FS: sma-to-bnc custom fit rubber covered antenna adapter
Do you have a need for a high-quality SMA-to-BNC rubber covered
factory look antenna adapter that is custom made to fit and protect your H.T. or scanner radio? Adapter allows you to: Quickly change antennas to base, mobile or different style use. Use the more popular and wider selection available of BNC antennas. Prevent chassis connector wear or from coming loose due to antenna changes. Adapter features: Gold plated contacts with a teflon insulator. A low profile design with a rubber covering for a factory antenna look. The rubber base seals to the top of the radio with no spacers needed for moisture and dirt protection. The base also provides an excellent support for any length of antenna or application. No need to remove adapter once installed to make a quick and safe BNC style antenna change. Sizes to fit radio models: Yaesu: VX-5R, VX-7R, VX-2R, VX-1R, FT-50-R, FT-60-R, VX-10, VX-150, VX-110, VXA-100, VXA-120, VX-800, VXA-700 Icom: IC-T90A, IC-R5, IC-R2, IC-T8A, IC-T81A, IC-Q7A, IC-M1V Kenwood: TH-D7, TH-G71, TH-F6A, TH-59, TH-K2AT Alinco: DJ-V5, DJ-X3, DJ-S40 Midland : G-11 Maycom : AR108 Standard: C508A, C510, HX-460S Uniden : Atlantis(marine) Tate Orca : Excel Radio Shack: HTX-200, HTX-400, HTX-245, HTX-420 Previewed in the May 2000 Issue of CQ Magazine, and the Nov. 2000 Issue of QST Magazine. $11.95 ea. + $1.50 S+H(One to unlimited) (Check or money order only in U.S.Funds) (Specify-radio-model) STEPHEN G.GULYAS 706 LALOR ST. TRENTON, N.J. 08610 U.S.A. A photo of the adapter is available upon request. I welcome any questions or comments at my email: Thanks for looking at my posting. S.G.G. KC2BHO 73's |
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samw thing without rubber 3.75 at any electroncs store what a rip off but you know you can get in serious trouble without your rubbers . . . Ed |
Brian wrote in
: samw thing without rubber 3.75 at any electroncs store what a rip off And without the rubber, the flex and bending of the antenna gets directly transferred to the sma connector. You'll be wishing you'd had some sort of support before long, as the rig is in the shop with a broken sma connector. Stephens connectors work well, I've had one for years, and think it was one of the smarter accessories I've purchased. (Ft-50) john |
And without the rubber, the flex and bending of the antenna gets directly transferred to the sma connector. You'll be wishing you'd had some sort of support before long, as the rig is in the shop with a broken sma connector. Stephens connectors work well, I've had one for years, and think it was one of the smarter accessories I've purchased. (Ft-50) john What are "Stephens connectors" ? Any pics and where to buy ? Thanks, Nick |
"nick smith" wrote in news:Sjsqd.221$P23.121
@newsfe5-gui.ntli.net: What are "Stephens connectors" ? Any pics and where to buy ? Thanks, Nick Sizes to fit radio models: Yaesu: VX-5R, VX-7R, VX-2R, VX-1R, FT-50-R, FT-60-R, VX-10, VX-150, VX-110, VXA-100, VXA-120, VX-800, VXA-700 Icom: IC-T90A, IC-R5, IC-R2, IC-T8A, IC-T81A, IC-Q7A, IC-M1V Kenwood: TH-D7, TH-G71, TH-F6A, TH-59, TH-K2AT Alinco: DJ-V5, DJ-X3, DJ-S40 Midland : G-11 Maycom : AR108 Standard: C508A, C510, HX-460S Uniden : Atlantis(marine) Tate Orca : Excel Radio Shack: HTX-200, HTX-400, HTX-245, HTX-420 Previewed in the May 2000 Issue of CQ Magazine, and the Nov. 2000 Issue of QST Magazine. $11.95 ea. + $1.50 S+H(One to unlimited) (Check or money order only in U.S.Funds) (Specify-radio-model) STEPHEN G.GULYAS 706 LALOR ST. TRENTON, N.J. 08610 U.S.A. A photo of the adapter is available upon request. I welcome any questions or comments at my email: Thanks for looking at my posting. S.G.G. KC2BHO 73's |
Adding any adaptor would seem to significantly move the radiating
portion of the antenna further away from the "ground plane" of the radio. This should affect the operation of the antenna adversely. Comments? Bob In article , (Stephen G. Gulyas) wrote: Do you have a need for a high-quality SMA-to-BNC rubber covered factory look antenna adapter that is custom made to fit and protect your H.T. or scanner radio? Adapter allows you to: Quickly change antennas to base, mobile or different style use. Use the more popular and wider selection available of BNC antennas. Prevent chassis connector wear or from coming loose due to antenna changes. Adapter features: Gold plated contacts with a teflon insulator. A low profile design with a rubber covering for a factory antenna look. |
In article
