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Thread has inspired me to knock the dust off the ham station and register for Field Day. nice! I run all Icom radios, among them a bulletproof IC-735 and a pair of PCR-100 wideband rigs that I've modified and tweaked (10.7 MHz IF out -> IC-735 for SSB/CW satellite decoding) I'm a bit of a brand loyalist. Antennas include a 25 foot vertical for HF, Diamond vertical for 2 meters, [homebrew eggbeaters for 2 meters and 440, and a homebrew 7 element 440 beam] - bracketed antennas are for satellite work. I've got an Alliance U100 perfectly restored and ready to put up for my steerable satellite array, but I need ~2weeks of free time and a new house to install all of that. Keep on listenin; I got discouraged this winter when I upgraded to Extra and spent ~300 hours trying to QSO on HF with no success. The sunspot cycle did me in. If memory serves me it should be improving a bit now, six months later - I think the cycle nadir was somewhere between Feb and April.
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Jun 19, 2007 03:51
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I'm a VHF nerd; if you guys want scanner stuff in the wiki, just say the word. Should be able to dump some info in.
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Aug 2, 2007 03:15
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AstroZamboni posted:
Messed around with weatherfax yet? All you need is a soundcard interface to receive and a list of the times/frequencies. I had great fun tuning those in; from my NW Arkansas location, I could easily get the NOLA or Boston broadcasts depending on time of day and band. It's pretty amazing to listen in and watch the image scan in, line by line. You can hear the 'black' and 'white' tones distinctly, and it's relatively easy to tune.
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Aug 2, 2007 23:42
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quote:Your asymmetric dipole setup is interesting, and if I could figure out how to use the NEC modeling software I'd see what kind of pattern you'd get with that. Off center fed dipoles are pretty neat for HF. http://www.cebik.com/gup/gup9.html Basically you're just feeding a dipole at the ~300 ohm point instead of the 75 ohm point, and using a 4:1 or 6:1 balun to connect that to 75 or 50 ohm coax, respectively. The usage and feeding of off-center-fed or "windom" antennas is one of shortwave/ham radio's holy wars; some people despise them as tools of Satan's deception, other look to them as proof that God loves hams and wants them to be happy. I think it falls somewhere in the middle in all actuality, and that they're great in the proper installation, but probably little more than dummy load/tuner mismatch in some other situations.
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Sep 18, 2007 04:54
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Just a reminder that 80 meters should be wide open for you guys with SSB radios. 3700-4000 is the allocation; you'll find most activity between 3800 and 4000. Everybody runs huge antennas at 150 feet in the air with 1000 watt amplifiers on this band; as a result, you'll get some serious powerhouses booming in. If you don't have SSB capability, you can still maybe get in on the fun - AM operators like to operate between 3875 and 3900 KHz. Spin down there and you might hear some of these ex-broadcaster golden throats yapping on 3885 one night. 40 meters seems to be shaping up, too. I threw a dipole up for 40, just 5 feet off the ground, and have gotten a few morning nets logged already. It slams down to perfect 1:1 SWR at 7200, too. I'm proud - cleanest tune I've ever done.
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Sep 22, 2007 03:43
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AstroZamboni posted:
That's a solid mag loop design. If you guys experiment with mag loops, make sure that all of your connections are very solid and secure. Mag loops operate in a different manner, and resistance in the antenna elements and connections hurts them quite a bit. You'll be good if you securely clean and solder all connections, probably - don't cheese it with clamps, though.
