lunedì 29 gennaio 2024

Nooelec LANA HF amplifier

 I am using a chinese build RF LNA model RF AMP 03A 0.1MHz - 60 MHz, despite this description, it works up to 150 MHz @11dB declared gain. As written elsewhere is powered with a battery pack of 3A, when this is exhausted the recharging to full takes various hours.

The Nooelec LANA is powered with 5V DC with a miniusb which I connect to the USB charger of the laptop external screen.

I got the Nooelec today, paid 43 Euros on Amazon, the performances between the two are quite similar, both LNA are good in terms of noise, could be the Nooelec is slightly less noisy and shows some better SNR...but it's a matter of peanuts.

The disadvantage of the Nooelec is that swutching it off the signal doesn't pass aymore, while the chinese LNA lets the signal passing through without amplificaton, which is a quite comfortable feature, listening with amplification is not always better than without.

Willing to suggest one or the other, I could not figure out what to say. Surely the Chinese is less expansive.






sabato 27 gennaio 2024

More experiments with Youloop + HF LNA

 I have just bought on the web a rotating stand-display for the Youloop, with a remote control.

It's quite an improvement while using the youloop, since I do not need anymore to stand from the chair to rotate the loop. I paid it 26 euros.

After getting the "rotor" and after putting the loop into a ridging plastic pipe, I decided to paint it with a solid army-green spray paint, it provides all the thing with a nice "rugged" aspect. I have been working with this set up quite a lot from MW to SW.

It's coupled wih a HF LNA working with a rechargable battery pack of 3 Amp, this way it feeds the Airspy HF+. I have noticed that the HF LNA on some bands brings in FM broadcasting noise, no issue: I still have a notch filter for FM band which I bought for few euros on the web. With this all the spurious signals from FM broadcasting have disappeared.

Here the notch filter connected to the HF LNA, the brand is not visible but the label just says: "Band reject 88-108 MHz"


However: what is surprising me, which is the reason to make this post, is the deep null of the Loop on every band ad the ability it has to reduce man made noise from neighbours.


Here the effect of rotation showing null and noise reduction on WRMI 9395 kHz eralier this morning (around 8 UTC):



Beaming the loop NW - SE the reception is stunningly clear with a SNR of 38, having the noise floor lowered down to -95dBFS


Beaming the loop E-W, WRMI signal gets burried in the noise with a SNR of 25, the noise floor rises to - 75 dBFS.

This Youloop is is becoming more and more interesting. One just needs to give it more attention and a chance. The LNA helps a lot.





venerdì 26 gennaio 2024

posts comments from readers

I have realised few days ago that I have hundreds of comments from readers that I never moderated and never read/published before. I have to honestly admit that I never went into the comments box to make a check simply because I have never seen that option in the menu of the blog.


I really apologise with everyone, many interesting comments some date back to 2016, I am not going to publish all of them, but I have just released the most recent ones.


Sorry gain for this, I will check with more attention in the future.

sabato 6 gennaio 2024

Anello per Youloop

Mi è sempre sembrato complicato lavorare con la Youloop dal momento che è un antenna costruita con semplice cavo coassiale.

Ho pertanto deciso di inserirla in un tubo in polietilene rigido da irrigazione con diametro 1 pollice, Il tubo è fissato in una scatola per usi elettrici. Questo assemblaggio lo tenevo in garage ed era una vecchia loop per onde medie he avevo costruito anni fa e che non utilizzavo più.

Per darle un po' di "sprint" l'ho collegata ad un amplificatore alimentato da un powerbank da 3A; è un amplificatore low noise e ad ampio spettro da 0,1 a 60 MHz che avevo acquistato in rete un paio di anni fa.

il risultato finale, visibile nella foto qua sotto, permette ora di manovrare e direzionare la loop in interno con maggiore facilità. Attualmente è collegata con il Malahit SDR V3 in DSC su 8414.5 kHz in contemporanea con un ATS25 a 8414.5 kHz collegato alla end fed esterna da 25m. E' un confronto un po' impari, ma fra qualche ora vedremo su anche la Youloop amplificata si comporta con onore.





venerdì 5 gennaio 2024

ATS 25 AMP Receiver

 I just got delivered - with 10days anticipation - my fifth ATS 25.

with this I have an old pink case ATS-25 with a soft touch tuning knob, which still performs good despite tuning with precision is quite tricky due to the soft touch knob. And I have ATS25X1 that suddensly stopped working some eeks ago after thousand hours of use, I guess is a battery trouble, and i got also an ATS25-Max with updated UI, an ATS25-Max Decoder, wch features native decoders for FT modes CW,RTTY and has also a WiFi connection for propagation foreacsts along the bands. And finally I have just got an ATS25-AMP, that has all above + a low noise amplifier which working status is detected by a blue led on the left side of the front panel. There  are as well other two leds for hi-Z and 50 ohm antennas.

 




As written many times these are just toys, but upgrading from one version to the next, the performances are also improving.

e.

today they are connected to YaddNet for DSC spot reporting, with quite interesting rate results as shown in the picture here on the left.

the ATS25 Amp (8414.5 kHz) is connected with an active loop on the house roof

the ATS25 max decoder (16804.5 kHz) is connected to a vertical antenna on the roof of the house

the ATS25 Max (12577 kHz) is connected with a random EF wire 25m long as well on the roof of the house.






The LNA - whch is not active in this moment - shows an amplification of the signal as measured on the s-meter of around 10-15 dB.


I have finally realised that the Bluetooth is not installed in any of the version I have, maybe in a next development and software updates (?), I have also seen around a video with trials of airband reception and Ham VHF.