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Author Topic: Recommendation for 'all-band' mobile transceiver?  (Read 1394 times)
KD0EIL
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Posts: 23




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« on: June 24, 2008, 01:07:07 AM »

Having obtained my general class license, I've been seriously looking at an HF radio and I have to say I'm rather lost.  I'm a beginner HAM and I'm concerned I'll buy something and then regret it (at least to the extent that I could have bought something with many more features for just a bit more $$).

I initially planned on using a Yaesu FT-8900 as I liked several of its key features, specifically (1) cross band repeat - I plan to add a hand-held in the next month or so and would like the extra boost when operating outside the truck; (2)the ability to listen to one frequency while scanning another band; (3) the ability to receive so many commercial and public service frequencies rather adding a dedicated scanner.

However, after getting my General Class License, I've been looking at the Yaesu FT-857 and FT-897 radios.  After a lot of reading on eham.net I've also been looking at the Icom IC-7000 but it sounds like the IC-7200 could be approved and available any day now (or so the story goes for the past year +).  Likewise, it seems the Yaesu models are due for an update.

Basically, it seems foolish not to buy something with the widest possible band coverage that my license allows - and that means the all-band radios, which will satisfy the scanner-like ability to monitor commercial and public service bands, but it appears I will lose cross-band repeat and dual receive in order to gain the full HF spectrum.

So, any recommendations other than what I am already considering?  And what's the vote between these?

On the financial side, I'd originally hoped to keep the cost under $500 but that now seems unrealistic once a quality antenna is added, so I'm now hoping to stay below $1200 for the mobile rig and antenna(s), with another $500 planned for the hand-held and accessories.

Which reminds me, I still have no idea which way to go regarding antenna(s) for the rig.  My preference is for a single antenna which seemed possible with the 8900 (though the reviews on the quad antennas are mixed); whereas the all-band FT-857/897 and the IC-7000 seem to require at least two antennas and possibly at a higher cost (I'm looking at the Atlas-120 and the Tarheel II plus Huh? for the other bands).

I don't have space or need for more than one rig in my vehicle(s), but I guess I could install the 8900 in my Landcruiser for off-road use, and then install one of the all-band rigs in the 'family truckster' Yukon XL for those long family road trips (though I'd rather just buy one radio and move it between vehicles given that I really only drive the Yukon for family trips and the Landcruiser only sees abut 8k miles annually).

Better still, I could move the all-band radio from the Yukon to the house for use as a base station - but that just leads to more time and money for a base antenna (not to mention the research time to determine which base antenna to go with . . . ).

You can see how this all just gets out of control - its almost as bad as determining which tire to buy or which lift to install or . . . .. I must have an undiagnosed mental condition.

Any advice is appreciated.
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N8EMR
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« Reply #1 on: June 24, 2008, 05:19:02 AM »

Find a radio in your budget, buy it, use it and as you gain experience in what you need you can always sell off the radio and move up or down. For a new ham just wanting to get on the air, aside from staying away from QRP, no radio is bad. Not that QRP is bad, just not where I would start a new ham.

Get on the air, see what areas of ham radio your interested in. After a few years you will know more of what you want to do in ham radio and can purchase radio'
s to meet those needs.
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K3GM
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« Reply #2 on: June 24, 2008, 05:50:49 AM »

Couple of thoughts:

Mobile HF isn't a cut and dry installation, and I'd say it's a considerable undertaking for a beginner.  Along with the radio and antenna install, meticulous grounding of the vehicle's body parts, exhaust system, and chassis is required for effecient operation.

Based on your budget, I think you'll come up short going the IC-7000 route.  You won't have enough for a decent antenna and mount.

The idea of hauling the radio back and forth between the house and vehicle sounds reasonable, but gets tired real quick.  You're going to want to secure the radio and the control head in vehicle so it doesn't slide around.  The idea of putting it on the seat or some other easily removed location just won't work, and is actually dangerous in the even of a collision.  You'll finding yourself disconnecting and reconnecting cables, coax, and unscrewing radio components from their mounts.

If I was just starting out, I'd choose something thats relatively easy to install and operate.  Using your example radio, the FT-8900 I'd mount the head separate from the relatively small body.  I would avoid the antenna which is designed for the '8900 and install a dual or tri-bander for the upper 2 or 3 bands, and a second whip for 10 and/or 6.  Use a diplexer to accomodate two roof installed NMO antenna mounts.

