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kidphc

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Posts posted by kidphc

  2. Cut Larsen 2/70 NMO to GMRS

    in Technical Discussion

    Posted

    Frankly, for an ammo can repeater. I probably would do a roll up jpole with some coax.

     

    Get some fishing sinkers and 50lb test (or heavy) mono filament. Tie the sinker to the line, and huck it over a tree branch. Even better if you have a sling shot and are decent shot. Then tie the roll up jpole, attach the coax to the line and pull upwards. Till you can't get it higher or run out of coax.  Really starting to like RG400 over LMR400 for some of the runs I am doing. But can be pretty lossy in 100 lengths. Plus you really don't need the Teflon isolator in GMRS. Nut OMG how flexible RG400 is over LMR400.

     

    But with that setup you can get the antenna up higher. Giving you better LOS and range. If you decide to add solar it will also give you some more isolation from the antenna, as long as RFI isn't making it in by the radio and power lines.

  3. Cut Larsen 2/70 NMO to GMRS

    in Technical Discussion

    Posted

    Instead of cutting. Contact larsen to see of you can get a po-450 whip. Should be about $10.

     

    Po450 is their gmrs 5/8th model tuned for 450-470. The bases and parts on larsens models are mostly interchangeable.

     

    If you are super impatient then find some steel stock rod from the hardware store about the same thickness. You'll be targeting a length around 1.25 range then adjust from there.

     

    The 2/70 is a collinear design. So tuning them is a no no. You usually screw it up more then anything for the 70cm service you basically have two stacked antennas with the coil being the separator. If you start trimming you may end up with phasing issues or even worse erratic and weird vswr numbers and curves..

     

     

    Sent from my SM-G975U using Tapatalk

  4. Damaged Antenna Cable Performance Question

    in Technical Discussion

    Posted

    I would do 3. But I have the tools to do it. The losses from the connectors isn't going to be huge.

     

    Or

     

    Personally if I was feeling lazy. I would patch repair it, if everything checked out. I would fill the cut ( I imagine a cut) with silicone all-weather adhesive (gasket former) style rtv. Then over wrap 2x with self almagating tape. Going several inches past the wound on both sides. Then a final 1/4 stretched wrap with a uv stablized electrical tape. We always used 88t when we where doing telephone work. Got yelled at a lot by the bosses for calling it electrical tape.

     

    Sent from my SM-G975U using Tapatalk

     

    Edited: because you know using the phone.

  6. Radio wave propagation question

    in General Discussion

    Posted

    Also, Fresnel zone effect: http://radiomobile.pe1mew.nl/?Calculations:Propagation_calculation:Fresnel_zones

     

    BTW, At UHF frequencies, once you have LOS, power makes little additional difference. The higher you go in frequency, the more true that becomes.

    Intesting read... would of thought there would have been more picket fencing from multi pathing. But it seams you basically are going to get crystal clear or nada due to phasing.

     

    Sent from my SM-G975U using Tapatalk

  7. Radio wave propagation question

    in General Discussion

    Posted

    That is the thing with propagation studies. You can get reflections, knife edge propagation, localized ducting. Any number of things could have occurred. Which make it better or worse.

     

    Funny enough even the type of foliage can aid or hinder propagation.

     

    Have you headed back up there since? Was the weather different?

     

     

     

    Sent from my SM-G975U using Tapatalk

  8. Woot woot... Random Wire is up. F you HOA.

    in Amateur Radio (Ham)

    Posted

    Suppose to be good for 160-6m. With a wide band tuner. I have an ltg 100 pro ii. We shall see. Since it is really for listening so should work well for that. Really wanted something permanent for NVIS and ground wave on 10/6.

     

    The photo was from a walk my wife took behind the house with the kids. She said IRL it looks just like a birdhird feeder and the wires are unnoticeable.

     

    Working on a fan dipole for 40/20/15/10/6. Just need to set it up to tune.. That will be stop gap till I get the general ticket. Then the next step will be either the Dx commander or nebula for DX work.0345ea1899ec474c8ec40af9ca28fe39.jpg

     

    Sent from my SM-G975U using Tapatalk

  9. Woot woot... Random Wire is up. F you HOA.

    in Amateur Radio (Ham)

    Posted

    Finally, got my Ultimax DX Extreme 72' Random Wire Antenna up. Mounted the transformer/unun to the bottom of a bird feeder with RG58 and counterpoise wire down bird feeder pole. In a vain attempt to hide it a bit from the HOA.

