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#1
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Antenna for my Kenwood R-1000 receiver?
Hello America and ships at sea,.. I just got a Kenwood R-1000 receiver
and I was wondering if anyone knew what kind of antenna I could rig up for it. Can I clip something on to the stainless steel backstay and expect to get a signal? I'm watching the other ssb thread that suggests you can get a weather fax from it too. Thanks as always. |
#2
posted to rec.boats.cruising
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Antenna for my Kenwood R-1000 receiver?
ray lunder wrote in
: Can I clip something on to the stainless steel backstay and expect to get a signal? Lots of sailboats have the neatest little antenna fed right into the main cabin.....where the chainplate bolts hold the shrouds to the plastic. Most of them are not grounded at this point. Hell, most of them are not grounded at all, leaving you with an ungrounded lightning rod sticking up out of the water just waiting to be hit, killing the family instantly. It's simply a credit to the conductivity of seawater that it doesn't happen more often than it does. So, if you just add another nut to a handy, existing chainplate bolt and put the hot wire of your receiver to it, you end up with a dandy antenna just waiting for a lightning hit. If you run a heavy battery cable WITHOUT those neat right angles boaters love from the bottom of the mast step to the engine block, it will shunt off MOST, but not all, of the static buildup that threatens the receiver and everyone aboard. It's not perfect but it is safer. Why didn't "they" ground everything? M-O-N-E-Y...same as always. Larry -- |
#3
posted to rec.boats.cruising
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Antenna for my Kenwood R-1000 receiver?
ray lunder wrote:
Hello America and ships at sea,.. I just got a Kenwood R-1000 receiver and I was wondering if anyone knew what kind of antenna I could rig up for it. Can I clip something on to the stainless steel backstay and expect to get a signal? I'm watching the other ssb thread that suggests you can get a weather fax from it too. Thanks as always. Hello Ray, Sure, you can try the lifelines, the backstay, or a random length of wire you have handy. Try them all. See which works best. The downside of that sort of antenna is that it is likely to pick up a lot of unwanted noise as well as signals of interest. Of course, at sea the noise issue will be less. If you find reception is poor with these antennas, you can always use an antenna resonant at the frequency of interest (hopefully you won't have more than one or two of these) or you can use a simple antenna tuner. For reception only, the tuner can use very small and inexpensive components. Keep in mind that we're at the bottom of the 11-year sunspot cycle and high frequency propagation can be pitiful at times. Chuck ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#4
posted to rec.boats.cruising
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Antenna for my Kenwood R-1000 receiver?
chuck wrote in news:1173789524_25635
@sp6iad.superfeed.net: high frequency propagation can be pitiful at times "Pitiful" can be ZERO at times, recently....it's awful. Larry -- |
#5
posted to rec.boats.cruising
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Antenna for my Kenwood R-1000 receiver?
On Wed, 14 Mar 2007 11:30:57 +0000, Larry wrote:
high frequency propagation can be pitiful at times "Pitiful" can be ZERO at times, recently....it's awful. Any sign yet of an upturn in the cycle? At night the only thing that's working for me on Winlink/Pactor is 80M. |
#6
posted to rec.boats.cruising
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Antenna for my Kenwood R-1000 receiver?
On Tue, 13 Mar 2007 07:43:10 -0500, Larry wrote:
ray lunder wrote in : Can I clip something on to the stainless steel backstay and expect to get a signal? Lots of sailboats have the neatest little antenna fed right into the main cabin.....where the chainplate bolts hold the shrouds to the plastic. Most of them are not grounded at this point. Hell, most of them are not grounded at all, leaving you with an ungrounded lightning rod sticking up out of the water just waiting to be hit, killing the family instantly. It's simply a credit to the conductivity of seawater that it doesn't happen more often than it does. So, if you just add another nut to a handy, existing chainplate bolt and put the hot wire of your receiver to it, you end up with a dandy antenna just waiting for a lightning hit. If you run a heavy battery cable WITHOUT those neat right angles boaters love from the bottom of the mast step to the engine block, it will shunt off MOST, but not all, of the static buildup that threatens the receiver and everyone aboard. It's not perfect but it is safer. Why didn't "they" ground everything? M-O-N-E-Y...same as always. Larry So what would a proper boat antenna look like? Examples, pictures, name brands? Thanks as always. |
#7
posted to rec.boats.cruising
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Antenna for my Kenwood R-1000 receiver?
