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Modifying the FD-150 Factory Antenna
from
Thomas E. Jones, KA4DQJ
on
June 26, 2009
View comments about this article!
Modifying the Factory FD-150 H/T Antenna to Resonate on 146mhz
Seems more-and-more hams are coming by the Chinese produced FDC series VHF/UHF handi-talkies that cost under $50. I bought an FD-150 from Hong Kong off eBay, and before it even arrived I was aware of fellow hams claiming that the factory antenna isn't adequate for maximum two-meter performance. My experience puts me in agreement, but if you own one of these little rigs you already know that quick-swapping antennas isn't possible since the rig doesn't use a BNC connector. Antenna changes require a rarer-than-chicken's-teeth adapter to accommodate the universally equipped h/t rubber duckies.
I found a solution to the out-of-band antenna problem by modifying the factory antenna. If any ham wants to try this, remember of course that anytime you dicker with your equipment you run the risk of messing it up. So, it's your gear... proceed with caution, if at all, and please don't blame me if things go badly. You need a few tools and some handymanship to do this. :)
First, I put the factory antenna on a VHF antenna analyzer and found that it resonates in the 155mhz range... quite a bit away from the 146mhz needed for two-meter work. Using the antenna analyzer, I experimented with adding varying lengths of wire to the existing antenna until I found a length that resonated at 146mhz. For those of you who want to perform this mod but don't have an antenna analyzer, the “right” length of additional rod that needs to be added to the factory antenna is 3.25” (81mm).
Here's my modification to the factory antenna that will allow it to resonate on two-meters:
1. First, pull the cap off the end of the antenna and expose the metal coil of the factory whip. Peel away about 1/4" of the insulation from the tip.
2. Find a short piece of any solid metal rod that is no larger than the coil braid of the factory antenna, and one that is preferably quite a bit narrower so that the finished job won't be top-heavy. As stated above, the piece you will be adding is only 3.25"(81mm) in length. My extension is quite a bit narrower than the factory antenna gauge, as explained later.
3. Get one of those crimp connectors that are used to electrically connect two runs of wire. The gauge of the crimp connector needs to be large enough to accommodate the diameter of the factory antenna, and the piece you are adding. Remove all the insulation from the crimp connector... you want just bare metal.
4. Place a properly sized 2" piece of black heat shrink tubing on the factory antenna whip, and let the tubing fall to the bottom of the antenna (for now).
5. Using the de-insulated crimp connector, connect the bare tip of the factory antenna with the 3.25" rod that you are going to be using. Make sure that both ends touch inside the connector, to make sure that the length is consistent. Keep the antenna elements as straight as you can before apply a light crimp. Use no more crimp than is necessary to hold the elements in place, since you'll want the connection to be as smooth, straight and round as your eye and hand will allow. . Cut/file away any sharp/irregular solder edges. Using the right sized connector helps; an oversized connector will have to be excessively flattened to hold the antenna elements, and an undersized connector won't accept them.
6. Heat up the connector and flood the connection with solder. The soldering job requires more heat than your 15-watt soldering tip, and even 25 watts may be too light. I found that my mini-propane torch worked just fine. Don't apply so much heat that you melt the antenna insulation.
7. Let cool, slide the 2" piece of heat shrink tubing up over the soldered connector, put a match under the tubing and let shrink securely.
8. Last, figure out a cap for the end of the modified antenna, letting your imagination guide you. Since I used the pull-up antenna from an old cell phone, it came with a cap... so I got lucky on that part. An old bead of some design, cork, styrofoam, etc. should work.
Screw the modified antenna back onto the little FD-150 and try out those repeaters that you couldn't get into with the unmodified factory antenna. Measured from the top of the h/t, the antenna length will be on the order of 10" to 10.15". Since the length never reached the 19" of a quarter-wave 2m whip before resonating on the analyzer, I figure that the factory antenna has some loading; maybe in the base. Since the length of the modified antenna resembles that of a known factory 5/8th wave 2m ducky, you may even have that. I can't say since I don't know what is inside the factory ducky; I only what additional length is necessary to resonate the antenna on two-meters, and that the modified antenna performs significantly better than an unmodified one.
This article has expired. No more comments may be added.
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Modifying the FD-150 Factory Antenna
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by WX7G on June 26, 2009
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I would be interested in the test fixture used to determine the antenna resonant frequency. For example, was the antenna mounted on a ground plane, hanging off a length of coax, or plugged directly into the analyzer?
