Re: {Collins} 75S3-B S meter seems way too optimistic



Thank you for that information Leigh.   

73's
Hanford  wa4lzc

-----Original Message-----
From: Leigh [mailto:bipi@xxxxxxxxxxx] 
Sent: Sunday, July 03, 2011 21:52
To: Bob Tufts; collins@xxxxxxxxxxxxx
Subject: Re: {Collins} 75S3-B S meter seems way too optimistic

I know this is the Collins list but...Elecraft makes a nice little signal 
source called the XG2 which has a 50uV and 1uV setting on 80/40/20 meters 
for $80.  Comes in real handy...they also have a more deluxe unit, the XG3 
which covers all bands, multiple outputs, and can even do sweeps for 
aligning IF's.  Just for info...GL.

de Mike
K7PI

----- Original Message ----- 
From: "Bob Tufts" <rbt@xxxxxxxxxxxxxxx>
To: <collins@xxxxxxxxxxxxx>
Sent: Sunday, July 03, 2011 4:37 PM
Subject: Re: {Collins} 75S3-B S meter seems way too optimistic


>A followup: I went rough the manual and found the location for R57 (right 
>under the S- meter so it's not out in as plain a sight as R13 (S meter 
>adjust)
> (not as observant as I once was I guess). Adjusting R57 seems to be the 
> answer alright!!  Of course unless I get a 50 uV source I won't know 
> exactly what S9 is on the meter but adjusting on gut feel for now the 
> noise level and overall signal levels have dropped and acting like I 
> expected they should. No question my noise level is still high at this 
> QTH, but more like S5 or S6 vs over S9 on 40M in the day with the 
> preselector peaked and only the very strongest signals are now near the 
> top of the meter (more at night) vs having more than expected pegging it. 
> I guess in lieu of test equip I could bring my 75S3-B over to another 
> ham's house with what he feels is an accurate meter and compare the same 
> signal near the S9 level on his.
>
> Once again, the front panel control pot R56 is labeled "RF gain" with a 
> rectangle around it on the schematic and R57 (what should probably be 
> labeled "IF gain")  is labeled "RF gain adjust ".
>
> Thanks again Glen, David, and all.
>
> Bob   - WA1KPA
>
>
>
> On 7/3/2011 6:43 PM, Bob Tufts wrote:
>> On 7/3/2011 5:31 PM, David C. Hallam wrote:
>>>> Glen's comment about the separate RF gain adjust in the cathode is what

>>>> I see as the RF gain pot on the front (don't know Glen if you're 
>>>> pulling my leg, but I only see that in the schematic, HI)
>>>>
>>> Bob,  I don't know about the numbers in the 75S-3B schematic because I 
>>> have a 75S-3, but there are two pots labeled RF gain adjust.  R56 is the

>>> front panel RF gain adjust and R57 is the one in the first IF amp 
>>> cathode.  This is the IF adjust that Glen spoke about.
>> David, sure enough you (and Glen ) are very correct!!! My apologies to 
>> Glen. I see now both the AF and RF gain controls are labeled with a box 
>> around them, no doubt a standard to differentiate those type of pots.  I 
>> see R56 (front panel RF) was hiding down the bottom of the schematic 
>> where my aging eyes did not notice it.
>>
>> I'll give R57 a shot (and I do realize if I ever get access to the proper

>> instruments a general tune up should be done per the manual.)
>>
>> Well see how it goes now and thanks all for your combined help!!!
>>
>>
>> -Bob WA1KPA
>
> _______________________________________________
> SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
> http://www.collinsradio.org/membership/
>
> NETS: Tues & Thur: 3.805 MHz-2000 Central + Fri: 3.895 MHz-2000 Pacific
>  SUNDAYS: 14.263 MHz-2000 UTC  +  AM Net: 29.050 MHz-1200 Central
>  1st Wednesday AM Net 3.880 MHz-2000 local (ET, CT, MT, PT)
>
> The Collins Reflector reserves the right to refuse access to anyone.
>
> LIST HELP?  ADMIN EMAIL:  collins-owner@xxxxxxxxxxxxx
> This ONLY goes to the list admins and does not post to the group! 

_______________________________________________
SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
http://www.collinsradio.org/membership/

 NETS: Tues & Thur: 3.805 MHz-2000 Central + Fri: 3.895 MHz-2000 Pacific
  SUNDAYS: 14.263 MHz-2000 UTC  +  AM Net: 29.050 MHz-1200 Central
  1st Wednesday AM Net 3.880 MHz-2000 local (ET, CT, MT, PT)

The Collins Reflector reserves the right to refuse access to anyone.

LIST HELP?  ADMIN EMAIL:  collins-owner@xxxxxxxxxxxxx
This ONLY goes to the list admins and does not post to the group!







This archive was generated by a fusion of Pipermail (Mailman edition) and MHonArc.