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  • JAx's Avatar
    Tue 23rd Jul 2019, 14:12
    JAx started a thread Carbon Fibre ground plane in Antennas
    I am trying to make a monopole antenna for 915Mhz that will be fitted in an aircraft which is made of Carbon fibre. Due to the conductivity of the CF I need to put the antenna outside. I assume the CF hull will act as a ground plane but do I need to connect it to the ground (shield of the coax) or is it just enough that it is a conducting area? I guess electrically connecting the CF/Epoxy to the ground may not be possible. Thanks
    6 replies | 391 view(s)
  • Kbr's Avatar
    Sun 21st Jul 2019, 19:06
    Kbr started a thread Mobile Radios Yaesu ft 8900r roger bleep issue in Yaesu
    Hi guys I bought a yaesu ft 8900r and have an issue with it, it was fine for a few days but now on all repeater frequencies but one when I transmit I am getting a roger bleep when I de key the mike, I must have knocked something or accidental pressed something, Can anyone help, int is switched off
    4 replies | 305 view(s)
  • KD0QEB's Avatar
    Fri 2nd Aug 2019, 20:39
    KD0QEB started a thread Is this possible? in The Junk Box
    Several weeks ago we had a lighting strike about 20 feet from our house, it struck the ground between my comet CHA250B and my home made fan dipole, no damage to either antenna. However, it tripped two 20 AMP circuit breakers and took out two desktop computers (power supplies), my FT-950, two cable modems (and the HDMI board of the two TVs they were connected to), and my router. All were on except the FT-950 it was off. The only thing all these items had in common is that they all connected were to my shack ground. My IC-718 & FT8800, which were both on, and two other laptop computes (which were also on) were not affected; difference being they were not connected to the ground. The system ground is separate from the house ground which is located out on the pole that the electric meter is on. Talking to several tech's at the power company and to the tech's that replaced our cable modems think the EMF must have entered through the grounding system as it was directly wired to the grounding rod with no fuse or CB...
    4 replies | 280 view(s)
  • aire's Avatar
    Thu 1st Aug 2019, 09:55
    aire started a thread Bandwidth in Exams & Training
    I've been studying for my UK foundation exam. Looking at the Amateur Radio Band Plan, by the VHF 2m channels it says 12kHz, which is the bandwidth I need to set when programming a radio? But looking at the UHF 70cm plan, the bandwidth isn't specified. Does this mean it is 25kHz? The spacing between channels on both the 2m and 70cm plans is 25kHz, so not sure why the bandwidths would be different? As there's 25khz between channels on the 2m band, then why does the bandwidth need to be 12.5kHz? Wouldn't that leave an unused gap between channels?
    6 replies | 240 view(s)
  • brandon lind's Avatar
    Mon 5th Aug 2019, 20:58
    Having no tracking generator on my spectrum analyzer, I wanted to make a broadband noise source for doing filters and such. After trying a few of the 2N3904/Zener or LED schematics online (the parts I have on hand), I could only get noise up to about 40MHz. If anyone could advise on how I might improve that using 3904's, I'd appreciate it. I have some KSP10's somewhere too. Where I'm thinking of going from here: I made an avalanche pulse generator for TDR measurements a while back that did about .75ns rise time and that thing puts out noise well into UHF, but its still a bit weak for getting a good picture of what a filter is doing. I was thinking of putting about 10 2N3904's on a board and have them all avalanching into the same load resistor (timed with different capacitances), perhaps through diodes if that don't cut down on the bandwidth. The goal is total RF chaos with junk box stuff, any thoughts?
    5 replies | 256 view(s)
  • brandon lind's Avatar
    Fri 9th Aug 2019, 06:27
    I never cease to be amazed when I watch videos from the old days before technology made things easy for the every day person. I've seen videos for changing a crystals frequency by sanding them or putting them in acid, I've seen wavelength and tuning measurements with a lecher line and a neon bulb, I've seen single conductor transmission lines that have less loss than coax or twin lead, and now I believe I've seen it all... An optical lens made of glass focusing RF energy! This particular video starts out very boring to the average wire nut, but the second half is an excellent demonstration of reflection, refraction, diffraction, and standing waves. Just thought I would share the link for those interested. https://www.youtube.com/watch?v=Vwjcn4Vl2iw&t=636s EDIT: "The way things used to be done" is almost worthy of its own section on the forum!
    3 replies | 182 view(s)
  • dervari's Avatar
    Wed 24th Jul 2019, 03:31
    dervari started a thread Handheld Radios FT270R - clip screw size in Yaesu
    Either my new FT270R was missing the screw to attach the clip, or it fell out as I was unboxing it. In any event, does anyone know what size/type screw I'd need to secure the clip onto the radio? Thanks!
