[1000mp] MP/MkV no work w. SM220

[Bill Miner]

Hello Yaesu Fans,

The interface to the SM-220 in the Kenwood TS-940 was a separate
broadband IF stage fed ahead of the roofing filter with the output going
to an RCA jack.  Yes you could use an FET buffer followed by a broadband
amp at some point in the 1000mp and do a similar thing.  It would then
take some major mods to the SM-220 to change the center frequency to
match the 1000mp  IF.  After all this trouble the pan display quality
and stability on the SM-220 is not all that great!

Yes you could also do a similar mod to the 455 Khz IF but all this would
do is allow you to look at the keying wave shape (clicks?) and SSB
envelope of other stations but I'm not sure you get an accurate display
after going through all the additional circuits and filters.

{Mike,  If you ever have to send your rig back to Yaesu for repair I bet
"Chippy boy" will have the repair guys do a special job for you!}

73,
Bill

John Bolduc wrote:
> 
> Mike
>      The letter you got from Chippy boy is the normal answer to protect
> themselves and of course,  we don't want to be bother deal.........I assure
> you  can connect the scope to the MP .. The MP is standard Yaseu receiver
> configuration that they have been using for the last 15 plus years along
> with the same noisy 455khz notch circuit !!.........Nothing new there.  You
> do not have to cut any circuit traces. You are just tapping in to get some
> sample signal. You will have to build two buffer amps ...... one for the
> 8.215 & 455 IF .. A good choice would be mpf- 102 Fet . They have a very
> high impedance & the circuits will not even know they are there. One big
> question is Kenwood IF is 8.83 and Yaesu is 8.215 and I think the Kenwood is
> 100khz on the low IF
> 
> I am not to sure how selective the pan adapter is. You will just have to get
> in there and experiment or better yet get a Kenwood 940 or 950 schematic to
> see what they did ......
> 
> Hope this help's
> 
> 73's john KI4NR
> 
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