Carl has it right; if you do not need higher (or different ???)
performance from your radio, then stay with the stock filters -
I live very close to the mainland of Europe/Scandinavia, which
justifies (for me at least) better filtering. I have the INRAD ten
pole 9 mHz filter in my Omni-V. I now get better audio reports,
especially on lower sideband where the original TT filter apparently has
some asymmetry (in my case only, perhaps). BUT even a ten pole filter
is not going to take out splatter which is IN the passband .....
I just heard stations in the WAE contest with splatter extending plus or
minus 10-20 kHz, even with -20dB attenuation switched in. On 40, I
actually operated with the attenuator in circuit, and I still managed
to work some DX through a wall of high powered racket.
I also have the INRAD 400 Hz 9 and 6 mHz filters, and I do 99% of my CW
with these (and the 10 pole 2.4 ahead of them). I would like to try the
INRAD 250 Hz filter - I do see lower filter attenuation with the INRADs
and the stock TT 250 seems a tad lossy - I cannot use it on very weak
signals because the signal/noise ratio is not as good as with the
(INRAD) 6 mHz 400 Hz filter in circuit. On 7mHz CW I often use the
external INRAD 801 7 mHz front end roofing filter as well (this does
need a fairly minor mod to the radio). The 801 clears cross-mod from
EU BC stations, which pin the meter at my place, from 7100 up. (The 801
was a last minute, strictly impulse buy at Dayton this year).
These comments reflect the fact that I spend a lot of my time looking
for weak signals, in a very hostile/noisy environment, using a marginal
backyard antenna farm (just one 40 m inverted V, for all bands). If you
can't hear them, you aint gonna work them - and its amazing how often I
hear DX stations answer calls, but then the caller keeps on hollering.
For example, I often hear VK6HD calling CQ on 80, even with the stock
filters in my Omni-V. He tells me he regularly calls stations on 80/160
who do not answer him. Maybe my Omni-V hears better than many other
radios, but it does not actually need any new filters to do it.
If I was a rag chewer, I'd be very happy with the regular TT filters.
There is also the very real problem of whether you actually get the full
performance out of the INRAD filters. Certainly at -80 dB, or even at
-60 dB down the filter skirts, it does not take much leakage INSIDE the
radio for strong signals to sneak past the filter. The six pole 801
front end filter is a good example; it needs extreme care in mounting,
to avoid strong 7 mHz BC signals sneaking past it. I used a die cast
box and good quality (not audio) coax. With it in circuit I now hear
virtually nothing outside the passband, 6999 to 7017.
Its a tough decision; only you can decide if your operating habits need
you to spend more money, whether on new filters, or on one inch hardline
to cut your feeder losses.
73 John G3JAG
P.S. forget the hardline - just get some of the real heavy duty
ladderline and a good (TT) ATU. It works like magic for me. I took
around 200 ft to HS0/G3NOM and he is hooked on the stuff now.
On 08-Sep-99 Carl Hyde wrote:
>
> The average 90% of us probably would be hard pressed
> to tell the difference between the TT and InRad
> filters in a side by side comparison. The TT filters
> are more than adequate for most of us. For the
> serious DXer or contester the InRad filters have an
> extra edge at a higher price than TT. The skirts are
> deeper and each filter is more or less hand built and
> tested. For those 10% who want that extra edge then
> the InRad filters are worth the price. Now consider
> also that InRad makes filters for the ICOMS, Yeasus
> and Kenwoods along with Drake and Heathkit. I have
> InRad filters in my Heathkit SB-102 and am ordering a
> set for an SB-104A . The InRad filters are far
> superior to any Heath or the aforementioned
> manufacturers had in their inventory. For these radios
> the InRad filters are a quantum leap in performance.
> Ten Tec already has an excellent performing filter
> inventory. The InRads are there for a certain few
> hams who need them. So this is the consideration you
> should give the purchase decision. What kind of
> operation do you do and do you really need that 10%
> edge in your operating. Its definitely not an easy
> decision.
>
> --- Robert <bigmack@nortexinfo.net> wrote:
>>
>> After reading all of this, what is the TenTec
>> response... Surely they see
>> (as I have in just these few messages) that there is
>> an obvious preference,
>> on this reflector, for the INRAD filters. Why
>> doesn't TenTec offer these
>> filters under the TenTec brand name? Just curious...
>>
>>
>> --
>> FAQ on WWW:
>> http://www.contesting.com/tentecfaq.htm
>> Submissions: tentec@contesting.com
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>> owner-tentec@contesting.com
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>> http://www.contesting.com/km9p/search.htm
>>
>>
>
> ===
> Carl S.HYDE
> W2CSH
>
> Eagles May Soar, But Weasles Never Get Sucked Into Jet Engines!
>
> Politics: From the Greek word Poli, meaning many and
> the word tics, meaning blood sucking parasites.
> __________________________________________________
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>
> --
> FAQ on WWW: http://www.contesting.com/tentecfaq.htm
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----------------------------------
E-Mail: John - G3JAG <patents@dx0man.prestel.co.uk>
To: <tentec@contesting.com>
Date: 12-Sep-99
Time: 10:20:55
This message was sent by XFMail
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