     

    The other end is tied to 50Lb Mono filament that I was fortunate to hook around the LNB of a satellite dish mounted to the chimney. This took several attempts, one attempt resulted in a cut monofilament when I hooked the angle adjuster. One attempt nearly end my day as I started to slide off the roof. Resulting in a lot of pulled muscles, burns from the hot shingles. *** it was a lot steeper then I thought originally. I do not recommend climbing the roof. Hire someone.

     

    The RG58 runs down the pole, I have yet to trench the RG213 from the DX Engineering NEMEA box which I had finally got installed and grounded the previous weekend.

     

    Sadly, now waiting on RG400 for the patch lines into the shack. Now I am contemplating switching from LMR400 to RG400 for the feed line to the 2m/70cm antenna in the attic.

     

    The bird feeder antenna in all it's glory. Photo is before the antenna was pulled and counterpoise was buried.

    uHmqNodl.jpg

  13. Intentional repeater jamming and how to deal with it

    in Technical Discussion

    Posted

    Yagis are excellent antennas, very useful for many permanent station locations, and, sturdy and easy to build. However, for DFing (Direction Finding) their reception pattern is broader with less of a null just off the center than a rhombic. Another antenna design that does quite well for DFing is the Loop Antenna.

    Oh I get it. There is a reason the AARL has it as part of the logo. Is the there that much difference in sensitivity between a loop and rhombic?

     

    Sent from my SM-G975U using Tapatalk

  14. Intentional repeater jamming and how to deal with it

    in Technical Discussion

    Posted

    Thank you for the link.....looks like an awesome project for me and my grandson.

    Ever thought about a yagi instead. Yes it is directional. But there are instructions all over the internet on homebrew styles, usually using yard stick tape (from harbor freight) and pvc pipe. You can also make an attenuator for fox hunts. Homebrew jpoles are popular to experiment with. All usually costing less $60.

     

    Sent from my SM-G975U using Tapatalk

  17. Intentional repeater jamming and how to deal with it

    in Technical Discussion

    Posted

    Marc: Knowing the repeater range meant it would be efficient to see if I could hunt the signal. The fact that I could hear them TX on the input side from within my house meant they were very near by. My logic was to locate them, then call their location over the air when they let up in an attempt to scare the hell out of them, instead they saw the big mean truck with several antennas slow up in-front of their place, then return and stop on the second pass. As you said its all about the mind games. Still I am considering ways to reduce jamming in the future, I'll be speaking with my father who is a co-owner and see what he thinks and come up with a plan.

     

    What is funny in a couple of years these yahoos will probably asking permissions to use the repeater once they get a clue.

  20. Skipping channels when scanning?

    in General Discussion

    Posted

    I want to make sure I understand this correctly.  If understood something I read, when on a channel without any code, you can hear chatter from everyone using that channel even if they're using codes.  Is that right?

     

    If that's right, is what you're saying to clear the code before using that channel for communications to make sure others aren't using the channel (without a code), otherwise I'd be talking over them?

     

    Something about that doesn't seem right... please clue me in. 

     

    No, the tone is a form of squelch. They are all a filter of sorts. if you set a tone for receive, it will only hear transmissions that have that tone.

     

    Kinda, like your name is say Mike. Everyone in the room is screaming names. You can only hear anything that precedes with "Mike!'. Although everyone is scream you can't hear them. Since you are ignoring everyone else, you want to remove this filter/tone when using the channel normally.

  21. Skipping channels when scanning?

    in General Discussion

    Posted

    I would be happy to actually hear chatter. In my area I hear virtually nothing, with the exception of some business use on occasion on FRS. One night I did hear a man ranting by himself, spouting profanities, etc., for hours.  I was able to figure out who he was and where he lived based on an FCC search. I called him by name at one point hoping he would stop, but he didn't. I switched off the radio. 

     

    Would of thought you would have heard more. Considering where you live there are about 3 repeaters. Using a handset or terrain?

     

    Might be time to get ham ticket. Look at all those repeaters calling your name out. https://www.repeaterbook.com/repeaters/map/proxmap.php?lat=40.43249893&long=-79.75119781&distance=25&Dunit=m&freq=&band1=%&band2=&call=&use=%&features%5B0%5D=FM&status_id=%

  25. Installation/Mounting in vehicle

    in General Discussion

    Posted

    Just buy a decent power supply for a base station. Probably won't be your last base station radio and you can never have too much excess available amperage. But not having enough is common. Just buy a used switching ham one (ashtron are cheap used) or just wire it to a old car battery you can charge back up (venting needs to be resolved with this method, you don't want hydrogen gas buildup in your shack).

     

    For the car simplest is just to wire it to the battery with some type of quick disconnect around the radio. Think deans or power poles. Then you can disconnect everything and take it inside.


    Sent from my SM-G975U using Tapatalk

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