ICOM IC-718/Wide SSB Filter- 'FL-257' or Collins Filter?

[Robb]

I'm looking to improve the SSB of the IC-718.
What advantages would the 3.2khz filter have over the stock unit?
Would I need to remove the OEM filter and install the FL-257 on its place to have the benefit on RX AND TX?

 

[Moleculo]

The filter is for RX only, although I have seen some posts online about experimenters attempting to mod the radio to have the filter affect TX with limited results. (View topic - Icom IC-718 to 3.3 wide... Experment Time).

That filter will give you better audio RX quality, though. It pops into the additional filter slot, and you leave the stock filter in. Then to activate it, just press the filter button. Turn it back off if there is another station a little too close to where you're operating if they're bleeding over.

 

[Robb]

Mole:

AS you have figured out, I had seen the same page - and a similar one like it:
View topic - New Guy
You can read in that page that by removing the stock fl-65 filter and putting the fl-257 filter in its place - it will affect the output/TX as well.
Interesting...

So - if I put the fl-257 in the place of the stock fl-65 filter - and then put the fl-65 filter in the optional filter spot - I should be able to switch between them and let the radio default on the fl-257.
Correct?

And yes; I am interested in finding out more about ESSB. I'm not trying to turn this little 718 into a commercial broadcast station; just trying to oink out some more usable audio for better clarity and a better understood transmit. I'm not going to take it to the hilt - just reasonably improve the audio - as you did with your setup.

As you know, I have a tube preamp, Heil cable, foot switch, and a MXL V88 Condenser mic. I think that I may need a direct box ("Rolls DB25 Match Box" (http://www.guitarcenter.com/Rolls-DB25b-Matchbox-Direct-Box-Pad-Ground-Lift-100257041-i1134894.gc) between the preamp and the Heil cable to ensure that I am not overloading the input of the radio.
Thoughts?

 

[Robb]

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

This mod uses a Collins mechanical filter.
Read the pdf.

 

[RickC.]

Hey, let us know what you think about what you ultimately decide to use. I've been mulling over the W4RT dual filters for a while now. Doing the AGC mod was a pain, but that was a HUGE improvement to me. Listening to the 718 on SSB was tiring, and I don't know why Icom didn't allow for AGC selection.

I used a foot switch for a while with the Heil ICM, but bought the hand switch at a hamfest on a whim, and found I like that much better. You probably saw my remarks in the Behringer mic thread so I won't repeat them here, but while I don't like the ICM all that much, the stations I talk to sure seem to. I played with several condensers and dynamics over about a year period and even with a noise gate found that the fan of my old SB-200 was very well reproduced by most of the condensers, so I just went back to a simple setup.

I've always wanted to try an EV 635, based on using one in a broadcast studio in the late 70s. The control room mic at the station I worked at had died and the engineer grabbed a well-worn 635 from the duffle bag used for remotes, basketball games, etc. That thing sounded great up close. It is an omni though.

Sorry to digress, I'd be interested in what you come up with on the filter.


Rick

 

[Robb]

Hey, let us know what you think about what you ultimately decide to use. I've been mulling over the W4RT dual filters for a while now. Doing the AGC mod was a pain, but that was a HUGE improvement to me. Listening to the 718 on SSB was tiring, and I don't know why Icom didn't allow for AGC selection.
Rick

What did you do for the AGC - and why?

Still digging for the info to get this radio to TX @ 3.3khz wide. Removing the stock filter and getting it to work on TX is the trick of the day. The radio will receive 3.3khz; but will default on the stock 2.4khz filter on TX. I'm not a tech guru - I need more info because I don't want to hack up an otherwise nice little radio unless I can be sure of results. So to get it to do the 3.3khz on TX needs to be made clearer, a copy of 'radio mods for dummies' would be nice! lol!

 

[RickC.]

The rcvr defaults to fast AGC on SSB, which is very tiresome to listen to, especially on the lower bands when it's noisy. The mod is just soldering a jumper but it's between legs of surface mount components. That is just NO fun to what are now middle-aged eyes!