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Sep 24, 2007 20:01
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Semi related hammy stuff, but I've got a recipe for you guys. 1: Pack your radio, 50 feet of wire and a change of clothes. 2: Go on a camping trip or something. Get the hell away from civilization. 10 miles is good. 50 is better. 3: Throw that wire up in a tree (tie a rock to the end or something), hook it to your radio, and TUNE IN THE GODDAMN WORLD. The key to this exercise is to get really far from electrical noise and interference. I went on a 3-day camping trip and brought my ham and other radio rigs out. I have a 102 inch CB whip on the back of my truck; to the end of that, I attached 50 feet of wire and strung it more or less horizontally, throwing the far end over a tree limb about 20 feet up. The radio was an Icom 735 (admittedly a good HF receiver) with my Kenwood antenna tuner in line. At first, I thought that something was wrong - my noise floor on the 40 meter ham band was literally zero. Then I spun the dial and had my ears blown off by a CW signal. This was the middle of the afternoon, in a natural valley roughly 500 feet below average terrain. There were literally 15-20 strong, intelligible CW operators between 7000 and 7050 KHz. As I went up, I was hit with a wall of S5-S9 RTTY and other digital modes; further up the band there were tons of nets and ragchews on sideband. Normally during the day I am able to tune in one, two CW ops and maybe a powerful sideband station. I made my first successful portable contact (with special event station W0W in Minnesota, not bad from NW Arkansas) with ten watts through a CB whip and spool of speaker wire, in the middle of the woods on a breezy afternoon day, with the birds chirping and the campfire crackling. It kicked so much rear end. On an even more techy ham note, I installed the rotor and mast for my 70 centimeter satellite receiving antenna. This completes the antenna system for my satellite station and brings the pokey-stick-in-backyard count to 4, plus a 40 meter dipole. I'm tuning SWR on it and testing on various satellite passes this weekend; if I remember, I'll record some satellite pass audio and take pictures of my station.
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Oct 6, 2007 04:41
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Built a new radio desk as MDF Wal-Mart poo poo furniture doesn't play well with 40 pound radios containing more steel than a Volkswagen. Shack pix!   Roll call, left to right: Icom PCR100 with 10.7 MHz IF out and discriminator out Uniden 396 Icom PCR100 (stock) Alliance U110 rotator (VHF/UHF) atop Kenwood AT-230 tuner - 440 preamp is peeking out to the left of the tuner Icom 735 with intact plastic door (this is rare :P) Icom 271A with an MFJ VHF/UHF cross needle meter on top, and my Icom 208H for the packet node/scanning poo poo Compaq laptop off to the right that handles PSK31/packet/PCR100/programming duties Desk cost me about $32. Lowe's and Home Depot will do a couple of cuts for free. Plan your desk intelligently - I only needed two 2x2' caps and three cuts in a single 4x8 sheet for this - and look for miscut lumber in the bargain bin. All the studs/legs/reinforcements for this ran $0.51 per, and they were all at least 4 feet (i had to cut them all). I can jump up and down on any part of this without flexing or any nastiness. Love it. Edit: You'd be perfectly right if you think that operating that old 271 is a complete pleasure to the eyes, ears and hands. I find myself getting caught up in simplex way too late at night. Currently bidding on an Icom 471, if I can pull that poo poo off, I'll be one happy satellite op. Jonny 290 fucked around with this message at 23:28 on Nov 23, 2007 |
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Nov 23, 2007 23:23
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jose you'd better be extra before jan 01 or i'm going to come to your house and steal that ft-1000 god, what a fuckin' classic rig. You picked well. I've been listening to and working a lot of PSK31 and other digital modes. See, there are a handful of digital modes out there that approach and even exceed CW in 'punch' or the ability to communiciate with low signal; there are even some very slow digital modes that can be decoded below the noise floor. yeah. So, if you guys have decently stable radios and good antennas, go download Digipan or MixW (all free), hook a speaker cable to the line in of your PC and visit: 3.580 (I have bad noise here so I can't play but this is the 75m freq) 7.035 (PSK31 DX/secondary freq) 7.070 (main US PSK31 freq) 10.140 (some very nice guys here on 30m) 14.070 (only during the day mainly but VERY active then) All frequencies are USB. 7.070 is blowing up just about 24 hours a day, depending on prop. I worked Cuba and Ontario this afternoon, VNC'd from my work computer. Hell yeah.
