Title: T-195 tips, suggestions Post by: AA4HA on December 31, 2012, 09:34:03 PM I picked up a T-195 (not A, not B) with a companion R-392 and would like some tips on the T-195 transmitter. I plan on going over the transmitter from top to bottom before firing it up and understand that there are some upgrades/ modifications that can be done. I have the maintenance and operations manuals and went through the theory.
The transmitter and receiver are currently operational so they "should" be in decent shape. I am good with the R-392, I have quite a bit of experience with the R-390 and the R-390A. Does anyone have any guidance to offer? thanks, Tisha, AA4HA Title: Re: T-195 tips, suggestions Post by: WQ9E on January 01, 2013, 09:48:43 AM Tisha,
I have no guidance to offer but please share your impressions about the T-195 once you have it going. I have been tempted several times to acquire one to go with my R-392. If you have not read them already take a look at the ER in Uniform article in Electric Radio for December 1997 and the three part design series in the Sept-Nov 1998 Electric Radio issues. Title: Re: T-195 tips, suggestions Post by: N8ETQ on January 01, 2013, 09:50:39 AM Hi, I had one for a while, they work great as is. Later models had an inverter for the TX HV versus the dynamotor but either one works fine. The TX will load a 20' whip through out it's coverage range however if you have a set of Military Cans on you may get an RF burn on your ear on 160 m. You may want to run the R392 from a seperate 28VDC supply as the TX will really haul down current when the dynamotor starts. GL /Dan Title: Re: T-195 tips, suggestions Post by: AA4HA on January 01, 2013, 10:17:19 AM Dan,
Thank you for your reply. I do plan on running the R-392 off of a separate supply as it would not mind running at 24VDC. I understand that the T-195 prefers a higher voltage (~28VDC) so the auto-tune will work correctly. A few things on my list so far;
Are there component value changes or circuit mods that I should consider? I know that the T-195 is different than the T-195a or T-195b. I have not found anything that explains those differences. I understand that the later revisions draw less current and if I can realize that advantage I would like to do it while the case is open. I am willing to consider all suggestions, thanks, Ms. Tisha Hayes, AA4HA Title: Re: T-195 tips, suggestions Post by: N8ETQ on January 01, 2013, 11:00:17 AM Hey Tisha, Well the only thing you can do to keep the Current and noise down is try to find the SS HV supply. They look exactly like the dynamotor and it was a plug and play swap. Keep your dynamotor however as the SS thing is pretty much unrepairable since all the components are sealed in with some sort of "Goo". As I recall they sounded pretty good in "RELAY" mode since that bypassed the Carbon Mic speech amp. They used to feed line level audio in to that. Here's a pix of mine prolly circa 1990 or so. I still have a TX/RX mount in my garage I picked up somewhere you can have it if you need it. The only complaint I ever had about the thing was the noise. Mine also had the HV Dynamotor. 73 /Dan Title: Re: T-195 tips, suggestions Post by: KA3EKH on January 01, 2013, 12:54:37 PM The start up current requirements for the transmitter can be an issue, your going to need a huge power supply. The newer versions of the 195 had the solid state inverters that were a direct replacement for the two dynamotors and were not quite as bad as the dynamotor version. The only dynamotor version I have seen in operation required a set of car batteries in line with the power supply in order to get it started. The auto tune system is a thing of beauty when working but sometimes fails and you have to let the radio try to tune again. I have my old M151A1 out in the garage and have thought about building up a GRC-19 (R-392/T-195) and stuffing it on the back but have decided that if anything will go with a newer set maybe something like a GRC-106 or one of my newer Harris sets being they are smaller, lighter and for me easy to work on, good luck and start rounding up heavy gauge wire and lots of 28 volts.
Title: Re: T-195 tips, suggestions Post by: AA4HA on January 01, 2013, 02:31:15 PM I am going to keep an eye out for the solid state inverter for the 1000 VDC supply. If I cannot find one I may make my own, just getting 500 mA at that voltage is going to be challenging while keeping it in the form-factor of the dynamotor space.
I already have a pretty stout 27.3 VDC bus setup for the other mil gear I operate. It is a 225 A/Hr battery bank with a 50A switching supply to keep things charged up and peaked up. Title: Re: T-195 tips, suggestions Post by: N8ETQ on January 01, 2013, 06:59:47 PM Set "Way Back On", I think the LV dyno supplied the 400cy AC for the tune motors.. Brain Clogged pretty gud about Now.. /Dan Title: Re: T-195 tips, suggestions Post by: N8ETQ on January 01, 2013, 07:33:33 PM Posted by: KA3EKH "The start up current requirements for the transmitter can be an issue, your going to need a huge power supply. " Hey Man, That may be the first "Understatement of the year" for 2013!! I had 2 X 28VDC Lamda supplies 30A each. Had to disable the Over Current thing on both of em.. Pretty "Manly" radio there Trisha, I think you'll be Ok. /Dan Pix of my "New" dog Mort. She is standing on the front fender of my Bud's M35A3 duece and a half scanning the tree line for pesky tree rats.. The start up current requirements for the transmitter can be an issue, your going to need a huge power supply. The newer versions of the 195 had the solid state inverters that were a direct replacement for the two dynamotors and were not quite as bad as the dynamotor version. The only dynamotor version I have seen in operation required a set of car batteries in line with the power supply in order to get it started. The auto tune system is a thing of beauty when working but sometimes fails and you have to let the radio try to tune again. I have my old M151A1 out in the garage and have thought about building up a GRC-19 (R-392/T-195) and stuffing it on the back but have decided that if anything will go with a newer set maybe something like a GRC-106 or one of my newer Harris sets being they are smaller, lighter and for me easy to work on, good luck and start rounding up heavy gauge wire and lots of 28 volts. |