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I want one now, just to make my radio look more like a 1950s horror movie laboratory
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Jun 14, 2016 01:35
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I dropped a bomb on SSTV tonight and got picked up by about 10+ stations at least that I know of including I know it's not a political / social discussion board but please at least ack that it took a little bit of strength to send that out on 14.230 bout 30w of it e: im K6XCQ Sniep fucked around with this message at 06:07 on Jun 14, 2016 |
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Jun 14, 2016 06:05
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Sniep posted:I dropped a bomb on SSTV tonight and got picked up by about 10+ stations at least that I know of including All hams share their political opinions unasked so you're just joining the tradition
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Jun 14, 2016 08:18
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What site is that,where all the received pictures are logged?
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Jun 14, 2016 23:14
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http://worldsstv.com kind of addictive
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Jun 14, 2016 23:30
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Dang, that's cool as hell.
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Jun 15, 2016 00:10
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I got a shiny new antenna analyzer today and I was shocked to discover my g5rv actually resonates nicely on 40m with an swr of 1.6. I've been dicking around on 20m lately and the swr there was like 3.2! the antenna is setup as an inverted vee, the top section is 35 feet off the ground in a tree in my backyard and the legs are roughly 45 degree angles tied to my front and back fence in a north to south orientation.  guy about 200 miles south of me said I completely blotted out his waterfall on PSK31 and I was only using 50w ha
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Jun 15, 2016 05:14
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What antenna tuner are you using on a G5RV that you're getting 3.2 SWR on 20m? I mean, that's like, not at all functionally okay at all is it? Huge mismatch and possibly damaging to your equipment?
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Jun 15, 2016 05:27
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G5RV swr should be lowest on 20 as that's what it's designed for. Still, if it's getting you on 40, don't question, just do it!
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Jun 15, 2016 05:27
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johnnyonetime posted:guy about 200 miles south of me said I completely blotted out his waterfall on PSK31 and I was only using 50w ha I haven't done digital modes in forever, but I remember waterfall splattering being caused by incorrect audio settings or input gain, not exactly by power. You could kick out 1500 watts cleanly and you signal would still be confined to its proper width. You really should get it sorted out because it ruins the band for everyone within range.
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Jun 15, 2016 05:44
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Oh, yeah, to that point, I've just been learning all this myself on my first HF digital mode experimenting Basic premise is: A) Set radio to 100w (max) B) Set TX audio level to minimum C) Bring up ALC however D) PTT a carrier and turn it up till you're pushing about 30, 35, maybe 40 watts up till you start seeing the ALC meter touch then back down Boom that's your digital levels set. You don't just randomly twist the tx po to up power or down power, it's important to the radio that it's fully open to the finals. Level set is done by the audio in volume on your USB interface.
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Jun 15, 2016 05:56
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I like to run filtering as well as tight as possible on Rx since any sort of agc seems to be an issue. I run crystal filtering since the digital seems to not be super effective.
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Jun 16, 2016 00:29
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Yeah you definitely want every single DSP/computering feature turned off completely, no noise blanking, no noise reduction, no filtering, processing, anything. I know cuz my main station is a FTdx1200 and it has a metric gently caress ton of it to make sure isn't on before going digi.
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Jun 16, 2016 02:03
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the layers of setup we had to do on that thing were like 4 times as thick as im used to. Still, we knocked it out and got it all lined up.
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Jun 16, 2016 02:59
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Sniep posted:What antenna tuner are you using on a G5RV that you're getting 3.2 SWR on 20m? It's an LDG AT-100 ProII Autotuner. I might clear the memory out and re-tune it again to see if it gets better SWR  eddiewalker posted:I haven't done digital modes in forever, but I remember waterfall splattering being caused by incorrect audio settings or input gain, not exactly by power. You could kick out 1500 watts cleanly and you signal would still be confined to its proper width. There's a good video from Icom I followed for those digital settings on the 7200 but I'll go over them again. The usb level set on the radio is at 50% and I run digital modes at 50w. I very well could have the gain still set way too high. Sniep posted:Oh, yeah, to that point, I've just been learning all this myself on my first HF digital mode experimenting I have been pumping up the tx the few times I didn't get a response... I'm no better than a cb radio user 
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Jun 16, 2016 04:21
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johnnyonetime posted:There's a good video from Icom I followed for those digital settings on the 7200 but I'll go over them again. The usb level set on the radio is at 50% and I run digital modes at 50w. I very well could have the gain still set way too high. quite possible. Depending on levels you might still be 20 db too hot. Put it this way, when I use MMSSTV, which has always-full-bore audio, I have to turn the device level in Windows mixer down to 3% and then I have to turn the windows master volume slider down to 2% to avoid hitting AGC.
