UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Amateur and Military Radio

Notices

Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

Reply
 
Thread Tools
Old 13th Nov 2019, 10:37 pm   #1
neutronic
Pentode
 
neutronic's Avatar
 
Join Date: Oct 2009
Location: Bergen, North Holland, The Netherlands
Posts: 154
Default Barlow Wadley alignment

I recently acquired a Barlow Wadley radio XCR-30 ,old and butchered and with a remarkable lot of holes drilled in the housing.
It works, but probably needs some adjustments.By example;Radio Caroline is received at 1648 kHz instead of 648 kHz.
I have a service manual with I think the correct alignment procedure.
But that is somehow confusing,because it tells me to keep the front panel on,while the adjusting coil L3 can only be reached from behind this front panel.
Has anyone some experience with aligning this old portable?
Jard N.
Attached Thumbnails
Click image for larger version

Name:	textbarlow.jpg
Views:	41
Size:	109.9 KB
ID:	193677  
neutronic is offline   Reply With Quote
Old 13th Nov 2019, 11:23 pm   #2
Craig Sawyers
Nonode
 
Craig Sawyers's Avatar
 
Join Date: Nov 2010
Location: Oxford, UK.
Posts: 2,084
Default Re: Barlow Wadley alignment

I'm not sure of the configuration of this set and how the bandpass filters are arranged in detail. However the Racal RA17, which also uses a Wadley loop, is a sod to align and needs a wobbulator to set the filters up.

Craig
Craig Sawyers is offline   Reply With Quote
Old 14th Nov 2019, 12:11 am   #3
Argus25
Nonode
 
Argus25's Avatar
 
Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,557
Default Re: Barlow Wadley alignment

Before attempting alignment or adjustment of any kind on the XCR-30 it is important to thoroughly understand the operation of the "Loop" (actually a mild misnomer, its a feed forward compensation system, not a typical loop of feedback).

I found the existing description of it totally sub-optimal and the method to set up the AGC defective. So I wrote my own article to explain the loop and how to set up the AGC.

Much of the other alignment instructions are "ok" but you require excellent lab gear generators & scope to do it properly. It is much more involved than a normal radio's alignment if you want perfect results from it. I have never yet found a single XCR-30 in perfect alignment. Many have been twiddled where the technician had no clue what they doing.

If you study this document it will help you:

http://worldphaco.com/uploads/THE_AM...LEY_XCR-30.pdf

Hugo.
Argus25 is offline   Reply With Quote
Old 14th Nov 2019, 11:35 am   #4
neutronic
Pentode
 
neutronic's Avatar
 
Join Date: Oct 2009
Location: Bergen, North Holland, The Netherlands
Posts: 154
Default Re: Barlow Wadley alignment

Thanks for your response Hugo,I already had your article printed out.
Test equipment nor experience should be the problem.
I ought to have both.

My concern is that the manual was written without feedback from practice.
By example;in the same script they tell you to set the fully opened capacitor to 0 MHz.
But then you do not get an equal of overtravel at both ends of the scale.
It is either way: or the thumbwheel is stopped by itīs mechanical endstops or by the maximum opening of the tuning capacitor.
Best wishes
Jard N.
neutronic is offline   Reply With Quote
Old 14th Nov 2019, 11:42 am   #5
Argus25
Nonode
 
Argus25's Avatar
 
Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,557
Default Re: Barlow Wadley alignment

Quote:
Originally Posted by neutronic View Post

My concern is that the manual was written without feedback from practice.

Jard N.
Often is the case , especially with alignment instructions where there are both electrical and mechanical alignment issues which interact that you have to contend with.

If you understand the design though, you can see what the designer intended, then its apparent what to do.
Argus25 is offline   Reply With Quote
Old 14th Nov 2019, 1:03 pm   #6
Radio Wrangler
Dekatron
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 12,726
Default Re: Barlow Wadley alignment

Quote:
Originally Posted by neutronic View Post
It works, but probably needs some adjustments.By example;Radio Caroline is received at 1648 kHz instead of 648 kHz.
Jard N.
Experience of RA17, RA117, RA1217 and FRG7.

That could simply be mis-adjustment of the first LO, the high frequency one versus its scale. You need to see how far out it is at the top end of its scale as well as the bottom.

Don't touch the filters yet. You may not need to touch them.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 3:02 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.