I wonder because if the measurement is in error the modified antenna may work worse than before modification.
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RE: Modifying the FD-150 Factory Antenna
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by N8EMR on June 26, 2009
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hmm, I didnt think those were legal to import into the US since it has no FCC acceptance/compliance.
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RE: Modifying the FD-150 Factory Antenna
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by KC0ROM on June 26, 2009
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n8emr, you do not need and fcc type acceptance to use that piece of equipment,read your part 97 rules. if you built a vhf/uhf radio and use it does it have f.c.c acceptance ? no,or a homemade amplifier ? no.......HERE'S YOUR SIGN. KC0ROM
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RE: Modifying the FD-150 Factory Antenna
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by K1CJS on June 26, 2009
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The use isn't illegal, the importing is, since those radios works on more than just the ham bands.
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RE: Modifying the FD-150 Factory Antenna
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by K9RFZ on June 26, 2009
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Just ask K1CRA why they got cited by the FCC for advertising/selling a similar cheap Chinese radio in the USA.
See http://www.w5yi.org/ama_news_article.php?id=266 for further details.
Joseph, K9RFZ
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RE: Modifying the FD-150 Factory Antenna
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by K0BG on June 26, 2009
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As the old adage says, a photo would have been worth a thousand words.
And I too want to know how you actually measured the impedance, as SWR means nothing!
Alan, KØBG
www.k0bg.com
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RE: Modifying the FD-150 Factory Antenna
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by WB4TJH on June 26, 2009
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I enjoy informative, tech articles, but some of them are beginning to remind me of a couple of old fools at the nursing home threatening each other with their canes and arguing over who got the bigger donut for breakfast....
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Modifying the FD-150 Factory Antenna
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by K1DA on June 26, 2009
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Or you could buy a real radio from the big three.
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RE: Modifying the FD-150 Factory Antenna
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by KB1LKR on June 26, 2009
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"And I too want to know how you actually measured the impedance, as SWR means nothing!"
He didn't state SWR or the real part of impedance, only resonance using a VHF antenna analyzer, to determine the length required to be added (3.25") to reset it to resonate at 146MHz from 155MHz.
All he needs to do now is drill the hole in his car's roof! (Can't disagree w/ you on this one though OM!)
Photos would be great though.
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RE: Modifying the FD-150 Factory Antenna
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by K0BG on June 26, 2009
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I have this really neat question to ask. How did you determine the resonant frequency? Did you use the lowest SWR? Or, did you do it correctly, and measure the input resistance when X equaled zero?
Remember too, the ground losses have a lot to do with the resonance point, and the resistive component. You just can't connect the antenna to the analyzer and expect the figures to be any where near close.
Lastly, if you do the same measurement with an average 2 meter HT ducky, you're in for a surprise.
Alan, KØBG
www.k0bg.com
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Modifying the FD-150 Factory Antenna
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by KA4DQJ on June 26, 2009
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I included a photograph with the article's submission. I don't know why it wasn't included in the article.
The results were checked using an active-circuit VHF field strength meter located 13 feet distant. Used on the ht, the modified antenna would move full meter scale against the unmodified antenna's less than 1/4 scale with the h/t locked into the same place for both tests. I should have put this in the article.
Some of the comments are astounding.
I didn't measure impedance of a rubber duckie on a "ground plane", or "hanging off a piece of coax". I measured it while attached to the chassis, the same conditions as actual use.
The "type acceptance" chatter I won't even address... someone needs to start their own thread. Ditto for the "real radio" stuff... it's a $45 radio that works, and has a one-year warranty; same as the "real" radios.
I didn't use "SWR". Please read and understand the article before commenting. Same advice for those wanting to know how I came by the "actual measured resonance", and "determine the resonant frequency". Someone may want to post an article about antenna bridges, what they do and how they work.
I'll pass on "drilling a hole" in the roof of the car to either test or use the antenna.
"X equals zero"? I'm not working with HF frequencies here. The broad frequency response of VHF antennas, and especially lossy antennas such as h/t duckies is such that X isn't a consideration. At VHF frequences ballpark is perfectly fine. In fact, it's hard enough to determine just where the null is occuring on a VHF duckie antenna... it is so broad.
And, no "surprise" here when measuring duckies on an analyzer... I routinely do it when I need to distinguish between a scanner, business band and 2m duckies when searching my collection. The 2m duckies will always be resonant in the 2m band presuming that they are well made for the 144-148mhz range.
