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#1
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I am a newly licensed technician, study for the general exam. I plan to
purchase an HF rig soon and would appreciate suggestions on a good starter rig. I am budgeting $800 for a rig and antenna. I would be happy with a good used rig but I am not sure where to start looking for information. Thanks, Jim KI6ISQ |
#2
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Jim,
Congratulations on the new ticket! Well I would suggest that you look at some of the late 1970's and 80's vintage rigs to start. Much of this gear is very capable for basic station use (CW and SSB) and may even serve you well on some of the sound card based digital modes. I found a very nice Yaesu FT-101zd at an estate sale for $75 that covers 160-10 meters (sans 60 Meters) that only required some minor repairs that I could do myself. Attend your local radio club meetings and ask around, check E-bay and the local news papers for possible sources. Be patient and you should be able to get a very nice fully working rig for $300 or even less if you don't mind fixing it. On the antenna budget I wouldn't know what to say except that the a good antenna can make a modest rig great and a bad antenna can make even the best rig worthless. Buying expensive antennas usually isn't "you get what you pay for" in terms of performance either so be careful here. Generally speaking, the larger and longer the antenna is, the more performance it will have. If you have the space and are allowed to put up antennas outside, I would suggest you build some wire antennas to start. If you can put up a G5RV or some other multi- band antenna you might be able to have a lot of fun at a pretty low cost. I think you can buy prebuilt versions of this antenna for under $200 or build your own for somewhat less. By all means, spend the time and money necessary to get an antenna system that performs well, or no amount of money spent on the rig will help you. I'll warn you that with the sun spot cycle being at the low end, it will be a number of years before HF will be as active as it's been on the higher frequency bands for long haul communications. This means that you may want to concentrate on the 80-40 meter bands from an antenna perspective right now as the higher frequency bands may be limited to mostly local communications for the time being. (You don't have privileges as a Tech on 160 Meters if I recall correctly so we can forget that band for now.) Other items you may want to consider in your budgeted items include: 1. Ground rods and ground wiring to get the best RF station ground possible. 2. Antenna "tuner" (If one is not included in the rig you buy) 3. 12 V DC power supply (if your purchased rig is DC powered) 4. Coax and connectors (For making up jumpers and antennas) Most of this stuff can be liberated from hamfests and junk sales fairly cheaply, or purchased online from a number of places. -= bob =- On Sep 21, 2:50 pm, wrote: I am a newly licensed technician, study for the general exam. I plan to purchase an HF rig soon and would appreciate suggestions on a good starter rig. I am budgeting $800 for a rig and antenna. I would be happy with a good used rig but I am not sure where to start looking for information. Thanks, Jim KI6ISQ |
#3
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Hi Jim,
While most rigs these days are at least "pretty good", I would put out a shameless plug for a rig like the Kennwood TS-830. I had the chance to go over one of those old beauties recently, and found it a sweet radio indeed. It has tube finals, and a very nice receiver. It has the Kenwood sound to boot. Lots of knobs if you are a tweaker. These can be found in the 3-400 dollar range. Other radios I've had the chance to evaluate are the: IC-761. A high quality radio. It is a big one though. But I like large radios. IC-745. Second Generation synthesized Rig. Pretty good one. Smaller radio for the day. You could go mobile with this one. IC-756 Pro - A fair radio. The Pro II is better, but probably priced outside your range. I might suggest picking up a tuner such as one of the MFJ 300 watt ones. Then get ladder line, and throw a general purpose dipole in your trees. That for my money is the best starter antenna going, and can service you long after you're a newbie. Some do not like to have to tune the antenna, but I can say that It is possible to contest with such a setup. Finally, look around and be patient, better deals come to the patient. From 5.5 years ago...... My first setup was: IC-745 - $250.00 used MFJ 949 Tuner - $129.00 new Ladder line - $30.00 new Antenna wire - $12.00 for a 500 foot reel of #12 THNN There is $421 dollars and on the air. I don't remember the costs of the nylon rope and misc stuff like end insulaters, but it wasn't much extra. And of course, you won't find copper at that price, but you can expect to pay 60 or so for 100 feet of ladder line, and whatever outrageoous price for wire these days. - 73 de Mike KB3EIA - |
#4
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"Michael Coslo" wrote
I might suggest picking up a tuner such as one of the MFJ 300 watt ones. Then get ladder line, and throw a general purpose dipole in your trees. That for my money is the best starter antenna going, and can service you long after you're a newbie. Some do not like to have to tune the antenna, but I can say that It is possible to contest with such a setup. I think it's even more than a "starter" antenna -- it's great, loads on just about any frequency, and if decently in the clear will work quite well. When I move to a place with the room for a hundred footer up in the trees, it will be the only antenna I'd really ever need for HF. However, I think a ladder-line fed antenna needs a tuner (i.e., transmatch) that has a pretty beefy balun. I had the MFJ-948 that gave me lots of trouble using a 55' long dipole with ladder line. I learned how to make a bigger and better 4:1 toroid balun to replace the dinky one that came with it... then it worked really well. Right, Cecil? ;-) Howard N7SO |
#5
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Howard Lester wrote:
