[Hammarlund] SP-600 JLX-15 vlf rcvr - NOT!

[Al Parker]

OK GUYS, take it easy  ---
    Here's what I sent to Bob (privately) re: the subject---
==============
----- Original Message ----- 
From: "Al Parker" <anchor at ec.rr.com>
To: "RJ Mattson" <rjmattson at hvi.net>
Sent: Tuesday, July 18, 2006 3:02 PM
Subject: Re: [Hammarlund] SP-600 JLX-15 vlf rcvr


> Hi Bob,
>     I just read a reply from someone that said he had -JX-31 that
covered
> from 10 or 15kc up.  Of course I can't find it now.
>     But I see we do have it on the website, "Dec. 1954 SP-600-VLF-31
> Special frequency range, 10-540khz X-tal frequency control (4 position).
> Very low frequency receiver."  Dunno how many bands.
>     "June 17, 1952 SP-600-JLX-15 Frequency range, 100-400 khz, 1.35-29.7
> mhz. Replaces JLX-2."
>     Maybe you can get a good price on the pair, qty discount?  I suspect
> the -31 is kinda rare, but I thought the other guy said he had 3 of
them.
>     Lemme know how you come out.
> 73,
> Al
===========================
    I copied the areas in the above quotes from the webpage, and they do
not show here the columns that some of the info was in.  If you look at
the webpage I think it can be fairly concluded that the receivers are not
exclusively xtal controlled, but have the extra "FCU" unit for some
separately selected fixed frequencies, designated by the "X" in the model
no.

    After reading Ken G's "tirade" I should  clarify what I said to Bob
(privately), and what is on The Hammarlund Historian website.
    We have listed on the website;
the SP-600-VLF-31 with freq. coverage 10-540khz
and the SP-600-JLX-15 with freq. coverage 100-400 khz, and 1.35-29.7 mhz

we do not list an SP-600-JLX-31 -- that designation may have surfaced in
the emails due to my reference, "I just read a reply from someone that
said he had -JX-31 that covered from 10 or 15kc up.  Of course I can't
find it now."  I don't know if there ever was such (either) an animal.

    Seeing the freq. ranges covered removes the necessity of debating the
semantics of VLF or not.  We have receivers that are designated HF which
do not cover all the HF freq.s, whatever they might be defined as.

73,
Al, W8UT
resident grouch
apprentice equal opportunity annoyer

----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at verizon.net>
To: "RJ Mattson" <rjmattson at hvi.net>
Cc: <Hammarlund at mailman.qth.net>
Sent: Wednesday, July 19, 2006 9:59 PM
Subject: Re: [Hammarlund] SP-600 JLX-15 vlf rcvr - NOT!


> > Hi Ken,
> > Is AL correct with the JLX-31 being xtal controlled on the vlf band?
> > My quest goes on for a RBL-3 competitor. bob...w2ami
>
> First of all, we must get this completely clear. The subject receiver,
the
> SP-600-JLX-15 is NOT, repeat NOT, a "vlf receiver", period. It covers
> SOME OF the 30 through 300 Khz LF band, but not all of it. It covers
> NO VLF frequencies at all.
>
> Secondly, in the answer to your question as to whether or not the  JLX-
> 31 is crystal-controlled on "the vlf band".  It may be. I've never had
one.
> The letter "X" in the nomenclature would certainly indicate that the
JLX-
> 31 has PROVISION for some crystal controlled channels, and the "L"
> would indicate to me that it has some LF capability. But what that is, I
> do not know.
>
> However, when you say "in the vlf band" you had better make perfectly
> clear what you mean by that. In point of fact VLF means ONLY
> frequencies from about 10 to about 30 Khz, the bands between 30 and
> 300 Khz are LF, the bands between 300 Khz and 3.0 Mhz are
> considered MF, and 3 to 30 Mhz is called HF.
>
> There is no single "vlf band" that covers from 10 Khz through something
> more than 30 Khz.
>
> Now, I repeat, and this is a very important distinction:
>
> The SP-600-JLX-31 is NOT, repeat NOT,
> the same receiver as the SP-600-VLF-31 !!!!!!!!!!!
>
> Not by a long shot!
>
> As I understand it, the SP-600-JLX-31 is simply one in a long line of HF
> band, or combined some-bit-of LF and HF band receivers.
>
> The SP-600-VLF-31 is a COMPLETELY different design, having
> different IF frequencies, and totally different main frequency coverage.
>
> The SP-600-VLF-31 continuously covers 10 Khz through 1500 Khz in
> seven bands.
>
> The ONLY thing they have in common in the nomenclature is the
> number "31" at the end. They are COMPLETELY DIFFERENT
> RECEIVERS, period.
>
> There are several receivers that would be a significant upgrade to your
> RBL-3 (of which I have several, BTW). They are the SP-600-VLF-31,
> the RCA SRR-11, the National AN/WRR-3, the Collins R-389, and
> several others more difficult to find.
>
> As of now, I have several each of the RAK, RBL, SRR-11, and one R-
> 389. I had to sell all three of my SP-600-VLF-31s, so I have no more of
> those, and I have never had an AN/WRR-3, although there is one for
> sale now on the Milsurplus list.
>
> We absolutely MUST get the distinction between the SP-600-JLX-31, or
> -15, and the SP-600-VLF-31 clear before we can do any more
> discussion on their relative merits. They are NOT the same receiver!
>
> Ken Gordon W7EKB
>
>