[ICOM] Wanted: Narrower (than stock) SSB filter for IC-735

[Gary P. Fiber]

Interesting.. seems to me the 455 KHz filter in the 735 was one of those 
little plastic Murata filters.
I know Icom never made a 455 KHz replacement filter for the IC-735. The 
FL-44A could not be installed in the IC-735, If you did you needed to 
use hard wiring as there was no room on the circuit board for it. The CW 
filter was 9 MHz type and it used long thin wire leads and soldered into 
place.
Inrad did a lot of things with their filters, mostly they had to be hard 
wired to the circuit board using RG-174U coax and then stuck someplace 
with in the rig. But they do make a good filter I have one of their 1.8 
KHz 455 KHz filters installed in my IC-718.

Gary K8IZ

On 8/22/2011 8:09 AM, D C *Mac* Macdonald wrote:
> Inrad shows that all six of those are applicable to the IC-735.
>
>
> Is Inrad in error?
>
> * * * * * * * * * * *
> * 73 - Mac, K2GKK/5 *
> * (Since 30 Nov 53) *
> * Oklahoma City, OK *
> * USAF, Ret (61-81) *
> * * * * * * * * * * *
>
>
>
>
>
>> Date: Sun, 21 Aug 2011 20:01:16 -0700
>> From: gfiber at comcast.net
>> To: icom at mailman.qth.net
>> Subject: Re: [ICOM] Wanted: Narrower (than stock) SSB filter for IC-735
>>
>> The 455 Khz filters will not work in the IC-735 Though the 455 Khz
>> filters generally have a better overall shape factor. I like to think
>> that's because the crystals are bigger and easier to grind than the 9
>> MHz crystals are.
>>
>> Gary K8IZ
>>
>>
>> On 8/21/2011 6:56 PM, D C *Mac* Macdonald wrote:
>>> Inrad makes two at the 9 MHz I.F. for $115;
>>>
>>> #123 for 2.8 kHz
>>> #320 for 1.8 kHz.
>>>
>>> They make four at the 455 kHz I.F. for $170;
>>>
>>> #124 for 2.8 kHz
>>> #109 for 2.4 kHz
>>> #314 for 2.1 kHz
>>> #322 for 1.8 kHz
>>>
>>> I guess it's tougher to build filters at 455 than 9,000 kHz???
>>>
>>> Are the 455 kHz filters better than those at 9 Mhz? I checked
>>> the data sheets and noted that several of the 9 MHz filters
>>> had noticably more ripple across the tops of their slope curves.
>>>
>>> The 123 appears to have just a bit sharper cutoff than the 124
>>> but the 320 is a miniscule amount wider than the 322.
>>>
>>> I have located a new 109 (2.4 kHz) filter, but the asking price
>>> is $140 which is about half of a bare 735 is current sell price.
>>>
>>> * * * * * * * * * * *
>>> * 73 - Mac, K2GKK/5 *
>>> * (Since 30 Nov 53) *
>>> * Oklahoma City, OK *
>>> * USAF, Ret (61-81) *
>>> * * * * * * * * * * *
>>>
>>>
>>>
>>>> Date: Sun, 21 Aug 2011 18:25:51 -0700
>>>> From: gfiber at comcast.net
>>>> To: icom at mailman.qth.net
>>>> Subject: Re: [ICOM] Wanted: Narrower (than stock) SSB filter for IC-735
>>>>
>>>> I want to say the FL-30 was the original SSB filter nut would have to
>>>> find a print and have a look. I suspect one of your choices will be
>>>> Inrad but it will not likely be a drop in, you may have to use some
>>>> RG-174 to connect it up and some double stick tape to mount it.
>>>> Possibly W4RT has a collins mechanical filter that would work too. I
>>>> don't think the Icom FL-223 1.8 KHz filter will work as the impedance
>>>> for the filter is likely wrong for the 735 circuit. And it has plug in
>>>> leads where the IC-735 lead placement likely will not match and the
>>>> original filter is a solder in type.
>>>>
>>>> Gary K8IZ
>>>>
>>>> On 8/21/2011 5:45 PM, D C *Mac* Macdonald wrote:
>>>>> Subject line says most all of it. I'm looking for an
>>>>> improvement for SSB selectivity at a reasonable(?) cost.
>>>>>
>>>>> * * * * * * * * * * *
>>>>> * 73 - Mac, K2GKK/5 *
>>>>> * (Since 30 Nov 53) *
>>>>> * Oklahoma City, OK *
>>>>> * USAF, Ret (61-81) *
>>>>> * * * * * * * * * * *
>   		 	   		
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-- 
Gary P. Fiber K8IZ

General Radio Telephone Operators License PG-19-6691,
with Shipboard Radar Endorsement.
Washington State Resident.

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