Thanks for sharing - I must build this! I have already bought a 3-stage filter, which works perfectly. By the way, do you know, how to tune a 3-stage-filter correctly? It's obviousely more complex than turning all 3 stages to maximum...
The tuning depend of which method you will used and which measure equipment you have. I highly recommend tuning with VNA (Vector network analyzer). There are many cheap VNA on the market today. For example, NanoVNA which cost less than 50 USD.
@@milekokotov1964 I've tuned with a VNA, all stages to minimum passband loss, but there is some ambiguity because of the 3 stages. I have read somewhere about shorting stages and tuning stage by stage, but I dont know how exactly.
@@trombabaroque There are several technic to tune 3 or more stage filters. I preferred to tune them to minimum passband loss and that`s it. Depend of what to want to trade off. Passband shape or passband loss
Would 30 mm copper plates work for this instead of 32 mm? I'm planning on making this filter to attenuate strong VDL2 blips on 136.7 that is ruining my LRPT captures on 137.1 and 137.9 MHz
I will try this on the transmissions of Grimeton Radio, SAQ. An electromechanical transmitter from the 1920ies using an Alexandesson Alternator to generate the VLF signal. They transmit three or four times a year in CW.
I need to polish up my CW ability, I learned it back in the seventies in evening school. I never used it though, now that I'm a pensioner I'll try again.
Prekrasen Shtip❤. Veruvam deka ushte preubav I gostoprimljiv narod zivee vo preubavite dolini vo ovoj kraj. Zboruvam lichno za mene jas toj del na Mk. epten malce mi e poznat. Nemi e poznata Mk. Sekogash koga sum doshol tamo sum se zamislil deka sum stranec i ako sum roden i ziveel tamo sve do moite 19 godini. Po napushtanjeto na Mk na moi 19 godini epten sum odalechen od Mk. So preku 40 godini po Svet i preku 35 godini vo dalechnata Sydney Australia🇦🇺❤️nemislam da se vratam a vo Srce e nosam Mk.Roden vo Gostivar blizu izvorite na Reka Vardar isto taka preubav kraj na Mk. Poradi nestabilnosta na Mk. koja prodolzuva na sve polosho i polosho nas Makedoncite vo dalechnite Zemji ushte poveke ne odalechuva od rodniot kraj na nevrakanje nazad . Zalosno i tragichno za Drzavnoto rukovodstvo shto nemisli i ne se grizi deka Mk.ke ostane bez Makedonski Narod. Jas poveke Svetot go poznavam odkolku Mk. Wish you all the Best and God bless Mk. and all Macedonian people.Good Luck Mk.🍀☘️❤❤🇲🇰🇦🇺Australia 🙏🙏🙏🙏🙏🙏
Hallo, sehr schöner überblick über die Stadt. Wir sind im Oktober auf unserer Reise in SHtip . Sieht man die General Mihajlo Apostolski, Strasse in dem Video ? Grüße
General Mihajlo Apostolski Street can be seen in several places in this video. That street goes along the river Otinja, to the left of it. In the video it can be seen from 8:37 - 8:49 and from 8:52 - 9:25
This is a very decent radio. Comparibley beats the Midland Xtalkers I have with better range and longer battery life.. 2 watts is more than enough to reach a good mile..
Just found this channel while looking for VLF SDR setups. You need to make more videos! I just subscribed and will be watching all your videos over the coming days! 73!
Great idea ! My onboard sound card allows sampling up to 192kHz but I can never get sdrsharp to tune above 21kHz. Am I missing an important setting somewhere ?
The higher the frequency - the higher losses will be, so the filter have to be build much more carefully, with silver plated copper if it is possible, and instead of helical filter, the design have to be with half wavelength or quarter wavelength stubs...
@@milekokotov1964 I have a CNC and 3D printer, figured I could use both machines to make something super accurate. By stubs do you mean a cavity filter?
@@milekokotov1964 brilliant, that’s what I’ll do then. I saw someone make a sort of cavity filter that looks like a comb. Unfortunately he didn’t rigorously characterize it, like insertion loss- just a spectrogram of it being a bandpass filter. Might look into those too.
Štip..grad moje mladosti a šta reči prvi puta bio u Štipu 1963,od 1967-1971 gimnazija Slavčo Stojmenov ...pozdrav svima...zadnji puta bio 1991 na 20 godina mature..godini odat,životot pominuva..ubavi sekavanja ostanuvat❤👋pozdrav od Hrvatska
05-02-2023 18 17. uur vanaf de gouverneurlaan werden die sine waves/sound waves luider en luider bij de erasmusweg aan de kant waar tram 16 rijd. waren die sound waves zo luid dat alles en iedereen om mij heen kon horen hoe luid dat geluid was (je kijkt nu mee) ik ben net binnen
22-02-2023 21 34 uur het is jaren geleden dat ik 1 seconden stilte heb gehad in mijn gedachte na jaren jaren zijn ze ff gestopt met het praten in mijn gedachte.
Great filter, but I couldn't find any info on doing it at 440MHz. found only results made at 145 MHz. can you help me by providing the necessary dimensions to make this filter at 440 MHz?
If I use a tune generator App that generates an audible sound tune at let's say 15.000 Hertz (15 KHz) would it be considered a transmission of VLF waves?
TX is without output RF power transistor, and have about 20-30 mW. With that power, and good location, the signal from the repeater covers almost all city (50.000 population) and few villages up to about 10 kilometers
@@milekokotov1964 Understood. Is there a way to pair two Baofengs, but have use the full power of the transmitter unit? Or they will interfere with each other ?
