# All Questions

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111 views

### Does a horizontally polarised yagi antenna have the same front to back ratio for horizontal and vertical received signals?

Can anyone answer this question : I have a 4 element yagi antenna which is horizontally polarized. Let's say it has a front to back ratio of 20 dB. Does that front to back ratio apply to received ...
51 views

### Can timing information be used to compress data for LoRa transmission?

I have a course challenge. It involves calculating an FFT of an audio signal of 2 combined frequencies (up to 20KHz) then sending it over LoRa through to a fixed receiver. There will be an interferer. ...
157 views

### antenna theory for beginners [closed]

I am new to amateur radio and am having trouble getting my head around antenna theory. Can anyone suggest a good 'introduction to antennas' that doesn't get too technical? Thanks.
54 views

### Motorola XT180 not charging

Some months back I bought a pair of XT180s and they've worked great. The problem is that it seems one of them was not charging all this time (I was wondering why the charging station only lit the ...
125 views

### NFC coil matching - Q factor improvement

I have been trying to match my NFC reader coil of size 20*20 cm with a three element circuit - one capacitor in series, another in parallel and one resistor in parallel. I have been using Texas ...
3k views

### Yaesu FT-60 vs. FT-70

I'm looking at a getting a Yaesu FT-60 but have found that the FT-70 is priced similarly (add \$30-\$50). I'm having a hard time determining the key differences between the two. Reading up online, it ...
55 views

### SDR (RTL-SDR v3) USB audio much less than LSB

Why does USB have so much less audio output than LSB? I've checked all settings and they are correctly set or not used, like AGC etc. Using same band pass on both modes.
367 views

### Gain in long wire antennas

DARA (you know, Hamvention) TNG is looking for projects. Thursday, I will be proposing building and characterizing a vertically-polarized 1 wavelength on a side reentrant rhombic. Since in doing the ...
300 views

### Alternative software for Hytera PD785G

I got a brand new Hytera PD785G. When I turn it on, it says that it needs to be programmed. I've got a USB programmer cable and I know that there are official drivers and software for download. Do I ...
65 views

### Are there receivers and transmitters that can be tuned to multiple frequencies at once? [closed]

What kind of hardware/circuitry would be needed for a device to be able to transmit and receive over a range of frequencies at once?
381 views

### Hopping from one frequency band to another in SDR (ex: USRP)

This question is not about Frequency Hopping Spread Spectrum! In SDRs, say USRP, if we are transmitting in a particular frequency band, can we dynamically hop from that band and transmit from ...
115 views

### Temporary Skip frequency on an Icom ID-51 PLUS2

On the scanning options for the Icom ID-51 PLUS2, there's one called Temporary Skip Timer that can be any of: 5 minutes 10 minutes 15 minutes The manual says: Temporary Skip Timer Selects ...
49 views

### communicate two different gnu radio files

My question is that is there any method to send data from a gnuradio file (or in the generated python code) to another one? There is a transmitter file and it transmits signals with different ...
2k views

### Is it legal to use BAOFENG BF-888S 16-CH 400~470MHz 5W Walkie Talkie in India?

If not, what can be used as mode of communication for group trekking. It is very urgent and important Please suggest some better options for walkie talkies
118 views

### How to find repeaters in Pakistan? [closed]

How would I find a repeater in my area (Pakistan)? Are there any web resources? Can I use repeaters to listen only (using an SDR)?
129 views

### Any ideas as to what I might be picking up on SDR?

Any ideas as to what I might be picking up on SDR? They make for some strange patterns. Picked them up at the following coordinates: (31.514596, 74.345092) using GQRX, tuned to 217.25 MHz. As for the ...
449 views

### How to diagnose DRAKE TR7 power problem

My son was recently gifted a vintage DRAKE TR7 ham radio. It's been "in the attic" for 20+ years. When we try to power it up, the (separate) power supply turns on and we have checked with a multi-...
163 views

### Amplified antenna & typical boombox radio

Can an amplified antenna be connected to a typical boombox radio with a telescoping antenna without damaging the radio?
1k views

### Good Hidden Antenna For 2m

I would like to have an antenna outside for 2 meter VHF use but I do not want it to be expensive and I won't be allowed to put it up if it stands out too much. Does anyone know a good antenna to buy ...
1k views

### My Baofeng radio won't recieve but transmit does not work when I hold the MONI button [closed]

My radio won't receive. Help? It literally went dead and I still have the rubber duck antenna
232 views

I'm a sound designer and I'm interested in using/simulating that effect of DAB radio when you have a low signal/interference, where voices become garbled, bubbling, burbling, broken up, etc. I ...
296 views

### Using the VHF port for 6m on an Icom IC-706mkIIg transceiver

My Icom IC-706mkIIg transceiver has two output ports: one for its VHF/UHF bands (i.e. 2m/70cm) one for the HF bands, and also 6m! I have a couple of broadband VHF/UHF antennas whose transmit specs ...
52 views

### Transmission Line Model of Co-ax Lines

I have got 2 questions on transmission line. In coax line, the centre wire is Copper, and the outer line is Aluminium, as far as I can see in the coax that I have. I have got couple of questions on ...
317 views

### What is the directivity of thin dipole antenna of length 1.25λ?

I want to know about the directivity of thin dipole antenna of length 1.25λ for my assignment.Is there any formula related to its length?
115 views

### How to compute/simulate signal propagation latency?

I need to transmit small amounts of data (~5kb/s) in the fastest way possible over the distance around 2500 km. What is the the best way to carry out such transmission? How could I estimate or ...
3k views