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Nov 29, 2007 02:42
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Jose: Put it this way, those Cuba and ON contacts were with 25 watts peak power. all these digital modes are pretty hard on radios, with the 200w FT-1000 you would be expecting to peak at about 120-150 watts MAYBE, and most of the time you'll be fine with 25 to 50 my ic-735 will spit out 135 watts SSB on 40 meters before my ALC kicks in, and it'll top out about 75-80 watts PSK31, though i rarely take it above 25. I had a nice contact with VE3NOO the other day and for shits I was backing my power down; we were still at 100% copy when I realized that I was shoving a grand total of 2 watts PEP down the line into a dipole five feet off the ground, haha. Pretty miraculous poo poo. Let me know if you (or anybody else) has any questions about taking ham exams or about digital stuff - i'll be more than happy to help anybody along. As for the SWL stuff, well, I haven't been able to tune around too too much as I've been busy with holiday stuff; hopefully I can get a few nice nights with good prop to tune some cool poo poo in.
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Nov 29, 2007 04:05
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quote:Most of em are a bunch of old guys though. I would prefer talking to goons on HF. I really don't enjoy our local clubs - I went to one meeting for my General/Extra upgrade last Jan and everybody there was about 70 years old and all they cared about was impressing the Red Cross with their whacker lights and "EMERGENCY COMMUNICATIONS" banners so the city would give them money. I'm all for promoting the emergency aspect of it, but we're a hobby service, not a volunteer dispatcher service. Don't let a meh local club turn you off, definitely. There are other ways of meeting up with hams; of course most notably radio. 
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Nov 30, 2007 02:20
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ham and monitoring updates for me this week: -SATELLITE SUCCESS. I completed a contact with NK0Z on the SO-50 SaudiSat on Saturday evening. The final stumbling block was - haha - my lovely 70cm preamp was giving me over 3 dB of loss in bypass mode, and wasn't amplifying properly when on. I ripped it out and threw it violently on the floor (cost me $12). 45 minutes later I had good copy on the bird with virtually no noise and we exchanged our pleasantries, after which I had a celebratory drink and giggled like a little girl. loving SPACE. -More HF fun. I'm operating PSK all the time now, even at work via Remote Desktop. having great fun with that. I am in the process of putting up an 80 meter dipole so I can try the "next to the top band" once again. I hate trying to get a QSO on that band - it's so hard. -Starting to listen to fax transmissions again. weatherfax is so cool, even the HF black-and-white ones. I am building an eggbeater antenna for 137 MHz so I can receive the awesome color satellite ones, too. Haha, I always forget that those FT-1000s and other 'flagship radios are so goddamned huge. I thought my IC-271 was a monster. And Jose, don't feel bad about freaking out the neighbors - I sometimes operate psk with the window open in nice WX and I always monitor the audio so they hear DEEEEEEEEEEEEEEDEEEEEEEEEEELELELELEEDEEEEEEEEEEE all night long.
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Dec 4, 2007 02:38
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Those are some pretty god-damned short waves. :P Log periodics are just dipole arrays fed alternately out of phase. I'm assuming you were giving the lengths of 'one side', correct? If so, your top end is going to be about 1900 MHz, and your low end somewhere around 800 MHz. Sounds to me like you have a 900/1800 MHZ GSM phone base antenna, which would absolutely rule balls if you were trying to hit a remote cell site, but is basically the same as plugging 5 feet of speaker wire into the back of your radio at HF frequencies.
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Dec 4, 2007 04:44
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quote:K5WCB no-code Technician here, with the General upgrade book sitting on my desk. I need to get off my rear and go take the test. Welcome to the thread. My suggestion is to a: take three to five QRZ practice tests a day until you can consistently nail 90% or better, and b: Study for, and take, your Extra at the same time.If you can get the material in the General book, Extra is only slightly more advanced and it's not that bad. You don't get charged any money for taking multiple tests in the same session, though you will have to wait till they grade your General to make sure you passed. I did about three QRZ.COM tests a day and got the general with 100% and the extra with 96 (missed two). Sorry i've been out of touch with a few of you privately, I've been really busy with the holiday season and I'm also neck-deep in designing what is most likely the world's pimpest radio mixer (for audio level signals). I'll try to get ahold of some of y'all ASAP. The sun is peeking over the horizon folks, the solar cycle minimum is almost certainly behind us now and it will start to come up a bit. Get your rigs now, I bet we'll see better prop by June.
