Small Coil FM Crystal Radio

Рет қаралды 17,357

BillyCdiy

3 жыл бұрын

billydiy.blogspot.com/2021/05/...

Пікірлер: 38

@alibarisik9709 Жыл бұрын

You can obtain more precise measurements by using a wristband with a ground connection. Touching the capacitor or coil with bare hands while measuring with an LC meter will give incorrect values due to static electricity. The LC meter I use in my workshop is JUNTEK Model: LC-200A (Made in PRC), and I combine and reset the probes before each measurement. Otherwise, the measurement will be inaccurate. As an additional note, I prefer a non-rechargeable Lithium 9V battery as the power source for the LC meter. I do not recommend using an 9V adapter from a BNC jack input or the 5V supply with the powerbank.

@chronobot2001 6 ай бұрын

This guy is a legend !!! I wonder how close the radio stations need to be?

@BillyCdiy 6 ай бұрын

My home is 13km from the FM broadcasting station. I can receive FM in my crystal radio using a Yagi FM antenna.

@wildcatcreeksurvival2414 3 жыл бұрын

Sounds better than the big loop.

@roccolarosa4654 Жыл бұрын

Molto interessante quali componenti ci sono

@alibarisik9709 Жыл бұрын

FM band frequency range is 88 MHz-108MHz L=61 nH ( or 0.061 uH) Cx=20 pF to 4 pF On internet Resonant Frequency Calculator says 145 MHz to 325 MHz, L=165 nH = 0,165 uH 88 MHz need C= 19.824 pF and 108 MHz need 13.162 pF proper FM frequency range... L=61 nH and Cx=54 pF to 38 pF capacitor range, We need at least about 33 pF capacitor. I guess you used a parallel 33 pF capacitor on that female audio jack 3.5 mm,

@BillyCdiy Жыл бұрын

Thanks for your calculations. There are stray inductance and capacitance involved that cannot be easily calculated. The values I used is based on many years of trial and error.

@petrusgherasim3529 6 ай бұрын

Hi I saw that you use different types of crystals for fm and am I use two schottky 1n5819 in series and it works perfectly for Am. I replaced with them the one with germanium that detects at 0.290mv, I didn't try it with fm due to lack of time. I have raw galena crystals and silver pyrite would it be possible to use for fm?

@BillyCdiy 6 ай бұрын

Fm reception by crystal is possible. I tried with fools gold crystals. However much less sensitive. So you need a stronger FM signal .

@petrusgherasim3529 6 ай бұрын

@@BillyCdiy thank you

@user-ri5nj4sz5m 2 жыл бұрын

👍👍👍

@erikdevriese671 2 жыл бұрын

Hello, can you tell me what the approximate distance is to the stations you can receive?

@BillyCdiy 2 жыл бұрын

The FM radio transmitters are about 15km away

@erikdevriese671 2 жыл бұрын

@@BillyCdiy Thank You. That"s better than I thought!

@Kangsteri Жыл бұрын

Do you have some kind of full kit for sale to build this? Or what parts do i need to order for optimal system?

@BillyCdiy Жыл бұрын

Apologies. I do this for hobby only. Not planning to sell at this moment. You can reference my videos to diy. kzfaq.info/get/bejne/ecylatWm07Crdmw.html You can also visit my blog where I suggest what parts to buy. 1.bp.blogspot.com/-NNHHC-qGswA/X1oOHSSOo7I/AAAAAAAADaA/xskpS6h7ZRAfgCoxOGFjJJsaWiGt5MJuQCLcBGAsYHQ/s2048/IMG_5669.JPG

@Kangsteri Жыл бұрын

@@BillyCdiy No worries. This helped a lot already. Have you considered to use some am signals, just to collect some additional power for signal or sound amplification? There is many led circuits that only use joule thief, or joule ringer and antenna (Tesla antenna and Barbosa Leal effect also boosts the power harvest).

