[INRAD] Roofing filter for 1st IF TS870

[George Cutsogeorge]

Hello Milan,

The radios which I have selected to work on are: FT 1000MP, Omni VI, FT 
1000, IC 765, IC 775, IC 781, TS 930, TS 940 and TS 950SDX, pretty much in 
that order.  These are the radios which have a coax cable connecting the 1st 
IF output to the 2nd mixer.  They are easy for the general population to 
modify.  Most other radios are designed differently like the Pro III, FT 
920, FT 990, TS 850 and the 870.  They would need to have extensive work 
done on the PC boards to insert a new roofing filter.  This is beyond the 
capability of most radio amateurs today.

I am currently in the final stages of testing the IC 765 mod.  These mods 
all take a long time because I am working alone and I must also do other 
things.

We will be offering the VHF filters without the amplifier and PC board for 
the radios which I have modified and some others which I have not.  This 
will happen in a couple of months when we have them in stock.  Some 
experimenters will be able to try their own modifications.

The filters are all designed to have a minimum bandwidth of 4 kHz and 50 
ohms input and output impedance.  Most filters come through with 5 kHz 
bandwidth on the average.  Insertion loss varies, but is 6 dB average.

The filters on order have the following center frequencies: 40.055 MHz, 
44.93, 45.05, 45.25, 46.115, 47.055, 69.0115, 70.455 and 73.62.  Unless 
something changes, the sale price will be about $125 each.

George


----- Original Message ----- 
From: "Milan Pelech" <ok1vwk at seznam.cz>
To: "George Cutsogeorge" <w2vjn at rosenet.net>
Sent: Friday, October 21, 2005 4:03 AM
Subject: Roofing filter for 1st IF TS870


> Hi George,
>
> Exist or will be exist INRAD roofing filter for 1st IF 70MHz to Kenwood 
> TS870, 850, 950 or another TRX from Kenwood with the same IF platform ? 
> Its very interesting for me, and I hope also for next Kenwood users. If 
> exist solution for TS870 I would like to order him. In advance thanks for 
> some info about prices and technical parameters.
>
> Milan, OK1VWK
>
> ----- Original Message ----- 
> From: "George Cutsogeorge" <w2vjn at rosenet.net>
> To: "Inrad List" <list at inrad.net>
> Sent: Sunday, October 16, 2005 12:01 AM
> Subject: [INRAD] Filter selection brochure on line
>
>
>> To see a discussion of filter selection and installation for the MP 
>> series
>> radios as well as further information on the modifications and some tips 
>> on
>> how to use your radio go here:
>> http://www.qth.com/inrad/MP-Filter-Selection.pdf
>>
>> Thie is the same 6 page brochure that has been included in any order that 
>> is
>> placed for FT 1000MP series filters or mods.  It has been revised every 
>> year
>> just before the Dayton hamfest.
>>
>> George, W2VJN
>>
>>
>>
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>
>