Hello guys
I have made some modifications on my ft1000mp: I change FI filters from 2,4khz to 6khz and put the audio mic thru balance modulator using a 220uF cap on pin 5. But the audio is very low, i have some behringer modules and when i use them on path rca conector i have a big audio but on balanced modulator it´s very low !!! What can i do to solve this ???
tks from pp1oz
FT1000MP modulation thru balanced modulator: poor modulation
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Voodoo Guru
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Howdy!!!!
Welcome to the forum,
When you feed the Balanced Modulator (BM) with Audio, the signal has to be of LINE LEVEL.
The input for the RCA Patch input is of Mic Audio and goes to the Mic Amplifiers.
So, when supplying the BM with audio signal, make sure the Audio Output of your Rack equipment is between -6dB to -3dB on voice peaks.
Hope this helps,
Take Care,
Welcome to the forum,
When you feed the Balanced Modulator (BM) with Audio, the signal has to be of LINE LEVEL.
The input for the RCA Patch input is of Mic Audio and goes to the Mic Amplifiers.
So, when supplying the BM with audio signal, make sure the Audio Output of your Rack equipment is between -6dB to -3dB on voice peaks.
Hope this helps,
Take Care,
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm
From Deep in the IDD of the Sub-Harmonix Realm
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Voodoo Guru
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- Joined: Wed Feb 23, 2005 8:47 am
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Voodoo Guru
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Well from what you have listed,
It should be just fine.
Just make sure your gain structure is up to about -6 to -3dB max on voice peaks and this should be more then enough to drive the BM.
Actually, you will usually need an attenuator to reduce the drive somewhat and be able to adjust this for proper ALC.
What are you using to adjust the input gain to the BM?
The only other thing that could be wrong is that you did not install the capacitor correctly.
Did you use W5CUL's Modification instructions to install it?
Take Care,
It should be just fine.
Just make sure your gain structure is up to about -6 to -3dB max on voice peaks and this should be more then enough to drive the BM.
Actually, you will usually need an attenuator to reduce the drive somewhat and be able to adjust this for proper ALC.
What are you using to adjust the input gain to the BM?
The only other thing that could be wrong is that you did not install the capacitor correctly.
Did you use W5CUL's Modification instructions to install it?
Take Care,
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm
From Deep in the IDD of the Sub-Harmonix Realm
gain
Yes, i followed the instructions on pdf file, i put two 220uf caps in serie by connecting their negatives together to make one 110 Mfd non-polar cap direct on pin 5 and the other side on RCA connector. I don´t use adjust input gain yet because i don´t have a significative gain , that is i don´t understand !! even i open all gain of mic 100 i still have poor audio !!
tks
tks
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Voodoo Guru
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We would suspect your installation or the capacitors.
We have not had good luck using 2ea polar caps wired as you said, the sonics were never that good in our opinion.
If you do not have a single Bi-polar capacitor (Panasonic SU series),
Try installing just one capacitor with the Positive lead to Pin 5 of the BM.
See if that does anything
Also, the capacitance that they specify (220uf) is really way too much, 47uf would be more then enough to pass low frequencies as well as reduce the physical size of the capacitor greatly.
Last thing is to double check your wiring.
Be sure that the coax signal lead (center lead) is going to Pin 5 and the shield to the ground plain.
Then the other end of the coax, the center signal lead of the coax will go to the positive capacitor lead and the negative lead to the Center pin of the RCA connector.
Try that out and see what happens.
Take Care,
We have not had good luck using 2ea polar caps wired as you said, the sonics were never that good in our opinion.
If you do not have a single Bi-polar capacitor (Panasonic SU series),
Try installing just one capacitor with the Positive lead to Pin 5 of the BM.
See if that does anything
Also, the capacitance that they specify (220uf) is really way too much, 47uf would be more then enough to pass low frequencies as well as reduce the physical size of the capacitor greatly.
Last thing is to double check your wiring.
Be sure that the coax signal lead (center lead) is going to Pin 5 and the shield to the ground plain.
Then the other end of the coax, the center signal lead of the coax will go to the positive capacitor lead and the negative lead to the Center pin of the RCA connector.
Try that out and see what happens.
Take Care,
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm
From Deep in the IDD of the Sub-Harmonix Realm
tks
I change the cap by 47uf bipolar and check connection on pin 5, it´s all ok, but it´s all the same !!! If someone discover what is happening i appreciate.
For the moment i will use the patch rca connector. Thank you very much for the help guru man !!!
73, pp1oz - mark
For the moment i will use the patch rca connector. Thank you very much for the help guru man !!!
73, pp1oz - mark
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Voodoo Guru
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Hmmm......This is a strange problem for sure.
It sounds like you have double checked everything in the rig so the last thing to suspect is the cable from the Rack gear to the RCA jack.
what kind of cable do you have connected from the Rack to the RCA, and how is it wired? I would suspect this for sure next.
Next time you have the rig open maybe you can take a picture of how you have the wires connected to Pin #5, also of the top of the board where you have the capacitors connected to the RCA jack.
This is just to have a second pair of eyes to look.