Regarding your intended use of the cross-band function.  Unless I'm mistaken or misunderstanding your comment, you cannot use it as you intend to.  It won't function as a portable repeater as you seem to describe above.

What year is your Yukon?  If it's at least an '07, you can get some pictures from my Tahoe installation on K0BG's web site.  Good luck with your decision.
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ZR1PJA
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« Reply #3 on: June 24, 2008, 06:14:33 AM »

You will not regret a IC-706 with the AH-4 with a whip and also a diamond dual band antenna for VHF/UHF. I have seen numerous of these installations in Africa including mine, and are bullet proof. The only issue I have had is that the whip tends to curl up at the tip when doing heavy driving in the bush. When stationary, we use a piece of wire 67' long clamped onto the spring of the whip with a battery clamp from a jumper lead and strung out. Those fancy antennas with working parts outside of the vehicle just dont stand up to African conditions.
Good luck and enjoy.
Paul
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K0BG
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« Reply #4 on: June 24, 2008, 07:26:35 AM »

You, and hundreds of other folks, ask for opinions about what radio to buy. And that's what you get, opinions. The correct radio is the one which fits your needs, your budget, and perhaps even your fancy. For several reasons, the limiting factor when operating mobile is background noise. As a result, there isn't much difference in performance between any of the top selling transceivers. That said, those with IF based DSP (IC-7000, FT-450) work somewhat better than the AF based ones (IC-706, FT857D). There is also a difference in cost, so the aforementioned criteria rules.

As for antennas. An AH-4 driving a CB whip, mounted in the best of locations, isn't any better than a Hamstick performance wise, and you can't work 80 or 160 with it unless the radiating element is about 60 feet long. The ATAS 120, while the largest selling, single model antenna in the world, it is one of the worse performers, and is about 10 dB down from the AH-4/whip combination, best case.

Length matters! A 9 foot antenna has twice the radiation resistance of a 6 foot one, and over twice the efficiency. The higher the coil Q the better too, but once the Q gets above about 250 to 300, doubling it (you can't actually) wouldn't buy you anything.

The most important item in HF mobile antennas, is the ground plane under it. Thus, it is the mass under the antenna, not along side, that counts. Although lots of folks use trailer hitch mounts, performance wise, it is one of the worse places to mount an antenna.

As stated in a previous post, there is a lot more to HF mobile than tossing the radio in the car, and sticking on an antenna where ever. If you want the rest of the story, visit my web site.

Alan, KØBG
www.k0bg.com
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KD0EIL
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Posts: 23




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« Reply #5 on: June 24, 2008, 02:55:29 PM »

First, thanks for the responses - I appreciate each and every one of them. I've spent a great deal of time on similiar technical forums (though not HAM) and I fully understand the feeling of "I can't believe this bloody new guy is asking this question" and the related lack of desire to bother wasting your time to even read the full text, much-less answer. Again, many thanks.

Second, I'll try to address some of the points/suggestions and, in the process, refine my needs and clarify my current stage of research.

N8EMR: You're definitely correct - I just need to make a decision and get moving! I've known for far too long that I suffer from obsessive-compulsive-pre-purchase-research. I'm the idiot who is nearly crippled by the need to research everything I buy to make sure my choice is the "best." I'm trying to overcome it, but with so many options, bells & whistles in this area of equipment it is difficult to just take the plunge and buy something. I've been lurking here and elsewhere for over two weeks (several hours a day) and figured I just need to buy something and get moving - which is what led to this post.

K3GM: The difficulty of the installation and the possible trouble issues does have me a bit concerned, but I think I'm up to the task - though I'm certainly no expert in this area, and I'll be the first to acknowledge that I haven't mastered all the technical information required for a General class license - I'm just skilled at learning (not memorizing) rules and other large amounts of info quickly. I don't fully understand all the electrical and antenna related information, but I was lucky in that my exam had very few questions in this area that were of the more complicated nature.

On the financial side, I wasn't very clear. I don't have any particular budget - I was just sharing what I originally expected to spend vs. what I expected to spend at the time of the post last night (vs what I now expect to spend :-). I've long ago accepted the fact that I spend way too much time and money on the few hobbies I pursue, but I'm OK with that. I don't want to spend money on something I'll never use, but I'm perfectly OK spending $2-5k instead of the $500 I initially expected if that yields features that will make my experience much easier and, therefore, better. Likewise, I'm not interested in spending $5k on two duplicate setups for two vehicles that I rarely drive even though it would be easier in that I wouldn't need to transfer anything. I'd rather just spend half that (or less) on one excellent setup that I can occassionally transfer between the two vehicles (I'm thinking 2-3 times per year max).

