 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.
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KE5DFK
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« Reply #12 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

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WX7G
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« Reply #13 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%.

« Last Edit: January 05, 2011, 01:28:47 PM by DAVE CUTHBERT » Logged
K0BG
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« Reply #14 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?
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