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Dec 14, 2007 22:00
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mas posted:woohoo! Girlfriend got me the 2008 Passport book for Xmas! Yep, it's glorious. Tip: If you want to experiment, go around with the radio and start shutting off breakers. If most of your noise stops on a single breaker, examine what's on that, and there's a chance you can kill or reduce that interference. If the interference is outside your house, though, you're SOL.
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Dec 21, 2007 19:20
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TetsuoTW posted:From that QRZ.com link: Solar flares are bad. They knock out communications. Sunspots, however, spit out magnetic energy, which enhances the ionosphere. More ionosphere -> better mirror for those signals -> better skywave propagation. The "bipolar sunspot" is one of the indications that the cycle has bottomed and is reversing. It's of a different type than the normal ones we've seen for a bit. Coronal holes are areas where for some reason, the solar magnetic lines do not loop back into the sun, but extend outwards. This also activates our ionosphere somewhat. To update the thread - I posted an epic on radioreference about this, but basically I threw up a 1/4 wave inverted L antenna for 75 meters. If you guys are having bad luck with your compromise antennas, I say again - go and throw wire up in trees. I've been ragchewing on 75 meters all weekend where previously I'd never landed a QSO. I stripped out some phone cable (basically half of CAT5 cable, two pairs instead of 4) and was out throwing poo poo up in trees at 3am Saturday night. As we all know, antenna performance is directly proportional to how ugly it is, and inversely proportional to how nice it was outside when you put it up.
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Jan 8, 2008 03:45
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I keep her fed with Cosmo, Glamour and a few other mags. She don't complain none. Thinks I'm cute when I'm out throwing wires up in trees or some poo poo. Radioreference thread on it. I'll post pics as soon as the sun comes out for a few hours some day this week. I've already got plans for the next one - higher, longer and stealthier.  e: that little lafayette is awesome. After I get a few spare bucks one of these days I'm going to buy an armload of all the old shortwave receivers like that - Hallicrafters, the old Realistic, etc. I think they're super-cool. Jonny 290 fucked around with this message at 22:33 on Jan 8, 2008 |
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Jan 8, 2008 22:27
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Topical. I ordered 150 feet of coax from Universal on Dec 20th and they hadn't shipped by Jan 6th. Had to cancel because they hadn't charged yet and I mis-budgeted for Christmas, sadly. Hopefully they'll catch up and I can re-order soon.
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Jan 9, 2008 18:21
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Mr.Electric Ocean posted:I have a question that may or may not pertain to radio, but I figure this is place to come even if it proves fruitless. When you broadcast do you ever say "MORE RAM MORE RAM" over and over? Sometimes in the early morning my computer speakers will blare "MORE RAM" but it's happened before to one of my radios and the living room TV set. That sounds like some rear end in a top hat with a 500 watt CB amplifier (illegal) nearby. They're notorious for blathering weird poo poo and making animal noises, just so they can watch the meters jump real high. CB amps usually have next to no filtering so if anything is going to interfere with stuff like PC speakers and TV's, it'll be that. Hams usually clean their poo poo up, and that's not a known radio communications phrase or a mutation of one.
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Jan 16, 2008 03:04
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TetsuoTW posted:I've started work on one of these, but hit a small issue - I have no idea what in the hell kind of place would have the aluminium disk it mentions. I'm a total DIY noob, so yeah, any hints'd be much appreciated. Use those little disposable aluminum pie plates for that. Should work A-ok.
