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zap

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Everything posted by zap

  1. How about a feature to automatically subscribe you to a thread you've posted on? Mobile device-wise, tapatalk works pretty well. Maybe a control panel similar to radio reference for the browse users to easily find info about new posts in threads they are subbed to?
  2. The Chinese radios really have changed the radio game. My apartment complex acquired a bunch of BF888's. I essentially help resale the UV5R's. I generally program with Chirp unless I specifically need to remove the vfo. I've noticed several things with the radios. A) Don't try and hot swap the programming cable or speaker/mic. Turn the radio off. I've seen many people blow either the ptt out speaker on the radio (usually works fine with a speaker Mic though). the receivers are good, the squelch circuits suck. They can get a little annoying on high rf environments, even with a receive pl on. C) I've found the stock UHF antenna on the bf-888 has 2-3 more dB of gain on the dual band antenna...and a Motorola Jedi series UHF antenna has 3 dB more gain than the "high gain" UHF antenna (same bandwidth). The Motorola antenna can be found on Amazon for $8. D) if you trash one, you are out $15-30.
  3. Kenwood. Most UHF analog Kenwood gear is 90/95A. 2 out of 3 of their current analog UHF mobiles are 90/95A.
  4. Nearly all of the Ritron VHF radios are MURS accepted. Even their little intercoms are type accepted for Part 95A and Part 95D operations (as well as Part 90). The Motorola VX series are pre-programmed with MURS frequencies as some of the channels. Motorola RDM series as well. GMRS ERP is never listed. Just transmit power. The 675 system in Lubbock, it runs 50W right out of the transmitter, looses about 1/2 dB going through the duplexer and then goes up to the tower mast about 80 ft in 1-1/4" hard line to a DB420 that is mounted roughly 360 ft up. ERP through that (including line loss and loss through the duplexer) is around 615W...if only we had put a DB413 up there instead. It only talks for about 40 miles (due to the fact it's perfectly flat up here). Path loss is just about insane to begin with. Low band, high band, UHF...higher frequencies means more practical gain antennas. Remember, NASA sent video nearly a quarter million miles from the moon using about 1.7W (UHF).
  5. They are very common in the amateur world, just not as common in commercial. Here's a little more reading on the subject. I probably should've lead with this but it didn't come to my mind until second post. http://www.repeater-builder.com/antenna/ant-sys-duplexers.html
  6. A simple diplexer will do what you want. http://www.theantennafarm.com/catalog/ncg-comet-cf-4160n-7620.html I'd recommend the models with N connectors.
  7. Negative ghost rider. All of my purpose built repeaters are older than I am. My newest two are R100's.
  8. Makes me feel good inside about my Micor with a 12W PA. And then there's the one I have with a 100W PA.
  9. I looked at building some out of TK880's but I couldn't find the little pigtail anywhere (I guess Kenwood's version of the OPC-617 that my Icom's use). 16 pin Moto's are easy, $10 cable from China, programming the pinouts and you are GTG (minus the duplexer/antenna setup). It's very rare to see low duty repeaters in commercial operation that aren't based off of mobile radios. Especially in applications where a desktop unit isn't needed (GE MASTR II and Kenwood TKR desktop units). The Icom CY-series of repeaters are mobile based as are the GR series from Motorola (GR1225 excluded), think I've even seen a GR style from Moto based off the CDM line. Two mobiles can be put together to form a repeater. In some cases with older (crystal controlled) mobiles, you can actually make the receiver and transmitter run full duplex and convert a mobile to a repeater. Examples of this are Motorola Micor, GE MASTR II, Motorola Mietrek…
  10. zap

    Voting System

    What about your own sub-net for all of your links? Legalities aside, one could use simplex channels for the control links, however, at that point it is far easier just to setup separate repeaters with a link radio for all three outlying repeaters.
  11. Anyone ever though of implementing a voting system on GMRS? Just curious.
  12. I'm just going to throw this in there… Maxtrac's use Mini UHF, not SMA. Nothing wrong with the Mini UHF as long as you keep it below 120W and below 1 GHz. The GR series repeaters initially used RG58. Any RG8 or RG58 is a very poor cable in a duplex environment. Best option would be RG142 or RG400 (for the RG58 size). Cut your line to odd quarter wave lengths (roughly) of the tuned frequency (the lines need to be within 1/4" or less of one another).
  13. I was thinking a remote receiver for the repeater would work as well (assuming one could get in touch with the owner and coordinate it).
  14. I see…says the blind man to the deaf mute.
  15. Why wouldn't you be able to link? All the rules say is that interconnection to the switched public telephone system is prohibited (written before VOIP was ever implemented anywhere). Asterisk is the basis for both Allstar and IRLP. VOIP linking may not be the best solution for natural disasters as internet can be assumed to have the same or less reliability as a phone line. A better option for disaster based setups would be an rf based link system with a VOIP node on the hubs.
  16. Personally, I wouldn't replace the RICK with the ID-O-Matic as the RICK has remote knockdown capabilities. Is just feed the ID-O-Matic into the RICK's accessory and use it just for ID. Since you have one, you might download the service manual if you don't already have a copy. http://www.repeater-builder.com/motorola/gm300/gr300-gr500-service-manual-6880903z42-a.pdf Repeater builder also has some info about split antennas versus duplexes and how far apart they should be.
  17. I've been thinking about an off grid repeater. Probably going to use a HT1000 (COR isn't hard to pull off of one) as the receiver and a mobile turned down somewhere between 10-20Which for the transmitter. Probably use an MSP430 as a controller. If I can get the site I want...should be a nice little setup. Basically the same setup for a portable repeater I've been working on...just designed to be self sustaining.
  18. Don't forget to use a quality antenna with gain (over the factory antenna) if you're going to a narrow band service.
  19. 36 miles on the .625 system we have in Lubbock. Run out of LOS on I-27 just south of (Go To) Hale Center.
  20. Logan, that is a setup a firefighter would die for...especially if he was fighting a fire in the building and the roof could no longer support the weight of that brick as he was walking under it. A really cheap but dependable repeater is a GE Mastr II mobile. The 128 W version will run 50W at continuous duty, any of them will run 40% their rated power at continuous duty. Anyway, you can usually find them for under $40 (I occasionally find them for free), spend $50 on re-crystaling channel elements, and another $20 and some time converting the radio to full duplex operation. The Mastr II Executive radios don't have a stable enough transmitter for GMRS though.
  21. Does your GR300 not have a Rick in it? The Chinese duplexes are just notchplexers, nothing really special about what radio they connect to.
  22. Not quite true. Look at the FCC ID for a Motorola GP300 (90/95), Icom F21 (90/95), Kenwood TK-880 (90/95), Motorola M1225 (90/95), nearly all of the Kenwood TKR-8XX repeaters, they are out there. A man with an extra ticket should seriously reconsider his closing statement. Many hams run Part 90 equipment (most of it is better built). Hams even have P25 and DMR repeaters up…I wonder how that works. Not to mention, 33 cm only has one Part 97 radio option (most of 1.25m and 33 cm is made up of Part 90 equipment).
  23. Question for those who's stations don't transmit PL while IDing… What controller are you using? I've got several R100's, GR300's and Micors that I was wanting to setup in such a manner for personal uses but haven't found a controller that will run them like that yet.
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