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Jun 16, 2016 04:36
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johnnyonetime posted:It's an LDG AT-100 ProII Autotuner. That thing should tune a coat hangar. I'd suspect your cabling before a close-to-band antenna getting a 3.2 johnnyonetime posted:I have been pumping up the tx the few times I didn't get a response... I'm no better than a cb radio user No I mean you can't even touch it, are you using your ALC meter to calibrate? Full power always 100% (100w or otherwise) - all computer poo poo off - and then raise TX till you bump into the ALC scale then back down and you're set and don't touchy anything from there forward.
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Jun 16, 2016 04:51
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Jonny 290 posted:quite possible. Depending on levels you might still be 20 db too hot. Put it this way, when I use MMSSTV, which has always-full-bore audio, I have to turn the device level in Windows mixer down to 3% and then I have to turn the windows master volume slider down to 2% to avoid hitting AGC. That's good to know, I lowered the Window mixer considerably from what it was to about 20% so I'll see how that works out. thanks! Sniep posted:That thing should tune a coat hangar. I'd suspect your cabling before a close-to-band antenna getting a 3.2 I read online that since the G5RV was ladder-line fed it needed a balun at the feedline so I just did a 4-wind ugly balun on the coax and loosely zip-tied it in place. Now that I have the analyzer I'll take out the ugly balun and see if that resolves my SWR issue. I'll test the coax cable too and make sure there aren't any shorts Sniep posted:No I mean you can't even touch it, are you using your ALC meter to calibrate? Full power always 100% (100w or otherwise) - all computer poo poo off - and then raise TX till you bump into the ALC scale then back down and you're set and don't touchy anything from there forward. I switched to ALC meter and slowly raised the USB Lvl on the radio until the ALC meter bumped up a notch from minimal and it was at USB Lvl 45. At that point the LDG tuner showed I was outputting between 30-40w. Kept the RF Power to set 100w on the radio itself. Windows mixer is set to 20% currently. Had a quick QSO with a guy in California on 40m, my signal report was 599. He was QRP on 5w and I was copying him over 90% so the Windows mixer is set right for receiving. Might still be too hot but I'm probably way better off than before. thanks!
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Jun 16, 2016 06:03
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johnnyonetime posted:That's good to know, I lowered the Window mixer considerably from what it was to about 20% so I'll see how that works out. thanks! Yeah, 30-40w is where you'll end up - you're right on the money. Edit: Breaking this out: johnnyonetime posted:I read online that since the G5RV was ladder-line fed it needed a balun at the feedline so I just did a 4-wind ugly balun on the coax and loosely zip-tied it in place. Now that I have the analyzer I'll take out the ugly balun and see if that resolves my SWR issue. I'll test the coax cable too and make sure there aren't any shorts Yes you want to feed it in ladder line, and definitely get a correct part for the job, again LDG, this: http://www.gigaparts.com/Product-Lines/Baluns-Ununs/LDG-Electronics-RBA-41.html It's not even 30 bucks and it's perfect for a G5RV with AT-100ProII, even if you shrink the antenna Sniep fucked around with this message at 06:20 on Jun 16, 2016 |
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Jun 16, 2016 06:04
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Seriously, break the G5rv formula and get the 4:1 unless you are a: installing a full size G5RV, b: installing it at least 1/2 wave above ground on its frequency of design (20 meters), c: using it mainly on 20 meters. the impedances swing high on the end of the ladder line on everything but 20, and the 4:1 gets things down into saner territory before your signal has to traverse the relatively lossy coax. If you want to be serious boy scout about it, add an RF choke/1:1 balun/line isolator right on the 50 ohm side as well. I roll with these and they changed my station. Not even just at HF. They cleaned up the patterns and fixed SWR problems from feedline radiation with every antenna I put them on, from my 85 foot multiband inverted L to my 2m sideband beam and my 70cm vertical.The cores fit nicely over RG8/LMR400 class cable, and you can get two turns of 8x/240 class cable or four turns of 58 size cable through it (recall that inductance goes up with square of turns count so this is most beneficial). If you're running something like RG8x, 3-5 of those cores with two turns through all of them would be a beautiful choke on all bands of interest. But you should throw the 8x in the trash, as a side note.