, Bob Dixon wrote: Adding any adaptor would seem to significantly move the radiating portion of the antenna further away from the "ground plane" of the radio. This should affect the operation of the antenna adversely. Comments? Bob Adding an adapter to a Transmission Line will have no effect, except to add insertion loss of the adapter. Adding an adapter to the antenna itself MAY cause the antenna charactoristics to change. Most SMA and BNC connecters are used in Transmission Lines, and not antennas themselves. The OP doesn't really explain where the adapter is to be used. Most small handheld devices with external antenna connections have those connection in the Transmission Line and not in the antenna itself. Me |
"Bob Dixon" wrote in message
... Adding any adaptor would seem to significantly move the radiating portion of the antenna further away from the "ground plane" of the radio. This should affect the operation of the antenna adversely. Comments? What makes you think the effect should be adverse? When you consider all the different radios that a given antenna could be connected to, the change from radio to radio is going to be far greater than what a 3/8" adapter is going to do (consider its electrical length at 2m...). In fact, I would hope that most HT antennas weren't meant to be used with counterpoises, but now that I think about it, I don't really know whether or not that's the case. Anyone? I mean... the radiation pattern of a wire cut 'to length' stuck into a BNC connector on the top of an HT is going to be very seriously distorted relative to the same wire above a near-infinite ground plane. Cell phones often use sleeve dispole antennas to avoid the need for a counterpoise... ---Joel |
Me wrote:
In article , Bob Dixon wrote: Adding any adaptor would seem to significantly move the radiating portion of the antenna further away from the "ground plane" of the radio. This should affect the operation of the antenna adversely. Comments? Bob Adding an adapter to a Transmission Line will have no effect, except to add insertion loss of the adapter. Adding an adapter to the antenna itself MAY cause the antenna charactoristics to change. Most SMA and BNC connecters are used in Transmission Lines, and not antennas themselves. The OP doesn't really explain where the adapter is to be used. Most small handheld devices with external antenna connections have those connection in the Transmission Line and not in the antenna itself. Me That is actually not quite true. On an HT, the transmission line ends somewhere inside the radio. The SMA/BNC connector is part of the antenna proper. If you add a sleeve (as the previous poster, "dixon", says), you will be changing the antenna itself. ASCII schematic follows: befo | | antenna | | _ ground + bnc/sma || || coax from PA strip || || after | | antenna | | || || shielded antenna (adapter) || _ ground (bnc || || coax from PA strip || || And as we remember, "maximum radiation at the current maximum" (that is, the base of a classic 1/4 wave antenna), you are shielding the point of maximum radiation. From a practical standpoint, you will probably be using a gain-retarded rubber duckie, and the 1 or 2 dB loss from even the worst adapter will be swamped by the -10 dB gain of the duck (that is "minus 10 dB gain"). The rubber-duck will make a 5 watt transmitter sound like a 1/2 watt one. Having another 1 dB of loss will make that 5-watt radio sound like 0.4 instead of 0.5. No big deal. If you can keep your radio from being broken by using a quality adapter, and with a negligible loss in performance, I say, "do it." If you are talking about squeaking out every last bit of signal, such as EME, the answer is "no". But if you are talking about walking around a hamfest on 2m, then spend a few extra bucks to keep from fracturing your antenna connector connection, which these days, most hams can't, or don't know how to, fix. flames invited Your mileage may vary. Dave KZ1O |
In article ,
Dave Bushong wrote: That is actually not quite true. On an HT, the transmission line ends somewhere inside the radio. The SMA/BNC connector is part of the antenna proper. If you add a sleeve (as the previous poster, "dixon", says), you will be changing the antenna itself. ASCII schematic follows: befo I have been in the communications field for 35 years, and I have NEVER seen a SMA/BNC antenna connector on a Handheld Radio that didn't have a the RF Ground connected to the ground side of the connector. there are some that use different antenna connectors than SMA/TNC?BNC that are singleended but I have never seen one used that way. CFR (Call for Rference) Tell us all which radios your talking about. Make, Model, Version. Me |
Me wrote:
In article , Dave Bushong wrote: That is actually not quite true. On an HT, the transmission line ends somewhere inside the radio. The SMA/BNC connector is part of the antenna proper. If you add a sleeve (as the previous poster, "dixon", says), you will be changing the antenna itself. ASCII schematic follows: befo I have been in the communications field for 35 years, and I have NEVER seen a SMA/BNC antenna connector on a Handheld Radio that didn't have a the RF Ground connected to the ground side of the connector. there are some that use different antenna connectors than SMA/TNC?BNC that are singleended but I have never seen one used that way. CFR (Call for Rference) Tell us all which radios your talking about. Make, Model, Version. Me You missed my point, I think. The counterpoise is the (poor) metal of the radio and of the user's hand. Any connector/adapter will be coaxial and probably low loss, but the counterpoise stays put. The feedpoint rises but the "ground" plane does not. For an SMA adapter, it might not be enough to hear a difference, but the radiated signal will be worse when using such an adapter. 73, Dave |
In article ,
Dave Bushong wrote: You missed my point, I think. The counterpoise is the (poor) metal of the radio and of the user's hand. Any connector/adapter will be coaxial and probably low loss, but the counterpoise stays put. The feedpoint rises but the "ground" plane does not. For an SMA adapter, it might not be enough to hear a difference, but the radiated signal will be worse when using such an adapter. I'd say "may be worse" rather than "will be worse". In some cases, it may be better. From what I've seen (and measured) the actual impedances, "counterpoise" effectiveness, etc. of HT antenna setups vary all over the map, and change constantly depending on a whole bunch of factors... how you grip the HT, whether you happen to be wearing a glove, how you angle the HT near your head (antenna-loading effects from the head can make SWR change dramatically), and probably whether you're sweating or not. A typical HT case is almost certainly _not_ serving as a tuned counterpoise at 2 meters, nor is your arm and body. Adding a centimeter or three of SMA-to-BNC connector to the length of the "counterpoise" may have some small effect in some cases, but I believe that [1] it's as likely to work for you as against you, and [2] it's probably less than the sorts of impedance variations which a typical HT has to face every day as it's moved around the user's head during transmission. -- Dave Platt AE6EO Hosting the 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! |
Not to mention the fact that the reason you're adding the adapter is most
likely because you are putting a better antenna on the HT. I doubt what you *might* lose by moving the feedpoint away from the "counterpoise" is not as much as you gain by changing the antenna; otherwise, why bother? At higher frequencies this may not be the case, but probably not within the realm of a dual-band HT. I've been using the Gulyas adapter for years now. I use it primarily for attaching a Smiley 270 telescopic whip to my VX-5, since that antenna works very well configured as a 5/8-wave on 70cm. The relative gain in performance over the stock antenna is quite noticeable, so in that case, the adapter causes no problems. The fit and appearance of the adapter on that rig is great, too! - Doug "Dave Platt" wrote in message ... In article , Dave Bushong wrote: You missed my point, I think. The counterpoise is the (poor) metal of the radio and of the user's hand. Any connector/adapter will be coaxial and probably low loss, but the counterpoise stays put. The feedpoint rises but the "ground" plane does not. For an SMA adapter, it might not be enough to hear a difference, but the radiated signal will be worse when using such an adapter. I'd say "may be worse" rather than "will be worse". In some cases, it may be better. From what I've seen (and measured) the actual impedances, "counterpoise" effectiveness, etc. of HT antenna setups vary all over the map, and change constantly depending on a whole bunch of factors... how you grip the HT, whether you happen to be wearing a glove, how you angle the HT near your head (antenna-loading effects from the head can make SWR change dramatically), and probably whether you're sweating or not. A typical HT case is almost certainly _not_ serving as a tuned counterpoise at 2 meters, nor is your arm and body. Adding a centimeter or three of SMA-to-BNC connector to the length of the "counterpoise" may have some small effect in some cases, but I believe that [1] it's as likely to work for you as against you, and [2] it's probably less than the sorts of impedance variations which a typical HT has to face every day as it's moved around the user's head during transmission. -- Dave Platt AE6EO |
