The client gets a complete report of the testing, including the network analyzer graphs showing proof of performance. The second of the two tower legs which bent and folder over. It is anticipated that erection of the new tower will take about ten days. Payment will be euplexer immediately upon notification of seller approval by email invoice, after the Seller approves the bids. This decommissioned tower was slated for dismantling in the Fall of according to the tower owners, but that work has not yet been done.
This website requires javascript in order to function properly. As can be seen in duplsxer photos showing the plungers before and after the application of some TLC, the difference is more than visible. Bring or ship the whole set to DuplexerRepair. Thu, December 20 — Mon, January 07 St. This generation of the project utilizes an Ethernet shield running on an Arduino Mega development board.
The 4-cavity models are rated at 80 dB or more of branch isolation; whereas the 6-cavity sets are rated for dB celwae higher isolation. This duplexer is currently tuned for Sign up for our auction bulletin now. Depending on your budget, location, skills, and available resources, the following options are available for converting a set to a -B model:.
Click on any cekwave to see a larger image. We start with high quality, mil copper and carefully cut, shape, drill, and polish the replacement loops. The same two tuning plungers after careful cleaning and polishing. The End Results A complete conversion, expansion, and overhaul job such as the ones described here, commonly involves between 15 to 20 hours of labor, plus With This capacitor had failed, causing the set set to be taken out of service.
It is important to verify that any unit has the proper length harness cables for the frequencies to which it will be tuned, celawve most duplexers will not meet their published specifications with celwwve wrong cables or the wrong length cables. Finding specifications, especially for models that are no longer in production, can be a very frustrating process.
A DB is very different from a PD Oh well, this item has been sold; that you to all who had inquired and moderators, please mark this listing as sold. After disassembly of the old cavities, one of the many steps in the overhaul and conversion process involves getting the tuning plungers back in good.
So is the resulting performance and ability to be accurately tuned and for that tuning to remain stable. We will not be the least bit surprised to get a call at any moment letting us know the tower has completely failed.
This tower is only about 50 feet from the utility lines running parallel to the road. N8NOEFeb 5, With all the components overhauled and reassembled using the new frame and mounting rails, each cable, Tee-connector, etc. Buyer responsible for inspecting the items before placing bids, and prompt item removal within ten 10 business days after receipt of invoice. They are measured and cut by hand, drilled, de-burred, shaped. As can be seen in these photos showing the plungers before and after the application of some TLC, the difference is more than visible.
Show Ignored Content Thread Status: This tower is only about 50 feet from the utility lines running parallel to the road. As can be seen in these photos showing the plungers before and after the application of some TLC, the difference is more than visible.
After disassembly of the old cavities, one of the many steps in the overhaul and conversion process involves getting the tuning plungers back in good. On non-stamped enclosures, you have to remove the cabling from the loop enclosure, remove the eight screws used to attach the enclosure to the top of the cavity, then look at the underside of the enclosure.
The same two tuning plungers after careful cleaning and polishing. This generation of the project utilizes an Ceelwave shield running on an Arduino Mega development board. Important Rules Have you read our Swapmeet Rules? Obviously, if it falls in the direction it is leaning, there is a high likelihood it will fall across the utility lines and the roadway. This website requires javascript in order to function properly.
When you get the loop enclosures back, just install them on the duplwxer cavities with the proper cables and have someone tune them for you or do it yourself, if you have the proper equipment and skills. Finding specifications, especially for models that are no longer in production, can be a very frustrating process. Register for a free QRZ account.
This duplexer is currently tuned for The guy wires are old and extremely rusted and six of the original nine guys have broken. See the next article as well. Some Notes on Fiberglass Antenna Painting Comments from several folks that accompany the above article. Andrew Andrew Corp. There is enough information here that anyone with a welder could make their own very strong winter-ice-proof welded 10 dB gain yagi antenna.
Note that the element length measurements shown in the diagram are for MHz frequencies. If you need a physically strong very good UHF point-to-point link antenna then use this design as your model. A letter suffix indicates the range that an antenna is built for: MHz, MHz, MHz, or MHz but that the actual end frequencies and the assigned letter is NOT consistent across the product line.
For example, on one product i. Be very careful that you check your range letter definition before you spend your money on new or used antennas! Data sheet on the DB ground plane omni antenna: This is the so-called "bent-over" ground plane that is rated at unit gain and watts. The charts cover MHz. Just measure the current length of the dipole and then multiply this length by current-freq divided by the new-freq. So if the current length is inches and the current freq is 46 MHz and your destination frequency is To change the length you will need to remove the pop-rivet and a little dimple that the production line uses to hold the trombone in place until the rivet is installed.
Sometimes the VSWR depends on the tower face. Then adjust the trombone to the length you calculated and apply a little RF power and check the reflected power.
Then get a long stick and start moving the trombone slowly while watching the reflected power. When you get the best possible VSWR, stop and redo the rivets. Personally I'd add a bead of non-acidic silicone bathub sealer to water-seal the joint. Both cost a little more than a fiberglass antenna but will easily last years, and don't have the cracked joint duplex noise problem , nor will you have a pile of fiberglass toothpicks on the ground after a nearby lightning strike.
How many Hustler, Comet or Diamond antennas will you go through in years? Frankly, chosing to mount your antenna on the tower top only to get a few extra feet isn't worth a bent or broken metal support tube, and if your antenna is side mounted even if the tip is only 6 feet down from the tower top the tower itself or someone else's antenna can be the lightning rod and take the hit. It amounts to separating the elements into two independent antennas on the same mast.
