Icom IC-718 to 3.3 wide... Experment Time

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Bow
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Icom IC-718 to 3.3 wide... Experment Time

Post by Bow »

I could be a hero...


I could be a Zero...

Follow this line of thought...

I already have the ICOM FL-257 Optional Filter installed for RX at 3.3 khz wide.

Using these guy's logic...

http://www.w4wb.com/Manuals/OBF_IC-718_Manual.pdf

1. I removed the stock Murata filter that "keeps da man down" to a 2.4 khz TX Bandwidth.

2. I unsoldered the signal pins on my FL-257 and isolated them from the board, but left the FL-257 sitting in the Optional Filter slot. Ohmed it to check for proper isolation.

3. I jumpered the signal pins on the FL-257 to the signal holes for the stock Murata filter.

4. I replaced the entire board into the Radio, powered up, everything checks cool ( I can't TX, I'm at work)

5. I went into the menu setting and turned off my "Optional Filter".

6. Just turning the Radio on, I get static through the speaker, selecting the "wide Filter" that isn't actually there, I get wider static audio freqs (Selecting the wide filter, with nothing in there give 6khz RX bandwidth)



SOOOOO...

Think it will work?!?!?!?!!?

3.3 Khz TX audio bandwidth from a rewired ICOM FL-257 Optional filter....
Bow


Quite possibilly the only 3.3 Khz wide Icom IC-718 in the world...

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Post by Voodoo Guru »

We thinks it will work!!!!
Great to hear ya on the air last night.
Now to find out from Mr. Icon if there is a manual Carrier Point setting......hmmmmmmm.
It's good that you thought about the rewire as you did, trick setup!!!
Let us know yer progress Bow!
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Post by Bow »

Thanks Mike,

Yeah.. I just gotta remember to tell them that:

My USB carrier point is good all of my 3.3 kHz on the USB

My LSB is only 3.1 kHz with 200hz bleeding into the USB

and that this was checked after setting up the filters as per the Service Manual
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Post by Bow »

Nope.. No manual adjustments for the carrier....

and it seems that the guy I ended up talking to at Icom today (not the same guy I talked to Friday) is not a fan of Hi-Fi SSB...

:lol:

He told me "You know the FCC is about to pass rules to keep you guys from doing that type of thing, right?"

I said "Yeah, the Jackbooted, personal agenda pushing ARRL is making sure that their little Pactor-bots can take over the HF spectrum, but real amatuers can't experiment anymore..."


He didn't like that....

:roll:
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Post by Voodoo Guru »

Pughhhh..... :roll:

Well, so much for that.
Well 3.1 is better then 2.1!! :lol:

Yea, I bet He didn't like that! :evil:
Good for him to hear it though.
At least He knows there are other ideas out there.
like...VOODOOOOOOOOO for the Masses!!!!! :twisted:
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Post by Bow »

wz5q wrote:Pughhhh..... :roll:

Well, so much for that.
Well 3.1 is better then 2.1!! :lol:
So I'm guessing that the 200 hz that is heading on the north side of my Lower side band isn't a problem?
Yea, I bet He didn't like that! :evil:
Good for him to hear it though.
At least He knows there are other ideas out there.
like...VOODOOOOOOOOO for the Masses!!!!! :twisted:
Yeah, he is a bean head..

Let the digital fookers run all over, but God forbid someone run 3.0 to 4.0 khz of decent sounding sideband...
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Post by w5cul »

Bow, I would try and contact your favorable ICOM Tech again. I think the other pinhead you talked to gave you a line of crap, or just plain doesn't know how to do it. If you do not have independent settings for LSB/USB, then there must be one setting that affects both sidebands. In that case, then there should be a way, either a manual physical tweak or a hidden menu tweak, that would affect the combined LSB/USB carrier set point. Now it may not be the actual carrier set point itself, but maybe one of the IF freqs can be adjusted to balance it out. In fact, if you have a freq counter or a spectrum analyzer, I would check out your local oscillators and all used derivatives and see where they sit. Keep in mind these things are analog, thus can swing some amount of +/- value and still be in spec. However, too much on one side could affect either the LSB or USB carrier set point. I hope this makes sense.

Take care,

Mike
W5CUL

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Post by Bow »

I was thinking about doing that Mike, I was going to try today, but I got too busy.

I'll try to talk to the same guy, someone a bit more "forward thinkng."

:roll:
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Post by SawzAll »

I've got a IC-718 as well. So, I am quite interested in what you have done - Bow.

Quite possibly, I may be the second person to mod my 718 for a 3.1 wide SSB - if I can get some more details first!

Q's:

1) So - you removed the stock filter and then turned on the fl-257 after you turned on the rig. Is there any way to wire the fl-257 where the stock Murata filter was?

2) Did you -after all- have to adjust anything inside the radio after installing and removing a filter?

3) Can one use the aux mic input -on the rear of the IC-718 radio- to bypass the radio's mic preamp - just like it is done on the Icom 746 and 756 series?