That mod is about half way down this page:

http://www.kb2ljj.com/data/icom/ic-718.htm

I think the factory filter is 2.1 KHz on mine (I'll have to go back and look) which is a bit narrow for ragchews on a quiet, non-crowded band but there have been times I've been thankful for that and the IF shift on 20m phone!

Rick

 

[Highlander_821]

It seems like you guys are talking about different things---I think Robb is talking about widening his TX bandwidth with a new filter, rather than trying to tighten up the RX with a new filter.

 

[RickC.]

Yeah, reading back over this, I think you're right. I was thinking replacing the recv IF filter with the Collins when I read that.

The AGC mod is worth doing, IMHO, you just need a fine tipped iron, a magnifier and good light!


Rick

 

[Highlander_821]

I had a Collins 2.5 Khz SSB filter in my FT-847. I replaced it with an Inrad 2.1 Khz crystal filter on the RX, and moved the Collins 2.5 to the TX side (which had the factory ceramic 2.6 in it, IIRC)

The 2.1 Inrad filter tightened it up some, but not enough to get away from those wide TX guys. UGH. I dont like that crap at all. I figure that if I hear a station talking on 14.280, and I go up to 14.284 with my 2.1 Khz bandpass and still get splashed by Mr. Near Broadcast Quality at 14.280, something is wrong. But that's just me. I like to share the bandwidth, not hog it.

 

[RickC.]

I figure that if I hear a station talking on 14.280, and I go up to 14.284 with my 2.1 Khz bandpass and still get splashed by Mr. Near Broadcast Quality at 14.280, something is wrong. But that's just me. I like to share the bandwidth, not hog it.

Hear, hear! I don't mind ESSB IF the bandwidth is within reason. But overdriven xmitters/amps are just as bad.

How steep are the skirts on this 3.3 Collins filter after the mod?

 

[Bow]

I'm looking to improve the SSB of the IC-718.
What advantages would the 3.2khz filter have over the stock unit?
Would I need to remove the OEM filter and install the FL-257 on its place to have the benefit on RX AND TX?

Robb,

I am the guy that did that mod with the filters on the Voodoo Site.

Yes, it works very well and will get you 3.3kHz wide TX and RX audio

My audio as received on a 6kHz wide Kenwood, on 10 meters

 

[AE6ZW]

collins 455khz mechanical filter in quantities.

I found a price lists of 455Khz collins filter, one used in those yaesu , icom radio, etc just buy bunch with friends or for future use , and hardwire them, don't forget impedance matching between filter input / output stage. do some RF design work save some money.

price is good if you can order in large quantity

I like those filter very much. however I prefer filter at first IF like they do in elecraft, etc .

The LOW COST SERIES of filters have all six bandwidths are centered at 455 kHz. The pricing on these filters is the same for all six filters,

526-8733-010 (300Hz B.W.), 526-8693-010 (500Hz B.W.), 526-8694-010 (2.5kHz B.W.), 526-8695-010 (5.5kHz B.W.), 526-8734-010 (7.0kHz B.W.), 526-8735-010
(10kHz B.W.) and is as follows per part number:

Quantity
100-299 $33.43

 

[Bow]

The LOW COST SERIES of filters have all six bandwidths are centered at 455 kHz. The pricing on these filters is the same for all six filters,

526-8733-010 (300Hz B.W.), 526-8693-010 (500Hz B.W.), 526-8694-010 (2.5kHz B.W.), 526-8695-010 (5.5kHz B.W.), 526-8734-010 (7.0kHz B.W.), 526-8735-010
(10kHz B.W.) and is as follows per part number:

Quantity
100-299 $33.43

Wow...

We need at least 100 friends?

the 10KHz one would do pretty good for AM and be a monster on SSB...

 

[2RT307]

Waking up this old thread.... Bow, did you feel that the mods to the 718 were worthwhile, or would you just go with a rig that is easier to play wideband with?

Also, can you please explain to me how you went direct to the ACC connection on the back of the rig for your mic/rack?

73,
RT307