Wayne.B wrote in
: Any sign yet of an upturn in the cycle? It's an 11 year cycle.... You can watch it on: http://solarscience.msfc.nasa.gov/predict.shtml The most fascinating place about it is at: http://www.spaceweather.com/ Today's sunspot number is ZERO! NO SUNSPOTS! Arrghh. Sure glad there's Skype...(c; Spaceweather can EASILY occupy an entire evening exploring. Canada accurately tracks the Solar Radio flux on 2.8 Ghz: http://www.drao-ofr.hia-iha.nrc-cnrc...sol_home.shtml So, from their prediction graph, it looks like a nice peak in 2012. This is perfect as that is the year my Socialist Security checks start rollin' in and I can stop working for all my money and live off the kids at Mickey D's flipping hamburgers. Who knows. I might just put W4CSC back on the air...(c; At night the only thing that's working for me on Winlink/Pactor is 80M. 80 and 160M act more like AM broadcast band than shortwaves. They're pretty predictable as a good nighttime freq with groundwave only on the sunny side of the planet. 40M up to 10M is what the solar cycle hits so hard. I have seen 75M SSB totally unusable for nets a few times. Of course, to become "net control" on an ARRL net, you must NOT own a proper ANTENNA or BIG LINEAR AMPLIFIER so you don't sound like you're talking on a wet string with 10 watts, no matter what the conditions...(c; I used to be active on the SC SSB net on 3915 many years ago. One night at net time you couldn't hear hardly anyone it was so bad. At that time, I was running an old Heathkit HW-100 SSB transceiver (tubes, cheap) and a home brew little amp I made out of some power company parts and a PAIR of 4-1000A tetrodes in a 7 ft tall old navy transmitter rack, about 4' wide. Using "minimum power to establish communications" that night meant running 6000 VDC at about 950ma on the little tubes. That's about a kilowatt, right?....(c; The AM station down the street ran 200W on 1260 at night in a 3-tower directional array over my house. EJ, the chief engineer and night DJ at the transmitter building used to call me and ask if I would hold off transmitting until he read the antenna current meters wildly moving around too far to fill in his log. He joked I had more current in his towers than he did...hee hee...(c; Those were fun days....no money, homebrew everything. I carried a melted 2' section of RG-8A/U coax into a ham club meeting and said they just don't make coax like they used to....my little amp melted it...(c; Larry "POWER is our FRIEND!" (Robert Mitchell, AAA Communications, paging) "You can tell when your ham station is tuned up, easily, by seeing how dim the lights are in your neighbor's house." - (me) |
#8
posted to rec.boats.cruising
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Antenna for my Kenwood R-1000 receiver?
ray lunder wrote in
: So what would a proper boat antenna look like? Examples, pictures, name brands? Thanks as always. Boats have no room for antennas that work good. So, there are two compromises that work, "sort of". One is an 18' whip coated in fiberglass to make it "yachtie", tuned from the bottom against a seawater ground (we hope, or it's going nowhere): http://www.boatersland.com/sha390.html Above 15 Mhz, it's somewhat of an antenna. Below 15 Mhz, the further down you go the worse it gets because it's just TOO SHORT! We put these awful lossy "tuners" between the bottom of the whip and the radio to match the impedance, at the cost of losing a lot of power. Being so short at lower HF frequencies, its radiation pattern looks more like an inflated hot air balloon, radiating mostly straight up...not out towards the receivers over the horizon. These antennas at low frequencies have almost no antenna CURRENT, which makes the required H field (the magnetic radiation part of the radio wave). They have lots of voltage, E-field, but E-field cannot exist without H-fields perpendicular to them so they radiate poorly. You need BOTH. Some of the "cure", about as much as you'll get, is to use a LONGER antenna with the tuner doing less of the work. One comes with sailboats. We call it the "backstay", a nice sloping piece of wire we can insulate from ground on the bottom (series feeding it's called because the tuner is installed in SERIES between ground and the bottom of the backstay, because of the insulator. We insulate the top to keep the antenna current from continuing up the backstay into the mast and going DOWN the mast...which makes a wave that CANCELS the wave made by the backstay! That's what the top insulator does. On "Lionheart", an Amel Sharki 41 ketch, this backstay is about 55' long, which is nicely resonant (where the length becomes 1/4 wavelength) at 4.4 Mhz. It radiates very well between 3-5 Mhz..maybe even wider. It also radiates very nicely as a 1/2 wavelength at 8.5 Mhz if you can get everyone away from the bottom of it and you have a tuner that can tune very high impedances. At 8.5 Mhz, it becomes a full dipole antenna with the tuner feeding the END of it, not the middle as a normal dipole is fed at low impedance. There is CONSIDERABLE voltage at 8.5 Mhz right at the bottom insulator. Keeping hands off it is easy. Just key the mic, whistle in it and listen for the cursing near the antenna...