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Nyhetsflöde med senaste 30 inläggen från forumet

1. How to produce overlapping vectors from a stream, using gnuradio?

   Overall aim: I'm trying to decode FT8 'from scratch'. One step of this is to run the FFT block on vectors produced from the stream (currently stored in a 44.1ksamps/sec audio file).

   The problem: There are 6.25 symbols sent each second (i.e. every 7056 samples), and the 8 tones are separated by 6.25Hz... to get a bin size of, say, 4Hz, would require 8192 samples in my FFT. But that takes 0.186s, so if this doesn't line up well with the transitions in the 8-FSK it's a bit of a pain (also it would be nice to visualise by having such overlapping windows, so the FFT output changes less drastically).

   What I'm looking for: Is there a block that does the job of "Stream to Vector" but produces vectors that e.g. overlap by some number of samples, e.g. if the input was 4,6,3,2,5,2,0,0; it might produce these vectors: [4,6,3,2];[3,2,5,2];[5,2,0,0],etc.

   What I've found so far: This looks like they're looking for something similar to what I need... https://github.com/kpreid/radio-wishlist/issues/8

   Maybe I'm doing it wrong!: Given no one else wants this, it might be a sign I've asked the wrong question/doing it wrong? I was wondering if I should be at a higher sampling rate (e.g. 441,000Hz) but then I'd need a bigger FFT input vector (to keep the bin size small) so the problem persists... but maybe I should be doing something more clever --> can I just feed this into some neat quadrature decoder block that handles all this for me? Maybe I'm approaching this the wrong way (although before I feed it into such a block I'd like to be able to visualise the actual signal/bits being sent).

   

2. Nooelec NESDR SMArt v5 with SatNOGS, What RF Gain?

   What is the recommended gain I should use in SatNOGS when the SDR is Nooelec NESDR SMArt v5 ? I know there might be different settings for different situations but what is the good value to start with.

3. Locked oscillator FM discriminator produces distorted output

   I was trying to build an FM-discriminator (for educational purposes), based on a design published in Elektor some 50 years ago (see first image).

   My own design is supplied with 5 V instead of 12 V, so I had to change some resistors to get more or less the same collector currents. (see second image)

   I'm sending in a 10.7 MHz "carrier" 200 mVrms, FM-modulated with a 1 kHz sine wave and a frequency deviation of 75 kHz. On the output, I get a 1 kHz signal out, but it's heavily distorted. I've been playing around with adjusting the input levels, but it doesn't fix it. I've also removed my input attenuator, but it doesn't make a difference.

   My second problem is that I don't understand very well how this circuit is supposed to operate. I haven't found any good references on the internet.

   I would be very grateful if someone could give me some leads how to fix this behavior, or that it might just be better to leave this circuit altogether.
   I have a pulse-counting FM-discriminator on the same board. Maybe that would be worth more of my time.

   ---

   Edit on 2026-05-02 19.41 UTC: I'm using a Murata SFECV10M7JA00-R0 ceramic filter. The frequency response shown is defined for an input and output impedance of 300 ohm, which my circuit is not providing.

   As pointed out by Marcus, the frequency response of the filter is key here. I added an extra screenshot on the bottom where a cheap 10.7 MHz resonator is used as filter.

   Thanks in advance.

   

4. Why doesn't a Class C amplifier AM modulate the lower envelope?

   

   

   I built a really simple modulating circuit, but it only modulates the upper envelope while keeping the lower envelope unchanged. This doesn't seem like normal Class C behaviour.

   NOTE: The original question used the terms "USB" and "LSB" referring to the envelopes on the positive side and negative side, respectively.

5. What's the purpose of L4 in the Kenwood KDC-MP5029 AM RF-amplifier

   I'd like to build an RF-frontend for an AM-radio using discrete components for educational purposes. The schematic below looks interesting. It was posted by @Ryuji AB1WX in an older related question.

