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Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

To: <[email protected]>
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz
From: "Alan Melia" <[email protected]>
Date: Fri, 12 Apr 2013 00:55:14 +0100
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Reply-to: [email protected]
Sender: [email protected]
Hi Pat Yes I did send Graham a thought that if he can get the old crystals open he might be able to move them down by "mechanically loading them" the easiest way is adding some mass by plating some copper on them electrolytically. It was done with the FT-243 (or was it 241...I cant remember these days) the one marked "54th harmonic" and that were used for 470kHz IF SSB filters in the 1960s.
 
Lapping them with "the famous foaming clenser" ( Ajax scouring powder for the younger members :-))  ) will only move them up in frequency. Pete is right. the worst problen with lapping is getting and keeping the faces parallel. Non-parallelism is the quickest way to lose activity.the other problem is microscopic chips off the edges. The best way is to "ring" several similar thickness blanks onto a half inch thick glass "flat" with hot wax and lap them on a sheet of plate glass. They stay fairly parallel like that. Etching does help as it removes the damage layer induced by the lapping. The etch rate slows as you get through the damage layer, but if you etch too far you can lose activity. This may be due to rounding the edges but it can alsi e due to leaving microscopic particles of lapping powder embedded in the surface, sticking up. Proper lapping compound is very accurately sieved for calibrated grain sizes. Sometimes a large grain will gouge a minute trough and the etch will deepen it. Its 50 years now since I was in the crystal lab, and it always struck me as more of an art than a science. The best techs were from the optical trade. I believe toothpaste is quite good as a fine grade lapping compound but I never tried it.
 
Most of the plated crystals were finished by measuring them in the vacuum chamber whilst evaporating gold onto the electrode areas. They move a little when mounted up but that can be taken up with the capacitive loading. A good tech knows where to stop plating to get spot on the spec. I was an interloper in the lab because I was working on silicon not quartz :-))
 
Alan
G3NYK
----- Original Message -----
From: pat
Sent: Thursday, April 11, 2013 8:54 PM
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

I'm glad you've just popped up on this xtal topic Alan. I was just going to recommend that you be contacted as a probable Guru.

73


On 11/04/13 20:26, Alan Melia wrote:
Interesting Pete I didnt get two that time. I had it happen the other day Idont know whether there is congestion (kids doing holiday projects) but I hit "send/receive" I got all the receive messages but got an error on send, and the message wasstill in outbox so I sent it again......and got two copies from the reflector. So I guess te server didnt ack the receipt the first time although it did receive the messages.
That's more like BOGOHP  :-))
Alan 
----- Original Message -----
From: M0FMT
Sent: Thursday, April 11, 2013 7:17 PM
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

Pat there's something up with your e-mail because it keeps sending the same thing twice? i.e. two e-mails for the price of one.
 73 es GL Pete M0FMT IO91UX
From: pat <[email protected]>
To: [email protected]
Cc: M0FMT <[email protected]>
Sent: Thursday, 11 April 2013, 18:53
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

Well, you might have been happy, Pete. I discovered that the family cat's whiskers wouldn't work with a bit of coke and we had to go back to a pair of baked bean cans and string!




On 11/04/13 16:20, M0FMT wrote:
And we all live in a hole in the road but we were happy!!.....:0)

73 es GL Pete M0FMT IO91UX
From: pat mailto:[email protected]
To: [email protected]
Cc: M0FMT mailto:[email protected]
Sent: Thursday, 11 April 2013, 13:06
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

And Wireless Set No.17 for £2:19:6 (2Volt accumulator and HT Battery 10/- extra)

And we're all getting older!

73




On 11/04/13 12:18, M0FMT wrote:
Hi Graham
 
How young you are my introduction to Tottenham Court Road (Proops?) , Lisles Street (GW Smiths), Charring Cross  and The Edgeware Road  about 1956. Aaaaah those were the days. learnt a lot about Radio, Life, the Universe and everything there...... hee!
Got my R107 from Lisle Street with money save from my apprentices pay. Carried it  (abt 1 CWT) via bus to Kings Cross in the days when the conductor would jump off the bus and give you had to get it on board........ imagine that on a "Bendy Bus" today. See http://www.retinascope.co.uk/lislestreet.html for the full story.
 
