WRAK968
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Posts posted by WRAK968
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Orion, first welcome to the group and congrats on becoming a GMRS license holder.
So, first thing everyone tries is a cheap system and trying to get up high. I know, I did it with poor results. I now have a RKR1225 and a good duplexer and antenna. When I started I actually used a flat pack duplexer, and a cheap antenna. I had about 4-5 blocks range. I changed the antenna to a diamond 200u when extended my rage to about 1 and a half miles, and when I upgraded the duplexer to a band pass I think it is, I now have 4 miles range at 15' high and 25W out. For now Im ok with that as really the repeater is used to boost our portable coverage and allows us to talk from portable to mobile.
What I'm getting at is, depending on what your needs are, consider setting up at your house first especially if your in a 2+ story residence. a 2 story building could easily get an antenna up 25-30 feet, and once your above the tree line your range will increase drastically. The nice thing is you can work out any problems or glitches with your setup right away without needing to wait for site access. Once everything is running and you know it all works and what your expectations are, then make plans for a tower location. -
Typically from my understanding, Part 90 is allowed on GMRS mostly because the specifications are generally the same. If I recall, the main difference is that part 90 has a narrow band requirement while part 95 is wide band. The other difference is maximum power output, part 90 is 100+W while part 95 is 50W. As long as your part 90 equipment is set up with part 95 specs, you can usually get away with it.
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RCM, If you need, I do have firmware (Cant remember which one off the top of my head but it does update the radio options for version 2 units) for the 880, I can also explain how to enable FPP, but in all honesty its a bit difficult (I could never figure out how to do it.) All I use are 880/380's so if you need anything give me a shout.
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I might suggest a little program, I think is still available for windows, if not there are others. ScanRec is a configurable recorder with vox for the PC, and you can run your radio into the sound card and monitor a channel for a week or a month....then just go back and see how much traffic was there when you play the recording back.
In commercial radio, I have used a vox tape recorder to do this in the past. And, while I am telling stories...A tech I once worked with, he had an analog clock hooked up in the mix, when the vox controller came on, it also fed 1.5 volts to the clock, and the clock would run when there was audio coming in. He set the clock for 12:00 and then checked the minutes, and seconds on it when he/we went back to check the recordings in a week. That's how we used to find the best frequency from the 4-5 the coordinator would send us.
Just thought I would share, monitoring a channel all day is tough, it needs to be at a fixed location too, preferably where the repeater will be, and on a similar height antenna. If you try to do it manually...well, as soon as you walk away there will be traffic...or could be. So a recording device is very handy.
I use an old radioshack scanner that has a hit counter on it. I put all pairs in and leave it for at least 30 days. When I return, its a matter of looking at the hits not just on the RX but the TX side as well. Doing this lets me choose the best pair for the area.
- quarterwave and RCM
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The M1225 series radios are good, if you have a way to program them as they need an older computer to program them. I personally use Kenwood TK880's which have software readily available online and will work on modern computers. They are first responder grade which means integrity & reliability are there, and not as expensive as the 1225's normally cost.
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Greg and Jones, If it helps, the SWR on the antenna, tested by both an MFJ analyzer and the surecom meter, shows a 1.2-1.3 SWR reading (Depending on if I am sweeping the 462 or 467 frequencies) so SWR feedback shouldn't be the problem when talking about power output. I suppose there could be an issue with the antenna itself but I would think if that was true that the repeater would back down power, which it doesn't now that I have a good duplexer. That's why I was at a loss. I do have another question though. When making a jumper, should I also include the 4-6" length of the TK880's antenna pigtail in my jumper measurement or do I start my measurement at the connection?
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The reading on a power meter will vary a LOT depending on where the meter sits in the overall total-length of coax cable. To get an accurate reading, the meter MUST sit at an interval of 1/2 wavelength along the transmission line. The only way to easily do this is by insuring that you are using a half-wave input jumper cable on your meter.
Cable electrical wavelength is figured by the Speed of Light (299,792,458 meters per second) divided by the frequency in Hertz, the dividend of which is multiplied by the velocity factor of the cable (look at the specs for the cable you are using).