"Michael Coslo" wrote I might suggest picking up a tuner such as one of the MFJ 300 watt ones. Then get ladder line, and throw a general purpose dipole in your trees. That for my money is the best starter antenna going, and can service you long after you're a newbie. Some do not like to have to tune the antenna, but I can say that It is possible to contest with such a setup. I think it's even more than a "starter" antenna -- it's great, loads on just about any frequency, and if decently in the clear will work quite well. When I move to a place with the room for a hundred footer up in the trees, it will be the only antenna I'd really ever need for HF. However, I think a ladder-line fed antenna needs a tuner (i.e., transmatch) that has a pretty beefy balun. I had the MFJ-948 that gave me lots of trouble using a 55' long dipole with ladder line. I learned how to make a bigger and better 4:1 toroid balun to replace the dinky one that came with it... then it worked really well. Right, Cecil? ;-) I agree that a random length dipole fed with ladder line makes a great antenna. I've used one for years with a traditional tuner. My question: If I put a balun between the ladder line and the tuner, can I use one of the automatic tuners built into modern rigs? If this works, it provides the advantages of one simple antenna for multiple bands without the hassle of having to retune when changing bands/frequencies. 73, Steve KB9X |
#6
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![]() "Steve Bonine" wrote I agree that a random length dipole fed with ladder line makes a great antenna. I've used one for years with a traditional tuner. My question: If I put a balun between the ladder line and the tuner, can I use one of the automatic tuners built into modern rigs? If this works, it provides the advantages of one simple antenna for multiple bands without the hassle of having to retune when changing bands/frequencies. Steve, if the auto tuner can handle very high SWR's.. then sure. ;-) Seriously, I don't think it'd work. I had one of those in-line baluns designed for the purpose of being able to run RG8 coax through the wall to the transmatch. The coax length was maybe 8 feet. My antenna was about 50' long, fed with 450 window line, and I used it on all bands from 10 - 40m. The balun was from RadioWorks and was rated at maybe, I forget.... 4KW? I was running 100 watts and that balun got HOT. After a while, it seemed that the balun broke down from the excessive heat and was no longer useable. (Can that really happen?) That should give you an idea about the auto tuner idea for this kind of setup. It's really not that hard to re-tune a transmatch. Find the right settings for each band [segment] and write down the numbers. There are typically just three transmatch knobs to re-set, and it can be done in five seconds. OK, maybe seven seconds. ;-) Howard N7SO |
#7
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I agree that a random length dipole fed with ladder line makes a great
antenna. I've used one for years with a traditional tuner. My question: If I put a balun between the ladder line and the tuner, can I use one of the automatic tuners built into modern rigs? If this works, it provides the advantages of one simple antenna for multiple bands without the hassle of having to retune when changing bands/frequencies. Depends a lot on the radio and on your individual installation. The ATUs built into a lot of modern rigs are of the "line flattener" persuasion. They're intended to be used with an antenna which isn't too awfully far from a resonant 50-ohm load. As a rule of thumb, I'd say that most of them can match a 3:1 load, some of them will cope with most loads of up to 5:1, and few of them can handle 10:1 loads at all well. For what it's worth, the ATU in my Kenwood TS-2000 won't even attempt to match anything above 10:1. It'll struggle with a lot of loads between 5:1 and 10:1, depending on whether they're low-Z, high-Z, and/or substantially reactive. I suspect that this ATU is probably fairly typical of modern rigs. External tuners often have a substantially wider matching range than an internal line-matcher, and probably have significantly lower losses when handling difficult loads. An unbalanced tuner plus a robust balun is probably going to work better than a rig's ATU plus a balun. The balun can be a problem in either case, with difficult (high-Z) loads - it's not easy to build a balun which has a high enough choking reactance to really balance out the line currents well if it has to work into, say, 5000 ohms or so. Link-coupled tuners seem to be a better technical choice for such difficult loads, although (as per your comment) they aren't the most convenient beasts in the world. If your doublet length and feedline length leave you with reasonably tolerable in-the-shack feedpoint impedances on the bands that you care about, then you might want to consider a sort of hybrid approach. Use a robust balun to connect to the feedline, and feed the unbalanced side of the balun to a (bandswitched) set of L networks. You'd want one L-network per band, selected to bring the impedance down to somewhere in the 3:1 SWR range (or so) in the band center. The output of the L networks would go to the transceiver. With this approach, the L networks would perform the "gross" tuning of the antenna feedpoint Z, and bring it down to the point at which the transceiver's internal ATU could do the rest of the matching across the full width of the band. Since the L networks wouldn't need to provide an exact match for a 1:1 SWR, selecting the component values and tuning the networks would be simplified. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#8
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"Steve Bonine" wrote in message
