RTOP Oct 2025 Uploaded

[Dr. Rich Russel]

RTOP Oct 2025: Leo Triplet Mapping Project, 43 GHz Observing, GNU Radio, Reflector Material, and AI

RTOP Oct 2025: Leo Triplet Mapping Project, 43 GHz Observing, GNU Radio,...

[Stephen Arbogast]

Just   got  home   and  watched   RTOP    for   October...     some   thoughts.....

1.  I  might   try  Peltier   cooling   for  my lna  not my sdr.

2.  My  sdr is  Air Spy R2   which  runs  inside  at  a  constant  temperature no problems.    I have a  GPSDO  plugged into the AirSpy  to see  if  any  difference.

3.  I have   ferrite beads around  all of my  usb  cables, not much  difference.

[Alex P]

H-Line band pass filter

https://gpio.com/collections/filters/products/1420-mhz-bandpass-filter

[Andrew Thornett]

They are good choice whilst Nooelec SAWBird H1s are out of stock.

Sent from Outlook for Android

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From: 'Alex P' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Sent: Monday, October 6, 2025 1:24:15 PM
To: Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Subject: [SARA] Re: RTOP Oct 2025 Uploaded

 

H-Line band pass filter

https://gpio.com/collections/filters/products/1420-mhz-bandpass-filter

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[b alex pettit jr]

This is an extremely good filter, but you must build an interface board for it 

[Andrew Thornett]

Hi Alex

How narrow does a hydrogen line filter need to be to be effective and is there any use in getting narrower than whatever that value is?

Andy

Sent from Outlook for Android

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From: 'b alex pettit jr' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Sent: Monday, October 6, 2025 3:02:47 PM
To: 'Andrew Thornett' via Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Subject: Re: [SARA] Re: RTOP Oct 2025 Uploaded

 

This is an extremely good filter, but you must build an interface board for it 

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[Alex P]

It can potentially prevent saturation in the second stage amplification of the LNA 

There is probably  value in reducing out of band RF to improve the FFT noise floor in the digital filtering . 

I think narrow band filtering is a carry over from the pre-SDR era when signal power levels were the goal,

and it probably also helped with the stepped-frequency analog analyzer performance.

Until an antenna and feed are optimized, any benefit from this is questionable .