Last, it would suit me fine if eham just took this article down. In any case I won't be writing another. If you think the modification will improve your FDC-150 peformance, then go for it. If not, then you're free to forget it. Since it's not a "real radio" anyway, you won't be out anything.
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Modifying the FD-150 Factory Antenna
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by KE7AKS on June 26, 2009
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In the good ol' DAZE we just used a FIELD STRENGTH METER like the one that is a SWR-FIELD STRENGTH METER.
Establish a fixed distance where youget mid scale Field Strength while transmitting. Try the additional wire and see if the strength gets better. Then try transmitting on a higher frequency and if it gets better, then the antenna is still too short...
The real proof of an antenna is - how does it really function, not in some other measurement.
It was a GREAT ARTICLE.
I was thinking of writing an article on using a 3 way light switch to switch from POWER SUPPLY power to 12V. BATTERY power, but I figured the GRAMMAR VOLTURES would have too much fun with it. Not to mention the techie types, not wanting an over simplified solution like that.
I want more helpfull hints like this ---
73
KE7AKS
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RE: Modifying the FD-150 Factory Antenna
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by K7DAA on June 26, 2009
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Thomas:
I feel your pain regarding all of the idiot comments--this is precisely the reason you won't find people like myself writing articles for eHam or QRZ. Just too many "experts" who have to chime in with their "brilliant" commentary.
I've read a quite a number of articles submitted by well-meaning people like yourself, hoping to share a bit of information and advance the hobby, who end up being discouraged by ever doing such a thing again because of the rudeness and even personal attacks by hams in our on-line community. Some people even complain that they get personal threats via email after posting!
Such a shame--and to those of you that seem to feel that your day is not complete unless you've added your two cents, or put down someone or their ideas online--shame on you! You are not helping the hobby one bit! You are driving people away and dissuading folks from participating in what could be very meaningful and useful discourse because of your need to spout off!
Guys, could you please, every once in a while, just say something like, "Hey, thanks for taking the time to write this article!", and just leave it at that? Would it kill some of you to just be kind to each other and encourage honest, open discussion?
Remember what mom said: "If you can't think of anything nice to say about someone, don't say anything at all"
Anyway, thanks Thomas, at least some of us appreciate the effort you put in to this.
73,
Dave - K7DAA
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RE: Modifying the FD-150 Factory Antenna
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by K8QV on June 26, 2009
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"I included a photograph with the article's submission. I don't know why it wasn't included in the article.
The results were checked using an active-circuit VHF field strength meter located 13 feet distant. Used on the ht, the modified antenna would move full meter scale against the unmodified antenna's less than 1/4 scale with the h/t locked into the same place for both tests. I should have put this in the article.
Some of the comments are astounding.
I didn't measure impedance of a rubber duckie on a "ground plane", or "hanging off a piece of coax". I measured it while attached to the chassis, the same conditions as actual use.
The "type acceptance" chatter I won't even address... someone needs to start their own thread. Ditto for the "real radio" stuff... it's a $45 radio that works, and has a one-year warranty; same as the "real" radios.
I didn't use "SWR". Please read and understand the article before commenting. Same advice for those wanting to know how I came by the "actual measured resonance", and "determine the resonant frequency". Someone may want to post an article about antenna bridges, what they do and how they work.
I'll pass on "drilling a hole" in the roof of the car to either test or use the antenna.
"X equals zero"? I'm not working with HF frequencies here. The broad frequency response of VHF antennas, and especially lossy antennas such as h/t duckies is such that X isn't a consideration. At VHF frequences ballpark is perfectly fine. In fact, it's hard enough to determine just where the null is occuring on a VHF duckie antenna... it is so broad.
And, no "surprise" here when measuring duckies on an analyzer... I routinely do it when I need to distinguish between a scanner, business band and 2m duckies when searching my collection. The 2m duckies will always be resonant in the 2m band presuming that they are well made for the 144-148mhz range.
Last, it would suit me fine if eham just took this article down. In any case I won't be writing another. If you think the modification will improve your FDC-150 peformance, then go for it. If not, then you're free to forget it. Since it's not a "real radio" anyway, you won't be out anything."
Well said. Thanks for trying, but this is a place where everybody already knows everything.
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RE: Modifying the FD-150 Factory Antenna
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by AH6RR on June 26, 2009
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I always say a expert = ex as in Has been and spert as in drip under pressure. Or if you cant dazzle them with brillance baffle them with BS.
