Dang cheap and awesome gain. I appreciate how you tested and explained each step. It runs off a 9V rechargeable? Incredible. I need one of these rigs. Thanks and 73, Bill.
Well, it surprised me Bill! The lithium-ion battery is best since it will hold out at 9 volts till it’s time for a recharge. This is better than a 9-volt alkaline battery that losses voltage with time which makes the gain of the amp go down slowly. Also, if I use 12 volts, I get about one more S-unit out of it!
I use a similar LNA for a loop on the ground antenna (kk5jy design) and the LNA makes a hugh improvement. Note that the LOG antenna has a very low noise floor.
Ahh, Is that battery one of those real 9v output types, or the traditional 7.2v types? Many of those Lithium batteries have a smps in them that could generate EMI. Take a AM transistor radio and hold it's antenna up to the battery with your amp off. Tune the dial and listen for noise/squealing sounds. Anyway, that little board is wild. Amazing the bandwidth! Crazy. I see the switch there will do a proper bypass of the signal when amp is off, otherwise I'd expect a super weak signal, if any, leaking though the circuit when it is off. Nice.
Great observation Curt! The battery puts out a solid 9.1 volts and shuts down immediately when exhausted. I like that. The amp doesn't lose gain when the battery loses its supply capacity. I have heard others say they can cause EMI, especially the musical instrument folks. Is it possible their is some kind of chemical action going on in these lithium ion batteries? I will try the transistor radio test you suggested.
The noise figures are in the specs for the RF device used . They use different devices on these boards so hard to define. The way I use one is with an attenuation and I can tune it for the least amount I need but can hear the signal and use the signal enhancement etc to get a good clean signal. I just had a thought are you asking about noise generated in the device ? Or the amplified band noise?
Is the led adding noise? For a quick check just disconnect it.. If it is just put a small value cap across it. Are those wires going to the switch from the in/out connections causing stray noise? The preamp may be oscillating way up around 1GHz with the wires like that and the gain involved, just a thought.
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That tube radio is huge! A proper boat anchor.
Yes indeed! My first ham radio receiver my father gave me 60 years ago.
Dang cheap and awesome gain. I appreciate how you tested and explained each step. It runs off a 9V rechargeable? Incredible. I need one of these rigs. Thanks and 73, Bill.
Well, it surprised me Bill! The lithium-ion battery is best since it will hold out at 9 volts till it’s time for a recharge. This is better than a 9-volt alkaline battery that losses voltage with time which makes the gain of the amp go down slowly. Also, if I use 12 volts, I get about one more S-unit out of it!
If you put it between a band pass filter and the receiver it might help more with the signal to noise, if… it’s a single band receiver.
Good comment…I agree.
I use a similar LNA for a loop on the ground antenna (kk5jy design) and the LNA makes a hugh improvement. Note that the LOG antenna has a very low noise floor.
I appreciate your comment!
Very useful little gadget!
Yes indeed!
Are you bypassing the amp in some ways, or when you switch the battery off the amp acts as an attenuator?
Ahh, Is that battery one of those real 9v output types, or the traditional 7.2v types? Many of those Lithium batteries have a smps in them that could generate EMI. Take a AM transistor radio and hold it's antenna up to the battery with your amp off. Tune the dial and listen for noise/squealing sounds. Anyway, that little board is wild. Amazing the bandwidth! Crazy. I see the switch there will do a proper bypass of the signal when amp is off, otherwise I'd expect a super weak signal, if any, leaking though the circuit when it is off. Nice.
Great observation Curt! The battery puts out a solid 9.1 volts and shuts down immediately when exhausted. I like that. The amp doesn't lose gain when the battery loses its supply capacity. I have heard others say they can cause EMI, especially the musical instrument folks. Is it possible their is some kind of chemical action going on in these lithium ion batteries? I will try the transistor radio test you suggested.
This looks perfect for a Loop on the ground receive antenna!
Yes, and perhaps worth the the effort to try. 73's
Obwohl mein Englisch schlecht ist, sehr interessant, Daumen hoch 👍
Glad you liked the video!
A source for this board assembly?
www.aliexpress.us/item/3256803352141378.html?spm=a2g0o.order_list.order_list_main.79.6d4a1802DstVqb&gatewayAdapt=glo2usa
@@rfburns3472thanks!
Thanks for the Information., Interesting ✌️👍👍👍
Your welcome John!
Is WWV still at 2.5,10,15,20 and 25MHZ??
"The station radiates 10 000 W on 5 MHz, 10 MHz, and 15 MHz; and 2500 W on 2.5 MHz and 20 MHz." - NIST
And 25 mhz as well.
@@Tobys-DadNot 25 MHz. It’s easy to check on the WWV/NIST website.
Nice for a deaf old man like myself
It’s a nice little device.
It amplifies noise as well.
Correct....About 3.1 dB. On my radio it added 1 S-Unit of noise.
@@rfburns3472 Not sure how you are getting that? What is the noise figure?
It amplifies the noise from the antenna, but not the one of the input stage of the receiver.
The noise figures are in the specs for the RF device used . They use different devices on these boards so hard to define. The way I use one is with an attenuation and I can tune it for the least amount I need but can hear the signal and use the signal enhancement etc to get a good clean signal. I just had a thought are you asking about noise generated in the device ? Or the amplified band noise?
Is the led adding noise? For a quick check just disconnect it.. If it is just put a small value cap across it.
Are those wires going to the switch from the in/out connections causing stray noise? The preamp may be oscillating way up around 1GHz with the wires like that and the gain involved, just a thought.