[amsat-bb] Fox telemetry software question

[Zach Metzinger]

On 12/22/18 12:44, JoAnne K9JKM wrote:
>> I wonder if a bandpass filter might help with the performance
>> of your RTL-SDR dongle?
> 
> It very well may. The RTL-SDR.com site has a choice of filters for sale. But how much more money should be thrown at a $100 experimental Fox Telemetry receiver designed to be an inexpensive, deployable unit. The goal of making a $10,000 super satellite station is not part of the system requirements for this project. Nor is the expectation that it is a primary satellite station in the shack.
 >
> It is a fun project though!

Ah, you've hit on it, JoAnne-

A cheap filter can be made very easily, and one has a lot of the test 
equipment to show/tune the response right in the shack!

"Paint can" style helical filters:

http://www.pa0nhc.nl/IMDfilter/EN/IndexEN.htm

Fancy combline filters, which use probably hard-to-get miniature air 
variable capacitors:

http://www.w1ghz.org/filter/Combline_Filters_for_VHF_and_UHF.pdf

Or, call on Andrew Jackson to solve the problem (cheaply):

https://www.hobbypcb.com/products/uhf-vhf-radio/144mhz-band-pass-filter

--- Zach
N0ZGO