|
Do you HAVE to have an “ID”? If so, why? Is it to access gateways and the like? Can one just key up on DMR simplex with their callsign and that’s fine? Edit: also is your callsign embedded in the outgoing signal a requirement (for whatever country folk are in - I’m UK)? I’ve seen people talk about that too.
|
#
¿
Sep 27, 2020 17:42
|
|
|
|
| # ¿ May 14, 2024 17:30 |
|
|
Thanks, that all makes sense.
|
|
#
¿
Sep 27, 2020 22:52
|
|
|
Silly question perhaps, but I have no SWR meter or antenna analyser, but I’d like to make sure I’m pulling my telescopic antenna out to the correct width (it goes longer than 2m half-wave so I need to stop before the end). If I use an SDR stick on the same frequency to monitor as I extend and retract the antenna, seeing when the received power is at its greatest, is this a decent approximation? Also, do you start measuring from where the loading coil stops when someone says “extend to x inches”?
|
|
#
¿
Oct 4, 2020 11:51
|
|
|
Jonny 290 posted:What antenna are you working with? On the SDR? Any old poo poo I have available, probably some 1/4 Diamond rubber duck type. Is a directional one better? The telescopic I’m testing I bought fifteen years ago and have no idea on who made it. It extends to about 126 cm so I shoot for 95-100cms when I use it on my HT on 2m. There’s a big fat bit on the bottom that I assume is the matching network or whatever. thehustler fucked around with this message at 23:10 on Oct 4, 2020 |
|
#
¿
Oct 4, 2020 23:07
|
|
|
Excellent, I’ll not worry too much then. When I set the HT to 50 milliwatt *with no antenna attached* and hit the PTT the entire visible 2MHz of SDR bandwidth on screen lit up. 
|
|
#
¿
Oct 4, 2020 23:45
|
|
|
Here's a few more stupid questions: * Can I put that 1/2 or 5/8 wave telescopic on the end of a length of coax and get it up high? Presumably yes if it's 1/2 wave, no if it's 5/8 wave due to the lack of a ground plane? * (Assuming the above is a bad idea) If I use a fiberglass pole to get something like a flowerpot antenna up high while already on top of a mountain, is that going to be any significantly better than said telescopic attached directly to the HT? I'm often amused by how much sitting down vs standing up matters, so I assume any amount of height will work better for VHF line of sight signals? But standing up vs say a 4-5 metre pole? Hmm... Essentially it's whether it's worth the extra weight to actually make my own antenna and use it in anger like that. I don't drive so I don't do mobile use, and I live in a ground-floor flat so I can't really improve that with any antenna really. This is just to help me with portable/hiking use. thehustler fucked around with this message at 16:46 on Oct 5, 2020 |
|
#
¿
Oct 5, 2020 16:43
|
|
|
I discovered MMGAL today. Also I made a cocktenna for 2M. https://twitter.com/markpentler/status/1314277354013949952?s=21 In reality I am genuinely trying to model a flowerpot antenna and I’m getting nowhere. How do I tell it which bit is the coax with braid and which bit is without?
|
|
#
¿
Oct 8, 2020 21:51
|
|
|
Ok - will just build it to instructions then. Was kinda interested to see it.
|
|
#
¿
Oct 8, 2020 22:05
|
|
|
Ok. There’s so many differences in dimensions online, with some calculations that just don’t work right, with the right velocity factor and everything. Folk don’t always take that into account and then just shove it in a PVC tube. I’m convinced everyone just makes this up. VK1AD’s coaxial dipole seems to be the best one, just needs the elements shortening a bit for 145.5 in the U.K.
|
|
#
¿
Oct 9, 2020 17:55
|
|
|
But they all say it’s so easy! I’ll give it a go anyway, got some scrap lying about.
|
|
#
¿
Oct 9, 2020 21:38
|
|
|
Is it possible to get some sort of kit to convert a HT from using its own internal battery to an external pack? Like you used to get those adapters for video cameras to plug them into the mains. Just has the battery contacts on and a cable? It’s for my Kenwood F6/F7. My HT and battery is old, 12 years or so, and I don’t want to replace it as I’ll replace the HT itself soon, but if I can run it off a power pack that I can use for other things going forward then it’s worth doing. Also my PortaPack that I bought in error is finally in SA Mart if anyone is interested.
|
|
#
¿
Oct 17, 2020 17:14
|
|
|
Yeah I just can’t spend 25 quid on a new battery and feel good about it if I’m getting a new HT soon. I’m in the U.K., prices aren’t bad but I’d rather put it to a new radio. But a power pack I can use on other radios and kit somehow going forward would be great I had to go to 50 milliwatt on a hill today to save power and made a 50km contact on FM. Ridiculous. We were both ~400 feet up.