    3 replies | 155 view(s)
  • M0BWZ's Avatar
    Thu 1st Aug 2019, 16:06
    Greetings all I have recently reinstated my Amateur Radio licence after 16 years and all being well next year my Wife and I we will be living and working in a touring Caravan site in the UK for around 8 months then wintering in Spain for the remainder of the year. Does anyone on this forum have any experience of setting up a HF station from a Caravan site and if so what antenna system did you use ? obviously it would need to be low impact possibly a loaded vertical of sorts as I only have a Windom at the moment and at 133 feet I am pretty sure it would not be welcome on a Caravan site. Any advice appreciated.
    2 replies | 207 view(s)
  • gilow's Avatar
    Sun 4th Aug 2019, 10:52
    gilow started a thread DIY Marine HF Whip in Antennas
    Hello all, New member and pretty inexperienced HF user, so please accept my apologies for any terminology mistakes and do not for one second assume that I know what I am talking about. I have my Australian standard HF radio license (VK5MJD), which I achieved a few years ago. I have had very little chance to use it so far, and I am sorry to say a lot of the theory has leaked out my head too. I also have my Marine Radio Operator's Certificate of Proficiency, the one that allows me to use marine HF frequencies from the boat. Finally, I have an ACMA issued ship's station license (VNZ2045). That's the license side, in terms of hardware, on the boat I have one of the Icom marine HF radios that will also transmit on HAM frequencies, coupled with an AT-130 antenna tuner. The radio works very well, and I have had a few conversations with a maritime HF group along the East Coast of Australia on the 40 meter band, over a range of 1000 to 2000 km. The radio uses the 10 mm 316 stainless wire backstay of the...
    3 replies | 168 view(s)
  • AA6WW's Avatar
    Thu 8th Aug 2019, 22:19
    I'm starting to rebuild my Butternut HF6V and have to build another coil for 40 meters since mine was stretched out and ripped apart. I can probably find replacement aluminum wire to rebuild the coil but I have no idea what the total physical length of the coil is. Does anyone know what the length of the 40meter coil is, or at least maybe the number of turns of one you already have and the diameter of the coil? Thanks for any information on this subject. Ralph in Sacramento AA6WW
    2 replies | 145 view(s)
  • Steven's Avatar
    Tue 13th Aug 2019, 23:31
    Wondering if someone can direct me to source of an incognito mobile antenna that looks like an ordinary pickup truck antenna. I plan to add a mobile to my pickup but just don't want a mag mount or other obviously HAM antenna. I'd really like to add a similar to the FM radio antenna that is on the passenger side to the drivers side of my truck and I think that would be reasonably in conspicuous. Surly someone else has wanted to do the same thing. I have scoured the internet and have yet to find anything close. A base loaded whip that ins't too long would be fine. Any ideas? Thanks Steven
    2 replies | 125 view(s)
  • brandon lind's Avatar
    Sat 3rd Aug 2019, 16:44
    While putting a Bearcat 980 (the newer one with less tuning coils inside) back on frequency I ran into trouble. Being my probe loads the oscillators too much to measure frequency (and there is only one oscillator having an adjustment anyhow), I added 1kHz modulation and measured it coming out of the back end. I was able to get the AM and USB transmit back on frequency with no trouble but the LSB coil wouldn't adjust enough to get it on frequency. With the ferrite screw completely removed, I was only able to get it up to 27.20381 MHz (Ch 20 LSB, 1kHz modulation - shooting for 27.204). I had to use a piece of threaded brass in place of the ferrite screw to get it up to 27.204. Anyhow, the radio is working great and people report that its right on as my counter suggested, but I am still left wondering... Why would it come out of the factory so far off that parts need changing? The guy I'm repairing it for said it hasn't been opened or modded in any way and I see nothing altered either. Has anyone ran into...
    2 replies | 199 view(s)
  • AJ4UY's Avatar
    Thu 1st Aug 2019, 22:05
    Kenwood models : TS480SAT and TS480HX Transceiver . Receive Output Audio will lessen to a whisper once unit is powered on for a few minutes. Unit may Power On initially with the Receive Output Audio at a very very low level, as well. Within the TX-RX Circuit Board - The circuit net which Fails is the + 3.32 v DC Supply Voltage which is sourced by IC215 and sinked to several of the Receive Audio Circuit including : DSP - IC 220, CODEC - IC217, FILTER AMP - IC214, ANTI-ALIASING FILTER - IC218, ANALOG SWITCH - IC219, MICROPHONE AMP - IC221, A/D Convertor - IC212, BUFFER IC - IC209, MCU - IC204, MULTIPLEXER - IC201, INVERTER - IC223 and BUFFER - IC222. Within the TX-RX Circuit Board Capacitor designation C281 has failed, possibly due to heat generated under a Metallic Shielding Can (which primary purpose is to enclose and protect the DSP ( digital signal processor ) IC220 ( 144 pin FPGA ) component and the MCU ( Main Microcomputer ) IC204 (144 pin FPGA )). C281 is a 100 uF 6.3v electrolytic...
