Wednesday, 28 November 2012

Won't be QRV

Unfortunately a family emergency means I won't now be QRV in the EME contest at the weekend. I will be in GI until Sunday.

73 de Sam

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Tuesday, 27 November 2012

Some results of tests with isolator and relays

Prior to putting my 23cm EME system back on-air I thought I would check out some isolators and relays I had used previously.
I had thought about using the Totsu CX600N at the output of the TS2000X, but the results show this is not a good idea. That relay is just OK at 432MHz, but definitely not at 1296MHz!
I have two identical 1200Mhz range isolators. The 'black' one shows the best results at 1296MHz, so will be used for the TS2000X transmitter 'protection'.
The isolator gives 0.33dB insertion loss ( forward) and 23.9dB reverse loss with reverse return loss of 16.3dB
CX600N @1296MHz
Insertion loss common to NC with other port terminated in 50R
Insertion loss common to NO ( relay operated) =0.19dB
Isolation common to NO 20.25dB
NC to NO isolation = 19.9dB
RLC electronics relay @1296MHz
Insertion loss common to NC or NO with other port terminated
= <0.1dB
Isolation common to NC or NO = ~85dB
NC to NO isolation = ~90dB
Not shown is the Relcomm RDL-SR006 relay used for preamp isolation
The main parameter here is insertion loss. This measured <0.1dB ( 0.06dB measured but there are uncertainties of the same order!).
I need to confirm the isolation figures again. But they were good.

More later.
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Sunday, 25 November 2012

A purpose in life!

My current thoughts are that I will write about my EME actvities, in the main, although there will be other stuff as well.
With the final part of the ARRL EME contest next weekend there is obviously a lot of interest, judging from the number of requests I am getting for preamps and spare parts for VLNA preamps!
I am going to try and get my own 23cm system up and running for next weekend and will aim to have a few QSOs.
I was active on receive only in the 50-1296MHz section at the beginning of this month. There were a lot of stations visible on my Spectravue screen. Unfortunately MAP65 performed rather poorly and only the bigger stations decoded. Changing to JT65C, decodes were close to 100% on all but the weakest stations.
As far as I can tell, there has been no wind damage to the dish or mast ( luffed over from the previous wind storm, last week) from last night's storm, at my QTH. Lots of branches down on surrounding country roads and lanes.
73 de Sam

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Location:Falkenham Road,Kirton,United Kingdom

Friday, 23 November 2012

A relaunch

After an almost two year hiatus I have decided to re-launch my blog. Now I no longer write the GHz Bands column for Radcom I need a new canvas to lay out my thoughts, current interests and project progress. Where better than a blog? Facebook and Twitter are too limiting.

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