   I was wondering what the purpose of L4 is. The service manual lists it as a choke coil, but no value is given. L4 is connected parallel to the antenna input. If the AM-antenna is a short whip, which is highly capacitive (so very high impedance), will L4 then shunt the signal to ground?

   

6. HF receiving antenna using Ethernet Cable

   I'm super new to the hobby and I know next to nothing. I would like to start listening to HF while I figure out licensing to broadcast. I read that I could make my own antenna using a run of Ethernet cable and some PVC piping to thread it through (I think it's called a sky loop?). Otherwise, I am not sure where to start.

   I can only lay this flat on top of my concrete roof. It's a ways above the rest of the house and doesn't have much of anything that needs to run when I will be doing my listening. Additionally, if I'm running it in a loop, do I need any counterpoise/grounding? Is there anything other than the cables and a direct connections to my coax? How far above the roof must it be raised? Do I need anything else with this thing? Is 18m of length enough?

   I'm going to be using the ATS25 max-Decoder Tune to listen, and I'm probably going to run the coax down a fair distance so I can listen indoor.

   Any advice is appreciated. I would also appreciate being directed to any good beginner sources where I can learn more about antenna design.

7. Flag Semaphore Question: crossing arm on top or bottom?

   I know flag semaphore is a bit off-topic for this stack exchange site, but it seemed to be the most relevant and I suspect there's a bit of overlap between HAM radio operators and people who know flag semaphore.

   Looking online, I see conflicting information about the arm positions of the letter 'O'. The wikipedia page links to a wiki commons image showing 'O' with the signaler's left arm crossing the body into the up-right (signaler's right) position. Compare that to the Encyclopedia Britannica entry, which has an image showing the 'O' with the signaler's left arm crossing the body horizontally -- the signaler's right arm is instead lifted into the up-right (signaler's right) position.

   https://commons.wikimedia.org/wiki/File:Semaphore_Signals_A-Z.jpg

   https://www.britannica.com/technology/semaphore

   Does it matter which arm holds which position, as long as there's a flag in the 9 and 10:30 positions (from the observer's perspective)? Is there a convention to always keep the crossed arm in the higher of the two positions?

8. G6ALU 20W PA for Radioberry

   I had my first ham license when I was 18 and have an engineering degree but then left it in the background for the next few decades and my neuron connections deteriorated. I want to get back into the hobby, so I got my ham license a few months ago and bought a Radioberry. I also want to get back into building circuits and was looking at the G6ALU 20w PA that is available on github under the user pa3gsb. I could just order the pcb and the components and build it but I want to understand the circuit a little better. So I have a couple of questions, maybe it is simple but I could not figure it out by myself.

   1. I see the output of the voltage regulator U1 is just connected to J7. Is this supposed to be connected back to J3 and J4 to apply Vdd to the transistors and to supply the bias voltage?
   2. But then I see that the 13.8V input to the board through J6 has the ground pin 2 connected to pin 1 on J3, which is what I can see would apply Vdd to the transistors. I could not understand this either.

   Perhaps my brain cells have deteriorated quite a bit :-), but any help would be highly appreciated. Thanks

   Edit: Apologies. I really appreciate the eagerness of this group to help. Here is the link to the repository: https://github.com/pa3gsb/Radioberry-2.x-extensions/tree/master/Radioberry-PA-20W

   And the schematic:

   Thanks again Edit: Sorry, forgot the board layout

   Edit:

   Added the LPF schematic.

9. FT232RL CONVERTER TO TX RADIO

   Trying to get my RP-70 10,11,12 meter (Aquario) to transmit through the PC.

   So I got a USB → 6-pin converter module called the FT232RL. But its DTR pin (which sends the PTT signal to the radio) is inverted. Its default idle state is HIGH (ON). And if I connect the PTT wire to the radio, it starts transmitting — so it's inverted.

   So what I had to do was study a bit and build the circuit (attached schematic). The component names are on it. I built it using a PNP transistor.

