HFU HF Underground

General Category => General Radio Discussion => Topic started by: Looking-Glass on September 01, 2018, 0632 UTC

Title: ICOM IC-736 lazy 'S' meter...
Post by: Looking-Glass on September 01, 2018, 0632 UTC
Just picked up a secondhand Icom IC-736 HF/50MHz transceiver very cheap, works great and in excellent condition, receives well compared to my other gear, but seems to have a very lazy analogue signal strength meter.

Around four signal units discrepancy compared to the FT-2000D and IC R-75 (which has crappy digital meter I generally ignore.).

No owners manual came with it, so prior to searching for a JPEG version on line, does any of our esteemed group know how to do a 'S' meter calibration? :)
Title: Re: ICOM IC-736 lazy 'S' meter...
Post by: didu heardat on September 01, 2018, 1014 UTC
is the att turned on? if it is turn it off.
http://www.icom.co.jp/world/support/download/manual/pdf/IC-736_738.pdf
Title: Re: ICOM IC-736 lazy 'S' meter...
Post by: Josh on September 01, 2018, 2000 UTC
I'd be looking out for any sensitivity issues, but perhaps it is simply a low reading smeter. Icom often set their hf rigs to read s9 at 14uv with preamp on, and the standard 50uv with the preamp off. You need to determine if the rig is as sensitive as designed and if not, fix it. Anyway, here's a link to mods.dk, join if you're not a member and you can make one dl per day for free, they have the service manual.

https://www.mods.dk/manual.php?brand=icom
Title: Re: ICOM IC-736 lazy 'S' meter...
Post by: Looking-Glass on September 02, 2018, 0252 UTC
"didu hearthat" yep, the attenuator is turned off, after 45 years as a licensed radio amateur I think I would look at that as obvious?  ;D

Josh there is little variation with the pre amp on or off on low bands but a two or three 'S' point gain above 2MHz.  It's hearing quiet well but compared to the other two radio sets on same frequency the 'S' meter is very lethargic, around four units down in comparison. 

I had an IC-736 prior to this one for a number of years and the 'S' meter in that seemed fine.

Otherwise, great little radio as a spare!  Thanks for the link Josh, will have a look at that later. ;)
Title: Re: ICOM IC-736 lazy 'S' meter...
Post by: didu heardat on September 02, 2018, 1058 UTC
you could just use it as is  ;)
here the service manual
http://www.radiomanual.info/schemi/ICOM_HF/IC-736_IC-738_serv.pdf