    2 replies | 188 view(s)
  • BFX's Avatar
    Wed 14th Aug 2019, 16:33
    Just posting for the first time to say hello. I look forward to learning from all of you. Right now I have a Baofeng UV-82 that I was gifted by my Elmer upon passing my Tech. I have just added a Negoya 771 that improves the performance noticeably. I have my father's FT-101Z in storage that I will get out in the next several months. It may need someone to look it over before I fire it up. It has not been powered on for several years. Cheers!
    1 replies | 164 view(s)
  • RealBrock's Avatar
    Fri 2nd Aug 2019, 00:48
    RealBrock started a thread Mobile Radios ICom 706 MKIIG Fine tuning 2 meter frequency in Icom
    I am a brand new ham and starting on an ICom 706 MKIIG radio. I must be missing something but when I try and go from say 146.710 to 146.715 it jumps in increments of 10 and goes 146.720 then 146.730 and so on and skips the .5 part of the frequency. I am trying to go through the operating manual but canít seem to make the more fine tune. I am trying to program in a local repeater 146.715 and canít seem to figure it out. Thanks for the help!
    1 replies | 158 view(s)
  • fauxfly's Avatar
    Mon 29th Jul 2019, 17:18
    So I'll be in a condo for a week in on the Gulf coast. The condo where we stay is on the 18th floor - it has a balcony which is about 4 feet wide - my question is what can I do to transmit my QRP from that balcony and try to make some contacts?? I cant have a very large antenna as I have to fit it in a suitcase or a duffle. I was originally thinking a mag loop but still wondering - Any ideas guys?? Steve KD9NMT
    1 replies | 157 view(s)
  • rwilabee's Avatar
    Tue 6th Aug 2019, 00:41
    I got my Drake 2A out of moth balls as I have been away from Low Band stuff for a while. We live in a community where I can't put up an antenna. I would like to listen around. I picked up an MFJ-1778M G5RV Junior wire antenna. The only thing I could do was to put it in the attic horizontally and I ran the leads in a V. I'm not hearing any chatter just static. Have all the bands been in the dumps lately or could it be my antenna. I had a friend come over with his small Xiegu G90 HF rig and the same thing. I live in the Palm Springs area and the house has a tile roof on it if that makes a difference. Any thoughts or ideas? His rig when you pressed tune seemed to tune up ok according to the digital indicator. Thanks Rich
    1 replies | 142 view(s)
  • rwilabee's Avatar
    Fri 9th Aug 2019, 02:22
    rwilabee started a thread DMR Radios in Amateur Radios
    Does DMR on 440 have pretty good range. I'm trying to figure out if I should get a Hand Held and use it at home with an external antenna and then I can take it mobile with a mag mount or go for a mobile rig for home. I don't know anything about DMR but would like to take a stab at it.
    1 replies | 135 view(s)
  • radarweb's Avatar
    Thu 1st Aug 2019, 16:43
    Does a directional antenna receive power from a transmitting omnidirectional antenna if the transmitting antenna sits outside the directional antennas beam pattern? A secondary radar has a beamwidth of roughly 2.4 degrees. An aircraft responds omnidirectionally. If the aircraft was say 1.6 degrees off boresight (.4 degrees outside of the beam pattern) and transmitted, would the radar antenna recive the transmission?
    1 replies | 124 view(s)
  • esa's Avatar
    Fri 16th Aug 2019, 13:53
    esa started a thread Round 2. in Introduce yourself
    Hi, Trying out the waves again. Stopped back in '96. It will be interesting to see how things have changed. KE6MHP
    1 replies | 77 view(s)
  • Flint's Avatar
    Sat 17th Aug 2019, 21:49
    Hi. Building my first QRP radio and almost finished- hope to test tonight. However Iím winding the final coil that calls for 14 wraps of 28 ga wire, but I just ran out and only have 30 ga. Will using the 30 ga wire have an adverse affect on my radio? Thanks...