Come on it's a cheap peice of Chinese hardware if it blows up it only $50 not $350 Jappanese Radio.
73
AH6RR
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RE: Modifying the FD-150 Factory Antenna
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by K8MMG on June 26, 2009
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Thanks for the article. You've got to have a thick skin when you write something and post in on the internet. Keep 'em coming. Regarding the radio: I've spent mucho dinero on some "big name" HTs and can easily say that this rock-solid import has out-performed them (no, not kidding). It is built like a tank and just works. Oh and it comes with a MARS mod already done! It may not come with all the fancy bells and whistles but you can't beat it for the price.
73,
Brandon
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RE: Modifying the FD-150 Factory Antenna
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by ALCO141 on June 27, 2009
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hey,
i thank you for writing this article, more than some of the hypercritical folks seem to do most of the time, i like these articles, they are low tech, can be done by most folks, dont require a lot of equipment, forget the monday morning quarterbacks. if they have something constructive to say then say it, otherwise like your mama told you if you dont have anything nice to say then....shut the ... up. maybe for those of us that are new here a constructive explanation of how to measure with what equipment may have been more insightfull than... did you hang the wire off a telephone pole at midnight in the quarter moon during the spring equinox, as we all know this is the only true way to measure the angle of the dangle... of the antenna that is.
as far as the chinese HT, i dont have one, but since when are hams gear snobs? oh you have one of thooose radios? most guys that i know like the simple, cheap, functional gear method of operating.
alex
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Modifying the FD-150 Factory Antenna
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by KC8PCL on June 27, 2009
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It never ceases to amaze me, The amount of so called illegal radio's that arrive in this country. If they are in fact illegal, Why is the import of these radios not monitored and enforced? The radio's are here now. What is the point of saying they are illegal? If you have one, Use it. As for improvements, keep them coming. Don't be put off by some that feel they need to point out their knowledge of the law. This is a FUN hobby, Enjoy it. If you can't say anything positive, Keep your posts to yourself. There is enough negativity in the world today. Why add to it, Just saying. 73, and keep posting. I for one enjoy reading things like this.
KC8PCL
Dave
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RE: Modifying the FD-150 Factory Antenna
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by K4RAF on June 27, 2009
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It is easier to beg forgiveness than ask for permission.
If you do it, keep it to yourself...
Today's hams only want to argue legality, not technical merits...
Raf
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Modifying the FD-150 Factory Antenna
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by W5DCT on June 27, 2009
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Thank you for the decently written article. I was sorry to read that you wont be writing another.
A little more detail as to how you checked for resonance might have been nice in the original post.
As far as the comments go, did you expect any better? You are the one who posted here. if you cant take the heat that you generate..stay out of the kitchen.
I'm not being mean just honest...if you had read posts and replies here before you would have known what to expect. if you dont like the replies that you received...than you have to make the decision as to if you post or not.
Once again...thanks for a decently written post...
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RE: Modifying the FD-150 Factory Antenna
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by N5ACK on June 27, 2009
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I'm very glad you wrote the article for 2 reasons:
1. I didn't know there was a cheap radio like this out there. I was looking for something in that price range and bought it on ebay 20 minutes ago. Thanks !!!
2. Gives people a way to extend the usability of the radio. Again, Thanks.
Forget about the OF's that always put down every article. You can't please everyone.
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RE: Modifying the FD-150 Factory Antenna
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by K4DPK on June 27, 2009
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Great article, and well delivered. Thanks.
Phil C. Sr.
k4dpk
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Modifying the FD-150 Factory Antenna
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by AD7QQ on June 28, 2009
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I also enjoyed the article and plan on checking out these inexpensive radios. I actually didn't think you were handled too roughly by the crowd- although the condescending tone of a few comments was irritating. I hope you will be willing to share more of your ideas and low cost modifications, even if it means a little baloney comes your way.
Thanks and 73,
John B
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RE: Modifying the FD-150 Factory Antenna
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by K9RFZ on June 29, 2009
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Let's be clear on the legality issue;
Section 302(b) of the Communication Act of 1934 states that : “...no person shall manufacture, import, sell, offer for sale, or ship devices or home electronic equipment and systems, or use devices which fail to comply with [FCC] regulations...” Section 2.803(a)(1) of the Rules provides: “No person shall sell or lease, or offer for sale or lease (including advertising for sale or lease), or import, ship or distribute for the purpose of selling or leasing or offering for sale or lease, any radio frequency device unless: (1) In the case of a device subject to certification, such device has been authorized by the Commission in accordance with the rules... and is properly identified and labeled....”
