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Everything posted by marcspaz
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Midland mxt275 as a s.h.t.f. base station / ground plane question
marcspaz replied to Ccleveland1226's question in Technical Discussion
I would not move a radio or radio parts back and forth between the vehicle and home very often. There is a limit on how long spring strength for connections holds out for, based on total number of times the spring is flexed. You will end up wearing out cables, cords and connectors pretty quickly. Do yourself a favor and get a dedicated radio for the house. As far as antennas go, a beam would be nice... but maybe pricey. There are companies that make screw-on ground radial kits so you could use a cheap mobile omnidirectional antenna. 2.5 miles through heavy woods should not be a problem. Yesterday I was talking simplex with my son, mobile to mobile, covering 8 miles of hills and woods with only 2 watts. There was a max of 100 feet in elevation change. Unless you have a ton of RFI, you should be fine. -
Short of profanity, you can do just about anything you want. Many people use their call sign with a custom suffix, as noted above. If my son is expecting to hear from me, I just get on the radio and call him by name. "Hey Nick, are you there?" On the repeater, you might get a response from the wrong Nick. So, appending call signs work great, since it ID's a specific group of licensed stations. So I would say something like "<call sign> mobile 2, this is <call sign> mobile 1, do you copy?*
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I have a buddy who come to VA to play on the rocks, who drives up from Goose Creek. Make a weekend of it and go to Chaos or The Cove. Or, Rausch Creek is just 3 hours further, in PA.
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Looks great!
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$150 for the one I have. You take them in to get them re-sharpened. The diamond belts are very cool... couldn't get a sharper edge if you tried. And it's fun to watch them do it.
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I thought you already changed the cable? Yes, quality cables will make a dramatic improvement. As far as the power reading being low on ch 1... it could be a meter accuracy issue. Most power meters are the most accurate in the upper 1/3rd of the scale.
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Am I the only one who goes full-send with a diamond-edge titanium step bit, a 30 year-old Craftsman variable speed drill and some cutting oil?
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Mobile radio over 15 watts causing issues with the Jeep JK
marcspaz replied to Mikeam's question in Technical Discussion
I had put 6 chokes on the harness and it made zero difference. The antenna was literally less than 2 inches away from the defroster. Nothing helped but removing the element from the wiring harness. Later, I added antennas up front, which gave me options... but when I wanted to use my 102" or 114" antennas for HF, I had to use the mount in the back, because the hood mounts couldn't hold the weight. It wasn't much of a hassle to just unplug and reconnect as needed, so I just kept doing that. -
You can bury all ground radials. They work better under ground a couple/few inches. It helps improve ground performance by increasing the radiation pattern (more surface area in direct contact with the earth) and it gets the leads away from lawn and turf surface care. The biggest benefit is it reduces the noise floor from electricity and electronic devices nearby.
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1.) You should have about 7 to 8 inches of reflective surface in all directions.... about 14 to 16 inches in diameter. So, I would move it back more. 2.) Yes and no. If you have high quality cable, looping it should not impact performance or SWR in any way. Even if you have poor performing cable, the chances of you creating just the right size coil to create performance problems is fairly low. However, not impossible. 3.) I think you mean SWR and Reflectance. Line loss is always measured as a positive DB and the smaller the number the better. Line loss describes loss in the length of line, loss in connectors, etc. So, lets say you insert X amount of power... a line loss of 0.3 db is better than a line loss of 0.5 db. Now, Reflectance, which measures the amount of back reflection created by a reflective event (i.e., high SWR) compared to the amount of power injected. It is the inverse of return loss. Reflectance is always a negative number and the lower the number the better. So a reflectance value of -30 db is better than -15 db, for example. Collectively, line loss and reflectance determine how much energy radiates out of the antenna and how much is reflected back to the radio. Based on what the VNA shows, you are only losing about a 10th of a watt. A moderate gain antenna will more than make up for it.
