[Moon] [Moon-Net] Pre-amp Isolation relay isolation question

[Edward R Cole]

Good luck with using HP mw relays.  I've not had much luck finding 
any with low insertion loss.  Best I have are 0.2 dB loss which 
raises your nice 0.24 dBNF LNA to 0.44 dBNF -yuck!

My biggest surprise was finding that the NARDA Sem123N relay had loss 
so low I could not measure it with any reasonable certainty.  Mine 
was under 0.05 dB.  Only way I could measure it was by adding the 
N-elbow to common port and N/sma adapter to NC or NO port to make 
combined loss measurement of 0.15 dB (the adapter measures 0.1 dB by itself).

I am hoping the HP8765A are better at 3400-MHz, though I will have to 
use N/sma adaptor on the VE4MA Feed to mate to the sma 
relay.  Fortunately the LNA has sma-male input.  Thinking of making 
up a short 90-degree section of 141 coax with N-male and sma-male on 
opposite ends vs using an adapter.

For the ARRL mw EME Contest (Sept. 5/6) I hope to get the 3400 
feed/LNA/transverter installed for Rx-only.  I will not have time to 
get the Toshiba Amp running (building two DEMI transverters for 
customers this week which is higher priority).

GL, 73
Ed - KL7UW

At 12:52 PM 8/30/2015, Stephen Hanselman wrote:
>I thought that would be to small, I'll use my external HP 
>relays.  Thanks to all who responded
>
>73's
>
>
>
>Stephen Hanselman, KC4SW
>
>Datagate Systems, LLC
>
><x-apple-data-detectors://0/0>3107 North Deer Run Road #24
>
><x-apple-data-detectors://0/0>Carson City, Nevada, 89701
>
><tel:(775)%20882-5117>(775) 882-5117 office
>
><tel:(775)%20720-6020>(775) 720-6020 mobile
>
><mailto:s.hanselman at datagatesystems.com>s.hanselman at datagatesystems.com
>
>www.datagatesystems.com
>
>a Service Disabled, Veteran Owned Small Business
>
>DISCLAIMER:
>This e-mail and any attachments are intended only for use by the 
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>Sent from my iPad
>
>On Aug 30, 2015, at 14:21, Stephen Hanselman 
><<mailto:eme at kc4sw.com>eme at kc4sw.com> wrote:
>
>>What would be the consensus value for isolation on a pre-amp?
>>
>>The anticipated circuit will be Common to input of device, NO to 
>>antenna and NC to 50ohm load.  Putting the 50 Ohms on the input of 
>>the device in transmit.  Frequency is 1296, anticipated RF at the 
>>antenna is 500W Xmit, Antenna is a rectangular Septum feed.
>>
>>I am looking at incorporating the isolation relay on the preamp PCA 
>>and have a nice low-insertion  loss SMD RF relay with 20dB (open 
>>contacts) and 30dB (contact sets). The relay is DPDT and the 
>>contacts will be paralleled.
>>
>>73's and Thanks,
>>
>>
>>
>>Stephen Hanselman, KC4SW
>>
>>Datagate Systems, LLC
>>
>><x-apple-data-detectors://0/0>3107 North Deer Run Road #24
>>
>><x-apple-data-detectors://0/0>Carson City, Nevada, 89701
>>
>><tel:(775)%20882-5117>(775) 882-5117 office
>>
>><tel:(775)%20720-6020>(775) 720-6020 mobile
>>
>><mailto:s.hanselman at datagatesystems.com>s.hanselman at datagatesystems.com
>>
>>www.datagatesystems.com
>>
>>a Service Disabled, Veteran Owned Small Business
>>
>>DISCLAIMER:
>>This e-mail and any attachments are intended only for use by the 
>>addressee(s) named herein and may contain legally privileged and/or 
>>proprietary information. If you are not the intended recipient, any 
>>dissemination, distribution or copying of this e-mail and any 
>>attachments is strictly prohibited. If you have received this 
>>e-mail in error, please immediately notify me and permanently 
>>delete the original and all copies and printouts of this e-mail and 
>>any attachments.
>>
>>Sent from my iPad
>>_______________________________________________
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73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
     dubususa at gmail.com
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