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Jun 16, 2016 07:01
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I think I have my 817 sorted in terms of everything else, but what do I need in terms of power for 1-3 day SOTA sorties? I'm only rocking the internal rechargeable, the AA tray, and a "60W" portable solar array currently. I'm not sure what kind of duty cycle is required for the first activation of a 10 point summit on HF SSB, so I'm not sure how much power I need to lug up a mountain yet.
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Jun 21, 2016 05:20
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how i ballpark it usually, take your RF output and double it, that's your possible DC consumption. multiply that by 30% for average SSB energy. that's how much watts you're going to draw on tx average. Then look up the rx current draw (think its about 300 mA?) and figure oh about a 10:1 rx to tx ratio. so 5 watts out, 10 watts DC, 3 watts average. 250-300 mA on tx Looking at ft-817 pages, it looks like current consumption goes up a bit with voltage, and your radio consumes way less power around 8 volts than say 12 or 14. It may be worth it to add a $3 Chinese buck converter board to bring 12V battery power down to 8, 8.5 volts or so. True, tx power will be down a bit, but you can always bypass the converter for a few to get full TX power then put it back in line for RX.
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Jun 21, 2016 06:19
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Jonny 290 posted:
well I went serious boy scout. I bought the rf chokes from the fellow on ebay and those things are stout. I wound the cable twice, clipped on a choke, wound two more times and went 90 degrees around the coil and clipped on the next choke, etc. Not sure if it makes a difference or if I should do them in a single file line down the coax. The ladder line on the left is staked to the ground so it's as straight down as possible from the apex of the inverted vee in the tree. Still waiting on that 4:1 balun and I'll look into upgrading the rg8x in the future  I haven't had time to measure the impedance using the analyzer just yet but if there's any serious improvements in the readings I'll post.
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Jun 21, 2016 18:07
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I know virtually nothing about radio. We have an air band scanner. Reception wasn't good enough so we had an outdoor antenna installed. Now reception is TOO good (?) and the squelch on the radio can't be turned up high enough to block all signals. Is there an affordable way to attenuate the signal down? I see attenuators, but the price varies from $ -- $$$$$ and they're tuned for specific bands and I get lost pretty quickly. I remember the installer had a tuner hooked up and it showed a peak -38dbi signal. Connector from the 50' cable running to the outdoor antenna to a smaller 6' cable:  Smaller 6' cable into back of unit:  Any recommendations? Sorry if this is outside the scope of the thread.
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Jun 21, 2016 21:39
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Do you have any idea how much attenuation you need? Since this is only for a receiver, we aren't talking about lots of power, so it should not be expensive. There are also home brew options. Just to play around, you can unhook the bnc connectors, and just put them near each other without touching and you will probably still hear your signal. If this works well, you could take a metal box, two RF connectors, and solder 2 wires to the center conductors, not touching each other, and moving them around will vary the amount of attenuation. Crude, but it'll work as long as you aren't transmitting. Another thing to consider is if your setup would benefit from a band pass filter, or if you have nearby interference and need a notch filter here or there.
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Jun 22, 2016 01:04
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Yeah, it's possible the front end is just making GBS threads out not from inband air signals, but because there are high power 150mhz VHF FM transmitters nearby or something. Bandpass filters also something to investigate. If this is an anywhere near mission critical installation, please buy a commercial step attenuator. Otherwise, you can pretty readily DIY stuff up with a project box, two BNCs and a fistful of resistors.
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Jun 22, 2016 02:28
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Oh wow. I was trying to avoid calling a radio specialist out, which will inevitably be a $1000 service call. But it sounds like I need to diagnose the source of the interference, and that's well beyond me. Thanks for the help.
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Jun 22, 2016 18:46
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KS posted:Oh wow. I was trying to avoid calling a radio specialist out, which will inevitably be a $1000 service call. But it sounds like I need to diagnose the source of the interference, and that's well beyond me. Who installed the antenna? This sounds like something they should have been dealing with.
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Jun 22, 2016 18:53
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I would roll out there with a cheap rtlsdr/android rig to figure out what's up on vhf before shelling out for filters. If you are out in the US west, i'd put money on pager transmitters.
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Jun 22, 2016 22:17
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Totally Reasonable posted:I would roll out there with a cheap rtlsdr/android rig to figure out what's up on vhf before shelling out for filters. If you are out in the US west, i'd put money on pager transmitters. Welp, that's too cool to not try. Ordered. Yes, east Bay area.