... I agree that a random length dipole fed with ladder line makes a great antenna. I've used one for years with a traditional tuner. My I would strongly suggest against a random length doublet. A non-resonant doublet will have impedances all over the place. At some freuencies it cannot be matched at all, at others the losses in the tuner make you wish you hadn't been able to tune it. The trick is keeping those nasty spots out of the ham bands. There are a number of G5RV type antennas that are doublets whose length has been chosen to keep those nasty spots out of the ham bands. Spend a few minutes looking up the right lengths for your doublet and avoid potentially a lot of grief. Random length, of course, is random. you COULD get lucky. Or not .... ... |
#9
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xpyttl wrote:
Random length, of course, is random. you COULD get lucky. Or not .... I guess I'm lucky. I've never had a problem matching a random-length dipole on any frequency I've tried. That does not imply, of course, that any random length can be successfully used on any arbitrary frequency. And of course, "random length" should have read "as long as possible, given the placement of the trees." Thanks to everyone who chimed in on using an external balum and an automatic tuner. My gut told me that the consensus ("it won't work") was correct, but it was nice to get some more factual backup for that. |
#10
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Steve Bonine posted on Wed, 26 Sep 2007 10:12:27 EDT
xpyttl wrote: Random length, of course, is random. you COULD get lucky. Or not .... I guess I'm lucky. I've never had a problem matching a random-length dipole on any frequency I've tried. That does not imply, of course, that any random length can be successfully used on any arbitrary frequency. And of course, "random length" should have read "as long as possible, given the placement of the trees." Thanks to everyone who chimed in on using an external balum and an automatic tuner. My gut told me that the consensus ("it won't work") was correct, but it was nice to get some more factual backup for that. Steve, the factual backup on antenna matching has abounded in texts, mostly the 'pro' kind, for years. It's been used for years to impedance-match all kinds of things within a radio box...as well as outside it. As to amateur equipment, the subject gets colored (and both glamorized and defamed) by the lack of comparisons to other matching equipment and the affinity that some have for certain brands from certain manufacturers. If you wish, I can send you a copy of the L-section matching math that I've previously sent to Mike Coslo in e-mail. It isn't "formal" but it is accurate, but it does involve simple algebra. The L- sections are used in most of the automatic antenna tuners because it is simple (and therefore low-cost) and adapts to the measure-and-change L- or C- component algorithms that fit into small microprocessor programs. The heart of all of them is the Bruene RF voltage and current detector that senses the phases of each at the load end. [or variations on that 1955-beginning detector] The micro then determines which parts of the L- or C-components are to be switched in or out to get close to the ideal in-phase E & I of RF for most power transfer. Now the designer-manufacturers don't make auto-tuners that will match ANYTHING...even though it CAN be done. To reduce manufacturing costs they limit the number of internal inductors and capacitors and THAT will reduce the ability to auto-match anything. They are trying to be competitive on price. The newer transceivers have SOME internal auto-tuning capability but they clearly state the limits of their equipment. Not all separate auto- tuners specify that. [I have both just as a backup] "Baluns" aren't all perfect, either. They are good but just not perfect. Some are better than others but it would take ALL of them and some good lab test equipment to do a good comparison. However, MOST work well enough for amateur radio purposes and do allow for balanced-to-unbalanced line conversion at HF. Now ANY impedance-matching tuner will let one load up just about anything. All that serves is to transfer the most RF power into a load. What is NOT known is WHERE all that RF is going. Unless some ham has a balloon-borne sensor and data transfer gizmo, NOBODY can know just where the pattern is going to be. Big trees WILL affect the pattern, especially changing it between dry and wet climate times and between different kinds of trees. So will structures and assorted conductive things (aluminum patio covers, small garden sheds, power, phone, and TV cables) all within the near-field (within five or so wavelengths). Even some houses which have had aluminum siding added on compared to similar houses with just wood or stucco or brick siding. One can take an example of the U.S. Army's little AN/PRC-104 backpack transceiver. It covers the whole of HF using a whip antenna. It has had an auto-tuner built-in since it went operational in 1986. A human bean is a poor counterpoise for any antenna with HF wavelengths and soldiers aren't all "built to spec" for that purpose. Further, the transceiver and whip must operate from unknown field environments, in trees or well away from them, in swampy soil or dry desert. The transceiver can't get any higher than the soldier carrying it. But, the little built- in antenna tuner assures him that the whip antenna is going to get as much RF power into/out-of it as possible. The rest of it is trying to keep the whip as vertical as possible while in-use. Now a PRC-104 won't win any DX awards or enable contacts with Antarctica or Yurp, but it is a case-in-point where an auto- tuner certainly helps maximize signals in a 1:10 frequency range with a practical-minimal fixed antenna, allowing for a highly-variaable counterpoise/ground-plane environment. The vertical whip will probably maximize its pattern between 10 and 40 degrees above horizontal, give-or-take. It works in practice (for the equivalent of QRP amateur-style). Works well enough, that is. The auto-tuner built-in certainly helps it. Everyone's residential location varies greatly and only a very few are "perfect" (as to the antenna analyzer programs). One can load up practically anything with a tuner but only the shape and arrangement of conductive elements is going to determine where most of the RF goes to (or comes from). No tuner can help that. 73, Len AF6AY |
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