Dave Platt wrote:
In article , Dave Bushong wrote: You missed my point, I think. The counterpoise is the (poor) metal of the radio and of the user's hand. Any connector/adapter will be coaxial and probably low loss, but the counterpoise stays put. The feedpoint rises but the "ground" plane does not. For an SMA adapter, it might not be enough to hear a difference, but the radiated signal will be worse when using such an adapter. I'd say "may be worse" rather than "will be worse". In some cases, it may be better. [...] Tell me, specifically, in which cases that my info would not be true. I made some measurements before I posted. Did you? I was just saying that extending the feedpoint / current node, as was suggested, will lower the radiated power. I measured field strength measurements and then posted my results. I still feel that the more aluminum in the sky, the better. Even if there is some loss in adapters... mmmm.... bigger antennas, happier hams. 73, Dave kz1o |
HT's are as close to having an isotropic antenna as anything to be had.
Dave WD9BDZ Dave Platt wrote: In article , Dave Bushong wrote: You missed my point, I think. The counterpoise is the (poor) metal of the radio and of the user's hand. Any connector/adapter will be coaxial and probably low loss, but the counterpoise stays put. The feedpoint rises but the "ground" plane does not. For an SMA adapter, it might not be enough to hear a difference, but the radiated signal will be worse when using such an adapter. I'd say "may be worse" rather than "will be worse". In some cases, it may be better. From what I've seen (and measured) the actual impedances, "counterpoise" effectiveness, etc. of HT antenna setups vary all over the map, and change constantly depending on a whole bunch of factors... how you grip the HT, whether you happen to be wearing a glove, how you angle the HT near your head (antenna-loading effects from the head can make SWR change dramatically), and probably whether you're sweating or not. A typical HT case is almost certainly _not_ serving as a tuned counterpoise at 2 meters, nor is your arm and body. Adding a centimeter or three of SMA-to-BNC connector to the length of the "counterpoise" may have some small effect in some cases, but I believe that [1] it's as likely to work for you as against you, and [2] it's probably less than the sorts of impedance variations which a typical HT has to face every day as it's moved around the user's head during transmission. |
A few themes have shown up on this thread that seem to reinforce some
misconceptions about antennas. They might not have been meant that way, but I think it's a good idea to clarify them in case a casual reader might drop by and be misled. The first one is about where the "transmission line" ends and where the "antenna" starts. The antenna starts at the point where the two current carrying conductors move far enough apart for significant radiation to take place. By way of illustration, let's take the example of a simple vertical mounted on a perfect ground plane. We'll feed it at the bottom via a piece of coax. It doesn't matter where the coax is, above or below the ground plane. Inside the coax, there's current on the outside of the inner conductor, and an equal amount, flowing the opposite direction, on the inside of the outer conductor. The fields from these two currents cancel everywhere outside the coax, so it doesn't radiate. At the point where the coax connects to the antenna, the current from the inner conductor flows up the antenna. The (equal) current from the inside of the shield flows over the ground plane, spreading out from the point where the shield connects to the ground plane. The currents are now physically separated, so their fields no longer cancel, and net radiation can result. An important feature of this setup is the effect of the current flowing along the ground plane. For every bit of current flowing outward in one direction, there's an equal bit flowing outward in exactly the other direction. The fields from these two bits of current cancel at right angles to the directions of flow. When you look at all the bits of current, you find that the net field from the whole amount of current is zero. So the current on the ground plane doesn't result in any radiation. (By contrast, the current on the antenna wire doesn't have any cancelling current, so it radiates.) A conductor which carries current but doesn't radiate (significantly) is often called a "counterpoise". Misuse of this term