(c; Burn the captain and you walk the plank! Both of these bands are very nicely around some great marine bands. Unfortunately for sailboaters, they keep making masts, shrouds, topping lifts, and other lines coming from the top of the masts to the bottom out of METAL....which becomes passive elements, not directly driven, by your backstay transmitter. The regenerated waves from any vertical metal, wire rope, cables, shrouds, are always slightly out of phase and most assuredly out of place with the main signal on the backstay. This causes the reasonably nice fat donut you're looking for in a radiation pattern into something that resembles the outside shape of an 8 leaf Shamrock (Happy St Patty's Day, everyone!) with peaks in some directions and nulls in others as the waves support and cancel each other around the azimuth. These damnable metal things sticking up also absorb a lot of our radiated signal, but are generally forgiven when the sailboat takes on diesel fuel for these transgressions against our SSB signal. Again, it's all a compromise. http://www.tpub.com/content/et/14092/css/14092_35.htm Oddly enough, those loud shore stations that haven't gone dead on marine radio use a mast with shrouds all around it called a "conical monopole" antenna which is VERY broadband over a wide variety of frequencies! Look at the conical monopole on this webpage, and compare it to your mast/shrouds/stays on the sailboat. Your boat is the TOP HALF of this antenna! So, all is not lost. Too bad yours cannot be totally isolated from ground and the whole rigging loaded as a giant antenna. On Geoffrey's former boat, an Endeavour 35 sloop, I used to load the port shroud through the ungrounded chainplate that lead right into the port storage cabinet over the settee...and ran a ground wire down under the cushions to the ground strap back to the engine I installed. This arrangement SHUNT fed the mainmast, which wasn't grounded properly to anything at its step. Shunt feeding has been used since the beginning of radio. We hams have been shunt feeding out "masts" for decades: http://www.qsl.net/w9rb/webdoc9.htm Because the feed runs right along side the mast its feeding, there is no changing phase angle the backstay creates running out from it. A series capacitor is tuned to balance out the inductance of the shunt wire running up, and insulated from the mast until it is attached at the top. Broadcasters also use shunt fed, GROUNDED towers, because the expensive AM transmitter is NOT in series with the 10 gigaamp lightning blast that hits the tower and goes straight to the huge ground network that's attached directly to the bottom of the tower, underground. You can see which type of feed your local AM stations use on their tower antenna by looking for the shunt wire running on insulators towards the top of the tower. Series fed will have a huge insulator at the base and no shunt wire. Shunt fed towers are firmly grounded at the base, not insulated. I don't know why more HF-savvy boaters don't fool around with shunt feeding their mainmast with a shunt wire insulated from the mast on the port or starboard side under the shrouds. They work great and give you a fantastic excuse to put a huge ground strap from the mast to ocean grounding blocks under the hull to protect you from lightning hits. http://nidxa.org/kb9cry_shunt_fed_tower.htm http://www.fybush.com/sites/2007/site-070223.html http://www.earthsignals.com/N6TZ/ Of course, some hams are MOST useful to HF boaters with their obsession of antennas: http://www.k7zsd.com/antennas.htm Very nice, indeed. No restrictive covenants in HIS neighborhood!...(c; Larry -- Roll up to the long checkout line.... Yell, "ICE RAID!" It's your turn to load the grocery belt...(c; |
#9
posted to rec.boats.cruising
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Antenna for my Kenwood R-1000 receiver?