I make no claims about the quality of these Chinese radios, nor do I question the author's method of making measurements he cites in the article. However, it is illegal to use these non-certified radios in the United States. Publishing an article showing FCC licensed operators how to modify a radio that is already illegal to use encourages a criminal act. The article itself serves as a confession that the author has committed an illegal act which could form the basis for an FCC citation.
The FCC does take these matters seriously. As I previously posted, the K1CRA radio store was cited for illegally selling a total of 7 non-certified Chinese radios. Do you want to jeopardize your FCC issued amateur radio license just to save $50? More disturbing is the number of thread posts that seem to scoff at FCC authority to regulate frequency usage. While I agree it takes a thick skin to publish an article on Eham because so many trolls and OF's wait to nit pick and pounce on authors with inane comments, this article fits in another category which deserves critical attention because it undermines the integrity of the amateur radio service by promoting illegal operation. I agree with the author (for different reasons) and I wish this article could be removed.
Joseph, K9RFZ
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RE: Modifying the FD-150 Factory Antenna
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by WA2JJH on June 29, 2009
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NICE HOMEBREW MOD. Eham really needs more TECH, and less dreak!
Do not ns zpooked by the clique of detractor-trolls.
IT IS CALLED AMATUER RADIO FOR A REASON!
THEY DO IT OUT OF NARSISTIC RAGE.
They do it out of insecurity. Many of them have do this, because tthey have to show off.
Do not be suprised, if many of them own HENRY RADIO EXPORT ONLY 4KW+ amps. Some do use ALC TO REDUCE TO 1500W. They just like having a prudent reserve. HI-HI
NO HAM IS PERFECT!
Heck, the burdon of proof is on them. For all they can know,is that it is an RX only antenna.
A few hams have run hundreds of watts for a commercial FM BDCST TRANSMITTER. One can buy a commercial FM EXCITOR for $200 on ebarf.
Most of the hi-fi ssb dudes were found innocent.
Making your shack from scratch is legal too.
If these jerks would spend more time helping others, they would enjoy the hobby again.
BTW....IT IS ALWAYS THE SAME DUDES, that live to make other hams drop out
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RE: Modifying the FD-150 Factory Antenna
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by WA2JJH on June 29, 2009
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They old buggers also committed defamation of character!
I settled out of court for $5000. The non ham jerk made up all sorts of crap about me.
I live for law suites, when I am slandered!
1)I am not involved in gun running. I do love my guns however. Happyness is a warm gun after you shot a robber in the Patella.(Knee cap) He tried to stab me first. His 'yellow sheet" was 12 pages long,
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I love these Chinese radios
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by SSBER on June 29, 2009
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I have several of these graymarket 440 Mhz. Puxing PX-777 radio's and my children love them. I just make sure they have a full charge on the battery and they're busy for hours at the campsite. What harm can these radio's do? They're just fancy FRS radios. And if it keeps them out of my hair, my life is easier.
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Amateru Radios need no certification
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by WI7B on June 29, 2009
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This should be clear to all Amater Radio Operators under the jurisdiction of the FCC:
Amateur Radio transmitters used in your station DO NOT have to be certified. They do have to comply with certain power and emission standards that are upto you to maintain. This is the heart of the Amateur Radio Service, setting it apart from every other radio service.
The ONLY requirements for certified equipment in the Amateur Radio Service are for certain external RF amplifiers. Yet even here, if the the external RF amplifier is sold to you, built by you, or modified by you - the Amateur Radio operator - for use in YOUR station, it does not need certification. As per,
"Sec. 97.315 Certification of external RF power amplifiers.
(a) Any external RF power amplifier (see Sec. 2.815 of the FCC Rules) manufactured or imported for use at an amateur radio station must be certificated for use in the amateur service in accordance with
subpart J of part 2 of the FCC Rules. No amplifier capable of operation below 144 MHz may be constructed or modified by a non-amateur service licensee without a grant of certification from the FCC.
(b) The requirement of paragraph (a) does not apply if one or more of the following conditions are met:
(1) The amplifier is constructed or modified by an amateur radio operator for use at an amateur station.