Take Care,
It sounds like you have double checked everything in the rig so the last thing to suspect is the cable from the Rack gear to the RCA jack.
what kind of cable do you have connected from the Rack to the RCA, and how is it wired? I would suspect this for sure next.
Next time you have the rig open maybe you can take a picture of how you have the wires connected to Pin #5, also of the top of the board where you have the capacitors connected to the RCA jack.
This is just to have a second pair of eyes to look.
Take Care,
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm
From Deep in the IDD of the Sub-Harmonix Realm
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SeymourDuncan
- Audio Head
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- Joined: Fri Dec 02, 2011 9:47 am
Hi pp1oz, I have a FT-1000MP (NOT A MARK V ! ! !) and modulating the Pin 5 Balanced modulator the result is great.
As you stated you've changed IF filter, could you please describe it better ?
I dunno if I have to change any filter, as I get 2.9 K bandwidth (that's DSP), but if there's any possible enhancement is exactly what I'd want to achieve.
I'm more expert in the audio area rather than the IF part, so I wouldn't buy crappy filters for gainining NOTHING
Many thanks for any good reply.
Is there any doc that relates to FT1000MP (again NOT MARK V that's totally different ??)
Thanks everyone.
As you stated you've changed IF filter, could you please describe it better ?
I dunno if I have to change any filter, as I get 2.9 K bandwidth (that's DSP), but if there's any possible enhancement is exactly what I'd want to achieve.
I'm more expert in the audio area rather than the IF part, so I wouldn't buy crappy filters for gainining NOTHING
Many thanks for any good reply.
Is there any doc that relates to FT1000MP (again NOT MARK V that's totally different ??)
Thanks everyone.
hi seymour
I changed only the 8215khz 2.4khz IF filter by one more wider, i used 6.0khz AM filter. It´s just unsolder one, solder another and do some adjusts on carrier like is described on pdf of ve7rf and w5cul. I had a great results on tx with a wide bw but unfortunatly i could not do the balanced modulator mod yet. Did you follow the tips in pdf to do the BM mod ?? It´s curious i have the same radio (mp) and this mod not worked for me. tks for your reply and 73 !! Excuse me, but my english is very bad !!
I changed only the 8215khz 2.4khz IF filter by one more wider, i used 6.0khz AM filter. It´s just unsolder one, solder another and do some adjusts on carrier like is described on pdf of ve7rf and w5cul. I had a great results on tx with a wide bw but unfortunatly i could not do the balanced modulator mod yet. Did you follow the tips in pdf to do the BM mod ?? It´s curious i have the same radio (mp) and this mod not worked for me. tks for your reply and 73 !! Excuse me, but my english is very bad !!
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SeymourDuncan
- Audio Head
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- Joined: Fri Dec 02, 2011 9:47 am
Hi again pp1oz.
There's something I have never understood. The choice by menu between 2.4 and 6.0 KHz, as the DSP gets only 2.9 KHz to leave the radio.
Changing those filters (2.4K) with 5.8 and 6.0 AM shouldn't affect TX, but again, I'not understanding well....I feel they are ONLY used in RX, no TX passung through....
I made the balanced modulator mod far before the release of that, or other document, since 2001.
I didn't shunt with any 270 resistor to ground, and the line level drives an incredible audio to the Pin 5, more than enough.
Don't be offended, by I don't really understand what you mean by 'poor audio', if it's mattero of level of what...So my qstn: I do hope you sety Menu 7-7 TLSB to OFF, not any 100-3100 or something else, or NO AUDIO AT ALL wil exit.
Have a nice day
/Roberto
There's something I have never understood. The choice by menu between 2.4 and 6.0 KHz, as the DSP gets only 2.9 KHz to leave the radio
.Changing those filters (2.4K) with 5.8 and 6.0 AM shouldn't affect TX, but again, I'not understanding well....I feel they are ONLY used in RX, no TX passung through....
I made the balanced modulator mod far before the release of that, or other document, since 2001.
I didn't shunt with any 270 resistor to ground, and the line level drives an incredible audio to the Pin 5, more than enough.
Don't be offended, by I don't really understand what you mean by 'poor audio', if it's mattero of level of what...So my qstn: I do hope you sety Menu 7-7 TLSB to OFF, not any 100-3100 or something else, or NO AUDIO AT ALL wil exit.
Have a nice day
/Roberto
hello Roberto
When i said "poor audio" i mean the audio was not enough to transmition. I modulated only 5w even with mic gain fully clockwise and about menu 7-7 it was in off position. I´m not concern about it any more. I´m using the pach RCA to input mic audio and receiving good reports. Anyway, thank you for your replies, now i want to solve the noise blanker distortion, i have a lot of power line QRM and when i turn on NB is very difficult to listen strong stations. I found a mod and hope this works. tks again !!!!!!!! 73
When i said "poor audio" i mean the audio was not enough to transmition. I modulated only 5w even with mic gain fully clockwise and about menu 7-7 it was in off position. I´m not concern about it any more. I´m using the pach RCA to input mic audio and receiving good reports. Anyway, thank you for your replies, now i want to solve the noise blanker distortion, i have a lot of power line QRM and when i turn on NB is very difficult to listen strong stations. I found a mod and hope this works. tks again !!!!!!!! 73