Larry wrote:
ray lunder wrote in : So what would a proper boat antenna look like? Examples, pictures, name brands? Thanks as always. Boats have no room for antennas that work good. So, there are two compromises that work, "sort of". One is an 18' whip coated in fiberglass to make it "yachtie", tuned from the bottom against a seawater ground (we hope, or it's going nowhere): http://www.boatersland.com/sha390.html Above 15 Mhz, it's somewhat of an antenna. Below 15 Mhz, the further down you go the worse it gets because it's just TOO SHORT! We put these awful lossy "tuners" between the bottom of the whip and the radio to match the impedance, at the cost of losing a lot of power. Being so short at lower HF frequencies, its radiation pattern looks more like an inflated hot air balloon, radiating mostly straight up...not out towards the receivers over the horizon. These antennas at low frequencies have almost no antenna CURRENT, which makes the required H field (the magnetic radiation part of the radio wave). They have lots of voltage, E-field, but E-field cannot exist without H-fields perpendicular to them so they radiate poorly. You need BOTH. Some of the "cure", about as much as you'll get, is to use a LONGER antenna with the tuner doing less of the work. One comes with sailboats. We call it the "backstay", a nice sloping piece of wire we can insulate from ground on the bottom (series feeding it's called because the tuner is installed in SERIES between ground and the bottom of the backstay, because of the insulator. We insulate the top to keep the antenna current from continuing up the backstay into the mast and going DOWN the mast...which makes a wave that CANCELS the wave made by the backstay! That's what the top insulator does. On "Lionheart", an Amel Sharki 41 ketch, this backstay is about 55' long, which is nicely resonant (where the length becomes 1/4 wavelength) at 4.4 Mhz. It radiates very well between 3-5 Mhz..maybe even wider. It also radiates very nicely as a 1/2 wavelength at 8.5 Mhz if you can get everyone away from the bottom of it and you have a tuner that can tune very high impedances. At 8.5 Mhz, it becomes a full dipole antenna with the tuner feeding the END of it, not the middle as a normal dipole is fed at low impedance. There is CONSIDERABLE voltage at 8.5 Mhz right at the bottom insulator. Keeping hands off it is easy. Just key the mic, whistle in it and listen for the cursing near the antenna...(c; Burn the captain and you walk the plank! Both of these bands are very nicely around some great marine bands. Unfortunately for sailboaters, they keep making masts, shrouds, topping lifts, and other lines coming from the top of the masts to the bottom out of METAL....which becomes passive elements, not directly driven, by your backstay transmitter. The regenerated waves from any vertical metal, wire rope, cables, shrouds, are always slightly out of phase and most assuredly out of place with the main signal on the backstay. This causes the reasonably nice fat donut you're looking for in a radiation pattern into something that resembles the outside shape of an 8 leaf Shamrock (Happy St Patty's Day, everyone!) with peaks in some directions and nulls in others as the waves support and cancel each other around the azimuth. These damnable metal things sticking up also absorb a lot of our radiated signal, but are generally forgiven when the sailboat takes on diesel fuel for these transgressions against our SSB signal. Again, it's all a compromise. http://www.tpub.com/content/et/14092/css/14092_35.htm Oddly enough, those loud shore stations that haven't gone dead on marine radio use a mast with shrouds all around it called a "conical monopole" antenna which is VERY broadband over a wide variety of frequencies! Look at the conical monopole on this webpage, and compare it to your mast/shrouds/stays on the sailboat. Your boat is the TOP HALF of this antenna! So, all is not lost. Too bad yours cannot be totally isolated from ground and the whole rigging loaded as a giant antenna. On Geoffrey's former boat, an Endeavour 35 sloop, I used to load the port shroud through the ungrounded chainplate that lead right into the port storage cabinet over the settee...and ran a ground wire down under the cushions to the ground strap back to the engine I installed. This arrangement SHUNT fed the mainmast, which wasn't grounded properly to anything at its step. Shunt feeding has been used since the beginning of radio. We hams have been shunt feeding out "masts" for decades: http://www.qsl.net/w9rb/webdoc9.htm Because the feed runs right along side the mast its feeding, there is no changing phase angle the backstay creates running out from it. A series capacitor is tuned to balance out the inductance of the shunt wire running up, and insulated from the mast until it is attached at the top. Broadcasters also use shunt fed, GROUNDED towers, because the expensive AM transmitter is NOT in series with the 10 gigaamp lightning blast that hits the tower and goes straight to the huge ground network that's attached directly to the bottom of the tower, underground. You can see which type of feed your local AM stations use on their tower antenna by looking for the shunt wire running on insulators towards the top of the tower. Series fed will have a huge insulator at the base and no shunt wire. Shunt fed towers are firmly grounded at the base, not insulated. I don't know why more HF-savvy boaters don't fool around with shunt feeding their mainmast with a shunt wire insulated from the mast on the port or starboard side under the shrouds. They work great and give you a fantastic excuse to put a huge ground strap from the mast to ocean grounding blocks under the hull to protect you from lightning hits. http://nidxa.org/kb9cry_shunt_fed_tower.htm http://www.fybush.com/sites/2007/site-070223.html http://www.earthsignals.com/N6TZ/ Of course, some hams are MOST useful to HF boaters with their obsession of antennas: http://www.k7zsd.com/antennas.htm Very nice, indeed. No restrictive covenants in HIS neighborhood!...(c; Larry Larry, I don't think the OP with an R-1000 has to worry about radiation pattern, antenna current and tuners. He just needs a good long wire for his receiver. krj |
#10
posted to rec.boats.cruising
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Antenna for my Kenwood R-1000 receiver?
