More Malahit DSP2 - IARU 2024

Another video showing the capabilities of the Malahit DSP2 SDR with only a homebrew untuned active loop aerial.
This video is not sponsored nor an endorsement of any product; it is merely for information.

[@RWBHere]

It's a superb receiver. Thanks for the demonstration. In more than 50 years of licensed operation, I've never quite understood the attraction of contests, and rarely even know when they're on, let alone what they're celebrating. Sure, if I'm accidentally caught by someone because an event is happening, I'll respond out of courtesy, log the contact and give a serial number, just to keep them happy. But if a pile-up starts, I'll either go QRP to finish my tests or else sign off until the frenzy has ended.

[@echelfordars8854]

I'm much the same. But to quote my late friend G2KQ (SK), "Never mind propagation; the activity of any band is directly proportional to the number of radio amateurs prepared to switch on their transmitters." If you want to log exotic countries, test an aerial or transceiver, or even just a receiver, the best time to do it is when there are a lot of stations on the air on many bands, so that is why I chose this contest to demonstrate the capabilities of this receiver. Wait for the big American international SSB DX contests, and I'll be trying to talk to them with 100W and a homebrew aerial.

[@joemurphy8972]

Thanks for the video. I've a Malahit on order, can't wait...

[@echelfordars8854]

👍

[@patrickmolloy6994]

loving the cat

[@echelfordars8854]

Thank you. I bought it at the last CATS bazaar.

[@davidlynas7768]

Got one recently very good.

[@mindorokano]

I remember this from the [73 Amateur Radio Today] magazine series. This type of circuit was very commonly used in early RF applications as an amplifier and amateur radio projects.

[@joemurphy8972]

Looks prone to 2nd-order harmonic distortion due to gain differences in the push-pull transistors, so could imagine strong 40m stations 'appearing' in the 20m band. On the plus side should offer some common-mode rejection.

[@echelfordars8854]

Thanks for the information. I selected the transistors quite carefully to try to match their gains. I haven't heard any cross-band imaging unless the RF gain is cranked right up on the Malahit, but this is a problem on most receivers and especially, it seems, with SDRs. Experience helps me to avoid this.

[@richardday2893]

Great video 👍
Do you know the difference between malahit and malachite?

[@echelfordars8854]

My understanding is that "malahit" is the Russian word for the mineral "malachite". I have heard the radio variously referred to as "Malahit", "Malahite" and "Malachite".

[@richardday2893]

@@echelfordars8854 thanks from Melbourne Australia 🦘

[@skylerphoenix8880]

I just got a new Malahit DSP2 - I thought for shortwave you had to use the left HiZ antenna port? It seems to default to this when you select the SW band (light turns blue on top). How/why are you using the right 50 ohm green light port?

[@echelfordars8854]

Instruction manual, page 8: If you are using an END-FED aerial on the HF / shortwave bands, these present a high impedance and you need to use a high impedance input to maximize the signal - this includes the telescopic aerial that you get with the radio (which is clearly also end-fed). If you are using a dipole or similar aerial, this has a low impedance and 50 ohms is the standard. My active loop antenna has a low-impedance output and so matches better to 50 ohms (although it will work on either, but the frequency range and sensitivity is best on 50 ohms). You can set the default in the RADIO menu.

[@skylerphoenix8880]

@@echelfordars8854 Yeah, I read that. “Clearly” - I’m too new at this for it to be that clear.