   The circuit works perfectly WITHOUT the PTT plugged into the radio. Just connected to the PC USB, it works great. When I trigger PTT in WSJTX, it turns on my optocoupler, hence, TX of tadio; when I release PTT on the PC (wsjtx test ptt), it turns off the optocoupler. That's exactly what I expected.

   But here's the problem... When I plug the PTT cable into the radio and test PTT via WSJTX to key the radio's TX. IT TURNS ON (expected so far), and the radio starts transmitting.

   BUT... when I tell WSJTX to release PTT, my circuit gets stuck. The DTR pin that controls the PTT — which should go back HIGH — stays locked, even if I unplug my circuit's cable from the radio. The board only goes back to normal when I unplug it from the PC and plug it back in.

   What would be de issue? i've tried to do a pull up, thru R3 resistor, but nothing.

   PROTOTYPE (There is an unconnected resistor — I was testing different resistance values to see if it would solve the problem and ended up leaving it soldered on. I don't believe it has any impact on the issue that is occurring.)

   SCHEMA

10. Eliminating "pop" in headphones when speaker activates?

    I spend a lot of time as an amateur radio public service volunteer, which means I often find myself wearing an earpiece for several hours. I've noticed that just about all cheap (and even some not-so-cheap) radios suffer from an annoying problem: they generate a loud "pop" whenever the speaker activates (because squelch opens or because key beep is enabled and a key has been pressed, etc). This ranges from "annoying" to "painful" depending on the radio.

    Tragically, this isn't something that anyone ever covers in their reviews.

    Would creating an adapter with an inline capacitor on the speaker wire reduce or eliminate the pops? Is there an existing product that would help here? I'm only slightly handy and creating a robust solution that wouldn't fall apart in the field might be a challenge for me.

11. MOSFET UHF PA and relay questions

    I'm trying to create my own 432/433 MHz power amplifier for FM and SSB operations using RA60H4047M1 MOSFET module. Relays like Omron G2RL and Relpol RM81 had too low isolation and made my RA60 self-resonant when ending transmitting.

    1. Is Takamisawa NA12W-K enough for 432/433 MHz switching with 60-80 watts of power after MOSFET? NO-C is bypass mode between antenna and first relay (in which NO-C is bypass between transceiver and second relay), NC-C is between RA60 and antenna.

    2. I plan to make bias for RA60 constant, switched ON every time (Vgg) with drain voltage also switched ON, for possible SSB operations. Is this correct? Does RA60 easily oscillate with constant Vgg? Even if there is no oscillation, will the module send any signal to the antenna? Cannot see anything in datasheet.

    3. If not using relays, I planned to make SPDT circuit with PIN diodes (L709CER or UM9401). How to switch OFF RX bias for one diode (+0.9-1.0 V) when transmitting and switch ON TX bias for another diode? -RX BIAS: voltage can range from +0.9 to +4.5V with 100 mA - constant, everytime available; provided by LM317m, also for Vgg RA60H4047M1 MOSFET. -TX BIAS: from +0.9 to +1.5V, only available when transmitting. 100 mA of current. Voltage could be higher, but the circuit would be changed.

    4. If relay has low isolation, how to check how many reactance does air coil needs to make higher isolation for one band (W6PQL method - https://www.w6pql.com/using_inexpensive_relays.htm)? Check capacitance between NC and C in relay and calculate LC resonance circuit for specific frequency?

    5. Beginning of circuit is to filtrate low amount of input RF power, rectify it and power up TX LED using NPN transistor, input relay and LM317m for TX BIAS for PIN diode. The relay is supported by two capacitors and a set of two high-resistance resistors, one of which is disconnected, depending on the FM/SSB modulation. There is no PTT sensing.

    Thanks for any help and response.

12. dipole antenna beam pattern or loss with mismatch frequency

    Assume that I have a dipole antenna. Its radiation pattern is "well known" if it is fed with a frequency f0 such that length(dipole) = lambda/2 However, what would the radiation pattern be if this condition is not met ? More pragmatically, can we say e.g. what the bandwidth of the dipole is (-3 dB power at broadside) ?