is another problem with some of the postings, and I'll address it in a minute. The important thing to remember is that a "counterpoise" doesn't radiate significantly. If it does, it's not a "counterpoise" but a part of the antenna. What happens if we put a piece of pipe around the bottom, say, 1/4 of the antenna, weld it to the ground plane, and connect the coax shield to its inside? Now the pipe is an extension of the transmission line. The portion of the antenna inside the pipe is the center conductor, and the pipe is the shield. So the portion of the antenna inside the pipe can't really be called an "antenna" any more, since it doesn't radiate. The current on the inside of the pipe reaching the top of the pipe flows over the edge and down the outside to the ground plane. Here's a very important point: *This current radiates just like the current on the antenna wire*. What we have now is a lopsided dipole. The antenna wire protruding from the top of the pipe is one side of the dipole, and the outside of the pipe is the other. The "feedpoint" is where the wire sticks out of the pipe. Once the current along the outside of the pipe hits the ground plane, it spreads as before. The current on the outside of the pipe radiates, the current on the ground plane doesn't. A statement was made about a situation sort of like this "shielding" the "high current" part of the antenna. This isn't what happens at all. What happens is that the portion of the original antenna wire inside the pipe is no longer an antenna at all, but part of a transmission line. The current on it isn't the same as before the pipe was put there. The radiating antenna is now the portion sticking out of the pipe, and the current at its bottom, all other things being equal, will now be greater than before the pipe was added. No signal or power is lost due to "shielding". All you've done is shortened the antenna a bit, just as though you'd cut a bit off the top. Now let's remove the pipe and bend the ground plane downward into a cone, with the antenna sticking out of the cone's apex. Here we'll find that the current flowing on the ground plane does indeed radiate. There's no net radiation straight up, but it radiates horizontally and in all other directions. The ground plane is no longer a "counterpoise", but simply a conically-shaped dipole half. If the ground plane radius was about the same as the "antenna" length, and the ground plane is bent downward at a reasonably sharp angle, the radiation from the conical ground plane will be about the same as the radiation from the "antenna". Calling it a "counterpoise" doesn't give it magical properties so we can ignore it -- it's every bit as much a part of the antenna as the "antenna". Finally, consider an HT. Here, one half of the antenna is the rubber ducky or other "antenna". If you put a sleeve over part of the outside of it, the real radiating top part of the antenna is the part sticking out of the sleeve. The other half of the antenna -- NOT a "counterpoise", but a real part of the antenna of at least equal importance to the intended part -- is the outside of the sleeve, and the outside of the HT, your hand, and your body. Whatever current flows up into your "antenna" also flows along the other half -- that is, along the HT and your body -- and radiates. Roy Lewallen, W7EL |
In article ,
Dave Bushong wrote: Me wrote: In article , Dave Bushong wrote: That is actually not quite true. On an HT, the transmission line ends somewhere inside the radio. The SMA/BNC connector is part of the antenna proper. If you add a sleeve (as the previous poster, "dixon", says), you will be changing the antenna itself. ASCII schematic follows: befo I have been in the communications field for 35 years, and I have NEVER seen a SMA/BNC antenna connector on a Handheld Radio that didn't have a the RF Ground connected to the ground side of the connector. there are some that use different antenna connectors than SMA/TNC?BNC that are singleended but I have never seen one used that way. CFR (Call for Rference) Tell us all which radios your talking about. Make, Model, Version. Me You missed my point, I think. The counterpoise is the (poor) metal of the radio and of the user's hand. Any connector/adapter will be coaxial and probably low loss, but the counterpoise stays put. The feedpoint rises but the "ground" plane does not. For an SMA adapter, it might not be enough to hear a difference, but the radiated signal will be worse when using such an adapter. 73, Dave No, you didn't read roy's post on how feedline and antennas systems work...... Me |
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