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

[M0FMT <m0fmt@yahoo.co.uk>]

Graham

 

Been reading the mail on Yahoo.

 

Before you start attacking those xtals its best to find an expert. For these reasons.

 

a/ Crystal grinding is a specialised art. It requires the xtal to be perfectly parallel

b/ If you don't do the full process like grinding, polishing and etching the xtal will "age" and at some point will jump frequency or stop all together.

c/ Etching alone is OK for very small shifts but will attack the edges of the xtal so it won't be flat and it will become less active and again can stop.

 

I am not sure of my facts but if you just grind it creates a condition like when plaster comes away from the wall. The abrasion creates subsurface cracking so it is necessary to etch this away otherwise it will jump or stop.

 

What I am trying to say is that serious xtal grinding needs to be done in the proper process. Granted a small shift can be done. I am sure loads of hams have done it and got away with it but it may pay to find an "Expert" to help.

The local RAF camp at Henlow had a Quartz Xtal manufacturing facility years ago and one of the people there was G4ALR. He doesn't have his e-mail on QRZ but I may be able to get it. I think he is an "expert" in the field.

 

If you like I will chase him for info?

73 es GL Pete M0FMT IO91UX

From: Graham <g8fzk@g8fzk.fsnet.co.uk>
To: rsgb_lf_group@blacksheep.org
Sent: Thursday, 11 April 2013, 19:21
Subject: Re: LF: Wanted 10XJ or FT243 XTALS Range 236.25 236.75 KHz

BOGOF     : ))

From: M0FMT

Sent: Thursday, April 11, 2013 7:17 PM

To: rsgb_lf_group@blacksheep.org

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 <g4gvw@aol.com>
To: rsgb_lf_group@blacksheep.org
Cc: M0FMT <m0fmt@yahoo.co.uk>
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:g4gvw@aol.com
To: rsgb_lf_group@blacksheep.org
Cc: M0FMT mailto:m0fmt@yahoo.co.uk
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:g8fzk@g8fzk.fsnet.co.uk
To: rsgb_lf_group@blacksheep.org
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

To: rsgb_lf_group@blacksheep.org

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:g8fzk@g8fzk.fsnet.co.uk
To: rsgb_lf_group@blacksheep.org
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

To: rsgb_lf_group@blacksheep.org

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:g8fzk@g8fzk.fsnet.co.uk
To: rsgb_lf_group@blacksheep.org
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