    Clément

13. What is the simplest way to measure antenna radiation patterns without a test range?

    Measuring antenna radiation patterns usually requires access to an anechoic chamber or a dedicated antenna test range.

    However many amateur radio operators build their own antennas and do not have access to these facilities.

    I am curious if anyone has experimented with measuring antenna radiation patterns outdoors using simpler setups.

    For example:

    • using a reference antenna at a fixed distance
    • rotating the antenna under test
    • measuring S21 with a VNA (NanoVNA or LiteVNA)

    In theory it seems possible to reconstruct the azimuth radiation pattern if measurements are taken while rotating the antenna.

    But I wonder what the main limitations would be in practice:

    • ground reflections
    • multipath
    • distance requirements for far-field conditions

    Has anyone in the amateur radio community tried something similar?

14. DIY 40m Antenna tuning: RLC and SWR

    I keep hearing the recommendation to make your SWR as low as possible and that would imply good tuning.

    I'm a new HAM and made a centre-fed half wave fan, 40m, 20, 15m. It works, and pretty well.

    I tuned it with a NanoVNA and the SWR is about 1:1 - 1:2 for all bands I use.

    But I suspect there's more to tuning than just SWR.

    • Is the perfect antenna going to be (50+0j) Ω?
    • Is it the imaginary part that changes the SWR?
    • How do you get a piece of copper wire to change its resistance to get to 50 Ω if its not?
    • How does all this fit together?
    • If I mess with it enough, am I ever going to get close to (50+0j) Ω?
    • Should I even care, if it works pretty well as is?

    Edit: Its an inverted V on top of my house. The V is about 120 degrees.I have a 1:1 balun at the feedpoint.

15. How to connect a David Clark headset to a Yaesu FT-710

    I have a question that I need a person a lot smarter than me (l’m a retired Firefighter not an electronic engineer). I found an article on how to hook up a David Clark H3340 headset to a Yaesu FT-100D radio. Aviation Headsets in Amateur Radio.

    I happen to have an H3340 that I would like to hook up to my Yasu FT-710 unfortunately the pins on the FT-710 are slightly different (see attached picture). The question is in the grounding. Which Yaesu ground (GND or MIC GND) should I connect the headset ground to? Or should it be both? Or neither?

    

    

    73, K0JLD

16. Packet Demodulation error in GNU Radio for Hackrf SDR

    I am trying to get the S-band chain of my ground station working. My setup is as follows:

    • Computer connected to a HackRf SDR via the USB and also connected to the Sband radio via UART connection.
    • I have a switch on the UART connection to put the radio on and off.
    • My radio is terminated by an Sband antenna emitting frequency 2.245 GHz.
    • My SATLAB Sband radio has GMSK modulation.
    • I am transmitting from the Sband radio using a minicom interface and reception from the Hack RF.
    • I am running a GRC flowgraph with the SATLAB SRS3 receiver and demodulating packets sent from the Sband radio.

    For this communication, I can properly receive pings and my QT spectrum shows a well modulated signal. However the message debug window prints nothing. I can not properly receive the demodulated packets.

    What could be the problems I can check for me to receive the demodulated packets? I verified the offset frequency, modulation rate, timing errors and encoding.

17. Clearest way to measure ferrite choke effectiveness?

    I have some snap-on ferrite chokes that are supposed to cut down on EMI, and I was wondering if there was any relatively direct way to measure — on the bench — whether they are effective or not. Is those something where you kinda just "try them on a noisy appliance and see what it does on the S-meter" or is there more of a "test fixture for the VNA" sort of approach available?

    I found How to meassure a ferrite using a VNA? here but I think the OP was after more a direct measurement of the material's permeability? And then there's my own How to measure a balun for effectiveness? which I'm trying to figure out if a balun is really trying to accomplish the same think as a choke.

