[Elecraft] Band pass filters

[Bill Steffey NY9H]

well said....

at field day  that famous SDR, very reasonably priced, abundant with 
features DID INDEED SPREAD wide band noise ..it was on 10 and wiped out 
all thru 80 meters on three other radios  of various makes. ( mine was a 
k3) ...

maybe all we needed was to have bandpass filters for THAT radio ... but 
4 band of good filters starts to move into the purchase price of that radio

   Sherwood has spoken of this...and hope he will be elaborating ...  as 
I hate being the bearer of bad news....


bill ny9h


On 7/27/2021 2:49 PM, David Hachadorian wrote:
> You need a filter on the TX radio to prevent its phase noise from 
> being heard on other bands.  Just pressing PTT on the TX radio, even 
> without putting out any measurable power, will raise the noise floor 
> on multiple bands. With suitable band decoders driving filter 
> selection, fast-switching between bands is possible.
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
>
> On 7/27/2021 9:09 AM, CUTTER DAVID via Elecraft wrote:
>> Given the improved performance of modern transceivers, is there still 
>> a call for high specification W3NQN band pass filters in a 
>> 2-transmitter station?  For example on a Multi-2 contest 
>> environment.  For instance K3S + KPA + KAT. The filter fitted between 
>> radio and amplifier.
>>
>> I have the *feeling* that a receive-only filter (with tx bypass) 
>> might be all that is needed.  This is much easier to implement than a 
>> full transmitter-rated set making fast switching between bands (eg 
>> for a quick look around) very quick and easy from the keyboard, etc.
>>
>> David G3UNA
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>