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Jan 16, 2008 04:56
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I was coming in here to post the HAARP tests but you got it. NW Arkansas is receiving the skywave at about S7 and moon echoes at S2-S5 on 6.792.5 right now Icom 735 with an NVIS dipole for ears. Amazing and fun experiment!
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Jan 19, 2008 06:21
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God bless JT65A. (it's the digital mode they use to nail these QSOs) That single development alone has allowed 'average' stations to do moonbounce with barefoot rigs and single yagis with preamps. From what I understand it can decode 10dB _below_ the noise floor. Don't ask me how. It's really good for QRP HF work too - you can get contacts worldwide with just a couple watts. Now you can't really talk on the mode as it's so slow, but it does work just great.
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Jan 19, 2008 19:50
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Dolemite posted:Excellent! I went ahead and bookmarked these guys. This is what I needed to know. Go stick about 75 feet of wire in the end pin of that Winradio BNC. Get it up high, and as clear as you can. Wait till about 8-9pm local time, and tune around in LSB mode between about 3600 and 4000 KHz. The 75 meter ham band will be alive with legal-limit signals from guys who sit there and ratchet-jaw all night. quote:Through some Google searching, some people suggest just only scanning in SSB mode. But, how will I know if I'm about to sweep over an AM station? Is there any way to tell you've stumbled onto an AM station while sweeping in SSB? I'd sure hate to miss a number station or crazy preacher station while searching for SBB stuff! Yep, it's the preferred way. An AM signal is just two SSB signals back-to-back with a 'carrier' signal sent out midway between the two (or more accurately, a SSB signal is an AM signal with the carrier and one sideband filtered out). Here's the thing - dependable reception of AM signals depends on your radio receiving that carrier tone. If you don't get it, the station fades, even if the _sidebands_ are still there. An AM station tuned in on an SSB receiver sounds exactly like an SSB signal, except that when you tune 'across' the signal, you'll hear the carrier (it'll just be a loud whine). SSB mode is much more sensitive, and there isn't anything you can pick up in AM mode that you can't in SSB. Hence, Occam says stay in SSB. HOWEVER, once you're tuned into a strong AM signal, there's absolutely nothing wrong with switching to AM mode for higher fidelity (the advantage of AM is that it sounds way effin better than SSB and you don't have to tune it 'on frequency' like SSB). One final note: if your WinRadio offers "Synchronous AM" mode, use it when listening to shortwave. It almost eliminates the shortwave fading issues (which are 90% caused by carrier fading) by re-inserting a 'fake carrier' to decode. Result: SSB's performance, AM's sound. quote:Also, my receiver offers the choices of scanning in FM wide and narrow options. For some reason, FM wide seems to always offer much better clarity and reception. Is there ever a reason I would want to use the FM narrow option? quote:Oh, and one last question: When in SSB mode, I have something called a BFO offset. I tried playing with that but it only seems to adjust the pitch of the signal (I played with it while listening to carrier tones). Is that all the BFO does? That's exactly what it does. BFO stands for 'Beat Frequency Oscillator' and refers to a circuit that reinjects the 'carrier' exactly like the synchronous AM detector I explained earlier. The detector uses the BFO signal as a reference frequency to figure out how to decode the incoming signals; hence, changing the reference frequency changes the pitch of the audio. BFO is critical on SSB units because nobody transmits exactly on frequency, nobody receives exactly on frequency, and it's fatiguing to listen to the human voice when the pitch ratios aren't right. Jonny 290 fucked around with this message at 03:40 on Feb 12, 2008 |
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Feb 12, 2008 03:35