|
|
#
¿
Oct 17, 2020 17:41
|
|
|
There is a USB plug to DC power jack thing which has a booster to 7.4V, but the F6 and F7 have issues on transmit sometimes when running on mains (they reset themselves on PTT) so if I can keep it thinking it’s “on battery” it’s better I think.
|
|
#
¿
Oct 17, 2020 17:42
|
|
|
As a further question, are data modes on the U.K. 2M simplex channels ok? The band plan says FM/DV but if that FM has SSTV in it does it matter? I heard some SSTV on 145.525 today and was surprised. I just assumed it was voice-only Edit: sorry for the post flood, I’ve just had a really fun afternoon! I’m so new to this despite being licensed long enough to be on page 1 of this thread. Just had mic fright all this time. Edit 2: looks like the 7.4 volt of the battery is the same as that used by many drone batteries. I figure it’s worth buying a battery eliminator, chop the plug off, whack a connector on the end and get packs to just plug in. That eliminator shell presumably does some voltage conversion. https://www.ebay.co.uk/itm/PB-42L-12V-Car-Charger-Battery-Eliminator-Kenwood-Radio-TH-F7A-TH-F7E-TH-F6-/164218324880 There’s a USB version too. Either way, think I have options here. Then just use the batteries for something else when I upgrade the HT. thehustler fucked around with this message at 19:50 on Oct 17, 2020 |
|
#
¿
Oct 17, 2020 18:00
|
|
|
I think that’s the way to go according to someone on mods.dk. They put a 9V battery snap with a DC jack on the end into the socket and it worked and didn’t charge the battery as it didn’t go over the required amount. The power source needs to be a bit more higher in capacity/possible draw than a 9V PP3, though.
|
|
#
¿
Oct 18, 2020 12:11
|
|
|
Finally made my Slim Jim. Didn’t have the right tools so snapped the ladder line on both sides while stripping the feed line point. Soldered it back on, bit weak now when I roll it up now but it’ll do. This thing isn’t even tuned yet and a guy across town said I went up 3 S points with him vs a 5/8 whip on my HT. Unreal. It isn’t even much higher up. Just make stuff and stop worrying about it, that’s what I’ve learnt. Edit: gently caress the flower pot, and I just used a kit but I checked all the dimensions first and I’m getting a NanoVNA next week so we’ll see how much I can improve it. thehustler fucked around with this message at 23:48 on Oct 22, 2020 |
|
#
¿
Oct 22, 2020 23:42
|
|
|
I’ve come up with a silly 433 MHz 3 element yagi handheld design which absolutely doesn’t have a 50 ohm feedpoint impedance (will find out on Monday when my nanoVNA arrives), and it’s not really the kind of construction where I can make some complex adjustable metal bar system thing, given that it’s very thin wood and just strands of wire for elements. I used hot glue gun to secure everything. I’ve been told the yagi impedance can be adjusted by using folded dipoles for driven elements, but I can’t really do that due to the construction method. Another method is to move the director and reflector elements towards the driven elements. Is this all I need to do? Will I get close to a useable SWR such that I can just solder the coax on to the elements? Or is there a hairpin match calculator somewhere I can use to match the (apparently) 20-ish ohm with a short length of wire? I couldn’t find one. Assuming moving the elements is a goer i did have the idea to use velcro for everything so I can adjust it and see the results in real time. Everything at 70cms is so small that experimentation is really fun!
|
|
#
¿
Oct 31, 2020 23:51
|
|
|
Anyone wanna buy a shitload of ladder line? Turns out making antennas is for chumps and is best avoided and you should just buy one. Who knew? I threw my wire cutters across the room after accidentally severing one side and just realised it was time to give up.
