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Mayor513
Junior Member
Username: Mayor513
Post Number: 46
Registered: 3-2002
| | Posted on Saturday, March 18, 2006 - 3:50 pm: | 
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--Hi, all. I took my radio (a General Sherman, which is a clone of Texas Ranger TR-296, old style Cobra 148/Grant XL) to a local tech to have my clarifier unlocked and to adjust my output yesterday. Well, he said he couldn't do anything to it because he didn't have any books on it (yeah, I told him it was the same as the TR-296, etc.). I can live without having my clarifier unlocked (would be nice to get those few inbetween channels, though), but I would like to have some "forward swing" to my power output.
--Just for fun, I opened my radio to see what the AM power would do. Well, the VR is as far as it will turn from the factory at 4 watts, and when turned all the way down, it runs about a half a watt, haha. I mainly want a bit more power so my amp will have a tad more output power. My modulation seems to be okay, and I do NOT want any limiters cut (don't wanna splatter). I would love for this radio to key up at say, 4 or 5 watts (or some appropriate amount, whatever that might be) carrier and "swing" to an appropriate amount (whatever that might be) to be used in conjunction with my Texas Star DX350HDV high drive amplifier. If I remember correctly, that amp will take as much as 20 watts.
--My radio pretty much just sits at four watts when I speak into the microphone. So, how would one go about getting a little bit of forward swing to help drive my new amp? Thanks for your help. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2579
Registered: 7-2004
| | Posted on Saturday, March 18, 2006 - 7:39 pm: |
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http://www.copperelectronics.com/cgi-bin/discus4/show.cgi?tpc=34&post=90428#POST90428
mayor, start with that link. if i remember, it has MOST of the mods that work on your sherman, but not all, there are a few more.
your dx350 will probably see LITTLE, IF ANY difference, dead key or swing, from inputting 3 watts or 8 watts dead key, 10 watts swing or 20 watts swing. your sherman should EASILY modify to 12 watts PEP, & with more involved modding, do 18 or more PEP. if it does 4 or 5 dead key now, you're fine with that, if anything it would need to be lowered, or put on a variable control. for some more swing right now, you need to turn the AMC's VR(for AM), & the ALC for SSB. those 2 controls alone, without any 'mods', should show 8 or more watts swing on AM. (what kind of meter are you reading this on??? if it is a meter with a switch for 'peak' or 'PEP' & only works when 12 volts is applied, that is the 8 watts & 18+ watts i am referring to. if the meter is 'avg' or 'rms' only, or has no external power source required, 50-60% of 8 & 18 is the swing you'll most likely be able to obtain. figures given are approximates). with a true PEP meter, when you get 60-75 watts dead key & 250 PEP swing from the dx350, you are at MAX. no matter what it takes from the radio to get it. anything less then doubling your output will not be noticeable on the other end, so don't waste your time, or risk destruction of property for 25 or even 50 watts of swing with that amp  |
Mayor513
Junior Member
Username: Mayor513
Post Number: 47
Registered: 3-2002
| | Posted on Sunday, March 19, 2006 - 12:08 pm: |
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--Thanks Patzerozero. I am not using a peak reading wattmeter...it is a Para Dynamics PDC-8. I have always heard that a NON peak reading meter would not be accurate when reading PEP, but when I keyed the microphone, I figure the meter should at least read a little bit of forward swing, accurate or not. The VR inside my radio is turned up as far as it will go (it came from the factory turned up all the way) and the radios carrier is only 4 watts. Now, turning it down is no problem at all...when I turn the VR all the way down, it reads less than one watt. If indeed 60-75 watts maximum is what I should get from dead key with this amp, my PDC-8 meter seems to be fairly accurate. With the variable knob on the amplifier ALMOST all the way clockwise, it is showing 50 watts carrier. Unfortunately, the PDC-8 meter will only go up to 50, haha. I turned down the variable power output on the amp to around 25 watts hoping to see what, if any, forward swing I could get, but the meter swung backwards just a bit...maybe to 22 watts give or take.
--I would just love to have what you stated above, and what I read in another post...60 watts carrier, and 240-250 watts PEP, but my meter is just showing no forward swing whatsoever (backwards, just a hair).
--Looking at the light that is on my amp, when I key up the radio, the amp light stays at a certain brightness, but when I speak into the microphone, the light gets brighter, leading me to believe I am drawing LESS current (If I had any forward swing, I would think that the light would dim a little bit, drawing more amps)
--I think what I will do right now, is just turn the radio down to 2 watts or so. Not that 4 watts is a strain on the radio, haha, I just figure the people on the other end won't be able to tell a difference anyway. Thanks for your help. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2586
Registered: 7-2004
| | Posted on Sunday, March 19, 2006 - 8:17 pm: |
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never used a PDC8, mayor, but, if you're gonna play radio & use amps, i'd say to search out a meter that at least handles 1000 watts, a DC-powered PEP reading meter would be nice, but RMS/AVG will work too. RMS swing on the dx350 should be around 120-150. you can't accurately tell what's going on if you can't see the 'full scale' of things.
