Re: SRF-M37V and SRF-M37W-Performance differences?

Gary DeBock

Hello Again Michael,
Thanks once more for your kind comments. I'm always amazed at how the Ultralight radio DXing boom has spread around the world, and am happy to have played a small part in making it happen.
To be honest, when I wrote the first SRF-59 review, I was quite concerned that I would be laughed out of the IRCA. The idea of transoceanic DXing with a Walkman radio seemed ludicrous to many in late 2007, and it is to Steve's eternal credit that he recognized the enthusiasm-boosting potential of this new form of DXing, and promptly published the SRF-59 review in MWN.
I'm very happy that my reviews have motivated you to purchase a few pocket radios for your DXing fun, and that my fanatical articles in MWN have been interesting. There are a few more articles in the works (both technical and radio reviews) for which Steve will hopefully find space in his outstanding bulletin.
73 and Best Wishes,
In a message dated 4/5/2009 11:25:31 A.M. Pacific Daylight Time, knallebo@... writes:

Hi Gary

Yes, I am a member of MWC and I've avidly read your fanatical
loopstick and other articles. Indeed Gary, it was your article in MW
News January 2008 about the Sony SRF-59 that rekindled my interest in
MW DXing. You've got such a readable easy style of writing that
retains the interest, making the reader want more. Your sheer
enthusiasm really leaps from the page. Sincerely, have you ever
thought of becoming a professional author?

There are many who owe you for founding the Ultralight movement. Not
just DXers, but also the radio vendors. The hobby could not have a
better advocate! Your articles have been responsible for my obtaining
the SRF-59, SRF-T615, DT-210L & DT-400W radios and generally 'doing'
radio again. Unfortunately I've yet to hear any TA DX on any of them.

Michael Slattery G8PNX
Sheffield, UK

On Sat, 4 Apr 2009 14:37:39 EDT, you wrote:

>Hi Michael,
>Thanks again for your filter modification work, and your kind comments.
>Actually both Guy Atkins and Steve Ratzlaff are far more experienced in
>filter modification work than me, and I've simply managed to learn a few things
>by having the privilege of working with them. My own contribution to the ULR
>experimentation efforts here has been in loopstick improvements, in attempts to
> make these tiny radios as sensitive as possible. If you are a member of MWC,
>you may have seen a few of my fanatical loopstick articles that were
>published in Medium Wave News.
>About a year ago, I learned the harsh lesson that sensitivity improvements
>alone were not going to make a major difference in chasing 9 kHz-split DX with
>Ultralight radios. A small radio needs both a major sensitivity boost and a
>major selectivity boost in combination, to make a radical improvement in
>overall performance.
>By a tremendous stroke of luck, one of the primary filter experts in the USA
>(Guy Atkins) lived right in my small home town, here in Washington state.
>Our cooperation last summer (along with contributions by John Bryant) produced
>the first major breakthrough in ULR 9 kHz-split DXing performance, the fully
>modified Eton E100. Steve and I were attempting to create something similar
>with the DT-400W in the winter, but despite our unrealistic expectations, we
>ran up against the harsh reality that all the commercially available 450 kHz
>IF filters are mediocre for transoceanic DXing.
>73 and Best Wishes,
>Gary DeBock
>In a message dated 4/3/2009 7:45:52 P.M. Pacific Daylight Time,
> writes:
>Hi Gary :)
>Thank you for your kind thanks for my mod articles. I'm sorry that
>some folk may have been misled into thinking the selectivity
>enhancement would be much greater.
>There was not that much effort expended in development. On obtaining
>both the DT-210L and the DT-400W I was extremely disappointed by the
>very poor selectivity. My gut reaction was that I had to do something
>about it and whilst I was 'at it' I took a few photos reckoning that
>it may be of use to someone somewhere!
>I'm fully aware of the performance provided by the premium filters you
>and others have been using for 9-kHz split DX chasing. I've used them
>myself in my AOR AR7030 for many years but not yet in a ULR.
>Some thoughts: I know you and Guy Atkins have spent quite some time
>developing filter mods for various ULRs. I wonder whether it might be
>worth investigating the Collins Low-Cost Series of mechanical filters
>that have a superior passband ripple to ceramic filters possibly
>enhancing the intelligibility of reception. Expensive, but when only
>the best will do. Inrad have a 2kHz 8 pole variant:
>( >
>or a 2.3kHz 10 pole variant:
>In the DT-200VX and DT-400W, if space cannot be found for the filter
>within the case maybe one of the AA cells could be disposed of to
>create a space for the installation the filter. The remaining AA cell
>bay could then be loaded with a 3.6V Lithium AA cell.
>Thanks once again for your consideration.

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