@BillyCdiy Жыл бұрын

@@Kangsteri , thanks for the suggestions. There were different ways to harvest additional power from other bands of radios to let the Mos FET operate in a regeneration mode which will boost the volume and increase selectivity. I tried that but found that a bit unstable hence did not make a video on these. Also the idea of using mos FET in crystal sets already stirs up enough debate whether this is really a crystal radio. Boosting volume by other means will certainly add oil to that debate .

@Kangsteri Жыл бұрын

@@BillyCdiy I think passive boosting is not cheating :D It's not practical to make pencil transistors and air capacitors if it's possible to buy. Even with 1.2 - 1.5v battery it would be fine. It usually is easy to get 0.5 - 1.5v from antenna harvesters or even earth battery. My dream is to get AM FM walkie-talkie that could be used without battery. Or could be used to charge small battery / super capacitor, in open areas.

@BillyCdiy Жыл бұрын

@@Kangsteri , my home is located within 4 km from an AM station on an island across the sea in HK. I used to be able to use the led as detectors and light them up at the same time. I also tried charge an Nimh battery with some success l. However since last year, the station has been shut down fir maintenance, hence I cannot get a strong enough signal to try these again .

@uncleruckus4060 3 жыл бұрын

Hello Billy I have question I have a variable capacitor 15 to 385 pf My range 500 to 2300 khz Too much Can I put a disc capacitor In parallel with the variable? Would that affect q etc ? I want to build a 1000 to 1700 khz Radio and only need a 115 to 485 pf Range Thanks !

@BillyCdiy 3 жыл бұрын

No. Connecting in parallel will increase the capacitance, not reduced it. To reduce it, you can connect a disc capacitor in series with the original variable capacitor. Any additional component to a radio circuit to add or reduce capacitance or inductance will only decrease the original Q factor, not increase it. Imagine adding some liquid to pure water. the liquid will only add impurity, not make original water more pure.

@javiermac381 21 күн бұрын

Hi Billy, why is the antenna coil made of silver wire? Could we just use 2mm copper wire for both of the coils? 😁

@BillyCdiy 21 күн бұрын

Yes, you can use regular 1mm or 2mm copper wire to replace the silver plated cover wire which has less resistance.

@pradeepkawale6688 3 жыл бұрын

CIRCUITS DIGRAM PLEASE

@BillyCdiy 3 жыл бұрын

here: billydiy.blogspot.com/2021/05/ring-fm-crystal-radio-i-purchased-few.html

@NaveedAkhtar-qc8zu 2 жыл бұрын

Diagram whear

@pierluigigemini2591 Ай бұрын

Scheme?

@BillyCdiy Ай бұрын

You can refer to the circuit diagram from thus video. kzfaq.info/get/bejne/ecylatWm07Crdmw.htmlsi=-38vnkDhxO7_6z-V

@ciro1449 Жыл бұрын

Compratelo

@surdinkalol 3 жыл бұрын

Сколько не пытался повторить, ничего не работает. СВ детектор без проблем работает, а фм это наверное надо под передатчиком стоять. Даже с внешним усилителем звука тишина.

@Lechoslowianin 3 жыл бұрын

Видимо проблема в качественных пьезо наушниках.

@surdinkalol 3 жыл бұрын

@@Lechoslowianin они военные, на СВ и КВ все отлично слышно. Да и не понятно как работает ФМ на детекторе принимающем АМ

@Lechoslowianin 3 жыл бұрын

@@surdinkalol Наушники должны быть не менее 10 кОм. Приемник улавливает два сигнала и сдвигает один синфазно. Он должен работать

@Mylo_Veryovkin Жыл бұрын

Надо подбирать детекторные диоды, не все работают на таких частотах

@surdinkalol Жыл бұрын

@@Mylo_Veryovkin всякие пробовал, много разных германиевых и советские свч, и даже рекомендованные из видео, видимо расстояние от вышки критично решает