RX ANT Switching box,    part 2 - Preamp IP3

   There is my next blog post. It is focused to the IP and gain measurements of the single and double preamplifier. I use Motorola 2N5109 transistors and classic W7IUV design. As I described in my previous post , there are two splitted ones.

   

   I can switch off stage by the jumpers and sets bias for each transistor. It the table, you can see what happenes for the different biases and voltages. I measured output P1dB point (OP1d) and than calculated output IP3 (OIP3) :

 OIP3 = OP1d + 12  [dBm; dBm, dB]

   All measurements are done at 3500 kHz. I used R&S FSH6 + ATT + amp + ATT.

  You can see that double preamp IP3 is almost by 3dB better than the single transistor one. This responds the theory... Do not forget that there should be +- 1dB mistake :-) And IP3 is just calculated, not measured by 2-tone generator! But anyway you can obtain UFB results with this design. Do not forget, this preamp can easily exceedes 27 dBm (500mW) of the output power! This is quite a lot for the "normal" receiver :-)

RX ANT Switching box,    part 1 - BPF

   It is a few years when I want to re-designing the RX antennas switching for Multi-Multi with two independant RX per band. There is our idea: 

High IP preamps in the feed point of each beverage --- long coax --- RX ant switching box

And RX ant switching box design:

Input connector (per ant) --- triband splitter --- two way splitter per band --- switch 1 of X (per RX) --- BPF + notch + ATT + preamp + ATT + diplexer + (high power TX protection)

So this article is about Singleband RX pream board:

PCB and schematic:

   The design: at the input, there is BPF. I have found really nice design from PA3AKE, please have a look at his full project! It is really nice piece of HW! There I added noth filters. I can easyly have stop band over 60dB! So this is the BPF design, than there is ATT, which you can switch ON and OFF and independant switching for preamp. In this case, preamp is done by splitting two W7IUW ones. By this you can obtain higher IP3 - see next post :-) Pream is loaded with 3dB ATT and diplexer.

And there are BPF measurings:

160m:

80m:

40m:

Full preamp ON (G=16dB):

NEW 6-to-1 antenna switch PCB

There is new PCB for 6-to-1 antenna switch which you can find at www.RemoteQTH.com .

PCB and schematic:

SWR 160m to 6m and 6m to 2m:

Insert loss 160m to 6m and 6m to 2m:

CQ WPX SSB 2015 results

20m "TOP GUN" stack: 2 x HB9CV

A few month ago we have placed HB9CV on the TWR4 to EA + PY dir. Because it works good I have decided to build another one to the south EU + AF. I ordered Al pipes and used some old element holders from 10m yagi. It is incredible how it fits on the boom! This was designed for pipes .

There is boom and holder detail. Boom is 40x40x2:

Waiting under the bigger brother and on the TWR

Something from our garden :)

Perseids 2015: Results  part 3

Thank you everyone for QSO. It was quit hot WX, but we did enjoy it a lot, also thanks to nice nature around! And there are some results:

6m opening SP/OK1MU and SP/OK1CID KO14na

 LY/OK1CU KO23bx and SP/OK1MU KO13nx

 Total QSOs from KO23bx and LY/OK2ZAW

And results:

SP/OK1MU - KO13NX - 50 QSOs on 50 MHz SSB/CW - QRV 50 min

SP/OK1MU - KO13NX - 105 QSO - 102 MS and 3 EME, QRV 35 h

SP/OK1CID - KO14NA - 50 MS QSO QRV 14 h 

LY/OK1CU - KO23BX -  45 MS QSO QRV 9 h

LY/OK2ZAW - KO23BX  -  174 QSO - 168 MS QSO and 6 EME QSO QRV 54 h

Total: 50 + 105 + 50 + 45 + 174 = abt 424 QSOs

See you next year from ??? :-)