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Author Topic: In an IC718 is a 300 hz Collins Mech filter better than a 500 hz one  (Read 9678 times)

Posts: 142

« on: December 15, 2013, 05:38:28 PM »

Greetings: I am not rich and can just afford a IC718.What saves me is my 2 el quad up 60 ft.I am going to put in either a 300 or 500hz  W4RT Collins mechanical filters. My iC706 cant zerobeat very well and I want that function.I am strictly a cw op since 1960 and would appreciate any advice.
Yours Truly
Richard D Vincent

Posts: 149

« Reply #1 on: December 15, 2013, 07:18:00 PM »

I don't have any special knowledge about the 718.  But, speaking of filters in general;

No filters is no fun.  DSP never works as well as they claim.
If I could only have one filter, it would be the 500 Hz filter.
In a perfect world, I have a 500 Hz filter for general purpose use, and a 250Hz filter for when the going gets tough.

That's my feelings on the subject.

73 mike


Posts: 3016

« Reply #2 on: December 15, 2013, 07:46:07 PM »

I think many hams waste money on ultra narrow SSB filters that carry a cost in terms of fidelity. I don't think there's a net benefit to voice filters narrower than about 2.3 KHz, even for contesting or DXing.

OTOH, I do most of my CW operating with my Flex5000's 250 Hz and even 100 Hz filters. Only use 500 Hz on a really dead band. That's my opinion for US ops. Your QRM is probably a lot less. Still, I think I'd go with 300 Hz.

Posts: 757

« Reply #3 on: December 16, 2013, 12:15:57 AM »

 Richard ; There is no reason why you cannot zero beat using your 718. You need to have the side tone set to your preferred pitch, while it is in break in 'off' position you will hold down the key, it will not transmit, and simply tune the signal to match that pitch perfectly or close.Switch back to full or semi auto break in and key to transmit.I use a foot switch along with my key when not using break in.It only will transmit when the foot switch was depressed and then keying the key.This way you have your side tone to zero beat with as well as a practice oscillator to warm your fist up with before a session.
 I have the 500hz filter you are looking to get.I also have a 250 hz filter in my R75 and R4c. I would not suggest you go lower than 500hz however.It is too restrictive and won't tolerate a weak signal as well as a 500.
 One thing to consider other that doing the filter installation, is to get yourself a Timewave 599+ filter, it is just as good and more adjustable as well as you can use it on more than one rig, keep it when you trade up too.More money but super versatile and I cannot tell Any difference on the receive audio between the Ic or 599+ except the 599+ does a better job in my opinion.
 Hope that will help you. Yes, the filtering makes CW much more fun...e mail questions if I did not fully explain..73 lane.

Posts: 2806

« Reply #4 on: December 16, 2013, 10:50:32 PM »

. . .  My iC706 can't zerobeat very well and I want that function. . . .

Let's see if we can save you some money --

. . . What procedure do you use to "zero-beat" on the IC-706?

I've forgotten if there's a dedicated "CW zero-beat tone" generator on that rig.    But what works on _every_ modern rig (including IC-706, which I used heavily for several years) is:

. . . turn BK-IN  off (so the rig doesn't transmit when you press the key)

. . . hold down the key (or paddle) so you get a side-tone;

. . . tune the rig until the sidetone pitch matches the pitch of the signal you want to respond to;

. . . turn BK-IN  on (so the rig transmits when you press the key).

You will be "zero-beat" (within a few Hz) with the incoming signal.  The process only takes a few seconds, even if you have to change the "tuning speed" during it.

I _suspect_ there's a way to generate a "zero-beat" signal using one of the front-panel buttons, but I haven't checked the manual.

Now, if you _can't hear_ the difference between two different pitches, that would be a problem.  But it's a rare condition, and you'll have the same problem on the IC-718.

The IC-718 doesn't have much better performance (if it's better at all) than the IC-706.  I don't think you need a new rig to solve the problem.

On filters, I had an Icom 350 Hz "CW/RTTY" filter on my IC-706, and it was "just right".  The W4RT filters might be better, though.

 .               Charles

Posts: 5184

« Reply #5 on: December 17, 2013, 04:03:32 AM »

My opinion:

A 300 Hz filter is too tight for day-in-day-out usage.

The 500 Hz filter is going to be more broadly useful in general conditions.


Posts: 180

« Reply #6 on: December 17, 2013, 06:55:07 AM »

Primary rig here is IC- 718 with 500hz filter. The filter is best money I spent. Received radio a couple of hours before ARRL 10 meter contest a couple years ago, worked contest with no filter, was brutal. Installed  filter ASAP after contest. I bought the 718 to replace a FT 897 as is least deep menu driven modern rig, for an old guy thats important. Don't have to have manual in front of me to operate. Bottom line : you will be happy with 500hz installed.

Posts: 1499

« Reply #7 on: December 18, 2013, 01:59:17 AM »

Such a poor receiver in the IC718 its hardly worth the effort investing in narrow  CW filters.

Buy a good radio like the K3 or TS590s that has decent IMD dynamic range  and phase noise performance that enables you to extract the maximum performance from using narrow CW filters. Nothing worst than listening to IMD, ringing and phase noise in a low end radio like the IC718 when equipped with 300hz filters that are not true 300hz filters.
Its kind like putting race car tyres on a  T model ford.


Posts: 4

« Reply #8 on: December 18, 2013, 08:21:05 AM »

Out of all the Icom rigs I own, the IC-718 is a wonderful simple radio to use. Its not to hard to read the manual to set up your filters and other settings. If you are hearing imd, phase noise or ringing, then you have something wrong in your radio.
I have never experienced poor performance from my IC-718. I installed the 300hz filter and I was very very happy with it.
That was the best investment I had made in that radio. Mabe Zenki can give the op a nice Christmas gift of a brand new K3 or a TS590. The 718 is a great entry level rig.

Posts: 990


« Reply #9 on: December 18, 2013, 08:48:30 AM »

I agree with KH2BR.

Also, I'd go with the 300 Hz filter if I could only have one. During crowded band conditions (contests, sprints, QSO parties, somebody being rude or who can't hear you) you'll want something tighter than 500Hz.

Posts: 1248

« Reply #10 on: December 18, 2013, 02:29:45 PM »

My opinion:

A 300 Hz filter is too tight for day-in-day-out usage.

The 500 Hz filter is going to be more broadly useful in general conditions.

I use a 500hz cw filter in my FT-857D. I never felt I needed anything narrower.

Posts: 328

« Reply #11 on: December 19, 2013, 11:10:41 AM »

If you're only going to get one, I recommend the 500Hz filter.

I put a 300 Hz filter in my Yaesu FT-857D. It works.
On Field Day using that in combination with the built in DSP on the radio, I can separate just about any two stations I wish.
But for day to day use, the 300Hz filter is too narrow. If I had it to do over again, I would purchase the 500Hz filter instead.

73 de N8AUC
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