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Jun 22, 2016 23:12
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oh, heh. Yeah, you are in the middle of an RF firehose 24/7/365. If this is a pro/commercial job (sounds like yes) they need to be addressing this. (Incidentally, as a tangent: this is why people's dreams of "Broadband Hamnet" on 2.4 ghz won't work. Even if you are running a _super special_ hidden SSID and only hams know it, you can't just put a 2.4 ghz 13 db gain antenna on top of a tower and not expect it to get blasted out by the large amount of just raw RF bouncing around. Your receiver goes deaf from desense and nobody can get heard)
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Jun 22, 2016 23:53
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I dunno enough to know if I'm looking at the source of interference or not  These are supposed to be 25 khz wide, right? That signal is 50+ khz away, so it shouldn't be a problem?  What a cool product for $20. I had no idea.
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Jun 23, 2016 22:38
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Well thread, thanks for putting me over the edge. Bought an RTL-SDR dongle and will plug it right into my rear end.
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Jun 24, 2016 16:37
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If you have any interest in radio at all you should definitely have at least one RTL-SDR. There's pretty much no better bang for the buck out there, they're so capable yet practically disposable.
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Jun 24, 2016 17:04
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It's like a Swiss army knife. I was playing with a pair of RFM69s and couldn't tell if my code was broken or if I'd messed up wiring the logic-level shifters and fried one or the other. Ordered an RTL-SDR, tuned it over to 915MHz, and I can see the little guys chirping away  Only one issue, has anyone been scrolling fast through the bands on it and had SDR# freeze hard with a looping stutter audio? https://www.sparkfun.com/products/12775
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Jun 24, 2016 18:25
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hogmartin posted:It's like a Swiss army knife. I was playing with a pair of RFM69s and couldn't tell if my code was broken or if I'd messed up wiring the logic-level shifters and fried one or the other. Ordered an RTL-SDR, tuned it over to 915MHz, and I can see the little guys chirping away That's a lot of what I use mine for as well, debugging RF things. Garage door opener/car remote fob not working? Let's see if it's sending a signal, then compare it to a known good one and see if it looks sane. They unfortunately don't reach up to the common 2.4GHz range, but a lot of things that need range over data rate are in the 900 and 400 MHz ranges which these will happily pick up. Most recently I was having problems where certain channels of my cable internet signal were having horrible error rates and low SNR. My modem told me the frequencies affected so I tuned them up on the SDR and I see the telltale waterfall profile of a LTE signal. Long story short when I pointed this out to the cable tech he immediately suspected a bad connector or cable damage, so he got tools out for testing that and found some chipmunk damage slightly upstream of me.
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Jun 24, 2016 19:25
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wolrah posted:That's a lot of what I use mine for as well, debugging RF things. Garage door opener/car remote fob not working? Let's see if it's sending a signal, then compare it to a known good one and see if it looks sane. They unfortunately don't reach up to the common 2.4GHz range, but a lot of things that need range over data rate are in the 900 and 400 MHz ranges which these will happily pick up. Looks like you can get to 2.4GHz with a downconverter (and likewise below 24MHz with an upconverter): http://www.rtl-sdr.com/tag/downconverter/
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Jun 24, 2016 21:14
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Jonny290 and I built up camp at 10,000 feet for FD this year:  9 total contacts. Seems only 20/40 were open and quintuple booked every single turn of the dial Check out this sweet action shot of how packed the band was from start+ 
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Jun 27, 2016 02:20
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The 75m hamstick dipole very much exceeded my expectations. (My expectations were that it wouldn't' work at all) That's a 92" piece of pipe in the bucket of concrete. At the top is an MFJ-347 hamstick dipole adapter with two MFJ-2375T 75m hamsticks. The hamsticks come with whips about 12" long. Having those extended all the way produced a dip at around 4.5 mhz, so I ended up having to obtain some longer whips to bring the dip down to my frequency of interest. Having too much whip going inside the hamstick throws off the inductance, so I had to trim them. I was able to get it down to a 1.1 to 1 SWR however it has very little bandwidth, just enough for the one frequency you are tuning for. Much to my surprise most people on my net were able to overcome the apartment complex noise, and people could actually hear me. I'm quite pleased considering the circumstances. 
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Jul 3, 2016 11:37
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Nice! I've mentioned to some others that a cool trick to tune the hamsticks down temporarily is to buy a few alligator clips of various sizes. Clip those on the whip where it goes into the fiberglass and it'll drop your resonant frequency a few khz. Use different size and/or multiple clips to fine tune.
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Jul 3, 2016 18:05
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