would actually improve the overall sensitivity since the radio was being tested
while receiving audio.
Milt
N3LTQ
- Original Message -
From: Tim Sawyer
To: Repeater-Builder@yahoogroups.com
Sent: Monday, September 06, 2010 3:48 PM
Subject: Re: [Repeater-Builder] Micor UHF
Yes, meter 4 shows the channel element is on frequency.
If by IF alignment you mean injecting 11.7 Mhz and setting meter 4 to zero, yes
I checked that. It was not far off.
--
Tim
:wq
On Sep 7, 2010, at 9:11 AM, Milt wrote:
Is the meter 4 circuit showing that the channel element is on
Tim,
Please confirm that you measured the sensitivity as 0.72 millivolts, or 720
uV- about 2400 times worse than the 0.3 uV you expect. Such a huge
disparity points to a failed transistor or a shorted capacitor on the
receive board. Perhaps your next step is to perform voltage checks and
Eric,
It's 0.72 microvolts. Not totally dead, just a bit numb.
--
Tim
:wq
On Sep 6, 2010, at 10:24 AM, Eric Lemmon wrote:
Please confirm that you measured the sensitivity as 0.72 millivolts, or 720
uV
There are shield covers on the RX board that need to be pulled off and have
the ground pins cleaned. I watched a Motorola service shop do that and the
sensitivity came back. He turned to me and said you'd have been forever
figuring that one out. Don't ask me why, but I saw it work.
Chuck
, September 06, 2010 10:29 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Micor UHF Sensivity
Eric,
It's 0.72 microvolts. Not totally dead, just a bit numb.
--
Tim
:wq
On Sep 6, 2010, at 10:24 AM, Eric Lemmon wrote:
Please confirm that you measured the sensitivity
Hello Tim.
I think the specs on your Micor are 402-430, But I could be wrong.
What freq was it crystalled on before you retuned it?
Also what is the frequency you tuned it on now?
That gives us better information as to where it was and where you tuned it
to.
Butch, KE7FEL/r
On Mon, Sep 6, 2010
Stuff to try:
1. Verify that the LO multiplier chain is peaked correctly. I've
seen a bunch of these that exhibit this symptom that had mistuned
LO chains.
2. Feed the test signal into the RX directly. If you see good
sensitivity, you know where to looks ;-)
3. Take
I'm getting about 0.35 for 12 db SINAD. But that looks about 10 db quieting to
me. What I typically do is open the squelch with no signal and set the volume
to 2 Vac then crank up the signal to 0.2 vac. Isn't that 20 db, or am I missing
something?
--
Tim
:wq
On Sep 6, 2010, at 10:46 AM, Eric
2V AC down to .2 v. AC is 20 DB quieting
John VE3AMZ
- Original Message -
From: Tim Sawyer
To: Repeater-Builder@yahoogroups.com
Sent: Monday, September 06, 2010 3:48 PM
Subject: Re: [Repeater-Builder] Micor UHF Sensivity
I'm getting about 0.35 for 12 db SINAD
Yea, I think 20 db quieting is more like 0.175 uV 12 db SINAD.
--
Tim
:wq
On Sep 6, 2010, at 12:52 PM, John J. Riddell wrote:
2V AC down to .2 v. AC is 20 DB quieting
:
2V AC down to .2 v. AC is 20 DB quieting
John VE3AMZ
- Original Message -
From: Tim Sawyer
To: Repeater-Builder@yahoogroups.com
Sent: Monday, September 06, 2010 3:48 PM
Subject: Re: [Repeater-Builder] Micor UHF Sensivity
I'm getting about 0.35 for 12 db SINAD. But that looks
Sent: Monday, September 06, 2010 6:07 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Micor UHF Sensivity
The Micor book says less than 0.5 uV for 20db quieting or
0.35 for 12 db SINAD. So the two are in fact equivalent. I
get better than 0.35 for 12 db SINAD
I have tried with 3 volt meters and 2 SINAD meters: a Fluke 77, a Sinadder 3
(SINAD AC voltmeter) and a HP8924c. Pretty much same results with all. That
is 20 db quieting around 0.7 uV, SINAD around 0.35. So what's the recommended
meter? Should I trust the SINAD reading and chock the quieting
I have tried with 3 volt meters and 2 SINAD meters: a Fluke
77, a Sinadder 3 (SINAD AC voltmeter) and a HP8924c.
Pretty much same results with all. That is 20 db quieting
around 0.7 uV, SINAD around 0.35. So what's the recommended
meter? Should I trust the SINAD reading and chock the
@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer
Sent: Monday, September 06, 2010 4:00 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Micor UHF Sensivity
I have tried with 3 volt meters and 2 SINAD meters: a Fluke 77, a Sinadder
3 (SINAD AC
: [Repeater-Builder] Micor UHF Sensivity
Here you go Jeff. Let me know what you see.
DePolo
Subject: Re: [Repeater-Builder] Micor UHF Sensivity
Yes, it is a DVP station. I have the DVP manual and I just checked the spec.
It's the same 0.5 uV for 20 dBQ. The test procedure does say to load the
speaker. I'll give that a try tomorrow.
--
Tim
:wq
On Sep 6, 2010, at 8:17 PM, Jeff
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