I certainly agree with your point about not hauling around a radio. My initial plan was to mount the 8900 in the rear of my landcruiser and use the seperation kit to locate the face and mic up front on a fixed mount (overall, similar to this:   http://web.mac.com/alvarorb/I_know_what_I_like/My_Albums/Pages/FT-8800_Install.html#grid ) but with easier access to the main unit so I can move it a few times a year to another vehicle. Then duplicate the setup in the Yukon XL and simply move the rig and antenna from the landcruiser to the yukon for the 2-3 long family trips we take each year. In both vehicles, everything would be hard-mounted. I really have no desire to leave a setup in the Yukon as our nannies drive that vehicle for 'kid transportation' duties and I don't want to worry about someone damaging or otherwise messing with an expensive radio and/or antenna.

Still, your suggestion and my original thought that the 8900 in this setup might be a better starting point is very valid.

On the issue of cross band repeat functionality, I'm in no position to argue as I'm as new to Ham as anyone and you've got significant experience (with this radio it seems). My understanding came from the Yaesu and many other retail sites and the discussions on various forums. Basically, my understanding is that with the 8900 properly configured, I could use a hand-held at 5w or less outside the vehicle and hit one side of the 8900 and then have it transmit on the other side at up to its 50w limit. This would obviously tax my three-battery setup in the landcruiser (and single battery setup in the Yukon even more), but would be fine for limited out-of-vehicle work when needed. I'll continue researching this issue to make sure I've not misunderstood the cross-band repeat feature advertised by Yaesu and their resellers.

ZR1PJA: Good to hear what setup is working in heavy brush and off-road scenarios - as those are the conditions I'll be using mine - Thanks!

K0BG: I was certainly hoping you would respond and very much appreciate your input. I've spent a lot of time on your site and learned a great deal (though I've only scratched the surface).

As you note, opinions are all I'll get and that is exactly what I wanted. I'll make the final decision(s) based on the many factors you mention and others, I just wanted to make sure I hadn't missed anything that others used in forming thier opinions. In particular, your statement that "those with IF based DSP (IC-7000, FT-450) work somewhat better than the AF based ones (IC-706, FT857D)" was very helpful as I wasn't aware of this - exactly the type of info/opinion I was seeking (thanks!).

On antennas and mounting, I'm afraid it is still too early for me to ask questions as I'm still researching and learning (mostly from your site). All of your comments are excellent, and I think I fully understand them all).

To clarify one point, you state that "The most important item in HF mobile antennas, is the ground plane under it." I think you actually mean 'image plane' but I want to be clear so I don't misunderstand.

My only experience with mobile antenna systems is from the CB world (collective argh!) which I entered to communicate with the off-road groups and only long enough to determine that there must be something better - which is how I discovered amateur radio. I'm not shy about drilling in any of my vehicles and have already done so to accomodate CB antennas. However, the top of the vehicle roof is not an option as it is completely covered by a roof-top tent and other gear on the landcruiser and a roof-top carrier and a mobile satellite dish on the Yukon (yet another potential interference problem with installation in that vehicle).

I have no desire for a hitch mount antenna. With the CB, I had success on the Yukon with a channel mount on the DS of the front hood, using the hood as an image plane. I had no RF or DC grounding issues, though the amount of 'stuff' on the roof-top did noticeably affect the transmit and receive. I used a 4ft Firestick (another collective argh!) on a quick release mount so that I could get more height to clear the 'stuff' on the roof but remove it most of the year when not in use. My plan was to start with a similar mounting location and see how it works, then make adjustments as needed.

On the Landcruiser, the same channel mount on the same position of the hood yielded very poor results regardless of tuning. I ultimately moved it to the front ARB bumper fully knowing I would have a DC ground issue. The DC ground issue was resolved with significant bonding. I *think* the image plane remained the large hood of the landcruiser, but this is one area I'm still not clear and further research is required. When mounted on the front ARB bumper with sufficient bonding to cure DC grounding, the mount and antenna are above the hood, but also beside it - so I'm uncertain if this meets the definition of image plane layed out on your site. I think it does, as the radio/antenna setup worked very well once tuned in this location (given the limits of CB) and the ARB front bumper provides a very sturdy mounting point. For this reason, I also plan to begin by mounting the antenna on the front ARB bumper and see how it works.

