Questions tagged [components]
Questions about electronic components used in radio or antenna construction.
13 questions
3
votes
1
answer
379
views
Development of quartz resonator qualities over the decades
While writing this answer here, I had to admit I only have "…, I think"-level of knowledge what a 1970's quartz resonator for a consumer radio device would have been spec'ed at.
My ...
- 18.4k
0
votes
1
answer
497
views
VHF / UHF modules for custom radio build
I’ve been looking at VHF / UHF modules for a potential custom HT build:
DRA818V
SA818-U
I came across a project that uses a module like this with an ESP32 to make a radio that is controlled via an ...
- 369
2
votes
2
answers
487
views
How best to tightly wind air core inductors?
We all know air-wound solenoid inductors. We typically wind AWG 18 to 28 UEW solid copper wire on a drill bit, pen shaft, or any other cylindrical support and remove it. The support's diameter is ...
- 3,971
0
votes
0
answers
390
views
2N5109 Replacement
I am constructing a pre-amp for the HF range and the transistor mentioned is the 2N5109. It is not readily available and was thinking about a suitable replacement which is readily available from large ...
- 1
1
vote
1
answer
164
views
Quartz Oscillation Output Signal Amplifying for more Power?
Quartz oscillation is well known for its high Q-Factor and stable frequency. I have read many articles which say that amplifying such quartz oscillations should not be easy. I am not a licensed radio ...
user24106
6
votes
4
answers
1k
views
Why do homebrew designs wrap toroids instead of using off the shelf inductors?
Why do homebrew designs wrap toroids instead of using off the shelf inductors?
Off the shelf inductors are easily available in a range of values, including uH and even some mH. And hand wrapping ...
- 301
1
vote
1
answer
222
views
Why is my homebrew copper sulphate resistor behaving like a capacitor? [closed]
I brewed a CuSO4 resistor in a glass jar. I got the idea from here. This was done by creating a solution of Copper Sulphate in distilled water. The lid on the jar was provided with a BNC socket into ...
- 2,854
1
vote
0
answers
92
views
Narrow bandstop filter not requiring ground connection in SMD package
I’m designing an antenna that I’ll implement on a printed circuit board. The antenna will be working on both sides of 900 MHz, so it’s not exactly for ham use. I’m planning to use a bandstop filter in ...
- 976
3
votes
1
answer
645
views
Globar resistor repair or alternative(s)?
I am restoring a Hallicrafters S-120 receiver and when trying to unsolder the wires, from the electrolytic capacitor, I noticed that one of the terminals of the Globar resistor (880-100 Ohm / 023-...
- 63
3
votes
2
answers
248
views
Tradeoffs: varicap vs. air variable capacitor for Rx bandpass?
What might be the tradeoffs between choosing varicap diodes versus air variable capacitors in the design and construction of tunable bandpass filters for HF receivers?
- 13.7k
2
votes
1
answer
235
views
How to select capacitor for diplexer use
Follow-up on this question: How to prevent cracking the capacitors in my diplexer?
Short story: 2m/70cm diplexer, to be used up to 50W.
Schematic from Elsie:
S21/S11:
I don't know exactly what to ...
1
vote
0
answers
108
views
2GFSK digital filter bandwidth calculation
I'm working on a S2LP from ST and I am configuring the RX digital filter.
I need to calculate the bandwidth of the signal which has 2GFSK modulation.
Do you think the code below is correct for ...
- 111
6
votes
1
answer
292
views
How to prevent cracking the capacitors in my diplexer?
Just made my first 2m/70cm diplexer. Important: I aim to be able to use this up to 50 Watts.
S21 from the LP section:
Having access to regular distributors such as Farnell/Element14, Mouser, Digikey,...