(2) The amplifier was manufactured before April 28, 1978, and has been issued a marketing waiver by the FCC, or the amplifier was purchased before April 28, 1978, by an amateur radio operator for use at that operator's station.
(3) The amplifier is sold to an amateur radio operator or to a dealer, the amplifier is purchased in used condition by a dealer, or the amplifier is sold to an amateur radio operator for use at that operator's station.
(c) Any external RF power amplifier appearing in the Commission's database as certificated for use in the amateur service may be marketed for use in the amateur service."
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RE: Amateru Radios need no certification
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by WB2WIK on June 29, 2009
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I'm glad the results validated the experiment; however it was pretty unscientific.
There's no way to measure impedance or resonance of the antenna while it's mounted on the HT. Introduction of any instrumentation changes the installation sufficiently to invalidate the measurement.
Measurement of near field FS doesn't tell much, either, unless it's performed in an RF anechoic chamber. Reflections invalidate any sort of FS measurement in a normal environment.
However, what does work is "what you can work," and if you can work more stuff after the change than before it, you're done!
WB2WIK/6
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RE: Amateru Radios need no certification
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by 5R8GQ on June 29, 2009
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WB2WIK
"Introduction of any instrumentation changes the installation sufficiently to invalidate the measurement."
Yup! We wouldn't want to kill Schrodinger's cat!
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RE: Amateru Radios need no certification
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by K9RFZ on June 30, 2009
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WI7B
You thoughtfully supply regulations which do not apply to these Chinese radios. I agree that an Amateur Radio Service transmitter does not require FCC certification. The flaw in your argument is that these Chinese radios aren't amateur radio service only transmitters. Most of them are wide open from 136 - 174 MHz and so they cross several radio services. These radios DO need FCC certification to be legal for use in the United States. As I have pointed out in both previous posts to this thread. The FCC has already cited an American business for advertising and selling these radios for violations under the Communications Act of 1934. Using these non-certified radios in the United States is illegal. Period. End of story. Some people may try to argue otherwise, but they would be wrong in their interpretation of the law.
As noted by a previous poster, no amateur radio operator is perfect. Every operator occasionally makes an innocent mistake on the air. To willfully continue to use these non-certified radios in the United States is not an innocent mistake.
I don't want to beat this point to death, but apparently some well-meaning operators like WI7B are still mis-informed. A similar legal issue arises when an operator modifies a 2m HT to operate on the MURS frequencies. While the operator may modify the radio, it is illegal for him to transmit on the MURS channels because the radio is not certified for that radio service.
Joseph, K9RFZ
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RE: Amateru Radios need no certification
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by WI7B on June 30, 2009
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K9RFZ,
You argument is incorrect. If these radios are sold to Amateur Radio operators for use in their stations, they can have potentially ANY FREQUENCY RANGE. It does not matter.
That is why WE in the Amateur Raido Service can build OR modify ANY RADIO for use in the Amateur Service as long as it complies with the regulated power, and emission standards of Part 97.
What is this practically mean? It means you can use a radio with a potential frequnecy set of 136-5000 MHZ (as an extreme example) in the Amateur Service. It means you cannot use these radios in any other radio service without certification, but in the Amateur Service it is FINE without certification.
73,
---* Ken
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RE: Amateru Radios need no certification
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by WA2JJH on June 30, 2009
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Ham radio was the original you design and build hobby.
Only spark gap transmitters were no good to the old FCC. So mechanical HF Generators came before tubes and trasistors.
There is much interpretation with the communications act of 1934.
Reason was interference with early BDCST. It is out of decency hams try to keep it clean.
Many commercial cheap ham rigs are filth generators ouut of the box.
The only 2 absolute NO-NO's. HF Amp Kits lacking decent filtering. Of course there are more.
The 10/11M 50W+ rigs are no good either.
If you build a transmitter and it is filthy, you should do better.
Otherwise the FCC trucks with the spec analysers and
photograhing of your rf spectrum will result from multiple complaints.
I also question your testing techs. However, I built devices that seemed to violate physics. However, if it works really well for you....experiment.
Less Hams experiment these days. Damn shame!
Could be your location.
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RE: Amateru Radios need no certification
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by WX7G on July 1, 2009
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The field strength measurement at 13 feet is a valid way to compare the 'before' and 'after' antenna tuning. An anechoic chamber is not needed for this measurement.
Had this information been included in the article I would not have questioned the test method.