Larry wrote:
SNIP Above 15 Mhz, it's somewhat of an antenna. Below 15 Mhz, the further down you go the worse it gets because it's just TOO SHORT! We put these awful lossy "tuners" between the bottom of the whip and the radio to match the impedance, at the cost of losing a lot of power. Being so short at lower HF frequencies, its radiation pattern looks more like an inflated hot air balloon, radiating mostly straight up...not out towards the receivers over the horizon. Actually, vertical antennas (even very short ones) radiate almost nothing directly overhead. Over seawater, vertical antennas radiate better at low angles toward the far horizon than just about any horizontal antenna. These antennas at low frequencies have almost no antenna CURRENT, which makes the required H field (the magnetic radiation part of the radio wave). They have lots of voltage, E-field, but E-field cannot exist without H-fields perpendicular to them so they radiate poorly. You need BOTH. If the short antenna is matched (i.e., you use a tuner) it will be nearly as efficient as its longer counterpart. A short vertical antenna has very HIGH current at its base. Any loss in efficiency is due almost exclusively to the tuner when operated over seawater. Over land, ground losses become a more significant factor in reducing efficiency. Some of the "cure", about as much as you'll get, is to use a LONGER antenna with the tuner doing less of the work. Ironically (as is often the case with natu if bread and crackers are exposed to the same environment, the bread becomes hard and the crackers soft. Go figure.) at the higher frequencies, a longer vertical antenna may actually radiate less toward the horizon (low angles). So an antenna that is the "right" size for 4 MHz may not work as well on 15 MHz as a shorter one! An antenna "too long" for a frequency will develop lobes and nulls in the vertical plane which may be detrimental to your desired propagation path. Yet another need for thoughtful compromise. One comes with sailboats. We call it the "backstay", a nice sloping piece of wire we can insulate from ground on the bottom (series feeding it's called because the tuner is installed in SERIES between ground and the bottom of the backstay, because of the insulator. We insulate the top to keep the antenna current from continuing up the backstay into the mast and going DOWN the mast...which makes a wave that CANCELS the wave made by the backstay! Well, if the mast is insulated at the base (some are) what you have is something like an inverted "V" (end-fed) and there will be some directionality, but cancellation is far too strong a term to describe it. Even if the mast base is grounded, the small amount of directionality would probably not be noticed in normal operation. SNIP On Geoffrey's former boat, an Endeavour 35 sloop, I used to load the port shroud through the ungrounded chainplate that lead right into the port storage cabinet over the settee...and ran a ground wire down under the cushions to the ground strap back to the engine I installed. This arrangement SHUNT fed the mainmast, which wasn't grounded properly to anything at its step. Shunt feeding has been used since the beginning of radio. We hams have been shunt feeding out "masts" for decades: http://www.qsl.net/w9rb/webdoc9.htm Shunt-feeding the mast (and back- and forestays) doesn't require the base of the mast to be insulated. I've been shunt-feeding a grounded mast on a 34' Tartan for years and never felt the need for a better antenna. Since I use a manual tuner, it was impractical to feed the bottom of the backstay with a tuner in the cabin. Because the lower ends of the forestay and backstay are ungrounded, they act as a top hat, making the mast appear longer (electrically) than it is. Since the stays are not symmetrical, they doubtless provide some often needed horizontal radiation. I must say that on some frequencies, particularly the 40 meter band, the feedpoint impedance of the system was wildly high. I ended up using some additional outboard reactances to tame it. Everywhere else, tuning was reasonable. An autotuner may have handled it OK. A key advantage is that you can install an SSB in minutes without worrying about insulating the backstay, etc. Chuck ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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