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1answer
568 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-...
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2answers
252 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?
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4answers
2k 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 ...
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votes
1answer
3k 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
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2answers
260 views

How does DAB radio garbled noise come about?

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 ...
0
votes
1answer
62 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 ...
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votes
1answer
366 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?
0
votes
1answer
126 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 ...
0
votes
2answers
5k 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 ...
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votes
1answer
80 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 ...
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votes
2answers
339 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 ...
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votes
1answer
239 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.
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votes
1answer
288 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 ...
0
votes
1answer
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 ...
0
votes
1answer
175 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 ...
0
votes
1answer
261 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. ...
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votes
1answer
198 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 ...
0
votes
1answer
143 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 ...
0
votes
1answer
214 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 ...
0
votes
1answer
216 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 ...
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votes
1answer
85 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?
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votes
3answers
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 ...
0
votes
1answer
233 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 ...
0
votes
1answer
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 ...
0
votes
1answer
179 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'...
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0answers
5 views

cant get my bftech radio to program with chirp software

I have a bftech bf-f8rt and they dont show that radio on chirp will they update chirp for that radio? Is there another place like chirp to program it or do i have to do it manual
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votes
0answers
19 views

16-FSK recovering bits

I'm looking for help with one exercise. Firstly I was supposed to download modulated signal. (It's Olivia 16-FSK) [y,fs] = audioread('Olivia16-500.wav'); And then ...
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votes
1answer
31 views

Way to bypass the second of silence when changing stations? [closed]

I am trying to mod a simple AM radio to scan through stations quickly. I've got a simple 555 timer that I hook to the tune up and down buttons to do this, but the problem arises on every single model ...
0
votes
0answers
21 views

RS41 weather balloon unable to decode data

Some times ago I tried to decode the signal from a weather radiosonde (RS41) passing in my area using a cheap RTL SDR (using both standard antenna and a home-made one, with similar result). The ...
0
votes
0answers
28 views

gnu-radio on Ubuntu 20.04 and AIS processing seems impossible

I have searched, installed, and tried every package there is to get AIS processing using the gnu-radio companion to no avail. I tried installing gnu-radio both with conda and apt on Ubuntu 20.04. The ...
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0answers
28 views

Ofdm carrier allocator block in gnu radio

I have some very basic question of the ofdm carrier allocation in gnu radio that am not understanding.please help me to understand. I want to pass a LTE based ofdm modulated signal simply like the ...
0
votes
0answers
18 views

Packet Error Rate measurement

I am struggling with the problem of measuring the Packet Error Rate (PER) in my receiver. I have implemented BER in the receiver system, but I don't know how to add a function that will also test PER (...
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votes
0answers
82 views

Long wire antenna end fed random length folded back on incline

Trying to lengthen my 10mtr. end fed to 39 metres in length. To do this I need the first leg (10mtr.) to run at a lower height approx (5mtr)turning back on a dog leg, and the final 29 meters then ...
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0answers
39 views

How to decide between Dipole and Monopole antenna for Cubesat Uplink (433 MHz)? [duplicate]

We are currently deciding between a dipole and a monopole for uplink (435MHz) , while the monopole is easier to feed, we are unsure of how effectively we'll be able to implement the ground plane, ...
0
votes
0answers
37 views

Simple minimum component RF Amplifier Design

Looking for advice/assistance in Retrofitting sans Cabinet Antique 2 and 3 Dialer 1920's TRF tube radios to operate with low safe Plate voltages.Both Hollow State and Solid State. The plan is to ...
0
votes
0answers
32 views

Using radio for musical collaboration [duplicate]

I'd like to collaborate (e.g. play together) with other musicians in my local area and/or beyond. Coronavirus has made in-person collaboration difficult. Latency makes internet-based collaboration ...
0
votes
1answer
62 views

Old 144MHz rig can transmit/receive signal but not voice

Situation: I have an old 144MHz rig from the 2000's, an IC-271. I am trying to get it up and running. Summary of the problem: I can receive fine on the rig, except for from my HT. I can transmit a ...
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votes
0answers
77 views

How to stabilize an antenna

I have an antenna on a building. It is made of steel and is about 10ft long. It wobbles a bit in high winds. It is not going to do a Tacoma Narrows but it is a bit annoying. Can I tie stainless steel ...
0
votes
0answers
88 views

what frequencies is this antenna cut for?

I just bought a magnet-mount whip antenna at a garage sale. It has no brand markings anywhere on it. it is 32" long overall but is broken up into three segments by what appear to be two small ...
0
votes
0answers
55 views

Omni 144 MHz antenna

I plan to build omni antenna. My goal all about better gain versus a 1/4 wave antenna. I am curious about radial position of the legendary ARX2B Ringo Ranger. Why is the position in below feed point? ...
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votes
0answers
95 views

Built a 2 meter 5 element Yagi

Straight dipoles. I can't get the Yagi to tune. I have tried the 4:1 Balun method with coax but not able to tune. With the straight unbalanced input to the dipole I get a 1:1 swr on about 129 MHz ...
0
votes
1answer
54 views

Effective area of a phased array

For a $N$-element planar phased array, all the elements are same isotropic antennas. Then, what is the effective area of this array? Is it $$A_e=\frac{\lambda^2}{4\pi}GN$$ where $G$ is the directivity ...
0
votes
0answers
17 views

R433A SAW Resonator

I have one of those wireless weather sensor things that stopped transmitting. Inside is one of those ubiquitous R433A SAW resonators that transmit on 433.92MHz. I've verified that the board it's on ...
0
votes
1answer
278 views

Creating a low cost ear protection/ PTT setup for hunting

I have been trying to create a low cost communication setup for when I go hunting. Using this setup the hope is to be able to talk to one another while separated without having the audio up too loud. ...
0
votes
1answer
111 views

How do I trigger hotkeys on AnyTone 878UV?

I've read the manual twice, and watched programming guide videos on youtube, but while I can program hotkey 1-6 just fine, I can't find how to actually trigger them. I found how to trigger the "Fun ...
0
votes
0answers
31 views

How to program a trunked System into radioshack pro 651?

am new to this forum, so tell me if this question is out of place - as it concerns a scanner. I have an old radioshack pro-651 (same model as pro 106, and whistler 1040) that I am trying to program ...
0
votes
0answers
38 views

How to calculate combined power of two amplifiers

If I have 1 amplifier running at 95%, and another identical one running at 60%, how may I calculate the output power of the combiner? I believe this combiner is a "Magic T", but if there is a ...
0
votes
1answer
300 views

Frequency modulation with gnuradio

I'm trying to understand way which Frequency Mod block works in gnuradio. According to my intuition there should be at least two inputs: signal to encode base frequency / carrier signal Instead ...
0
votes
0answers
89 views

Is there any 2.4 GHz tuner ICs for SDR receivers?

I have a hackrf one sdr, which i use to transmit test signals. I am using ISM bands, so I can omit transmitting my callsign, checking correct sub band (FM, digital) etc. And one of most interesting ...
0
votes
0answers
65 views

50 Ohm Active Termination

I'm looking for a circuit topology that has unity gain, a 50 Ohm resistive input impedance, a 50 Ohm resistive output impedance, and here is the kicker, at least 60 dBm OIP3 over a 2 - 30 MHz HF ...

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