Hi Kevin,

 

     The Sony SRF-M37V is indeed a puzzle--  an Ultralight with fairly decent sensitivity but barn-door selectivity, in stock form. Allen Willie in Newfoundland has used it to receive more new TA countries than all other Ultralight DXers combined, but for most of us, it's just not as competitive as an SRF-T615, E100 or DT-200VX.

 

     During a recent visit to Oregon, I noticed the new SRF-M37W model for sale at a Fred Meyer, so I picked up one for the Ultralight Summertime Shootout.  It looks almost identical to the SRF-M37V, but the TV audio coverage has been replaced by weather band coverage (like the DT-200VX and DT-400W).  Price was $34.95, like the old SRF-M37V.  It hasn't been tested out yet, but if Sony improves the AM IF filter in this new model, it would make a huge difference for us (even though it's probably wishful thinking).

 

     The 450 kHz IF of the model makes some decent filter modifications possible (as you and Jim have experienced), but the E100's 1 kHz tuning steps provide a huge advantage for 9 kHz split-frequency DXing, to chase TP's and TA's.  The 455 kHz IF of the E100 also makes installation of some VERY effective IF filters possible, such as the Murata CFJ455K5 ceramic filter.

 

     Your modified SRF-M37V's would make a very interesting project for a large loopstick transplant, Kevin.  We have discovered that whenever a selectivity boost is combined with a major sensitivity boost, an Ultralight suddenly becomes an Ultra-effective DX chaser.

 

                                                                    73, Gary