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Dolemite posted:If I am interpreting this correctly, that means that if I stay in SSB mode, I'll hear anything that is an AM station as well as SSB? So if I pick up a hint of a signal, I can change over to AM and receive it better if necessary? You got it, right on. quote:I think the reason I am confused is because when I've tried to use SSB before, I've never managed to receive a signal! OK, as far as SSB shortwave reception goes, your antenna does the same job that it does for AM and any other mode. Your antenna is pretty rotten at shortwave frequencies - short wires just don't get enough voltage from the incoming signals to make it past the noise and static - and further more, most SSB stations transmit at much lower power. Your average ham transmits on 75 meters between 100 and 1500 watts, with most around 3-600 watts these days. Your average shortwave station is 100,000 watts - they're engineered to shove so much RF into the sky that lovely $2 shortwave radios in Namibia can't help but receive their signal. If you have a few bucks to experiment, the cheapest and most convenient way to get a basic antenna up is to go to Radio Shack or Wal-Mart and buy a 25 or 50 foot roll of cheap speaker wire. Split the two wires apart and join them end to end so that they form a single 50 or 100 foot wire. Jam that bastard in the center pin of your Winradio and watch it come alive. A good way to test AM vs SSB signal strength is to tune in to 5.00 MHz, WWV in Colorado. Try it in AM and then SSB. You may find that though the S-meter moves more in AM mode, the signal has much better signal to noise ratio in SSB. This is why we can talk all day long in SSB at power levels that don't even move the S-meter, as long as we're stronger than the noise. You need much more signal for a decodable AM signal. If you can hear WWV on 5.000, your next neat test is to try listening to CHU Canada on 7.335 MHz. CHU is a very interesting station because they transmit a signal that is basically SSB, but they include the carrier signal as well. This allows them to transmit a more efficient signal (since they're only transmitting one sideband, they can put more power into the other sideband) BUT since they transmit the carrier, cheap AM shortwave radios can tune them in too. So, what you hear on CHU is the carrier right on 7.335, then a USB audio sideband up to about 7.338, but there is no signal on the lower sideband from 7.335 to 7.332. Compare this with the WWV signal which has sidebands on both sides, from 4.997 to 5.000, a carrier at 5.000, and another sideband from 5.000 to 5.003.
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Feb 12, 2008 05:37
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Desuism posted:I'm sure this is no big deal among you 'folk, but I felt pretty proud as I stood on a ladder with a handheld shortwave radio listening to Radio Havana(2214, 6000KHz) I don't have a Passport to World Band (or whatever it's called D: ) and the frequency chart on the (probably outdated by several eons) website doesn't match up at all (they aren't even broadcasting on 6000KHz, ever) I'm currently out of listening mode but I definitely recall Radio Havana on 6000, and somewhere around 6180 as well. You're not crazy. Prime Time Shortwave - very nice freq schedule
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Feb 16, 2008 20:08
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Your average new shortwave listener is about 50-70 years old, looking for something to do in the long, slow summer evenings, and likely views Aldrin, Armstrong, etc. as the scientific superman explorers of their generation. I can think of a few worse random names to silkscreen on, given that context. I want a Stephen Hawking edition Grundig with built in RTTY text to speech synth =/ edit: Does the Richard Dawkins Special Edition filter out the megawatt religious stations? THAT'd be a selling point.
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May 27, 2008 22:32
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I'm glad this thread is still around. After a really bad ice storm in Feb. that took everything down but my 20 meter vertical, I have had my stuff packed up and sleeping. It's starting to cool off, though, so it's almost radio time again!
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Sep 1, 2009 15:55
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Annual (or whatever) checkin. I resurrected my Icom PCR-100's and figured out how to get the software running on win7. Listened to some SW the other night. they still work great off my 80 meter dipole! I'm going to be writing a Python/ncurses based PCR100 control app over the winter. I'll post it here when I get it usable.
