[Antennas] Diplexers (Hue)

[George Frederick]

Hue......   It depends on physical design limitations. First & foremost is
if the tuning devices are "still adjustable." Secondly, is if those
adjustments will actually "stretch" to the desired frequencies (assume
down to 440 MHz).  It would help if you could send me a picture off the
unit, in particular of any areas that look like slotted threaded screws
protruding above lock nuts. Other types are tuned internally during
fabrication literally by pushing on coil & capacitive elements and then
usually soft-soldered closed, or, welded shut (hermetically sealed). While
some designs can actually be re-opened & subsequently "re-aligned" it
typically requires a machine shop operation (vice un-soldering) to get at
the insides.  If one was really good with tools it could be done homebrew
but is risky.  So send me some pics and if possible any part numbers and I
will give you a better opinion with suggestions on how best to re-align.
73 George af6jt
On May 29, 2014 9:00 AM, <antennas-request at mailman.qth.net> wrote:

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> Message: 1
> Date: Wed, 28 May 2014 20:54:37 -0700
> From: "Hue Miller" <kargo_cult at msn.com>
> To: <Antennas at mailman.qth.net>
> Subject: [Antennas] Diplexers
> Message-ID: <BAY179-DS23BE0CFD33BB0CADB307BFE4240 at phx.gbl>
> Content-Type: text/plain; format=flowed; charset="utf-8";
>         reply-type=original
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> I have 3 diplexers made by Decibel Co. that are marked "450-470 MHz".
> Can these somehow be tuned lower, or are they scrap metal?
> tnx
> Hue K7HUE
>
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> End of Antennas Digest, Vol 120, Issue 4
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