For instance, if my meter's input jumper was made from RG-213u, I would see that the velocity factor for that cable is 0.66. (sometimes shown as 66%)
(NOTE: In this example, I have used 462.600 in the GMRS band as my desired frequency. 462,600,000 Hz)
Let's do the math: 299792458 / 462600000 = 0.6480597881539127 * Velocity factor of 0.66 = 0.4277194601815824 Meters. That is a full-wavelength of cable, and we need a half wavelength, so cut it in half. So, your jumper cable into the meter should be about 21.5 centimeters long, or about 8.5 inches.
If you were using a smaller cable, like RG-58u with a foam dielectric, which has a velocity factor of 0.535, then you would need .1734 Meter jumper, or about 6.8 inch jumper to correctly match the input of your meter.
If you are using just some random-length input jumper, particularly if it is over a full wavelength long, then you may not be even close to the half-wave point, depending on the length of the rest of the cable going to the antenna, and the meter will not read right. If you use this calculated length of input jumper, accounting for its velocity factor, then whatever is on the output side makes no difference to the reading accuracy.
By the way, this rule goes for SWR meters as well as power meters. If you set up your UHF antenna with a 3-foot truck-stop CB jumper going into your meter, then you are likely WAY out of 'whack'. These rules still apply at HF also. It isn't as critical below 30 MHz since the wavelength is so long, but if you use a 4 or 5 foot long meter jumper at CB frequencies, it WILL be wrong. At 27.205 MHz, use a 6 inch jumper, or else a 9.6 foot one for accuracy.
Tech hint: I keep several different lengths of pre-made jumpers in my Bird watt meter case for different frequency bands that I normally work with, and have them all tagged as to what band range they are for. The higher you go in frequency, the more critical this gets, and the SHORTER they get... sometimes TOO short, thus for 950 MHz, I keep a 15.6 inch jumper of LMR-400, which is 1.5 Wavelengths, but still on a calculated half-wavelength point in the line. A 5.2 inch long LMR-400 jumper is too short to work with.
Long winded, sorry, but I hope this helps.
-Jones
Not at all Jones. Im still new to how all this stuff works, and being I never had an elmer to teach me some things I've just been doing my best to put it together myself. Ok, so I need to build a shorter jumper as I have a 2' jumper currently in line. Ill look into that.
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What swr meter are you using? Ive noticed meters that read close to each other on VHF can differ significantly on UHF.
I am using a Surecom digital meter, The thing is, I am using the same meter on different antennas and getting different results with power out, which makes me wonder if the meter is messed up or if perhaps I am not reading it correctly.
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Have you checked the SWR on the coax and antenna? Excessive SWR can cause the power amplifier to clamp the output to protect the transistors.
1.1-1 on the roof ant, 1.5-1 on the base ant, 1.8-1 on the 1/4wave that read 48W
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So, after receiving a few TK880's I threw them onto my meter to test them and ensure they were working. I noticed that on the tower antenna, they were only putting out 5-6 watts on high power (suppose to be 25 watts.) I figured there was an issue with the software on the radio and I went to test mode and turned up the power level, but was surprised when I maxed the level out and it was still only transmitting at 18 watts. So I moved to a smaller antenna and BOOM, the meter now reads 48 watts out. Switch to a base antenna that is in the shop and it reads 28 watts...
What the hell lol, I've never seen a radio that the TX power changes depending on what antenna is being used. But I am sure many of you see where I went wrong. Im using an antenna rather than a dummy load for transmitter testing. Still though, I am curious as to why the power fluctuates so much.
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Im a little confused as to what your looking for, but I can try to answer your questions to the best of my ability.
I can understand home repeaters, those are stationary and easy to set up. You can use two UHF part 95 radios, (I know a friend that is using a pair of Kenwood 8150's) with a controller, or buy an all in one system (I use a GR1225, which is basically a receiver, transmitter, and controller all in one.) Duplexers ARE needed unless you have the 30+ meters of separation between the two antennas. This prevents desense between the transmitter and receiver. Im not sure about "ladder line" filters, as from my understanding thats mostly used in HF, but I could be wrong. I use a DB products duplexer. Its designed to be mounted in a 19" rack and only takes up 2 slots (about 4 inches) so Im not sure why you prefer not to use them. Your repeater will not be listening to 462, but rather 467 Mhz and then transmit on 462. Keep in mind that height is everything depending on the terrain. If you live on a farm and the closest house or tree is 10+ miles away, running the repeaters antenna off your roof should yield good range covering quite a bit of that distance. If you live in a city, the same antenna at the same height may transmit only a couple miles.