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RE: Amateru Radios need no certification
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by KK2DOG on July 5, 2009
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From Amateur Radio Newsline (July 3, 2009):
ENFORCEMENT: CHINESE MADE HT'S ILLEGAL AND NOT THAT GOOD OF A DEAL
Some deals are too good to be true or legal. That's the story with
some rather inexpensive HT's being sold on-line. Bill Pasternak,
WA6ITF, is in our newsroom with more:
--
Inexpensive VHF and UHF transceivers made in China that transmit and
receive on the 2 meter and 70 centimeter bands appear to be illegal
for hams to buy from overseas dealers and have shipped into the United
States. This is because the radios have not passed the FCC
certification procedure nor can they as they are designed to transmit
on frequencies outside of the United States amateur radio allocations
right out of the box.
The radios in question bear names like Puxing, FDC, Wouxon, and
numerous others. They are being mainly sold on Bay and similar on-line
auction sites world-wide at prices ranging from $30 to $80 plus
shipping. Most of the ads originate from dealers in Taiwan or Hong
Kong though some have come from other Pacific Rim nations as well.
According to postings on various chat websites, the radios themselves
are not all that bad quality. Not great, but not to shabby. Almost
all of them feature a back-lit LCD display, up to 100 memory channels,
programmable repeater offsets, and even a built-in CTCSS tone encoder.
Output power on the VHF units approaches 5 watts while the UHF models
average around 2 watts out.
Hams using them report that the transmit audio quality ranges from a
bit muffled to good depending on the model and manufacturer of the set.
With retail prices far below that of similar radios from Alinco, Icom,
Kenwood and Yaesu, hams on this side of the Pacific might find these
Chinese built transceivers hard to resist. But as pointed out in on-
line postings, the biggest problem aside from it being illegal to
import is where to get one fixed if its dropped or stops operating?
Also, replacement battery packs might be very hard to find if the one
that comes with the radio goes flat and cannot be revived.
For the Amateur Radio Newsline, I'm Bill Pasternak, WA6ITF, in the
newsroom in Los Angeles.
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Modifying the FD-150 Factory Antenna
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by VE3WBE on July 6, 2009
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Good article with a practical solution based on knowledge to a real world problem. A weakness of theinternet is the equal time and space given to responses that sre just " noise". It would be a shame to discourage hams with knowledge to share in our misguided zeal to give everyone a voice. Thanks again for the article.
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RE: Modifying the FD-150 Factory Antenna
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by KE3HO on July 6, 2009
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The legal issue with these radios has nothing to do with them transmitting outside of US ham band, or their spectral purity, or the quality of their audio, or their output power, etc. As has already been pointed out, there is NO "type acceptance" or "type certification" for ham transceivers.
Have you read the FCC certification label on any of your ham radios recently? What does it say? It says, "This device complies with Part 15 of the FCC rules." Yes, folks, Part 15. Not Part 97, Part 15. Most electronic devices have to comply with Part 15 as a condition of being imported or sold in the US. You will find this label on your alarm clock, your TV set, your telephone, your calculator, your computer, and these days, probably even on your refrigerator and dishwasher. If the radio is not certified to meet Part 15 requirements, it is illegal. The next time you want to complain about some cheap electronic device that your neighbor bought that is spreading hash all over the ham bands, don't say, "It is OK for me to buy a $60 radio that does not meet Part 15 regulations, but my neighbor better not buy that $60 TV set that doesn't meet Part 15 requirements."
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RE: Modifying the FD-150 Factory Antenna
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by N5ACK on July 7, 2009
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You make the point about comparing the neighbor having the cheap TV which is creating noise for you. The same would apply to the cheap ham rig, but it's up to the owner of the rig to make sure it is in compliance and not making a mess out of the band. Just because it's cheap, doesn't mean it's going to be a piece of crap.
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RE: Modifying the FD-150 Factory Antenna
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by KE3HO on July 7, 2009
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"You make the point about comparing the neighbor having the cheap TV which is creating noise for you. The same would apply to the cheap ham rig, but it's up to the owner of the rig to make sure it is in compliance and not making a mess out of the band. Just because it's cheap, doesn't mean it's going to be a piece of crap."
You are correct. Just because a radio, TV, or other electronic device is cheap does not mean that it is crap. That is beside the point. Yes, the user has the responsibility to make sure his device is not causing harmful interference. This is true for the ham and also equally true for the cheap TV owner. Yet how many TV owners immediately turn off their TV and stop using it when a ham tells them that it is causing harmful interference? How many hams buy these cheap HTs and check them to make sure they comply with Part 15 emission levels? We have hams on this site who come right out and say that they use $40 CB amplifiers on the HF bands and they intend to continue to use them because they get good signal reports, so obviously there is nothing wrong with the amp.