4) Like most Icoms, there is a +8v that has to be eliminated in the mic preamp so that damage doesn't occur. The Heil cable has a capacitor wired into the cable to prevent radio damage due to the presence of this +8v if using the front mic plug. Does going thru the rear mic input bypass the need for this capacitor as well? Or is there a +8v there as well? I would think it would, but I thought I would mention it to be sure - and not leave a stone unturned for someone else that may have an Icom and be wondering the same things.

I sent a note to W2IHY and asked some questions about their 'iBox'.
Apparently, they said that it is NOT a 12:1 transformer.

*SO where can I find a dedicated 12:1 audio transformer to get the best audio?

*OR - will any direct box with an audio transformer work as well?

:?: :?: :?:

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Post by Bow »

SawzAll wrote:I've got a IC-718 as well. So, I am quite interested in what you have done - Bow.

Quite possibly, I may be the second person to mod my 718 for a 3.1 wide SSB - if I can get some more details first!

Q's:

1) So - you removed the stock filter and then turned on the fl-257 after you turned on the rig. Is there any way to wire the fl-257 where the stock Murata filter was?
You install the New filter in the optional filter slot
Remove the stock filter
Hard wire from the stock filter holes over to the optional filter
2) Did you -after all- have to adjust anything inside the radio after installing and removing a filter?
Nope, fire it up and go.
We discovered on-air that the carrier set point is a bit off on LSB, but the 718 has no adjustment for it.
3) Can one use the aux mic input -on the rear of the IC-718 radio- to bypass the radio's mic preamp - just like it is done on the Icom 746 and 756 series?
Yup, that is how I've always run this radio, I've never even hooked up to the front mic connector
4) Like most Icoms, there is a +8v that has to be eliminated in the mic preamp so that damage doesn't occur. The Heil cable has a capacitor wired into the cable to prevent radio damage due to the presence of this +8v if using the front mic plug. Does going thru the rear mic input bypass the need for this capacitor as well? Or is there a +8v there as well? I would think it would, but I thought I would mention it to be sure - and not leave a stone unturned for someone else that may have an Icom and be wondering the same things.
There is no problems with this on the ACC jack in the rear. If you run through the front Mic jack, the mic preamp filtering in the radio will negate all the audio you are trying to push through the radio, the rear ACC jack bypasses all the junk
I sent a note to W2IHY and asked some questions about their 'iBox'.
Apparently, they said that it is NOT a 12:1 transformer.

*SO where can I find a dedicated 12:1 audio transformer to get the best audio?

*OR - will any direct box with an audio transformer work as well?

:?: :?: :?:
the rear jack takes a line level input, I pump the audio into the ACC jack straight outta my Mixer outputs
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Post by SawzAll »

I appreciate all of your insights on this radio, Bow. I also saw your post on the WWRF too. Seems that the IC-718 can be a Mid-Fi contender, and you have proved it so.

In the mean time, I have also acquired a Kenwood TS-2000 and a Flexradio SDR-1000. These is a lot of shuffling around the shack here, as well as putting up an Alpha Delta DX-CC. That is my current project.

Thanks for the reply.

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Post by Bow »

SawzAll wrote:I appreciate all of your insights on this radio, Bow. I also saw your post on the WWRF too. Seems that the IC-718 can be a Mid-Fi contender, and you have proved it so.

In the mean time, I have also acquired a Kenwood TS-2000 and a Flexradio SDR-1000. These is a lot of shuffling around the shack here, as well as putting up an Alpha Delta DX-CC. That is my current project.

Thanks for the reply.
Sure thing.
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Post by AD7VH »

Actually, I am working on a way to fix the carrier point shift problem. I think that I may have the solution, but I am not going to post anything about it until I am sure that I have it working correctly.

I am using an Inrad 3.1kHz filter, which I have the same problem with it clipping off the low-end of the audio on LSB; curiously, it's not doing it on USB. Once I have the solution to the problem, I will post my findings.

Oh, and actually, I am probably the 2nd person to do the ESSB mod on the IC-718; did it back in Jan '09.

73, John, NV6R, east central Nevada

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Post by Voodoo Guru »

Excellent!!!!!

It's good to know that there are Maniacal Madmen out there that are not afraid to Violate the Virginity of their unsuspecting & innocent radios!

MOOHOOOHAAAhahahahaha...............
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A little help with the 3.3 filter in the Icom 718

Post by w4cox »

I have the Icom FL-257 and want to do this modification. I am pretty sure I understand everything except for identifying the "signal pins" on this filter. The pins on the 3.3 filter are marked 1 through 4. Could you tell me which ones are the signal pins?
Also, by isolating these pins while the 3.3 filter sits in the optional slot, what was done to isolate them?
My understanding of this mod as it is written is this;
Remove the original filter, install the optional filter in it's stock location. Isolate and identify the signal pins and connect these 2 pins to the empty holes left by the Murata filter. Re-install the board and all the connections.
Is this correct or have i missed something. Thank you for any assistance you can provide. The radio is apart and ready to be modified.
Many thanks,
Mitch

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