[HBQRP] Fw: [QRP-L] high current crystals [fwd]

[raymcn at gmail.com]

  Don't know if there may be some interest in a group order, but based on  
the picture, sure does look nice.  Maybe a discussion item for the Nov  
meeting - or for those finding their way to that great hamfest a bit north  
of Omaha.

73, 
Ray

-----Original message-----
From: Carlo Strozzi <carlos at linux.it>
To: qrp-l at mailman.qth.net
Cc: 4sqrp at ae5k.us
Sent: Thu, Sep 27, 2012 10:44:26 GMT+00:00
Subject: [QRP-L] high current crystals [fwd]

Hi,

I've just posted this message to the Glowbugs reflector.
I repost it here in case it is of interest also to QRPers.

72/73 de Carlo, IZ4KBS


----- Forwarded message from Carlo Strozzi <iz4kbs at gmail.com> -----

Date: Thu, 27 Sep 2012 12:40:10 +0200
From: Carlo Strozzi <iz4kbs at gmail.com>
To: tetrode at googlegroups.com
Subject: high current crystals
Organization: Ondina Slow Radio Club

Hi,

lately I've been doing quite a bit of vintage homebrewing, and one
of the main problems when it comes to single-tube power oscillators
is that modern crystals are not designed to withstand the high
currents that were common in the old days. There are repackaged
units available, but they usually contain tiny HC49/U or even HC49/S
rocks disguised as FT-243 or FT-171. While they are fine for low
powers and for aesthetics, they are mostly unsuitable to back, say,
a QSL Forty or other similar powerful one-tube crystal controlled rigs,
with which even a true FT-243 may have a hard time. Unfortunately,
big crystals are no longer manufactured, to my knowledge, so we are
left with very few options, the most common possibly being crystal
grinding of old off-freq big "rocks". Well, no more, or so it seems.
A fellow ham from Germany, Tom DJ5RE, discovered a company in the Czech
Republic that can still produce really big quartz slabs for custom QRGs!
And they are not very expensive either! The only down side is that
(at the moment) they can only make the naked quartz slabs, with no
enclosures, so these need to be homebrewed, or possibly "ungutted"
largish vintage cases can be used. You can read the whole story here:

http://www.paraset.nl/hut15_workshopXV-16/wb-tom-dj5re/pages/customxtals.htm

The homebrew crystal holder shown in the page is what Tom came up with,
but he owns a small lathe and he is quite good at it.

Unfortunately that company have long lead times, so be prepared to wait.
Maybe if the business gets larger then they may get more speedy.

I have ordered my own set of those crystals, for 40m and 80m, and
apparently they are on their way.

Usual disclaimer applies: I have no connection with that company, I
just hope this piece of news can be useful also to other fellow hams.

72/73,
Carlo, IZ4KBS

-- 
Software Patents kill Innovation: say NO to Software Patents!
I Brevetti Software uccidono l'innovazione: di NO ai Brevetti Software!

----- End forwarded message -----
______________________________________________________________
QRP-L mailing list
Home: http://mailman.qth.net/mailman/listinfo/qrp-l
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:QRP-L at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html