### Motorola Maxtrac Programming with windows 7 and DOSBox

I found an old Motorola Maxtrac in a parts truck I bought. I'd like to program some channels into it with a Windows 7 computer and DOSbox. My first issue, is I'm having trouble identifying the radio ...
71 views

### Magnetic antenna for the UV8000E

I have the new UV8000E ht and I'm trying to find a magnetic antenna or at least the adapter that allows the unit to be attached to a pl259 connector. I have no clue what the connector is other than ...
256 views

### Why is this signal recognized as PACTOR II but not decoded?

I'm using SDR# and with virtual audio cable sound is piped to Wavecom W-CODE. W-code recognizes a frequency on 4 and 24 MHz as Pactor-II with 100% confidence, but he can't decode in terminal text ...
217 views

### Using RF6886 Power Amplifier for VHF design

I want to use RF 6886 power amplifier for VHF band design. The datasheet doesn't mention VHF design specifications. Has anyone used the PA for VHF design? If yes then please share your designs.
258 views

### RCA victor 35x tube radio loop antenna replica?

There is this one youtube video I have not been able to find again, where someone with a similar model radio was making replica of the original loop antenna on the back. I am wanting to make a ...
82 views

### What parameters are currently possible in a directional antenna less than 5mm long?

I'm curious what kind of directional antennas could fit inside a cell phone, which would require it to be 5mm or less in its longest dimension. I know that the length of a directional antenna is often ...
168 views

### Military Amateur Radio Service (MARS)

The Navy MARS program was officially decommissioned effective 30 September 2015. What is the state of the other MARS programs (Army and Air Force)? Is it known that they too will be decommissioned in ...
230 views

### Kenwood TS-440SAT & TS-930SAT Refurbishing

Inside my TS-440 & TS-930 are (former) foam pieces. They have disintigrated into a pile of dust in the bottoms of the rigs. I am more than sure that Kenwood does not have fresh stock off these. ...
178 views

### CC1125 reference design matching network using Smith chart

I am trying to confirm on a Smith chart the matching network for 169MHz frequency using an external PA and and 437Mhz with an external LNA. I am not able to end at the origin of the Smith chart using ...
139 views

### Is there a satellite tracking software with S-band downlink

we are trying to track "DTUsat-2" which transmit at 2.402 GHz using automatic frequency adjustment to compensate for Doppler shift. Our receiver ( a professional one) have the ability to set frequency ...
176 views

### CW paddle interface wiring problem

I have the MFJ-564B iambic paddle which I need to wire to the MFJ-552 CW interface. The paddle is stereo (dits/dahs) and the interface is mono (when connected to paddle, only gives DITS). How can I ...
191 views

### How can I reduce power consumption and thermal dissipation in power amp?

I am designing a Class-E power amplifier in UHF band using ADS. Now I have 20dBm fundamental output power with 13% PAE, which is low for this class of PA. The problem is that I have thermal ...
73 views

### What is the required signal-to-noise ratio for a AX5042 transceiver?

What is the required signal-to-noise ratio of a AX5042 transceiver IC?
1k views

### Baofeng not finding CTCSS tone

I have this Baofeng and I want listen to my school radios. The problem is that I want to find the CTCSS tone for the fun of it, but when I scan the tones on the Baofeng it cycles through but does not ...
218 views

### Testing my HB-1B QRP CW Transceiver on 40m

I'm a new ham and have only used 2m/70cm so far. I have recently completed a QRP CW setup: a YouKits HB-1B transceiver and a simple wire dipole. I haven't made any contacts yet, and I'm wodering if ...
661 views

### 2-Pin Kenwood to Sound Card (Beofeng UV-82HP & ASUS Xonar Essence STX)

I have a Baofeng UV-82HP that I want to use to TX and RX to a TeamSpeak Server. For this I'm going to use a dedicated computer, for both the client and server that has a sound card (ASUS Xonar Essence ...
1k views

### Chip with price and functionality to the RDA1846?

Is it possible to buy a cheap transceiver chip with similar functionality to the RDA1846? I'm looking for something else, because I'm wary of buying a probably counterfeit chip on AliExpress, and I ...
322 views

### What are the signal loss mechanisms between a ground station antenna and a satellite receiver?

What are ALL the potential signal loss mechanisms between the output of the earth station antenna and the input of the satellite receiver. With a bit of explanation for each if possible please.
171 views

### How does a multi-element vertical work?

For example, Diamond makes the X700HNA which is stated as a 4x5/8 vertical on 2m. Does this just mean that it is 20/8 wavelength long vertical? Or is there some magic to phasing the 5/8 segments? I'...
89 views

### What does the current signal look like just south of Las Vegas? [closed]

I was wondering if it would be worth it to engage some of the hotels south of the strip to see if they would allow us to put a repeater on one of the buildings there. Just wondering as the Marriott, ...
6k views

### Vertical Antennas: Compare Cushcraft R9, no radials to 43 foot vertical with ground radials

Small lot, must go vertical. Which antenna will preform better, with less noise, good DX. Cushcraft R9, NO ground radials. Or, 43' with ground radials.
94 views

### Can wood be used to build 6m quad? [closed]

Could I use wood to build 6m quad? If not, what material(s) would be better/more useful?
8 views

### Is roaming strictly a DMR feature or does it also relate to analog?

I've an AnyTone 878uv pluss and I want to know if roaming is only a DMR feature or if it can be used with analog repeaters?