    In either case I'm not really following the answers. I think part of the issue is that EMI stuff always kind of throws me. Like, on a piece of coax the ferrite really wouldn't mess with the normal signal, right? Just somehow a signal on the "outside of the shield"…? Or on just a simple pair of power supply wires or motor lines or whatever I would clamp these onto. Is there a way to measure the "noise" aspect of the wire before/after adding the ferrite?

18. How can I control my FT-857 with CAT?

    UPDATE: The problem I was having was just a loose cable, but I'm leaving this question up for any other 857 users who want to know how to configure the software.

    ---

    I am trying to control my Yaesu FT-857 with CAT using N7YG's controller software (https://n7yg.net/software/ft857-cat-controller). According to the Readme included in the software, the buttons should turn green when the computer is communicating with the radio. All the buttons on mine are red (third picture below). Here's what I tried/what I have:

    • RT Systems USB-62C cable plugged into the radio's CAT port (I know this cable works because I can upload memories from CHIRP with the cable)
    • The official Windows driver from RT Systems (https://www.rtsystems.us/drivers, it's labeled USB-62B instead of C; I don't know if this is an issue)
    • Menu #20 (port mode) set to CAT
    • Update: Per GreyBeardedGeek's suggestion, I changed the values in Device Manager to 8 data bits, no parity, and 2 stop bits (it still doesn't work).

    The developer recommends setting the following options, which I did:

    • Menu #19 and the software both set to a baud rate of 38400
    • The radio is turned on and set to VFO A
    • DTR and RTS are enabled in the software, since this is a non-Yaesu cable

    There is also a "Port Settings" tab in Device Manager (first picture below). I'm not sure about those options (except for "Bits per second"). If you know how to set those, let me know. Does anyone know how to make this work? What options should I change?

    

19. In QSSTV on Linux, how do I configure control of PTT using RTS via an FTDI cable?

    I have an FTDI cable, whose RTS is connected through an opto isolator to my PTT. When I connect it to a Windows PC and run MMSSTV, it works, but inverted (PTT is on when not sending and off when sending). That's an easy fix, but it demonstrates that the hardware is solid.

    When I connect it to my Linux laptop, QSSTV does not appear to make any changes to the RTS pin at all. I verified with a DMM: it puts out 3.3V regardless.

    Initially, I had an error writing to the port, but I fixed that by adding my user to the dialup and tty groups. I can execute

    stty -F /dev/ttyUSB0 -a
    

    which shows I have rights. ttyUSB0 is the only USB tty port on my system and it disapears when I unplug the cable, so I know that's the correct port.

    I have tried all sorts of combinations of +RTS +DTR -RTS -DTR and nothing causes the +3.3V to change on the RTS line.

    Are there any other suggestions, please?

20. Yaesu ADMS-13 software: open saved file without reading config from radio first?

    I recently purchased a Yaesu FTM-6000. I like the radio, and I'm happy that the ADMS-13 software runs under WINE without a problem, but the software has some truly odd behavior and I'm wondering if I'm just missing something obvious.

    When you first start the software, it opens an empty document. The "Open..." menu item in the File menu is disabled, so even if you have a saved configuration, you can't open it to edit it/export it/write it to a radio.

    After reading the configuration from the radio successfully, the "Open..." item is enabled...so you can discard the configuration you just read from the radio and open a saved version instead.

    Is that expected behavior? I generally don't want to read the radio configuration; I want to update a saved configuration and then write it out.

    This is my first time working with Yaesu software, so I don't know if this is expected/typical behavior or not.

21. How to determine if filter is well matched?

    Hello i'm in process of creating band pass filters for my ham radio. I calculated the filter for 80m band basing on this website:

    And recreated it in reality:

    Then I started measuring it with nanoVNA, and tuning the trimmers to get best frequency response:

    As You can see, the frequency response is nearly as simulated, but I'm not sure about the impedance matching. Is this how the Smith chart should look like? Is this filter good or bad? I'm concerned about that, because the rosponse is not 50ohm in whole passband, but only on the sides of it. Also, is this How logmag of s11 should look like?

