Re: Hints for finding why my RXTX 6.1 is deaf?
- Hi Tony,
Thanks! It's alive now but I think sensitivity isn't very good
so I will look into the T4 aswell.
I'm only testing with a few meters of cable as antenna inside
but I can only hear 1 or 2 very faint CW signals.
If the kit is working 100% I should be able to pick up some stronger
even with a simple antenna? I'm living in a flat at the moment so my
whole shack is packed in boxes at the moment and have no means of
putting my bigger antennas up. :)
73 de Jörgen SM4WWG
--- In firstname.lastname@example.org, "Tony Parks" <raparks@...> wrote:
> Hi Jörgen,
> Please check to make sure pins 1 and 7 of U8 are at about 2.5 volts
DC. Also make sure the QSD circuit is enabled with pins 1 and 15 of
U7 near zero volts DC. The gate of Q6 needs to be high to connect the
RX input to the antenna connection on the board as well as having the
PA LPF components, (L3, etc. ), mounted on the board. The signal
level on pins 3, 6, 11, and 12 of U7 will be very low unless an RF
source is used to inject a -20 dBm signal at the antenna input.
> One common problem is how T4 is connected to the circuit board. If
leads are not connected properly the RX sensitivity will be reduced by
40 dB or so.
> Thanks for getting the information to me on the circuit board
problem. I will post soon you findings.
> Thanks and 73,
> Tony KB9YIG
> ----- Original Message -----
> From: pontjakken
> To: email@example.com
> Sent: Monday, February 26, 2007 8:04 AM
> Subject: [softrock40] Hints for finding why my RXTX 6.1 is deaf?
> Hi all,
> I just finished building the RXTX 6.1 kit.
> When checking the 800 Ohms between ground and +5V i discovered
> some shorted pads (I have informed Tony on this)
> Anyway, after fixing the grounded pads I now tried the kit.
> It draws about 30 mA in receive mode (the only mode tested so far)
> but it seems absolutely deaf. No signal on the I Q-output.
> I've checked the clocks and I have signals on pins 14 and 2 on the
> FST3253 (S0 and S1).
> But nothing special on pins 6,3,11,12 (1B1, 1B4, 1B2, 2B3) or pins 7
> and 9 (1A and 2A). The scope measures anything on those pins (in
> Shouldn't there be something to see on the scope on any of the other
> pins, even without any antenna connected while receiving?
> Nothing special happening on the op-amps on U8 either.
> Any ideas on what to check for, do, etc?
> Best regards // Jörgen SM4WWG