[1000mp] MP Roofing Filter from INRAD -- hiss reduction needed?

Tue May 18 14:43:40 EDT 2004

Hi Mike,

Well, thankyou for the tips and about 7-7.  I just tried turning off 
7-7, (off to 100-3100 Rx)  I cannot for the life of me tell a 
difference, must be my ears?  I did put my sound level meter on it and 
it also showed no difference.  So I am stumped, no kidding.  My radio 
was built in Feb 04 could it have some updates no one knows about?  I 
will keep checking and watching the postings for more information.  Yes 
that roofing filter idea of Georges is the best idea I've seen yet for 
improving these receivers.  I had a Mil-Spec 1030 some time ago which 
had a 8 khz roofing filter, and Collins 250 hz filte in the 455  IFr, 
it was a kool machine.

I don't think you need to change those diodes.  I looked up the ones 
for switching rx bandpass filters and they are pins already.  I think 
when you change pin diodes the biasing may have to be changed also 
depending on the diode, maybe only one resistor.  Will you go to the 
HP's?  I bought a bunch one time from Newark.  Mouser most likely has 
them too.  I think they were -3080s, but not for sure.

73
Dale, K9VUJ

On May 18, 2004, at 12:54, Mike Schatzberg wrote:

> Hello Dale:
>
> If you want to check the difference between the digital product 
> detector,
> and the analog detector in the Mark V, it can be turned on and off in 
> menu
> 7-7.  If you select off, you will be using the analog detector.  I 
> like to
> use the 100-3100 setting, with the digital detector on SSB.  This 
> works very
> well for weak stations, and seems to improve the signal to noise ratio.
>
> If the band conditions permit, and you want to improve the signal to 
> noise
> ratio further, I like to use menu 5-0, and set it to the 8.2-455 
> position,
> to remove the filter from the 2nd IF, and use only the 6.0 filter in 
> the 3rd
> IF.  If you do the comparison between the two detectors as above, with 
> the
> normal filter selection button lit, you will see a rather dramatic
> difference.  I like to use this set up generally, as it also produces 
> the
> best fidelity with stronger SSB stations.  If the QRM becomes a 
> problem, you
> can either push the IDBT button, and superimpose the digital filters 
> over
> the analog positions, or push the NAR1 filter selection, and have the 
> 2.4
> khz filters cascaded in place the single 3rd IF filter.
>
> I also have noted that the best signal to noise ratio seems to come 
> with
> about a negative 0.180 setting in menu 8-9, r-usbcar.  This also seems 
> to
> improve the noise floor noticeably.
>
> Regardless, later this summer, following some other projects, and 
> despite
> some criticism that it may not work well, I intend to change all the
> switching diodes in both the preamps and front end.  I will finally 
> find out
> what PIN diodes do, or don't do for the Mark V.
>
> As long as the new roofing filter is switchable, it certainly looks 
> like it
> is a worthwhile change if you suffer from intermod issues.  Even out 
> here in
> the country I have one or two signals I would like to see removed, 
> probably
> from strong broadcast station mixes.  I also intend to enable the 
> antenna
> tuner to work during receive when desired, to improve the Q of the 
> front
> end.  I wonder what the reason is that Yaesu doesn't offer that 
> option, I
> want to give it a try.
>
> Regards,
>
> Mike Schatzberg
> WB2AJI
> ----- Original Message -----
> From: "D. J." <dalej2 at mac.com>
> To: "All Things Pertaining To The 1000mp Series" 
> <1000mp at mailman.qth.net>
> Sent: Tuesday, May 18, 2004 1:14 PM
> Subject: Re: [1000mp] MP Roofing Filter from INRAD -- hiss reduction 
> needed?
>
>
>> I just tried turning of the EDSP in menu 0-9 and I could tell no
>> difference in receiver noise, the tone changed slightly but the output
>> from the speaker did not, I had a sound level meter on the speaker.
>> The antenna input was on a dummy load.  Am I doing it right?
>>
>> Also, could you provide details about disconnecting the manual notch,
>> where did you do it?
>>
>> tnx
>> Dale, K9VUJ
>>
>> On May 18, 2004, at 9:31, Harry Yingst wrote:
>>
>>> if you turn off the DSP in the Menus you should hear the hiss quite
>>> well
>>>
>>>
>>>
>>>
>>> --- Pete Smith <n4zr at contesting.com> wrote:
>>>> At 10:25 AM 5/18/2004, you wrote:
>>>>> Harry Yingst <ab2pn at yahoo.com>
>>>>
>>>>
>>>> Sorry, Harry, I don't understand -- turning *what* off?
>>>>
>>>>
>>>> 73, Pete N4ZR
>>>> The World HF Contest Station Database
>>>> was updated on April 26, 2004
>>>> 2706 contest stations at
>>>> www.pvrc.org/WCSD/WCSDsearch.htm
>>>>
>>>> _______________________________________________
>>>> 1000mp mailing list
>>>> 1000mp at mailman.qth.net
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>>>
>>>
>>> =====
>>> Harry - AB2PN
>>>
>>> -
>>>
>>>
>>>
>>>
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