|
|
#
¿
Nov 6, 2020 16:46
|
|
|
manero posted:What? Just do a Western Union Splice and cover it up with some weatherpoof goop. Problem is that you're shortening your already-cut-antenna then. I had a decent ish 2M one and snapped it too many times and ended up cutting it in half and making two 70cms versions. One turned out OK, the other turned out poo poo, but now I've overcut them both during tuning and they're resonate at 446MHz so that may be a happy accident. But I have a 2M 300 Ohm one that I've just made according to yet another random page of dimensions online and I know it won't work right. I'm getting to the stage where I am genuinely considering paying somebody to make me one resonate for the UK 2M band for SOTA use. I just want something that works, I can't be arsed loving about anymore. I have a NanoVNA, I just wasn't prepared for how much literally moving the unit with cable attached would change the properties. I am trying to tune antennas on the shortest length of coax I can and then I plug my 5 metre length in and the VNA reads totally different - expected, perhaps, but your numbers go all to cock and you aren't sure what is true anymore. Edit: followed dimensions perfectly on that 300 ohm version and got 140mhz. I can just shorten the top a bit and resolder the ends together I guess? Will that bring it up? thehustler fucked around with this message at 17:25 on Nov 7, 2020 |
|
#
¿
Nov 7, 2020 02:26
|
|
|
I have a clip on ferrite and the SWR is 1.12 with the antennas short coax of like 30 cms. As soon as I attach the 5 meter coax I want to use with a pole it goes up to 2:1. Is that a true measurement or is my NanoVNA lying? Snipping the matching stub made the frequency go up where I wanted it
|
|
#
¿
Nov 8, 2020 21:32
|
|
|
I just wanted to report back and say that I finally got something working ok-ish 2M with my Slim Jim and managed to join my first ever net tonight (Edinburgh and District ARC)  there’s room for improvement but I don’t want to gently caress it up - it’s good enough. Time to order a fiberglass pole and see how much it breaks it and hoof the whole lot up a mountain for SOTA. Appreciate the help from folk here.I still haven’t had much luck with one for 70cms so I may have a crack tomorrow. 2M Slim Jims tend to be resonant at 440 which is way above U.K. 70cms allocation. I do have parts for a 1/4 ground plane on a socket type thing so I’ll give that a go. May be simpler. Still hampered by a crap QTH though. Edit: after I got a proper air choke on it the SWR came back down to like 1.3-1.4 ish. Edit 2: one other question, because nobody could hear me on 70 someone set up a rebroadcast to 70 of the channel we used on 2M. Is that... legal in the U.K.? It’s not a repeater, but it feels dodgy. thehustler fucked around with this message at 01:20 on Nov 10, 2020 |
|
#
¿
Nov 10, 2020 00:45
|
|
|
I've just picked up a DMR radio on test (MD-390) and it's loving weird. I have a UHF repeater near me that I can open fairly well on analogue. It's only a mile away. But on DMR I am just not getting in to another repeater at the same QTH. I'm using a 70 Slim Jim with an SWR around 1.1 on the input frequency of 438MHz, and I've also tried a couple of 1/4 wave HT antennas too. I get a full signal on Rx from the repeater and it decodes with no audible errors. But my input just isn't getting in at all. That same Slim Jim (or the 1/4 wave antennas really) has zero issues working the other repeater on analogue at all. One thing I have noticed is that when I hit PTT the red light sometimes flashes 3-4 times and then stops. There's no signal coming out of the repeater at the time so I'm not blocking someone. But there's no connection at all made. I also noticed that my clock on the display is in no way correct. Does this have an effect on your outgoing signal at all? Does it need to be accurate? Not liking this at all, it's very weird. I don't want to plug the hotspot in because I feel it defeats the point, but I will to make this test fun if I have to.
|
|
#
¿
Dec 1, 2020 11:49
|
|
|
It seems my radio may be hosed so I’m getting it swapped for an MD-380. We’ll see how it goes.
|
|
#
¿
Dec 1, 2020 18:24
|
|
|
Got my replacement test radio and now DMR is cool and I am starting to like it. I do definitely think the hotspot stuff doesn't interest me, but I don't mind internet-connected "proper" repeaters. Getting the same signal in to it as I did with my analogue TXing to the same RX site now. How much do people use DMR simplex? Is it very geographic in its use, does nobody really use it, or do people actually give it a go vs analogue FM? I am tempted for SOTA use, but I guess for remote activations it may be better to pull a voice out of static instead. Depends how much is around you. In other news I have no idea why 2m Slim Jims resonate so high up in the 70cm band - can anyone explain that? They *work* on 433 FM but the trough is more towards 438 - perfect for 7.6MHz split repeaters, but not really for analogue FM. It's not like other antennas where if it works on 145 it works on 433, etc. Edit: ignore me, the resonance seems to only changes with coax attached so something must be up. thehustler fucked around with this message at 18:39 on Dec 2, 2020 |
|
#
¿
Dec 2, 2020 16:39
|
|
|
If I know my output power, height of antennas, and both locations, and I know that got a signal report from a certain distance of miles away to that second station, is there a way to take that S number and estimate how far that signal actually went? I know radiomobile does coverage maps, but this is me wanting to work with real world readings
|
|
#
¿
Dec 13, 2020 17:20
|
|
|
Thanks, that helps a lot, I can just calculate from there then.
|
|
#
¿
Dec 13, 2020 18:08
|
|
|
Comes to about 50 miles. My contact today was 22 miles away and had me at S8 on 5W into the Slim Jim (2.15dBi gain?). Presumably there is a bit of a cliff drop off the closer you get to the end of the range, but I’ve had some perfectly readable S1 signals before. Very interesting, I know this is nothing new to folk but it’s fun to actually learn it and do it.
