OMNI V AND VI SPECIAL CW FILTERS

[Ron Stone]

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| Ron Stone, GW3YDX -    EMail ron at gw3ydx.demon.co.uk                 
                               
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Chaps


Those amongst you who are owners of the Omni 5 and 6 transceivers will 
know that the NAR filter on CW is built for a 750 Hz audio tone. 
Tuning into a tone lower than this (I prefer around 300 - 400 Hz and 
using the narrow filter attenuates signals unacceptably. 

I have spoken to Ten Tec about this problem (some while ago) and they 
said that they did not intend to offer any filter options above what 
was available then. The position has not changed. 

Ten Tec filters are made by Network Sciences in Arizona. I spoke to 
them about having a special filter made. They were quoting $200 for a 
single with quantity reductions. At the time I was not prepared to pay 
$200, and sent PacketCluster messages to the various Cluster systems 
to see if there was any interest for such a "low note" filter. 

In all, about 6 people replied saying they would buy a filter at a 
reasonable price, but there are now more Omni 6's around and interest 
may be greater. I am prepared to go to Network Sciences again and talk 
pricing if others are interested.

The proposal is to commission the construction of a filter with the 
following specifications (same as the current Model 217 - for 750 Hz 
note, filter - but with 400 Hz bandwidth and optimised for 400 Hz 
note)

Centre freq - 9.000400
- 6 dB Bandwidth - 400 Hz
- 6:60 dB shape factor 2 : 1 or better.
- Insertion loss - 7.5 dB
- Ultimate rejection - 90 dB
- Z in / out - 200 ohms
- Poles - 8

Please let me know if you are interested. Also please (via Cluster, DX 
and Contest Clubs etc) tell your friends with Omni 5 and 6 
transceivers. I'll wait a month or so and then issue a bulletin with 
responses and pricing info. 

Trey - if this is a bit off the mark for the Contest Reflector, 
apologies, but I can't think of a better forum.

73
Ron

ps - The Omni is not the worlds best SSB transceiver. Have you 
measured the filter response ? Mine is 2.0 KHz at the -6 dB point !! 
Network Sciences have built specials for 2.7 KHz so that operators can 
sound human on SSB. 

pps

I have no connection at all with Network Sciences and am not gaining 
any financial advantage from this !