Each antenna has a separate feedline terminated at the bottom of the mast. And I've been told that at one point maybe still can you could order a new DB less the tubular mast, and supply your own. Supposedly one group built up a "single antenna" as defined by their tower agreement that was made up of a UHF stationmaster-type fiberglass stick on the top of an extended length tube, a VHF DB in the middle, and a end-mount UHF beam clamped a couple of feet below the bottom element and a few inches above the lower end of the tube.
There is enough information here that anyone with some experience bending aluminum tubing can build one for themselves. Or if you are going to build your own and want extra strength you could use aluminum rod.
Complete with calculations. Details of the DBE wiring harness 1. It uses a director element that is built into the dipole assembly to shape the pattern - if you end up with a used one and it is missing the director there's no telling what the final pattern will look like. The antenna can be ordered for any frequency from 30 MHz to MHz. The catalog claims that you can stack the antennas and get 8 dB gain with 2 antennas and 11 dB gain with 4 antennas.
The data sheet is very specific that it must be mounted "2 to 3 feet below the top of the tower or pipe support. At the same time it must be clear of all guy wires or metal objects for 2 to 3 feet.
I thought it might be useful in the R-B Antenna section. DB data kB PDF file The DB is essentially two DBs on one foot long mast, and can be ordered with a phasing harness that makes it one antenna - and that makes it the ultimate 2m repeater antenna 10 to 12 dB depending on the pattern.
The catalog sheet shows the "normal" mounting has being a split mount: the top half is above and the bottom half is below the top of a tower i. Or if you need extra RX-TX separation: order it with the -S split kit option and use it with two feedlines and a split duplexer as separate DB receiving and transmitting antennas.
This is the model that has the feed harness hidden inside the support pipe. I've seen one of these on MHz, and it's rugged! If you need a commercial grade dual-band antenna, this is it. Or if you are limited to one antenna, then order this guy and use it as separate 2m and antennas with two feedlines, or with a pair of commercial-grade TX-RX Corp.
But don't try and use one on a Do it by frequency range, not suffix letter. The SWR is specified as under 1. According to the spec sheet the standard connector is a male N, but I've seen installations with a PL on the harness, and it looked like a factory harness.
The DB is essentially two DBs stacked on one longer mast almost 9. Specify Omni or Offset pattern when ordering, and if top or side mounting when ordering. For side mounting order the DB mounting kit. The "E" range is either or depending on which catalog you read, be very, very careful when ordering one of these. The DB is essentially two DBs stacked on one longer mast and can be ordered with one or with two feedlines the "split kit". Specify Omni or Offset pattern, and if top or side mounting when ordering.
Anybody have a drawing or the measurements for MHz? The data sheet on the DB UHF dipole array kB PDF file The DB is an array of 8 dual dipoles that can be configured as a single 8-element antenna or as two 4-element antennas on the same mast conversion requires a different harness.
The and are light duty, the is heavy duty. Phasing harnesses for 2 or 4 antennas are available for up to 15 dB of gain. If anyone has a translation list or chart even just a few model numbers we'd love to offer it here. VHF 5. Sinclair Sinclair Multiband Antennas offsite link Sinclair is one if the few companies left that offer a dual band repater antenna. Not cheap, but it will last you a few decades. Telewave Click here for the Telewave on-line antennas section Does anyone have additional data sheets or scans of the box-stuffing literature that Telewave ships with their antennas?
Towers How to look up towers Search all of the FCC registered towers - broadcast, cellular, everything A nice explanation of where the "RG" in cable numbers came from. Crites WA9ZZU As a result of my extensive review of documents in my possession and in response to the document referenced above I am the author and others only extracted parts to be used in an Engineering Report which included my measurements and log book gathered data, and drawings, to which my engineering supervisor appointed by the company assembled the data and other pages, and added his name first above mine, even tho I had done the work.
You Kevin Custer, do hereby have my permission to publish this document in its entirety on your website Repeater Builder. Their products can be purchased through MFJ. Like the LMR-nnn cable where nnn is any 3 or 4 digit number it is not appropriate for duplex service. Later versions have a tougher outer jacket, and at one point jumpers made from were shipped with commercial LMR antennas.
This is a high loss cable, over 30 dB per feet at MHz. Most of what is sold as RG these days isn't anywhere close to mil-spec stuff - all you have to do is check the density or tightness of the braid, then count the strands on the inner conductor and make sure it's tinned.
Note that this is a PVC based cable that can no longer be used in aerospace applications due to the fact that when PVC is burnt i. It has a loss per feet of 1. The PDF file also has return loss specifications. Note that this coax is intended for use as RF jumpers in general purpose, high temperature, vibration and movement-free applications, NOT as feedline.
The loss per feet is 3 dB at 50 MHz, and 9. The braid coverage is important, but the major drawback is the very high loss - per feet is 10 dB at MHz, and about 25 dB loss at MHz.
The small size contributes to the low power handling capability - don't run more than 25 to 30 watts through it at MHz or 20 to 25 watts through it at MHz. I've seen a melted piece of RG; not pretty. And when it shorted it killed the PA deck. Personally, I won't use it at RF unless I have to, and despite the negatives listed above I do have a roll of it in my shop: I use it for audio coax in everything I build. My dad WB6SOX taught me a trick that you can use on both RG and RG you can peel back the outer jacket an inch or more, spread the braid a little just above the end of the jacket and use a spring hook to pull the center conductor through the hole in the braid.
You can then put some tubing heat shrink or normal over the braid pigtail.
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