The FCC has regulations governing electronic devices. These regulations are in place to help minimize cases of harmful interference. When someone says, "I don't care if it passed Part 15 or not, it is cheap so I am going to buy it and use it" they are a scofflaw. They are thumbing their nose at the FCC regulations. Hams who do this should loose their license.
What makes it OK for a ham to buy a piece of illegal equipment and operate it just because it is cheap?
73 - Jim
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Modifying the FD-150 Factory Antenna
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by K1DA on July 7, 2009
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"The length now 'resembles' that of a 5/8 wave commercial ducky" I am not sure how one length resembles another but a 5/8 on two meters is over 3 feet long, not 10 inches. Looks like the manufacturer of this unit picked 155 mHZ for the antenna as the middle of the operating range, adding some extra length brought it down to 2 meters, and it is NOW a shorter than 1/4 wave inductively loaded 2 meter antenna. Unknown is how close to 50 ohms the antenna but if the final amp in the unit is designed to tolerate a wider range (and it ought to because not many "ducks" are anywhere near 50 ohms) it is an easy improvement. To paraphrase Red Green: "Any test gear can be the RIGHT test gear" -if you know what it is telling you. My little one diode field strength meter has tipped me off to many problems over the years including the inevitable loading the tuner into itself
mistake.
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RE: Modifying the FD-150 Factory Antenna
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by KE4NYV on July 7, 2009
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I own several of these FDC-150 radios and being a former Motorola radio tech, the connector used on the radio was not foreign. The connector is a standard SMA MALE and Motorola uses the exact same scheme. I use Motorola's VHF antennas meant for the Jedi and XTS series radios and they work great. Direct replacement, no adapters and you get a high quality Motorola antenna. This is the Motorola part number: 8505644V01
Search eBay, it's full of these.
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RE: Modifying the FD-150 Factory Antenna
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by WB4IVG on July 14, 2009
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I for one think this is a fine article! We need more things like this for new hams and old ones who are getting into new areas (for Them) of Ham Radio. These are inexpensive devices that will work fine for any Ham on a Budget! Of course you well healed folks can buy the "BIG THREE" or you real rich ones can order Motorola or other brand new custom order, but for the ones who are cost conscious these radios are a good alternative solution, plus anyone buying one can experiment and get experience working on and with them to make them work as they desire without fear of great loss of funds if the soldering iron slips. This of course presents a serious challenge for you "APPLIANCE OPERATORS", who I suspect are the very ones doing the mouthing! Unless they are some disgruntle sales rep from one of the HIGH PRICED BIG THREE! Some of these self righteous Jerks need to engage their Brain Before Operating their mouth (Key Board)! Too many people want to give advice not ask for. I hope you keep writing and I for one will write some like your article. These people are forgetting about Motorola and other companies who make radios (That start out Type Accepted, which are NOT after Modification to the HAM BANDS!) commonly used on the Ham Bands not to mention Military Radios used for Ham use, many of these radios made Ham Radio exactly what it is today, and the ones of us who were there know this, these others must think the Japanese just started putting Cute Little Radios and HT's in cereal boxes! These radios come under the same guise as a home built unit as they are modified and NO LONGER MEET ANY TYPE ACCEPTANCE so the Hams using them are relying on their expertise to use and operate and stay within FCC Amateur Rules and Regs Specs. As for the Questions about the Antenna I have found in practice in the last 30 years of daily application an antenna should be tested in as close to operating real conditions as possible. As a Communications Engineer of some 30 PLUS years I have found Rubber Ducks are almost radiating POOR Dummy Loads anyway, but are acceptable because they serve a purpose for what they are, which is not an efficient radiator, let alone resonant! So I say more power to you if you get it resonant by any means possible. These folks worry about where it was tested should think that in real life body capacity near field inductance and other disturbances like seat springs render it impossible for an antenna in close proximity to the human body and other outside influences to be much of anything other that a device for the capture area it presents. As far as transmitting if the antenna with or without adapter is directly connected to the top of an analyzer similar to an MFJ unit it's functionality will be closely resemblant of it being installed on the radio in reality. Laurin Cavender WB4IVG BTW Ham for 43+ years!
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