Again, thanks for all the responses and help.

73,
KD0EIL
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K0BG
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« Reply #6 on: June 25, 2008, 11:35:35 AM »

Bill, you're quite right, it is image plane, but most folks just don't get the picture. The other issue is, there are so many diverse things we call ground, and even one of those you missed.

The easiest way to express it is this; it is the mass under the antenna, not along side, that counts. Most amateurs wouldn't think about installing a resonant dipole or G5RV with the legs parallel to one another, but they don't think twice about doing so mobile! So in order to make up for the lack of mass under the antenna, they add a ground strap. Apparently, in the mistaken notion that the strap will suddenly make up for the lack of a decent image (ground) plane. Such isn't the case.

What's more, the image (ground) plane losses are the most significant, and way ahead of a high coil Q, albeit that's important to a point.

They also don't get that length matters. Increase the length by 50%, and you increase the efficiency by more than double. That is, if you have the requisite image (ground) plane under the antenna, not a substitute ground strap.

In the end, they justify their position by expounding how many DX stations they've managed to work.

Thankfully you're not in that group, and realize that the seven Ps are the only way to go!

Alan, KØBG
www.k0bg.com
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KD0EIL
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« Reply #7 on: June 25, 2008, 01:12:54 PM »

Alan,

You and the others here have been a great help.  I still have only a very marginal understanding of antenna theory, but I'll keep working on it.  As others have mentioned, I am at the point that I just need to buy something and start using it, as I think that will help me better understand some of the antenna theory (both mobile and base).

The only pressing question I have regarding mobile antenna theory is whether an antenna mounted on a front ARB bumper that is sufficiently bonded to the vehicle frame can use the vehicle hood as an image (ground) plane?

As I can't add a picture or drawing here, maybe a reference to a more common mount will help.  If an antenna is mounted using a hitch on the rear of a sedan, and the coupling is raised to a point slightly above the sedan trunk lid with the overall height of the antenna above both the trunk lid and the sedan roof, will either the sedan trunk or the roof provide sufficient image (ground) plane?

73,
William
KD0EIL
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K0BG
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« Reply #8 on: June 25, 2008, 01:29:16 PM »

The easiest way to understand where the image lane starts is where the coax attaches to the antenna. If it is a post, or elongated bracket, the losses go up, and some times by a magnitude.

If just want to get on the air, just about anything will work to some extent. If you don't want to spend hundreds, then by a Hamstick and wish for the best.

Alan, KØBG
www.k0bg.com
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K3GM
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« Reply #9 on: June 25, 2008, 08:11:40 PM »

"The difficulty of the installation and the possible trouble issues does have me a bit concerned, but I think I'm up to the task..."

That's really a good attitude to have.  But, assuming you know NOTHING about the installation and operations of a typical transceiver, you are going to have your hands full with the 4 bands the FT-8900 offers.  My concern is that you will be overwhelmed with the proper installation then operation of an all band, mobile transceiver.  I'm not trying to sell you short.  But I'd like to see you get on, and get talking, and not have to worry about the problems associated with mobile HF and the discouragement that may follow if you get dismal performance.

Here's an alternative idea.  You could get an all band transceiver like the IC-7000, and for the interim concentrate only on the VHF and UHF bands.  Spend a weekend installing the antenna or antennas, routing the transceiver's supply line and then get on and start operating, load the memories with area repeaters, and simplex frequencies.  Then, once you feel comfortable with the gear and operating you could begin to dabble with HF.  Perhaps screwing down a 10 meter antenna on your mount, and trying some side band operations before moving on to the lower bands.

Speaking of antenna mounts.  Assuming you're going to have 2m and 70cm in your vehicles. I think we'd all agree that the recommended mount is the NMO style.  Avoid the urge to slap a mag mount on the roof, and spend a day installing a permanent NMO mount.  You'll need a preferably a 3/4" Greenlee chassis punch, or an Antennex hole saw.  You'll also want a genuine Larsen NMO mount, and not a cheap off-shore version.  Regardless of which direction you choose to go, you'll want to get one or two of these in your roof for VHF/UHF operations. Start now scoping out locations for your mount(s).  A good place to begin is just above the dome lights. Enjoy!
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