TTG Lora32 V2.1 ESP32 Power Amplifier 4W

Thanks for the share!

I have the RAK 5.8dBi which I haven’t trialed in the wild yet. It also tested very well on the NanoVNA so I would expect it to perform well.

Eliminating a cable and using only an adapter as you plan will help out too of course.

By look good, do you mean that they appear to be resonant and have a low VSWR at 915 Mhz?

At least, it’s measuring that there are no impedance mismatches at those frequencies more so than any of my other antennas.

I took the chance and purchased a pairf (got the covid relief check, so less than $20.00 won’t upset the household budget and spouse).

I’ll make some measurements, comparing them against the half wave “rubber ducky” verticals that Heltec furnishes with thier ESP32 modules using an SDR and RTLpower to see how they look before doing a field test. and post the results.

Using a 5 element yagi on one end didn’t make much of an improvement (at SF12 and minimum data packet settings), so I’m not expecting miracles.

Hello, is there an amplifier that I can plug in, between my ttgo tbeam and my antenna, and not have to rewire, reduce, reprogram, or rewrite a rats nest worth of wires? I am not an inventor, or a programmer, and I can not read schematics beyond oh hey look here’s a resistor. (I had someone else solder the screens on my tbeams) I’m looking for a simple, plug and play USB powered amplifier to get more power and range from my 915Mhz tbeam.
I appreciate any help I can get.
Jeff

No idea your situation or what you like for range, put your antenna higher up? Or using a directional antenna as option?
More power not always bring solution.

If there is it would likely be rather expensive as it would would have to have the RF bypass switch and attenuator built-in, and have a way of managing power states and automatically sensing transmit.

Maybe something like this: https://www.google.com/shopping/product/8709509397448821389?q=915mhz+amplifier&prds=epd:2243512352920748716,prmr:3,eto:2243512352920748716_1,rto:1,tpim:CNn-4_eig7iWUhC1_rW09f30z8MBGPCyv6oCIgNVU0QooJzNjwYw778c&utm_medium=tu_prop&utm_content=eid-lsjeuxoeqt&utm_campaign=466927

I just suggest that as a starting point, there are a lot of factors to take in to consideration and I’ve never done this myself.

Wow, 600 bucks, for 5 watts… The only word that comes to mind is piracy. Thanks though, I do appreciate you taking the time. I guess there is a lot more to an amplifier than I thought. You have a good weekend.

WiFi amplifiers have solution
Again repeat, more power not always give more range.
Antenna just 2 or 3, 4 , 5 meters higher up, give much more effect in range improvements.
Just try it, you find out it works.

I think this is probably high enough.

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Just try 1 - 2 meter or more you notice differenc let me know you thank me afterwards, 100%.
The actual max rf radiation is where the coax go in to antenna. Now you radiated against the rooftop So that part must way way up.
Lowloss cable and short as possible

Howdy all,

Here is the amp I am messing around with, it is a bi-directional amp and its supposed to automatically switch between transmit and receive mode based on the what is being supplied at the input, the Meshtastic LoRa devices I am using seem to be with in spec to properly activate it.

The problem I am having is I get almost zero reception with it in place? The transmission seems to be working well and it really improves the range.

Any idea why I might have trouble with this blocking reception? According to the LED status it is usually in reception mode as it is supposed to be and periodically goes into transmit mode on its own or when I send a Meshtastic message.

ScreenHunter 466

I think you have to bypass the amp to receive.

I hear you and that would go with what I’m experiencing but it does not go with the description of the amplifier:

“Transmit Receive Two-Way Power Amplifier”

“AB-915 Series Bi-directional signal amplification module”

“The product is a two-way amplified TDD working mode (that is, the transmit power and receiving sensitivity will be amplified equally)”

That listing is the only place I have seen offering to amplify receiving on Lora, looks like a scam.

Ooh that stinks :frowning: hope not

Anyone any good at looking at the circuitry to see if it even looks like it should be capable of what it states it’s capable of?





For meshtastic you are going to have to bypass it, maybe it works for some other lora case? There do not seem to be any happy real customers on the listing, so that is usually a bad sign.

They did not use circulator for bi-directional, the idea they used is smart but may have some minor problems.

According to your photo, they do used RF switch for controlling RX/TX, however they control the RF switch by using the RF power level(directional coupler or something similar). What if the receive power higher then the TX/RX threshold after RX LNA? This may happen if there are some other 868Mhz to 915Mhz devices around you, and your RX signal chain has some mismatching and reflection. For most RF circuits copied from the reference design, mismatching is likely to occur. Because it is difficult for manufacturers to use the exact same substrate as the reference design.

Ps. according to the photos, there may be some recycled chips in the circuit, which will reduce the yield.

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Thank you very much for your reply this gives me something more technical to reply to the seller with. I tested it with a nano VNA and the odd thing was the rx DB level according to a test I found online got even higher when I powered the thing on.