[R-390] Interested in R390A Filters? PLEASE READ !!

[chuck.rippel at cox.net]

There has been a lot of discussion about surrounding R390A filters.  It 
seems there are a variety of reasons; the 4KC's are falling at the 
highest rate, when a 2KC fails, that causes the loss of 3 bandwidth 
positions, the .1, 100 and 2KC.  The 8's (really 11KC) fail and I expect 
that 16's are failing but that is almost a "who cares" unless the owner 
has a need to receive MUX.

So, there is a need for filters.  Here is a possible solution:

Some of you may remember the R390A filters Longwave Products made 
available a few years ago.  I remember they were offered in 3 
bandwidths, .5KC, 2.5KC and 6KC; they were priced at $199.00 each.   The 
Longwave Product filters were not some slopped in after thought.  Each 
was a new design, Collins Mechanical filter which was mounted on a 
circuit board with that assy enclosed in a machined brass tube complete 
with a mounting flange and were exact replacements for the stock filter. 
Longwave built the filters such that the physical isolation between the 
input of a filter and its output provided by the aluminum top of the IF 
deck was maintained.   This was good stuff !

Unfortunately, Longwave stopped building R390A filters due to lack of 
interest however, they still sell 75A-4 filters.

I've had a sidebar conversation with Dave Curry, owner of Longwave 
Products.  He is considering a 1 time run of R390A filters if enough 
people roger up and make a commitment in the form of a deposit ahead of 
time.   Let me stress that at this time, Dave is only CONSIDERING 
building filters !   Its not time to make any sort of commitment to 
Longwave.  Dave has travel scheduled and won't be back for about 3 
weeks.  We also don't know what bandwidths are available from Collins 
although I'm sure Dave will try and source 2-3 bandwidths that best 
accommodate the requests.

Dave is going to have to source the filters and price the machining of 
the brass enclosure.  He did not share what the actual selling price 
might be but suffice to say, it will probably exceed the $195 each cost 
of the last offering.   My involvement is solely to engage Dave and 
suggest he build the filters again and share his initial thoughts with 
you.  How the commitment deposits and filter purchasing will take place 
will be solely up to him.

Here is some information on the filters.  I used to have a picture of 
one but can't locate it just now.

http://www.r-390a.net/Collins-Curry-Study.pdf

FWIW, I have one of his 6 kc filters that was installed in place of the, 
(IMHO) "useless" 16 kc.  It works wonderfully !!  There have been 
several people who have picked up completed radios from me and I make it 
a point to demonstrate the filter.

Until we hear back from Dave, each of us needs to decide if we are 
serious about making a firm commitment.  Of course, its ultimately 
depends on price, the bandwidth(s) available, how many each individual 
might need, etc..


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No  trees were killed to deliver this message.  However, a large number 
of electrons were terribly inconvenienced.

Chuck Rippel