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Mtn_man_754
New member
Username: Mtn_man_754
Post Number: 7
Registered: 2-2007
| | Posted on Sunday, February 18, 2007 - 12:40 am: | 
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Why do these radios have an extra cap- 560 p directly connected from emitter to base on the finals? Are they for audio , power ?? The 2517 doesent have these caps its a duel final radio -a base, but still basically the same final section components. And the dual final mod doesent mention anything about these either.. Why couldnt a single final radio have this cap ?
Ohh if you see something streaking thru the sky- dont worry its my RCI 6900f 150 that i winged out the window
Maybe i expected too much from this radio that only swings to 120 or so.. Any tips on how to get more from this soon to be streak in the sky?? |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2400
Registered: 9-2004
| | Posted on Sunday, February 18, 2007 - 5:51 pm: |
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the cap is for biasing or for negative feedback.
you would probably find that if you had 20 of these radios in front of you, that 17 of them had the cap and 3 didnt.
its just one of those variables that you cant account for until the actual radio is built.
dont remove it.
as for the radio, i have been looking around at some info on your chassis, and i agree that you should be seeing more than 120 watts out of it.
it has 2X2290's in it, and that should get you up to 180-200 watts if tuned right.
i do not think the radio is a lemon, it just needs a proper tune up, and maybe there are some other issues not related to the radio itself.
first, what kind of power supply are you running this radio on?
if it is less than a 35 amp power supply, you are not going to see the high output because the radio simply cant get enough juice from the supply to do its thing.
second, what kind of wattmeter are you reading?
is it the one in the radio?
if so, do not trust it at all. it is merely a referrence for you to see if something has changed.
it is in NO WAY meant to correspond to actual numbers.
how is your SWR, and what kind of antenna system are you running this radio into?
(be detailed)
and last, but by no means least;
understand that this is a 10 meter radio and has been tuned for the freq. range of 28-29.7mhz.
whats that you say? you had the radio converted and tuned up when you bought it?
well, sort of.
when they convert your radio to the lower freq. range, they only turn a couple of adjustments, if any.
an alignment takes time, like an hour. they simply do not have the time to align these radios properly after conversion, so what you get is a radio that will operate on 27.185 but is peaked for 28.585.
this would account for your lower numbers.
this may or may not be the case with your radio.
try this test.
you must have dummy load as it is very rude and illegal to transmit in the 28mhz range.
check the watts out at about 28.5 mhz.
is the output greater?
if so, this is one of your issues, and you need a proper alignment. not a peak and tune, and the shop MUST have an oscilloscope and know how to use it.
if the output is the same across the whole range of the radio, then i would suspect one of the other possibilities.
please post your answers to my questions here, im interested to see what you come up with.
good luck,
matt |
Mtn_man_754
New member
Username: Mtn_man_754
Post Number: 8
Registered: 2-2007
| | Posted on Sunday, February 18, 2007 - 10:22 pm: |
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My power supply is a brand new alinco 32 amp The radio only draws 23 amps with a 140 dead key.. Im using a mfj 969 tuner it has a watt meter up to 300 watts. peak meter reading too.
watts are near the same on 28.5
Antron 99 antenna tip 60 feet high , I cant get the swr to 1-1 its about 1.6 - 1 on 28 mhz-- 27 mhz its 1-1
I didnt have the radio alligned when i bought it. Im sure that is the problem Thanks Matt |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2407
Registered: 9-2004
| | Posted on Tuesday, February 20, 2007 - 12:44 am: |
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well, i was kinda hoping that your response would be that the watts were higher at 28mhz.
sounds like you have a great setup there!
the difference between 1.1 and 1.6 SWR is nothing to even bat an eyelash at.
regardless of any problems with a radio, having an alignment done the right way will make a positive difference, and also gives you a true referrence for what "correct operation" really is.
remember when looking for a shop, to find one that makes their money fixing radios, not selling them.
you dont want a "peak and tune" or a "whackpak" or anything like that. you want an alignment. nothing less.
when you get the radio aligned; make sure you tell them what freqs. you use most so they can tailor the alignment to that portion of the band.
aside from the alignment, i noticed you said you were using an antenna tuner.
is it actually tuning the antenna, or just reading out the watts?
like, is there a "tuner bypass" or something like that?
what is your SWR without the tuner inline?
what is the SWR from the radio to the tuner?
do you have another SWR/wattmeter to referrence against the tuner?
as in, take the tuner out of line and check the readings on a different meter.
tell me a bit about how you use the tuner.
sorry we havent figured this out yet, but these things take time.
matt |
Mtn_man_754
Junior Member
Username: Mtn_man_754
Post Number: 10
Registered: 2-2007
| | Posted on Wednesday, February 21, 2007 - 9:15 pm: |
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I am using a mfj 969 tuner -with the bypass on with a 90 watt dead key it swings 120 and the swr is 1.7 on channal 1 and 1.4 on channel 40 i use the transmitter knob first if that doesent get it to zero i use the antenna knob. and possibly the big knob to the right I dont kow the swr from the radio to the tuner never heard of that |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2411
Registered: 9-2004
| | Posted on Friday, February 23, 2007 - 12:05 am: |
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well, im starting to think that the MFJ is your problem. IF you really have a problem.
when i said that the 2x2290 amp should get you 200 watts PEP, i was referring to most 2x2290 amps that are on the market these days.
coppers ad for this radio says 100 watts PEP, and you and i both know that in advertising, they ALWAYS round up instead of down.
if this radio could do 200 watts, they would say so in the ad. they would probably even say so if it couldnt really do 200 watts.
this leads me to believe that the amp in this radio is designed a bit different than the comperable stand alone amp.
you should be going for a 4 to 1 ratio with regard to modulation versus deadkey.
30 watt dead key to 120 watt PEP. etc...
you do not need that antenna tuner, and im guessing that you are only using it for the wattmeter function.
make certain that you are not using the built in 4 to 1 balun.
if the wattmeter works with the tuner off, i would leave it off.
do your readings vary between your antenna and the dummy load position?
the SWR going into the tuner can be read on the radio's SWR meter.
later,
matt |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2412
Registered: 9-2004
| | Posted on Friday, February 23, 2007 - 12:12 am: |
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im really starting to think that this radio is only capable of the wattage you are describing.
just to make sure you are getting maximum modulation out of it; VR17 is the modulation control.
try turning it up and see if you get any more peak watts.
sorry we couldnt get the power up any more.
i still think the alignment will be beneficial.
best of luck to ya,
matt |
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