I am having little Voodoo Audio thoughts in my head, so I send them an Email....
I have an Icom IC-718 and was looking at your 1 board filter modifications.
If I install an OBF-718 with the SSB and CW filters, replacing the stock MuRata filter, my transmit audio bandwith will be increased in SSB mode, correct?
I know the stock MuRata filter is only good for around 2.1khz at -6db. So installing the 2.3 Khz filter will increase my transmit to 2.3 khz. Am I correct in this thinking?
Here is the reply.....
The MuRata has wide skirts. I suggest that you look at the paper by K9QI http://www.w4wb.com/Reviews/QQ-Oct-01-Filter-Review.pdf Issue is more about how well you can be understood and talk power. The lows muddy your voice and the real high don't carry a lot of intelligence. The Collins filter makes it a lot better.
73 de ****
I think he didn't really HEAR what I was asking...
But if I can figure out what he does on those boards, I can build my own...
Bow
Quite possibilly the only 3.3 Khz wide Icom IC-718 in the world...
Boy is he WRONG!!!---"Highs don't carry alot of INTELLIGENCE"....Is he deaf???!!! higher frequencies definitely makes things more INTELLIGIBLE, it's been proven time and time again.
Sounds like he's not one who is in support of the practice of ESSB. You have to be wary of the way in which you inquire about products from venders / manufactures when it comes to using their products other than the way it was intended use is for. They usually "shoot-down" the idea before you get the opportunity to pull out the credit card, even though IT'S YOUR MOOLAH.
!kant is right on there.
You really need to watch how you ask questions to some companies.
We read his response, and don't think it was an attack directly at ESSB.
That was just his personal opinion on audio.
But of course He is definitely in error on his statement about the lows and highs.
We think he was referring to the wide skirts of the Murrata, they really let the lows and highs blow threw rather easily, as compared to the steep skirts of the Collins.
He evidently doesn't like the lows and highs and loves Duty Cycle so the Collins is his choice with a narrower ultimate bandwidth probably packed with Talk Power Midrange Audio Frequencies.
He just didn't understand your question.
Well....the Answer is yes, you are correct in your thinking.
Up to a point.
The skirts have allot to do with it like he said, but the loose skirts work to our favor.
For 2.3Kc bandwidth, We would say absolutely no problem.
You might be able to get good opposite sideband suppression up to about 3kc if the Carrier Point can swing that far.
Anything over that bandwidth, you will begin to Transmit Double Sideband.
As far as what he is doing on the boards,
It's simple.....nothing.
All he is doing is relocating the physical position of the filters in order to be able to put the larger Collins in there.
The Collins has a rather large footprint and wont fit in the Murata position which has a very small footprint.
If you can find a Murata with the bandwidth you want, just replace it.
This will leave the optional slot open for whatever you want in there.
But if you want to use the Collins, or another crystal type, then buy his product.
Or you could just double side tape the filter somewhere and use small pieces of coax (rg174) and connect to the filter pads.
We think this is a better solution due to there are no exposed long runs of signal wire hanging out there.
As far as any components on the board, We don't feel there are any.
The impedance of the Collins filter is very close to the other filters so its just a plug and play deal.
Hej Då,
Last edited by Voodoo Guru on Fri Sep 18, 2009 2:47 pm, edited 1 time in total.
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm
You Know, that is what I was thinking... Thanks for confirming my thoughts, that yes, I can increase my audio, and Yes, he isn't keen on anything other than DX audio...
Friends shouldn't let friend use DX audio...
I thing I kjust figured out a fairly easy ay to increase my TX bandwidth on my 718....
Now I need to choose a filter...
Bow
Quite possibilly the only 3.3 Khz wide Icom IC-718 in the world...