22. Icom RS-MS3W setup

    I am trying to use terminal mode for the first time on my Icom ID-52A. I am already registered on DStar (through the UTRUST/national site, not a specific repeater). I am trying to understand what the various RS-MS3W fields mean but the instructions are of little help.

    Where do I get a domain name/ip for the gateway repeater? I'm a not registered with a specific repeater (I registered with the nation dstar website). I know a local repeater's dashboard is visible at BB2BBB.dstargateway.org, can I use that? (It seems to resolve to the IP of a local repeater)

    For terminal/AP callsign, I assume I put my call sign like "AA1AA I" (where I is a random suffix I picked)

    After that, all attempts to transmit say:

    RPT1: Failed to connect to network
    RPT2: Failed to connect to network
    UR:         I
    MY: AA1AA 
    

    then the screen goes back to

    RPT2: AA1AA I
    RPT1: AA1AA G
    UR: AA1AA 
    MY: AA1AA
    

    I confirmed my firewall is not blocking any ports.

23. Linking DStar repeaters using Icom syntax

    I would like to monitor a remote repeater (VE2RM) through my local repeater (VE3TTT). I am trying to figure out how to link them - specifically using the Icom ID-52A commands/syntax. I found some old posts which explain how to manually enter L and U commands in UR and RPT2, but I think there is a new way using Icom menu commands.

    I tried setting VE3TTT B as my FROM repeater, and VE2RM B as my TO repeater. But there is no "link" or "Unlink" possible. which makes me think I'm doing this wrong.

    I tried setting VE3TTT B as my FROM repeater, and VE3TTT G as my TO repeater. But there is no way to specify VE2RM B as the UR.

    Can someone explain how to do this using Icom menus?

    UPDATE: I called Icom support and was told this is not possible using the menus (in DR mode). I had to create three memorized channels to Link/Unlink/Use the repeater-to-repeater link. That seems crazy...even in DR mode I can't do it? I'm hoping he was wrong.

24. alinco dr-635T receive squelch will not open in DCS mode

    Newbie here with a question:

    I have programmed my Alinco DR-635T for use with a variety of local repeaters. Half of these are opened with CTCSS codes and the rest with DCS codes. When monitoring any of the CTCSS repeater frequencies, the Tx/Rx diode lights up and shows Rx and I can hear static, repeater traffic and repeater ID transmissions. When I key my transmitter, the diode lights up for Tx and I can hit the repeaters and hear the repeater squelch closure after I stop transmitting, so all is OK with talking to the CTCSS repeaters and hearing their responses.

    But when I am tuned to any of the DCS repeater frequencies (all in the same Peak Radio Service Oregon network, all using the same DCS code 023, which is set on my 635) the following things happen:

    The Tx/Rx indicator diode goes OUT and the audio is silenced (no static with the squelch setting wide open). The S-meter jumps around and pops up to +9 when someone else opens the repeater but at no time does the squelch on my radio open, nor does the Rx diode light up.

    When I key transmit, the Tx diode lights up and when I watch the S-meter, I can see it hold at +9 for one second after I switch to Rx, indicating that I did hit the repeater and it then gave me the normal squelch closure tail, but then there is no audio and the Rx light never comes on. Then I watch the S-meter jump up to +9, indicating that someone out there heard my transmission through the repeater and is trying to answer, but the Rx diode stays dark and there is no audio- while the S-meter is at +9. Then they sign off, the S-meter drops down- and the Rx diode stays out and the audio stays off.

    It is as if the 635's squelch is always closed when I am in DCS mode, and here is the puzzle: I successfully programmed the radio over a year ago and it worked properly on both CTCSS and DCS repeaters, but I did not use it again until just now. Did the radio's memory fail while it sat idle? If so, how could it remember everything else except opening the Rx squelch while monitoring a DCS repeater frequency? Please help! I am new to this business and do not know what to do.

25. Choice of PCB coil design for filter inductor at ca 20 to 400 MHz, 5 W

    Looking at the diplexer schematic from this nice question,

    

    I realized this can completely be done in PCB-formed elements (minus the connectors). (As a kind of counter-action to the original question's intent to get leaded capacitors, I'm not only trying to eliminate the leads, but also the discrete components.)