|
|
#
¿
Dec 13, 2020 18:15
|
|
|
Just making a Pixie kit, what's the best transistor I can use as a replacement for the S8050 it comes with? I have some 2222s - they should allow for more current from C to E, so I would expect that's more power out? Is it just as simple as replacing one for another? Depends if it requires a different bias voltage I guess on the base. Edit: absolutely fine, should a few more measily mA. thehustler fucked around with this message at 17:06 on Dec 15, 2020 |
|
#
¿
Dec 15, 2020 12:55
|
|
|
The LM386 on my Pixie is motorboating 
|
|
#
¿
Dec 17, 2020 01:49
|
|
|
Experimenting with Slim Jims again, I just cut one that’s shorter overall than my current best effort for 2M but it’s resonant at 130MHz. I don’t get it. Should I be making the top shorter? Cut and resolder? I’ve tried that and it hasn’t really shifted the curve to the right at all. I’m not cut out for this. If I can’t rescue this one I’m just gonna buy an N9TAX.
|
|
#
¿
Dec 19, 2020 13:42
|
|
|
On the plus side I’m about to buy a near mint FT-817 (original model sadly) for £225 and that’ll be my first ever HF radio. I’m pretty excited. All the stuff is with it too. Edit: On the down side, that's twice now I've heard a particular radio amateur call me out on-air (not by name) for being a foundation licence holder with lovely equipment and a lack of skills. Mentioned my kit very specifically so can only really be me. This hobby is full of absolute cunts. thehustler fucked around with this message at 12:49 on Dec 21, 2020 |
|
#
¿
Dec 19, 2020 14:21
|
|
|
My issue was just the antenna reacting to things near the antenna, but not so near that I imagined they’d have an effect. For gently caress’s sake. All good!
|
|
#
¿
Dec 22, 2020 22:51
|
|
|
That’s the thing: he didn’t know I was listening. He forgets that while I can’t do SSB transmit the Kenwood F6/F7 is a decent SSB receiver. Caught him talking to our club chair (who is really nice and helpful) about how he was sick of the lack for progression (he has it in for foundation licence holders, yawn) and is bored of hearing about our “pathetic antennas” and being happy when we can reach a non-local repeater. Well gently caress you, I WAS happy. I learnt a lot. And now things are going well. And you moan constantly about not being able to use computers. Also his surname is Dick in what is a great confirmation of nominative determinism.
|
|
#
¿
Dec 23, 2020 10:36
|
|
|
It’s okay, I went out today up a hill and deployed my mast and all worked well apart from literally being next to the Edinburgh ATIS mast - the breakthrough was across the entire 2M band and made copying stations anywhere but the city impossible. So strange to hear it come through on FM so clearly - why does that work? But it was a lot of fun and I know my setup will work really well once restrictions are lifted for SOTA now. Screw those other guys. Thanks for everyone’s patience!
|
|
#
¿
Dec 23, 2020 17:28
|
|
|
Some AM is carrierless so there’s more power to the side bands, aye? That’s another reason to regen it on the radio
|
|
#
¿
Dec 25, 2020 11:05
|
|
|
Does the online club only work for US licensees then? It’d be impossible to make a truly international club, wouldn’t it? Could I use that callsign in the U.K.? Don’t know too much about how clubs work elsewhere.
|
|
#
¿
Jan 2, 2021 11:21
|
|
|
I’m all for arranging a DMR net on a convenient day. I do tend to ignore the internet connectivity side of DMR so it’ll be fun to switch the Edinburgh repeater to goonchat for an hour. A club that is no judgement, friendly, and encouraging to all levels is what this hobby requires. Reddit as a forum isn’t too bad and I think they may have a net as far as “international collaborations/clubs” go, but there are still some bellends around even on there.
|
|
#
¿
Jan 2, 2021 19:07
|
|
|
Horse Clocks posted:I am down for a DMR net too... but at the moment I only have a handheld that I need to go sit on my balcony to use. Which isn’t fun when it’s only 2 degrees outside. Well, don’t overcomplicate it. Get/make yourself a Slim Jim and hang one up somewhere. Coax doesn’t have to be top grade, you’re on a handheld so you’ll be gaining fractions of a watt back with each upgrade and it isn’t always worth the extra cost. If the connector isn’t SMA I’ll eat my hat. Get an adapter to BNC and you’re laughing.
|
|
#
¿
Jan 3, 2021 13:33
|
|
|
Looks like the ISS gear is broken http://www.arrl.org/news/ariss-and-partners-are-investigating-space-station-ham-radio-failure
|
|
#
¿
Jan 30, 2021 19:33
|
|
|
|
| # ¿ May 14, 2024 17:30 |
|
|
Also a cheap data mode setup for whatever radio you get, hooked into your computer, will provide even more fun! Welcome! I am hoping to do my U.K. intermediate licence this year but I’ve slacked off on the studying lately. I guess this should be motivation and inspiration to carry on.
|
|
#
¿
Feb 7, 2021 20:58
|
|