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Mobile radio over 15 watts causing issues with the Jeep JK
marcspaz replied to Mikeam's question in Technical Discussion
I did experience a massive problem with any RF transmitter if the antenna was mounted on the swing gate. Every time I keyed up, my dash would do a hard reboot, my windshield wipers would turn on and my climate control would turn off for a quick second. The problem was that I ran dual tops. When the soft top was on, I had no issues. However, when the hard top was on, the antenna was so close to the back window that is would send a ton of RFI into the Jeep through the rear window defogger and rear windshield wiper assembly. My solution was to leave the back window electronics completely unplugged unless it was snowing or we had very heavy rain, and not use that radio when they were plugged in. Any radios that went through antennas mounted on the hood were fine. When the hard top was off, it was fine. I ran 180 watt amp most days... occasionally up to 500 watts. -
I would have to check my notes about the JK. I won't run a radio if I have anything higher than a 1.5:1. On the Gladiator, it floats between 1.1 and 1.2 depending on weather. It was somewhat directional. On the blind side, off the back, the simplex range was just less than if I am driving toward the other station. The SWR was fine and I could work repeaters 20+ miles away with no issues. It's my go-to antenna when I'm going 4-wheeling.
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Picture freezing on cable system when transmitting
marcspaz replied to Riktar's question in Technical Discussion
Wrap the cable box in foil and make sure the foil is wrapped tight, touching the ground leads on the cables. See if making a local Faraday cage changes anything. If you have a meter to test with, add a wire or alligator clip from the foil to the electrical ground on an outlet (normally the screw to hold the face plate on is grounded for safety). Don't put anything in the outlet though... bad stuff will happen. -
I can't find any pics with the Diamond mount. I'll look around some more. Here is a Comet NMO mount and the Comet CA-2x4SR on my JK. http://fiveguysracing.com/marc/HAM-GMRS/Comet_Mount_And_Antenna_1.jpg Same mount with the Tram antenna http://fiveguysracing.com/marc/HAM-GMRS/Comet_Mount_And_Tram_Antenna_.jpg This is my JT with the Ham antenna (screwdriver) on the passenger's side and the GMRS antenna on the driver's side. http://fiveguysracing.com/marc/JT_Rubicon/JT_Drive.jpg
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You can try using the front bolt. On my JK, I had to use a lip mount on the hood, centered between the O and the N on the Rubicon graphic. On my JT, I mounted my antennas to the top of the bed rail. For the Jeep, I had great luck using a Diamond K400s and K400c mounts on the lip of the hood (which come with cables) and a variety of antennas. The best performing antenna I have used so far is a Comet CSB-790a Super Beam, but its 62" tall. Many people are looking for low profile. If you are looking for mid-sized, I like the Comet CA-2x4SR or the Diamond NR770HB. The SWR and performance are not as good as the CSB-790a, but its better all around than the traditional 1/4 wave antennas without the massive height. Then, if you want a traditional 1/4 wave, I have had good luck with both the Browning and the Tram. I have heard lots of good things about Larsen and Laird, too. However, you would need to get the Diamond Diamond K400sNMO or Diamond K400cNMO if you go that route, as most 1/4 wave antennas are NMO style. So, be sure to pick your antenna first, and then get the proper mount.
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Actually, they are a shade more than 6 inches high. Very small and work fairly well.
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I know the feeling. It is pretty satisfying when you finally get it working, though. Good luck! I hope you get something going,
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Ditch the Midland antenna and cable. They are not good... and when they are good, its not for long. The part of the window/roof frame you are talking about is called an A Pillar. The small UHF antennas need to be at least 8"-10" away from the A Pillar. The cowl cover is fine for an HF Firestick for the CB, but its too close for the GMRS antenna. You are very close to radio damage territory with those SWR readings. I wouldn't use it until its fixed. No more than 2.0:1. 1.5:1 or better would be ideal. Your power reading on 8 is low because the SWR is bad. The lower the SWR, the more the forward power increases. If you have a 1.1 or 1.2 to 1 SWR, it would be close to 13.5 watts (assuming the PA's a putting out the advertised 15w).
