# ARGtek wifi booster

• Hi Guys,
which unit do you use for return loss? What shoes your network analyzer for S21?

With modern concepts like network and spectrum analyzers and SDR-Technology we have to get used to logarithmic systems. There is a little software from Rohde & Schwarz for Android and PCs also. It is called "dBm Calculator". You can transform linear and logarithmic units to each other. It helps, to get familiar with all this.

73
Andreas

• Hi Andreas,

do you use a 20 W amplifier or a 43 dBm amplifier?

Once I've used a 88 dBm amplifier on 1 000 kHz.

Detlev

• Please, could you help me to understand why are there negative input dBm values?

Adalm plut outputs as I recall positive 5dBm. How can I match it with this -5 to -20 dBm range?

-5 starting point means 5dB insertion loss?

May interpret the table as it has been offsetted so -20 means 0 and -5 means +15 dBm?

How many dBms can I get out If I put Adalms 5 dBm in? or do I need at least 10 dBm attenuator to limit input to -5?

All PA specs I saw refers positive input numbers, that's why I'm lost

• Dear Kornel,

It seems that all the expert statements so far do not help you much in understanding.

Focussing on the power amplifier as offered by BG0AUB I will try to clarify how to calculate.

As you mention yourself about having a Adalm Pluto module, you must be aware that the TX output level can be programmed in dBm's (yes, we live in a dBm world, hi), so you only have to select the input drive level from the table for the PA output you aim for.

With a PA input of -19 dBm you get 37.6 dBm which equals to 5.7 Watts; a drive of -18 dBm gives 38.6 dBm which equals to 7,25 Watts, etc. (40dBm = 10W, 43dBm = 20W, 46dBm = 40W but not linear anymore).

By reducing the supply voltage to e.g. 24-28Volt you can lower the output level a bit.

Also it may be wise for stability reasons to have a resistive attenuator placed between the Pluto and the PA.

For further info you can contact BG0AUB direct via eBAY or on Twitter,

Here is his latest offer on eBAY:

https://www.ebay.com/itm/28440…ewItem=&item=284403687949

The package includes:

1: Used S-Band power amplifier, which has 56dB high gain, and up to 20 Watts (43dBmW) output * 1 set

2: Brand new multifunctional interface board * 1 set ( which is designed for working with Pluto SDR

3: RF jumper (15cm SMA TO SMA) * 2 sets

4: SMA to MMBX connector * 1 set

5: One PCB for extending Pluto SDR PPT GPIO converter * 1 set

6: PA power cable, USB OTG cable, 2x3 pins 2.0mm connector, retaining screws

The multi-functional interface board provides the following functions:

A: A USB network adapter, which is also working with Pluto SDR.

B: 30V to 5V DC-DC converter, which could provide power source for PA pre-amp and Pluto SDR.

C: 30V to 12V/18V DC-DC converter, which used for supply the LNB. Different voltage could be select via a jumper.

D: Over-temperature protection and power supply reverse connection prevention function.

Also here is something that should be noticed.

A: Input voltage 24-30V, and should have at least 5A capacity.

B: LNB power out is 12/18V, 250mA Max.

C: USB OTG power out is 5V , 2A Max.

D: 24V/30V power supply, Pluto SDR, LNB and network cable is not included in this item.

OK, at last please be kindly advised again: Pluto SDR should be purchased separate, it is not included in this item.

Thanks a lot !

The amplifier has a good internal condition, PCB, but its housing case has some scratches which is not affecting the functionality.

Each amplifier will be fully tested before shipping.

The output connector of the amplifier is a SMA connector, and the input is a MMBX connector. A MMCX connector goes to an output direct coupler indicating the output power.

A Pluto SDR can drive this amplifier working at the desired band with no modifications needed.

Added Note: This PA comes with a baseplate with uniform heat at the bottom and an aluminum shielding cavity processed by CNC. The appearance has scratches and the bottom coating is partially peeled off. However, the PCB is guaranteed to be flawless, and 100% will be delivered after energized gain measurement and power test.The PA needs to be mounted on a heatsink !!

Kornel, here is a typical duplex set-up from a French OM using the Pluto without the interface board:

I do hope to have cleared the matter for you a bit with this.

73 de Cor PA0P

• Hi,
yet another wish. If you talk about amplifers and power don't forget the intermodulation distortion. Single tone values are useless.

The Console in combination with Pluto gives an excellent two tone signal.

The screen shot is an AMSAT-PA (with preamp) with good linearity. Please note, two carriers with 30 dBm give 36 dBm, that are 4 Watts.

With the preamp, the amplifier does not need any driver and can be used direct after the Pluto.
The intermodlation distortion products can be related to the carrier level or to the PEP-level, which is 6 db more. This looks much better in the datasheets.

Not only a "dB world" but a linear world too :-).

73
Andreas

Edited once, last by DL5CN ().