Posts by DH5MK

Has someone soldered the pcb of the amp? I used a iron from the back to heat up the pcb to about 150C and then hot air from the top. Works great for the R and C but not for the 16pin amp! Tried two times but there where short circuits

73, Mike

kann jemand reflow SMD löten? Habe Teile für DB4UM PA.

pse hlp!

(looking for help in reflow soldering here in Germany)

tnx de Michael

Quote from DH2VA

some words here on the TQP7M9103. I got my driver board today, which claimed 16dB Gain and 29dBm P1dB. From the datasheet, it was obvious that this cannot be given over the full frequency range as the Qorvo device needs a bit of matching at the input and output.

First measurements: 6dB gain and ca. 20 dBm P1dB. I suspect therefore that this could be improved with some snowflaking (Faehnchenschieben) and as this is low enough power to be safe, I'll go for it

The output inductance (L1) for the bias supply also seemed a bit large to me (too low SRF) so I exchanged it to a part with known parameters (22nH, 0603, 4.6GHz SRF) but this improved matters only little. Will try some snowflaking over the weekend.

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Hello Achim,

do you have new conclusions about that device?

73, Mike

@do1ctl

IMHO the best way would have been:

1. asking Kuhne by mail

2. posting the results in a forum

73 Mike

Quote from G4KCM

Saw this a while back whilst looking at home brew options...

DB4UM 13cm 2W

biggest problem is the milled case and of course the soldering. ... any ideas?

This design seems good for the LimeSDR!

I just listened to a 30db over noice signal produced by a 2m dish with 3W.

The operator mentioned it as "usual equipment".

Can someone please tell him how terrible this behaviour is?

Not stronger than the beacon, like the last decades on AO10, 13 and 40. Nothing has changed, but some guys will not understand such a easy rule. And sorry to say but most of them are germans.

I´m sorry for that!

73

Mike

Hi Rob,

nice to meet you in FT8.

Here 100mW, 85cm duoband feed. Sigs abt. 20db over noice. Maybe 1mW could be enough

73

Mike

Hi Allesio,

I found a 29db "rf Florida" chip attenuator in the surplus.

So I can drive the BU-500 with my TS-2000 using max. 20W. It will give about 0,3W out for the SG-Lab Amp -> ca. 15W max. out

So I can regulate between 3-15W on 2,4GHz (5 to 20W from the TS-2000).

If 3W is still to much, I can use the 0,3W from the BU-500

73

Michael

Powertest

The two spikes beside must be from the RTL SDR stick. They came up while I reduce the gain because of the strong signal!

now we have the two beacons on

actually it looks like this:

Hi Guys,

starting the first RX test with 85cm offset dish and Octagon single (original). Dish ist focused on ASTRA 3B, 23,5deg.

73 de Michael

DH5MK

JO41KW