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Nov 9, 2010 18:03
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Radio Nowhere posted:freenode has one called #priyom that has a number stations focus but they talk anything shortwave related. This is cool, i need a little fix of radiochat now and then. Thanks for mentioning. --- Currently in the process of putting up a full wave 80m loop antenna. I have four trees I'm using, and I am going to make my own balanced open wire feed line for it out of fence wire and PVC pipe. Should be tedious but interesting. I got most of the ropes run for the loop so far; waiting for spring deals on fence wire. Jonny 290 fucked around with this message at 08:45 on Jan 20, 2012 |
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Jan 20, 2012 08:43
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I'm back in the game! It's cold, and winter is a good time to play radio. I built a simple L-network random wire tuner in an ATX PSU case for my Icom, and am going to reroute the feedline to my old 75m dipole to the bedroom window. It's just a casual Radio Habana/broadcast AM dialspin setup, nothing too intense. And it all got driven by me finding an XBOX 360 PSU and noting that it delivered 12v @ 16 amps, hacking it to be a general purpose PSU and then thinking about what I could use 12 volts at 16 amps for.
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Jan 15, 2013 23:08
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You will not be able to get 1/4" copper tubing to solder temp with anything less than a 100 watt iron, and it would be extreme pain to try it with that. Easiest would be to get a $8 propane torch head from Home Depot or Harbor Freight, though a $10 butane pencil torch will do the job and is a bit more nimble, for future use. I use mine all the time. When building mag loops, it is extremely important that you get all the connections very, very low resistance. The loop has radiation resistances of fractions of an ohm, so if you have 0.1 ohm resistance at one of your connections, there's half of your power right there. Are you following a howto or guide, or just kind of whipping this up?
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Jan 21, 2013 16:07
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Fog Tripper posted:Following the mag loop how-to linked in the OP. OK, great! It's a simple and tested design. Antennas have a 'radiation resistance', which is a property of them that makes them appear (to a power source of a specific frequency) as being simply a big old resistor of a certain value. This has nothing to do with resonance, but is sort of related to size (although it's not just a linear relationship). An antenna can have one ohm or a thousand ohms of radiation resistance at resonance, or at any point off resonance, depending on its design. Loop antennas are very very small as a function of wavelength, and their radiation resistance is very low. Like, less than one ohm. This means that any resistances in the actual antenna circuit ( ohmic losses - like skinny copper wires or bad connections) dissipate a non-trivial fraction of your incoming signal. If you have an antenna with one ohm radiation resistance, and the connections have 10 ohms of resistance, only ~1/10th of the signal the antenna is receiving is actually going to appear as a voltage - the rest is going to be literally burnt up as (a tiny amount of) heat. Your two big connections to pay attention to are the two connections on the big loop, between each end and a side of the tuning cap. At the very least, you want to attach some sort of terminals to the ends of the pipe, or flatten it and drill a hole, then run a screw through to the capacitor terminal. Crimping and soldering is best, followed by just (solidly) crimping, followed by soldering. Basically, do not just twist the wires on or use skinny little jumper leads to connect the tubing to the capacitor. Going to extreme measures isn't going to mean the difference between white noise and hearing a mouse fart, but it is always the right thing to do to "build it once and build it right."
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Jan 24, 2013 01:23
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The braid idea is spot on. You've got the right idea. What I would do is to flux and tin the ends of the copper tubing with a torch away from the capacitor, and then crimp it up and finish by soldering it where the braid goes into the tube with your 100 watt iron. If you have a pair of forceps or a small pair of needlenose pliers and a rubber band, clamp it on the braid near the capacitor as you solder - it'll heatsink a lot of excess heat away and help protect your cap. You won't need a big globby solder joint,just enough to fill in between the contour of the end of the tube and the braid, to make a good solid connection. The bulk of your connection will be actually in the crimped part. Don't try to tin the inside of the tube all the way in or anything, you just want bare copper on that crimp. The long wire wrapped around the rod is indeed the AM antenna. That rod is made of ferrite, which makes for very high inductance coils when you wrap wire around it. I would not use it for hookup wire, it is especially fragile and thin. You want to make sure to get the correct two connections on the capacitor. The terminals should NOT have DC continuity between them. Make sure you hit the terminals with a multimeter, and if you get any resistance other than 'infinity', either