the last sherman i did keyed just under 4 & swung about 5 RMS, on the 30 watt scale on my diamond SX100. a mild tune, not going NPC-RC route, ended with 1-5 variable, & 15 PEP/almost 9 RMS swing(more wild modding MAY get 20+ PEP/12+ RMS swing). it keyed my davemade the same as my XL, & PEP swing was MAYBE 100 watts less. hardly enough difference to notice.
does the meter on the amp swing backwards as well as on the external meter? the light getting BRIGHTER during modulation could be a sign of a high SWR-have you checked 'em? or even decent SWR with a high reflect. try a 6' or even longer jumper from radio to amp-especially if the one you are using is shorter then 3'.
turning down the radio to 2 watts should show forward swing if you're overdriving it. also, did you turn the AMC/ALC? how does swing compare AM vs SSB? again, though, i'd say to go easy til you have a decent meter in line. if it's off, you could be dumping more then 4 watts into the amp, hence the reverse swing. (the high drive texas stars will show the same dead key out, with 4-10 in, unlike a custom high drive which will show output corresponding to input). |
Mayor513
Junior Member
Username: Mayor513
Post Number: 48
Registered: 3-2002
| | Posted on Sunday, March 19, 2006 - 9:50 pm: |
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--Hi, Pat. I am actually thinking of ordering one of those Autek WM1 meters. I have heard they are extremely accurate.
--The external watt/swr meter is the only thing that swings backward. The small meter on the radio and the meter on the amp both swing a fairly good amount. I've checked my SWR with both the PDC8 meter and the one built into the Sherman and they both register virtually the same, 1.2:1 or so. I also checked it with my Kenwood TS-2000 and it registers about the same as well. I only adjusted the AM output (to 2 watts or so) and did not adjust the SSB output. Though the meter is probably not super accurate, the SSB power when I go "ahhh" reads about 12-16 watts.
--Right now I run the amp. between 40-50 watts carrier. Oh yeah, I also have a small 9 inch fan blowing on the heat sinks as well. I like the looks of my TS350HDV, and I have gotten good audio reports, etc., but why Texas Star chose to put heat sinks underneath their amps is beyond me! One last thing, though. Friday night, somebody said my signal had forward swing to it on their S-meter, so maybe all is not lost. Thanks again! |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2590
Registered: 7-2004
| | Posted on Monday, March 20, 2006 - 6:21 pm: |
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the autek is a real NICE meter!!! go for it!!
i think you may just be getting false readings from the PDC, it just doesn't read enough watts & you're overloading it. 12-16 is about right for SSB, & if the amp's meter shows forward-it probably is! same with another station saying you are swinging forward, i wouldn't worry about it til you get another meter.
as for fins on the bottom, they figured you were going to use the bracket & mount it under the dashboard.... |
Paganville
New member
Username: Paganville
Post Number: 7
Registered: 2-2006
| | Posted on Monday, March 20, 2006 - 11:29 pm: |
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Mayor513
I believe we got our GS radios at app the same time...I have been trying differen't things that I have found on this forum...I like the diode changes D1 D2 D21 D22...but the biggest RX change was changing the TR14 to a 2sc2999...I've got AM recieving pretty good, SSB is not so hot, but I have not worked with it very much yet... I don't plan on doing any freq mods right now...just want to get the swing a little better...mine came from the factory like yours..the dead key was maxed out, but that was only 3.5w...it swings pep about 9.5w...SSB pep is app 19w...still trying to decide what to try...I just went up and read Pat00's post about turning the DK down to 2w to see if that helped with forward swing, but when I do that the amount of swing stays about the same...in other words it drops proportionally to the lower DK...BTW after reading hours and hours over the last few weeks on this forum (archives)there are several people on here that seem to know their stuff...two of them I really believe are on the money with there advice and when I come across an idea presented about whatever subject I try to find out what they think either from the archives or I just wait to see their post concerning the idea...Pat00 and tech808 Thanks guys for all your input..now back to the subject at hand, I also think the factory mic is suspect...I have a couple of mobile mikes I could rewire, but have not done that yet..I was supprised at what I found inside the head of the GS mic...I think a good mic might change what we are seeing on the meters...and speaking of that about a week ago I recieved my new Autek WM1 meter...I like it..still getting use to the numbers I am seeing...too many years with the cheap Radio Shack meters I guess ha..anyway I should quit babbling and let someone else that can offer more help than me take up the post space...it just seems we are on very similar roads right now with the equipment we are working with...BTW my base antenna is a M400 SD...don't have it very high yet and may leave it low and put a small beam up high for the distance talking...still in a time of decision on all this radio STUFF!! |
Mayor513
Member
Username: Mayor513
Post Number: 52
Registered: 3-2002
| | Posted on Tuesday, March 21, 2006 - 12:52 am: |
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--Hi, Paganville. Well, I don't plan on messing with that radio anymore until I get my Autek WM1 meter. I ordered it late last night, and they said it would ship tomorrow, so hopefully I will love this meter. Can't wait. |
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