    1 replies | 44 view(s)
  • fkavanagh96's Avatar
    Wed 24th Jul 2019, 23:26
    Hey guys, New here, just got my technician license. My job wants me to use some 3d shape-based we have to modulate signals. I've already written the matlab code that can turn the shapes into continuous waves via fourier transform for (to my knowledge) analog modulation, and created binary step functions out of the shapes for digital modulation. The goal here is to be able to use those functions, which fully describe the shapes in question, to modulate waves and send information to a receiver that could invert the process and get the shape up on their monitor or something. My question is how. I'm new to this stuff and both the necessary hardware and the necessary software elude me on how I might begin this process, since, to a radio, the waves I've made are just pixels on a screen. I would likely also have some follow up questions about scaling them to proper sizes and whatnot. Any help would be greatly appreciated, I'm lost here! Thanks, KD2SKI
    0 replies | 186 view(s)
  • camerart's Avatar
    Fri 9th Aug 2019, 09:52
    Hi, When programming Handy with CHIRP, is it transmitting when red LED flashes Camerart
    0 replies | 151 view(s)
  • Neevese's Avatar
    Sun 28th Jul 2019, 20:52
    Neevese started a thread Yeasu 8900 in Icom
    Can anyone help.my Yeasu 8900 is suffering from low power on tx on all settings.on high power it should deliver 50 watts but the output is only about 20 watts every thing else is working on and I get good audio reports.I was just wondering if anyone has had the same problem
    0 replies | 149 view(s)
  • fkavanagh96's Avatar
    Sat 3rd Aug 2019, 23:43
    Hey guys, New here, just got my technician license. My job wants me to use some 3d shape-based software we have to modulate signals. I've already written the matlab code that can turn the shapes into continuous waves via fourier transform for (to my knowledge) analog modulation, and created binary step functions out of the shapes for digital modulation. The goal here is to be able to use those functions, which fully describe the shapes in question, to modulate waves and send information to a receiver that could invert the process and get the shape up on their monitor or something. My question is how. I'm new to this stuff and both the necessary hardware and the necessary software elude me on how I might begin this process, since, to a radio, the waves I've made are just pixels on a screen. I would likely also have some follow up questions about scaling them to proper sizes and whatnot. Any help would be greatly appreciated, I'm lost here! Thanks, KD2SKI
    0 replies | 134 view(s)
  • Twave's Avatar
    Thu 1st Aug 2019, 21:18
    Hi, I found this interesting article: http://f6cte.free.fr/Wireless_transmission_using_the_sole_electric_field_rev.C.pdf It basically describes non radiant communication using the sole electric field on 9kHz with a communication range of up to few hundred meters I was able to do some simulations for higher frequencies (80m band) with a slightly different setup and I would get a few 1000kms in theory. Ofcourse building and testing is the way to verification and I should be semi-optimistic about this. What are your toughts ? Is achieving long range possible using this technique ?
    0 replies | 112 view(s)
  • KG7HCL's Avatar
    Wed 31st Jul 2019, 19:08
    KG7HCL started a thread Radio Accessories Car battery to car trx in Yaesu
    If the ground fuse opens but the power lead remains good can this bring harm to the radio?
    0 replies | 106 view(s)
  • bluejaws's Avatar
    Mon 12th Aug 2019, 12:32
    I'm looking into running a longwire with an antenna tuner for my 100W HF station and I'm a bit confused whether I need to also use a balun with the tuner. I'd like to keep the rf out of the shack. Shack is in the basement. Coax feedline running up to the longwire that begins near the top of my chimney. Plan to use a counterpoise as well. Any help/suggestions greatly appreciated. Dave
    0 replies | 97 view(s)
  • EB5HDT's Avatar
    Thu 25th Jul 2019, 12:28
    EB5HDT started a thread Icom IC 726 Problem in Icom
    the problem is that when I turn on the device a loud plop is heard on the speaker and in the electronic scheme I do not find what is the component or components that makes that plop so loud, I do not know if it is on the main board board or in the PLL board, otherwise everything works perfectly also a small plop is heard when changing the band and when changing AM and FM modes, in SSB and CW does not occur, also when transmitting when you press the microphone to transmit hey that annoying plop on the speaker ... I can't figure out which component is missing.
    0 replies | 95 view(s)
  • fkavanagh96's Avatar
    Wed 31st Jul 2019, 17:57
    Hey guys, New here, just got my technician license. For my job, I'm supposed to figure out how to use some 3d shape-based software we have to modulate signals. I've already written the matlab code that can turn the shapes into continuous waves via fourier transform for (to my knowledge) analog modulation, and created binary step functions out of the shapes for digital modulation. The goal here is to be able to use those functions, which fully describe the shapes in question, to modulate waves and send information to a receiver that could invert the process and get the shape up on their monitor or something. My question is how. I'm new to this stuff and both the necessary hardware and the necessary software elude me on how I might begin this process, since, to a radio, the waves I've made are just pixels on a screen. I would likely also have some follow up questions about scaling them to proper sizes and whatnot. Any help would be greatly appreciated, I'm lost here! TLDR: How do I turn matlab-generated...
    0 replies | 92 view(s)
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