OK on the stick info yes but I am CW only really can't get too excited about sterile data although as you know I do partake occasionally.
73 es GL Pete M0FMT IO91UX
From: Graham mailto:[email protected]
To: [email protected]
Sent: Thursday, 11 April 2013, 11:52
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

R Pete
 
Well , its possible to  use the  emergency  vfo  , but that  results  in a very  unstable  signal , I   remember  down the  Tottenham court road , there  where  tea chests of  crystals , but that  was  1970 .. seems  a  lot  of the  traditional  firms have  closed ,
 
One  of the  £5  dds  with  a driver  would  work , but  they  want to  keep  it  standard
 
DS -   That's really  the  'correct'  situation  ,  that  -33 db decode, -3 db  lower than  normal  was  a  good  indication   that  the  system  is  working ,   over ranging  the  a/d  is the  only  problem . I think  dynamic  range is  60 d b after  processing  , is it   3 db per  bit  ?  8 bits  , 24  db + 3   that's   27 dB ?  500:1 ?   , but   by  removing    qty  2  mixers   and  2  oscillators   , [ may  be 3  oscillators  1 , hf-up-conv  2 , pll  conv osc  3  ref osc )  that  is a  lot  of  noise + jitter  removed  from the  signal  path as well  as   imd  from  2  mixers , I found  a attenuator  helped  for  mw  and  I have  a  mw-filter  , which  cleaned  up  sw  bands  ......  nice to  have a  panoramic  display , 2  mhz this time , the  ra17  was 1 mhz  and   28  valves + 20 ish  > in the  radio   
 
73-G.
 

From: M0FMT
Sent: Thursday, April 11, 2013 10:47 AM
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

OK Graham
 
Thought it was home brew retro.......... I am in that mode and think everbody else is! What do you do at the moment inject a Sig Genny?
 
Have you checked the net or checked out Vincent - QuartzLab etc?
 
Anyway what's that master osc circuit. I build from old RADCOM (pre 1975 when they published real amateur radio) and PW,QST etal. I use modern xtals with no known issues. Well trying to get third overtone for 10m not to chirp is an issue with me at the moment. 
 
OK yes got a stick on its way didn't want to tear up my existing upconverter design. But not sure there is much wrong with the UC approach it works for me. But want to try the direct approach. Do you get much Cross mod and IM products?

73 es GL Pete M0FMT IO91UX
From: Graham mailto:[email protected]
To: [email protected]
Sent: Thursday, 11 April 2013, 0:47
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

Ok Pete
 
Q where to  have  them  made  ?
 
The  set  , Marconi  Ocean span 1950's  valve  tx   needs  the  big  rock's  as the  oscillator  pass's   quite a  lot  of  power  via them ...hc6u  are  no  good  , drive level is very low - the ones fitted  are the wired- gold  flashed  ones  , so  cannot  etch  into the  band ...
 
the  gang  want  to  keep  it  standard
 
73 -G.
 
Ps  waiting  for  qty-3  £6   dongles : )

From: M0FMT
Sent: Wednesday, April 10, 2013 11:43 PM
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

Hi
 
If you want to spend a small fortune get them cut. However build a Mixer VXO from El cheapo standard xtals and or old PMR rocks. Then at your next rally buy a couple of Screw together 10xj or FT243 rocks of any frequency and put the El-cheapo xtals inside. And Hey Presto you have Retro rocks.
I have a small all valve 472 tx that uses 6.00 -6.472=0.472 vxo-able a couple of kc/s 12ax7-6am6-6cl6= 4wattso/p. Local QRP rig.
Hope this helps
 
73 es GL Pete M0FMT IO91UX
From: Graham mailto:[email protected]
To: [email protected]
Sent: Wednesday, 10 April 2013, 20:30
Subject: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

Wanted  10XJ  or  FT243  XTALS   Range   236.25    236.75  KHz   
 
Q  Is there  any  manufacture  of   crystals  in this  range  ?
 
Or  Surplus    items   available 
 
QTY 1  or  2  off 
 
TNX- Graham
 
G0NBD








-- 
73 de pat g4gvw
es gd dx
qth nr Felixstowe
East Coast UK




-- 
73 de pat g4gvw
es gd dx
qth nr Felixstowe
East Coast UK




-- 
73 de pat g4gvw
es gd dx
qth nr Felixstowe
East Coast UK
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