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High SWR and reflected power using repeaters
marcspaz replied to jsouth's question in Technical Discussion
The antenna should work fine. Do you have asphalt shingles? Some folks have metal roofing and/or trim and overlook that. Especially flashing materials and face boards. Make sure the antenna is at least 6 feet away from any metal or electrical lines. That includes any metal outside on the roof and side of the house. -
If you are going to be doing your own work, I would recommend getting a quality SWR meter. I have found that many of the inexpensive meters are only accurate for a very small amount of the "advertised" frequency range, and the higher the SWR, the less accurate they are. I started off with a MXTA26 on all 3 vehicles. Turned out to be a terrible idea. on the 467 MHz channels, the SWR was way too high. I ended up using some small Browning and Tram antennas that are good from 450 MHz to 470 MHz. One of my trucks has a Comet CSB-790A. It is three 5/8 waves long, in phase at 62 inches long. Its rated at 7.7dBi gain and cost about $100. I get a near perfect SWR of 1.1:1 on all GMRS channels. Yesterday I was talking to a friend of mine, mobile to mobile about 9 miles apart, using just 2 watts. It work fantastic... but its a lot of antenna. Most people don't like the size, because its so tall, but I love it.
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I usually don't push any particular brand of product, but if you don't have the room or means to safely have a dipole, I would consider looking at a Wolf River vertical antenna. It has a radiation pattern that is safe for mounting on the roof, it can work very well on the ground, and if you keep it in arms length, you can adjust it for whatever frequencies you want to operate on. I have talked to a few people around the country who are using them with a 100w and they seemed to be working fine. https://www.wolfrivercoils.com/
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Horrible idea. The antenna needs to be at least 35 feet off the ground. A log home will cause interference, almost as if the antenna is on the ground. I wold guess you likely will not be very interested in the expense of building a sturdy 35 foot mast on the roof of the house, unless it's your only option. I would also be very, very concerned about radiation exposure for people and other living animals in the house. You could make yourself and others fatally ill. Are you going to run it as a horizontal or inverted V? For an inverted V, the ends of the wire should be about 10 feet off the ground and the ideal angle is 45 degrees off the center vertical axis, for a total of 90 degrees between the elements.
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Any UHF amplifier that covers up to 470 MHz should be fine. However, there are some really big warnings I have about using an amplifier. First, on the 462 MHz and 467 MHz main channels, 50 watts is the legal limit for mobiles, repeaters and base stations. Fixed stations are limited to 15 watts. (A Fixed station is defined as a station at a fixed location that directly communicates with other fixed stations only.) Second, on the 462 MHz interstitial channels (the channels between the main channels) stations are limited to an effective radiated power (ERP) of 5 watts, witch means the final power amplifier (PA) will likely need to have much less than 5 watts of output power. This applies to mobiles, hand-helds, portables and base stations. Then, to make things even more complicated, on the 467 MHz interstitial channels, stations are limited to an effective radiated power (ERP) of 0.5 watts, witch means the PA will likely need to have much less than 0.5 watts of output power. So, be very careful on what frequencies you opt to use an amp on. Frankly, I wouldn't spend the money, I would just get a new radio. Quality UHF amplifiers are much more expensive than a radio that runs up to 50 watts.
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Picture freezing on cable system when transmitting
marcspaz replied to Riktar's question in Technical Discussion
That seems to be an excessive amount of RFI. I run 1500 watts and high-gain antennas on UHF, VHF and HF at home and there is no RF interference with anything in my house. Along with a bad connector on the cable lines, as mentioned above, there could be an improperly installed connector on the radio's antenna transmission line on the radio or antenna side. I would ground the cable box, cable coax connectors, the radio, antenna transmission line on both ends, and be sure the antenna and mast are properly grounded. May end up being a junk cable, though. -
CW Coder/Decoder Software vs. Learning Morse Code and Attitudes
marcspaz replied to SeldomSeen's topic in Amateur Radio (Ham)
There are a ton of encoders and decoders out there, but if another operator is free-handing it and is not transmitting in a consistent speed, they fail to copy correctly. Yes old-timers and people who took the time to learn will give you grief. But many of those same people will brag about all of their unattended, automatic FT8 contacts to Japan when they were sleeping. So I wouldn't sweat it. There really is no way of gauging how many people use automatic tools, but I'm willing to say it's a lot. Especially since many HF radios made in the last 20 years have memory slots for pre-programmed words and phrases that are used often.