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 > Other Discussions > Homebrew Equipment

Notices

Homebrew Equipment A place to show, design and discuss the weird and wonderful electronic creations from the hands of individual members.

Reply
 
Thread Tools
Old 7th Jan 2019, 2:49 pm   #1
Scimitar
Hexode
 
Scimitar's Avatar
 
Join Date: Oct 2015
Location: Gloucestershire, UK.
Posts: 445
Default Amateur radio interfacing

I am struggling a bit with an interface to connect the Yaesu FT-10SR to my Starcom Digital intercom unit on the bike. I have wired it as per the advice I have found so far, but have a ground loop. This is causing a loud alternator whine on the transmitted audio and just background whine on receive.
With testing that I have done so far, I need to isolate the two devices and preliminary tests with a pair of audio transformers worked to deal with the noise.

The issue I have is working out how to trigger the PTT. This works by grounding the two 390K resistors connected to data lines. My idea is to use an opto isolator there as we are only talking picoAmps. The LED in the opto needs to be driven from the Starcom which has no separate PTT output but uses the "single line" method of control. Starcom have been asked for their advice but are unable to disclose the circuit diagram of it. It is clear however that the Starcom must have its own PTT input enabled before any audio will be passed to the RADIO interface connector.

I am still not sure how I can sense the Starcom going into TX mode. Diagrams attached.

Looks like this chap has similar troubles... https://www.st-owners.com/forums/thr...terface.44939/
Attached Thumbnails
Click image for larger version

Name:	IMG_3482.jpg
Views:	44
Size:	51.0 KB
ID:	176078   Click image for larger version

Name:	IMG_3480.jpg
Views:	29
Size:	59.8 KB
ID:	176079   Click image for larger version

Name:	StarComConnectorPinOut.jpg
Views:	22
Size:	64.6 KB
ID:	176080  

Last edited by Scimitar; 7th Jan 2019 at 2:56 pm.
Scimitar is offline   Reply With Quote
Old 7th Jan 2019, 3:46 pm   #2
Scimitar
Hexode
 
Scimitar's Avatar
 
Join Date: Oct 2015
Location: Gloucestershire, UK.
Posts: 445
Default Re: Amateur radio interfacing

The installation on the bike. The panel mounting arrangement is very poor quality, so that is going to rattle about until I can improve it. The base unit is daft also, one hole for mounting hence the sub panel and Velcro mount.

PTT switch in the only place it can go. Only just within reach.

The loose wiring in the under seat area is a pending job. I need to build another interface there to select rider / pillion / both for the BC radio output. 'Indoors doesn't have any interest in being on the bike nowadays so low priority!
Attached Thumbnails
Click image for larger version

Name:	IMG_3486.jpg
Views:	30
Size:	80.9 KB
ID:	176081   Click image for larger version

Name:	IMG_3485.jpg
Views:	28
Size:	86.8 KB
ID:	176082   Click image for larger version

Name:	IMG_3458.jpg
Views:	25
Size:	106.4 KB
ID:	176084   Click image for larger version

Name:	IMG_3471.jpg
Views:	27
Size:	89.4 KB
ID:	176085   Click image for larger version

Name:	IMG_3462.jpg
Views:	22
Size:	50.2 KB
ID:	176086  


Last edited by Scimitar; 7th Jan 2019 at 3:54 pm.
Scimitar is offline   Reply With Quote
Old 7th Jan 2019, 4:18 pm   #3
merlinmaxwell
Dekatron
 
merlinmaxwell's Avatar
 
Join Date: Jul 2008
Location: Maidenhead, Berkshire, UK.
Posts: 8,215
Default Re: Amateur radio interfacing

I tried amateur radio on my bike (FT-857 HF/VHF/UHF with auto tuner) it worked well but I found myself much to busy riding the bike to use it. Did get a contact to south France on 20m one afternoon. I did find that 20W or so of carrier on 430MHz dumps mobile phones used by silly drivers. The 390k looks much too high, 390 ohms more like to 'press' the PTT.
__________________
Cats have staff, it's dogs that have owners.
merlinmaxwell is offline   Reply With Quote
Old 7th Jan 2019, 4:33 pm   #4
Scimitar
Hexode
 
Scimitar's Avatar
 
Join Date: Oct 2015
Location: Gloucestershire, UK.
Posts: 445
Default Re: Amateur radio interfacing

Quote:
Originally Posted by merlinmaxwell View Post
The 390k looks much too high, 390 ohms more like to 'press' the PTT.
That is from Yaesu themselves and it does work fine. It also keeps the current way down. Other Yaesu microphones use a chain of different value resistors to select various functions. Clever idea but I like separate buttons, separate functions so that it makes sense to my declining grey matter.
Scimitar is offline   Reply With Quote
Old 7th Jan 2019, 5:03 pm   #5
merlinmaxwell
Dekatron
 
merlinmaxwell's Avatar
 
Join Date: Jul 2008
Location: Maidenhead, Berkshire, UK.
Posts: 8,215
Default Re: Amateur radio interfacing

Fair enough, I wouldn't use such high values in a motorcycle environment, far to damp. I suppose you are stuck with what Yaesu wants, maybe a relay right next to the radio with the high values there. Is VOX an option?
__________________
Cats have staff, it's dogs that have owners.
merlinmaxwell is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 1:01 pm.


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 - 2018, Paul Stenning.