Linking is allowed, however there is still a rule against "patched repeaters" meaning the repeater can not hook into the phone system. Im still not 100% sure phone internet is included in that or not, but I think as long as your repeater can't place phone calls you should be ok. A lot of folks use something called team speak with a controller and micro computer that allows them to interconnect.
Not sure you would really need a repeater for your personal car unless you plan to do a lot of camping or hiking where your out of your coverage area and away from your car. Really its more trouble than its worth risking a dead car battery and unlawful RF exposures. Its just an added expense. If you really need to extend range for, lets say a portable while your shopping, you can get a two way controller which would allow you to talk into the radio in your car (Via simplex), then re-transmit that message into the repeater (which is duplex.) The entire system with a vehicle is rather complicated and would cause confusion in the long run.
Repeater capable handhelds are all over. The BF888 I believe is part 90, as is the BF82. The BFGMRSV1 is part 95, but if you want other companies, Kenwoods TK380 is repeater capable and part 95 compliant.
CWID is NOT 100% legally compliant. The reason is because the CWID is only transmitted on the "Transmit" (462) side of the repeater. ID is still required on the 467 (Receive) side of the repeater though I do believe it is helpful when there is an issue with the repeater for other uses to identify the repeaters call. I do run CWID on my repeater, even though I still give my call sign in English. Trying to CWID a google link would take way to long and be pointless, your better just registering your repeater on MyGMRS.com so that users can simply look your system up.
I'm again lost with the "Australian CB" radio thing. I do not know any Australian radios with US type acceptance, but again I could be wrong with that as I do not know what radios are used as Australian UHF CB's. As for wireless mics, I cant say I know of any mobile speaker mics, but I do know many manufacturers like Motorola, Kenwood, and Vertex are selling wireless kits which consist of a dongle that plugs into the radios mic port and connects via bluetooth to a palm mic.
I hope some of this was helpful
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Nope, just nobody is posting anything lol. I saw your post and thought something interesting was happening
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I agree with Pastorgary, My family only uses the TK880 series radios for mobile use. However, I get the feeling you are looking for dual band, VHF+UHF radios. To my knowledge, while there are part 90 dual band radios, the only ones I have seen are from motorola and are expensive. I may be wrong about Motorola being the only dual band part 90 mobile though.
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As someone who worked through and after Sandy on the shore, this is not a storm to play with. BE CAREFULL
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Perfectly fine, in fact we use MURS as a back-up and BS channel for when the repeater goes down, [Or for when we want to discuss something without the PD or supervisors hearing] MURS doesn't cover the entire property but we can get a few blocks range, especially when on the beach.
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Interesting data there, Unfortunately I am headed to work so I cant read into it just yet, but when I get home Ill try to decode it and see what is there
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PB30X, I cant say I have ever heard a message go over 30 seconds where I am. I believe the W2NJR system will even reset if the message is over 45 as a default because it ties up repeaters across the state of NJ. I did laugh at the use of judgement comment lol. Seems like the world is lacking in common sense and logic. Quite scary when one thinks about it.
Jones, thanks for the added info, and I hope my post didn't scare you about using EAS on the repeater, I was more curious and I cant think of any repeaters or systems that use them locally for GMRS. Now that I learned the EAS alert tone is FSK data I am curious what info FLDigi would spit out when decoding it. Off I go to do more research!
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Seems to work for me
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Test test
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Sounds good Jones. I believe a re-transmit would be unlawful, however, W2NJR simply uses its own voice to say "Thunder storm warning" or whatever major weather events are going on. I would think that it would be ok as long as it is in this format, but would likely require the repeater to transmit an ID. I also believe that the "Broadcasting" clause may play a factor as well.
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So, the other day I was listening to the W2NJR ham radio network and heard an alert go out with an electronic statement "Thunder Storm Warning."
Basically, the W2NJR system uses the NOAA SAME code for the area to get weather alert and warnings. It then re-transmits the information following the coded signal, which is how the system knows what warning it is giving. This is legal on ham radio but what about GMRS? I am not planning on adding this feature to my repeater but if its legal I would think other systems could make use of it. The idea has just made me curious.
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Thank you, Ill put in a message to the site staff
New License Wants GMRS Repeater
in General Discussion
Posted
Just cause I'm curious, How high are your antennas, and are you on the peak of a hill?
Thats range sounds awesome for being on a house 