Questions tagged [power-supply]

Questions regarding devices for supplying power to electronics.

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2
votes
5answers
107 views

Does 3 W vs 5 W TX power make a huge difference in QRP CW operation?

I've bought the QCX+ 40 m band radio. I will be powering this off a 12 V battery. I read on the manual the RF power at 12 V is just 3 W whereas on 15 V it is 5 W. Should I buy a boost converter for ...
1
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2answers
106 views

Wiring Cobra 29LTD CB for home use?

I'm a beginner trying to use one of my two CB radios as a "base station." The problem is that the power cable is just two wires (no connectors/12v car plug) and a 2A fuse along one. Is it ...
1
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2answers
50 views

How to connect IC-271 DC power connector to 12 V battery

What I am trying to do Radio is an IC-271, ~ 20 years old. I want to run it with a 12 V lead acid battery. I need to connect the battery to the radio. The radio's DC power connector is a 6-pin molex(?...
4
votes
2answers
199 views

Using an SDR on a Laptop with Noisy Power Supply

I'm going to start this off by saying I'm very new to this and I don't really know a lot so any detailed information would be much appreciated. I have just started using an SDR (a cheap RTL model) ...
10
votes
4answers
295 views

What sources of power are useful in emergency situations?

Situations that call for emergency operating usually have some hams working in field conditions. Relying on the mains grid could be problematic. A lead-acid battery would probably be heavy to lug ...
3
votes
2answers
231 views

Calculation of transceiver current draw

My radio manual says its current draw is 22A. But in my naivety I would have calculated as follows: If the radio 'put out' 100W and I have a 13.8V supply then (using the formula power = VxI) 100W/13....
0
votes
1answer
65 views

Power supply for shortwave portables

I have the Tecsun PL-310ET and PL-660 SW portables which are spec’d for 5V and 6V power sources respectively. Would it damage them if I tried to power them with a 9V Bioenno battery (actual steady ...
5
votes
3answers
4k views

Practical differences between switching and linear power supplies?

Power supplies for ham radio equipment (and other equipment of course) seem to come in two flavours: switching and linear. The switching gear tends to be cheaper and smaller as well as more ...
2
votes
0answers
73 views

First linear power supply build - design questions

I have decided to build my own linear regulated power supply to provide the power for an upcoming build. Since I'm no pro, I was hoping I could get some feedback on my design before building it, just ...
0
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2answers
236 views

How much power does an RTL-SDR draw?

Background: Last night (and the night before) I was playing with my RTL-SDR and GNU-Radio again. Working with my FM Receiver, (which was working previously by the way), I detected that last night I ...
3
votes
3answers
590 views

Is using a generic DC 3V adapter dangerous to a radio?

I have the mini Eton radio and it has a DC 3V port but I haven't been able to find the official plug. Is using a generic one safe? How do i know if I found the correct AC adapter? It goes through 2 ...
1
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1answer
43 views

Passive receiver power needs & data rate

I'm working on a project to design a space-based low frequency array. It will only be receiving signals, and it will operate between 10MHz - 100MHz. It is made of short wave crossed dipole antennas. I ...
0
votes
0answers
117 views

Troubleshooting ICOM PS15 Power Supply

I got a power-supply gifted by my friend. When I powered ON, the main (120V) FUSE blows up. I started by disconnecting the transformer from the control circuit and powered ON. This time the fuse is ...
1
vote
2answers
264 views

From where do repeaters get their power supply?

I imagine that a repeater atop a building for which the repeater owner has sought permission would be sharing the same power source as that of the building occupants, but: What if the repeater is ...
1
vote
3answers
628 views

How to reduce voltage ripple of a linear power supply?

I made a simple linear power supply for my transceiver using 12V 30A transformer, four diodes RHRP3060 forming a rectifier and three 30_000 µF capacitors connected in parallel. I also used a 200 Ω 50W ...
5
votes
1answer
95 views

Powering transceiver and SWR/power meter from same supply?

I'm mostly sure this will be ok, but I'd like to confirm. I have a switching power supply (can't remember the model right now, but it's for ham use, 13.8V/30A) and I'd like to power both the FT-857D ...
1
vote
1answer
106 views

Parallel tube amplifier power supply using 6DE4 tubes [closed]

I’m looking to build a vacuum-tube based linear amplifier. I’d like to do it all tube based, including the power supply. The original ARRL design I’m looking at (from the 60s) has two paralleled 807s ...
5
votes
2answers
122 views

How can I sound-proof my generator?

Looking for advice to semi-soundproof my extremely noisy gas generator, which kept everybody edgy on Field Day. It's a real powerhouse, but the cost of that power is my hearing. I'm looking to buy or ...
1
vote
1answer
96 views

Power supply for small radio board

I need a powersupply for a radio board (I will shield it), and have experienced bad interference from step-down converters. I have been told to use linear regulators (LM317 or LM350) with caps to trim ...
0
votes
1answer
540 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-...
0
votes
2answers
801 views

Regulated Power Supply vs Class 2 AC/DC Adapters

I'm wondering if it would be more efficient for me to replace several AC/DC adapters (linear, non-switching) with a regulated power supply? Two of the adapters get very warm and are rated 9 watts ...
2
votes
2answers
207 views

Ham Variable Lab Power Supply

I'm looking into purchasing a mobile radio (TYT TH-9800) for my Jeep Wrangler. I am hoping to be able to use it in my apartment as well. Since I'm going to need a power supply for this, I think it ...
5
votes
2answers
117 views

Stacked shell inductor — what's its function/use?

I have a device of copper and iron (about 8 kg) which looks like two shell inductors joined so that there is some coupling but high leakage. The windings seem to be identical. Each is a single ...
2
votes
1answer
74 views

Does the varactor bias supply have to be independent of Vcc?

A quick follow-up to How can I tell the frequency without an oscilloscope, or frequency counter? My supply is a transformer plucked from a dead power adapter rated for 1.5A. This is rectified cap-...
3
votes
1answer
187 views

Does using a computer SMPS to supply a transceiver bleed hum into the signal?

A dedicated/custom power-supply for an HF rig may, on occasion, be unavailable. The internet lists any number of articles on the subject of modifying a computer power-supply. E.g. http://www.wikihow....