    • the 50Ω aren't actually resistors, they are the wave impedance of the cable / device you attach there
    • a 20mm × 20mm rectangular plate capacitor formed by patches on the top and bottom layer of a 0.8mm thick piece of FR-4 ($\varepsilon=4.7\varepsilon_0$) is about 20 pF
    • There's PCB coil designs that provice up to µH in inductance.

    Now, assuming I don't plan to work with as high power as the original question, but still substantial power (5W) in a relevant range of 20 MHz – 500 MHz:

    Would

    1. a planar coil antenna
       
    2. a coil formed through alternating between layers (so that the main magnetic flux is inside the substrate)

    be most effective?

    • I'm told (but I don't have access to the software to simulate that) that planars have low Q. I have no such information on the other choice.
    • Which design has lower self-capacitance?

26. Why does attenuation between two antennas increase with frequency?

    While studying for a HAM license exam I ran into a question that I am having trouble with answering. There are two aspects that I cannot explain, given my current admittedly little understanding of the subject.

    Given the following statement in the exam text...

    The dampingattenuation between two vertical half-wave dipoles is measured at a certain frequency. The antennas are set up in free space. If the frequency is doubled and the dimensions of the half-wave dipoles are adjusted accordingly, the dampingattenuation will increase by 6 dB. (Translation is my own, original is in Dutch)

    ... I have the following questions:

    • Why does dampingattenuation increase rather than decrease with increasing frequency, with their relative distance of the antennae being (assumed) constant?
    • What is the appropriate logic or formula to apply here that explains why there is a 6 dB increase rather than (say) 3 dB?

    Should you wish to look at the original dutch wording, it's question 37 in the 6 November 2019 full-license exam. The answer table lists answer A (6 dB increase) as being correct.

27. Using Satnogs' *.ogg files in GNU Radio flowgraphs

    I want to use the *.ogg files available in Satnogs' database to test demodulation software for several satellites (using gnuradio).

    Can I use the ogg file source (available in gr-satnogs module) and transform its output to complex data and then do the signal processing as if I were using raw IQ data coming from an SDR? And in this case, what sample rate is suitable in the throttle block ?

    

    Or, if not possible, should I convert the *.ogg file first to a *.raw file, using sox for example (Sound eXchange program) and then use it in GNU Radio? In this case, what are the parameters (input file sample rate, output file sample rate, encoding, sample size in bits, etc...) i must use ?

28. What is "Busy Channel Lockout"? Why do I want to control this feature?

    I was reading up on a radio review, and it mentioned something I was not familiar with, "Busy Channel Lockout".

    Unfamiliar with the term, I did an Internet Search, but didn't get back much, and for some reason the most promising results did not work. This page seems to be product specific, but it appears that it's a way to prevent radios from transmitting on top of each other.

    What is Busy Channel Lockout? Why do I want, or not want, this feature? Is this feature often abbreviated to BCL?

29. Can I use two yagi aerials back-to-back for a bi-directional system?

    I need to create a setup where I have three radio transceivers (869.4MHz) setup in a straight line.

    I need to be able to communicate, in both directions, from the centre pole to the outside two poles, and back.

    I had planned to use yagi aerials but, whilst that's fine for the two outside poles, it means my centre pole has an issue as it could only face in one direction.

    So, I guess I now have 3 options:

    1. Revert to an omni aerial in the middle
    2. Use two separate transceivers, each with its own yagi aerial, facing one in each direction
    3. Attaching two yagi aerials to a single transceiver

    Is 3 actually viable?

30. Storage of a Baofeng UV-5R

    I am trying to find a convenient place to store my Baofeng UV-5R, I believe the most convenient place to store it would be on its charger.

    I was wondering if storing the UV-5R with its battery still installed, on the unplugged charger with its wall-wart power supply removed would drain the battery or have any negative effect on it.