the capacitor has touching plates (unlikely) or it's just two terminals for the same set of plates, and the antenna won't work. If you have any more of that braid, try to solder a short piece on to the other terminal, so your connections are the same. If you don't, you can go buy a small spool of desoldering braid at an electronics store, which is the exact same thing. Then you also have desoldering braid for future projects! Your mounting plate seems to be okay but you may see a little bit of detuning when you move your hand near it - at certain settings you may need to 'tune past' with your hand on the dial, so that it's on frequency when you pull your hand away. A small metal plate may assist in this. I would only worry about this if you get this thing built and it works, but you get too annoyed from detuning effects. We can deal with that later. E: Here's a link to the little antenna tuner I mentioned above; it's not really related to your project but it shows you what a nice air variable capacitor looks like, which you should keep an eye out for. If you can find any old tube or non-portable radio that covers AM older than about 1975 or so, it will have one of them in there. Even if the radio's dead, that capacitor will cost you ten bucks online easily. if the radio costs $5, get it just for the cap. A capacitor like this will have less loss and better range than the one you're currently using; if you're going to have fun with loops, you should try to get a few different variable caps to play with as you won't want to tear apart one loop to build another. http://jonny290.tumblr.com/post/40652895492 Jonny 290 fucked around with this message at 04:45 on Jan 24, 2013 |
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Jan 24, 2013 04:32
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Hmm. I see what you're saying. Just keep the lead as short as you can, and crimp/solder it best you can. You're working with junkbox parts, after all, so you might need to fudge a bit. As long as those leads are shorter than a couple inches, you won't see serious problems.
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Jan 24, 2013 20:36
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Man, I can remember when we used to hack beat frequency oscillators into our AM-only shortwave radios so we could tune SSB, because even the Sangean ATS-803A was $200. Under a hundo for an SSB receiver is great.
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Feb 4, 2013 19:47
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Account_Username posted:Able to pick up a few stations so far. I can get radio Cuba at night on 6165k, and I found a Chinese station somewhere in the low 13mhz freqs. Right now I'm listening to a crazy-rear end preacher on 9980k. If you tune between 7100 and 7300 LSB in the evenings, you are almost guaranteed to pick up some hams chatting away on 40 meters. Don't be surprised if you can only hear one side well.
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Feb 6, 2013 20:34
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Radio Nowhere posted:I have a head-unit in my car that does shortwave, my regulars are usually Radio Australia in the morning and BBC for Africa driving home. I do check WBCQ and the DXing shows on WWCR weekends. The other day doing a scan I freaked my wife out when it stopped on a Cuban numbers station. Also noticed the Cubans have gone digital, in-between the usual sets of numbers read by the mechanical-sounding female you get a digital hash. Anyone ever try decoding it? Please tell me you have a Phillips DC777. I've wanted one of those for like twenty years, even before I could drive.
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Feb 25, 2013 17:42
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Citycop posted:Well I'm sending the Grundig back to Amazon today for a full refund, they are good like that. On the RMA I just quoted the "external antenna port does not work properly". I can tell that the G3 is just not going to be enough for me and at the price point it's at I don't want it gathering dust. I don't really want anything portable anyway, I want features, and most importantly, a more robust antenna input. I'll be ordering a Aferdi SDR-Net shortly as it seems to be the only decent assembled sub $300 SDR option. Also I can use an ethernet cable to connect it right at the input to my longwire in the attic and not run it near any electrical wires. Cleanest and quickest way would to be like a 3 foot jumper cable with the connector you want on one end (don't care about the other end), cut off the other end, strip the coax and get your wires connected up and insulated. One wire to the braid, one wire to the center.
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May 15, 2013 16:09
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Ugh, so tired of coming in to share sad news. http://www.arrl.org/news/view/voice-of-russia-former-radio-moscow-to-end-shortwave-broadcasts another one bites the dust 
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Dec 9, 2013 20:51
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I've been thinking about buying one of the $30 Rat Shack specials just to add a BFO and have a sooooper cheap radio for listening to the 40 meter powerhouse fellas. I guess some of them use magic tuner chips though that don't expose an IF or anything like that
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Apr 1, 2014 04:02
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