Software Defined Radio Lost All Sensitivity

While in receive mode, shunt the suspect capacitor, with a known good capacitor and check if the weather satellite signal strength improves.

What values of capacitor are normally used? It is for 137.5 MHz.

For this frequency, even 10 pF should work out.

I am totally confused by what has happened to it. I was able to get beautiful images from it but not now. It picks up the pagers on 137.1 much better than it has ever done but weather satellites just do not work at all for it now the signals come up on the watefall spectrum display but they sound very weak. The software SDR Sharp has a filter order option which is always at 400. Does this mean anything?

Look in your user manual. I do not have the privilege of using any SDR unit yet. Would love to. I think the filter will affect, just change up/down value & see the result.

So 137.1 is Ok. What is the frequency for the weather sat?

What is a waterfall spectrum display?

On your specan do the pager and sat signals have the same amplitude?

Why does the connector look so crap?

The satellites are on 137.1 137.9125 and 137.620. The signal comes up on the spectrum display the same as it did when the system worked properly. I have also noticed that when I tune into a certain frequency on the radio, I sometimes hear other frequencies nearby even If I am not tuned to them.

Reduce your bandwidth, it is too wide/broad. You tend to receive like that only when you are on wide band setting.

And the crappy connector?

That is the connector where it worked really well.

Huh?

You're getting all vague on us here HH.

Spell it all out again, type slowly, some of us are old.

It could be sun spot interference; we have had some activity.

Wait a few days and see if it improves.

It can not be that because my other radio picks the satellites up really well but its bandwidth is too narrow.

Check the antenna, for break or short. Are you receiving other signals/stations well?

I am receiving everything else on it very well.

I am foxed, since the same satellite signals in two different receivers don't compare & their strength does not match.

Me too. Possibly the radio has lost sensitivity to circularly polarised signals but I do not see how as I am using the same 2m long piece of wire for them both.

Could it be that the SDR is unable or failing to select circular polarisation?

Can't be as it used to pick them up really well.

Did you use the same antenna and cable with your other radio? If you did, maybe the socket is bad and there is a cable reflection [load mismatch] causing a null at the satellite frequency.

Please visit: http://www.arrl.org/ You can gather lots of use full info. here. What software are you using? Did you buy it or open source? This has lots of reading material on SDR: http://www.arrl.org/software-defined-radio Soldering of your antenna connector is not as one would say "Ship shape & Bristol fashion" You may run over a higher wattage soldering iron & let the lead flow like liquid, around the antenna connector. It may be perfect electrically, but appears to be crude. My apologies.