[MAMS] 5.7 GHz rainscatter question

[Danny Pease]

You are right Jerry, the mixer is followed by a filter, no amplifiers of any
sort after the mixer output probably lucky to be -10 dBm. It will need a
couple of stages to get up to 1 watt, probably 3 or 4 if I add more
filtering. I am guessing the 18 inch offset feed dish I have at maybe 25 dB
of gain, so even a 1 watt output still is pretty low ERP. I am still on the
lookout for a free 2 to 3 foot dish, but one that size is a bit harder to
hold up for portable use. I have a place nearby that has one of the farm
data dishes in the front yard, I may eventually get that one, no one has
lived in the house for a few years now, so I know it is not being used.

Danny


-----Original Message-----
From: mams-bounces at mailman.qth.net [mailto:mams-bounces at mailman.qth.net] On
Behalf Of Dr. Gerald N. Johnson
Sent: Wednesday, August 08, 2012 12:38 PM
To: mams at mailman.qth.net
Subject: Re: [MAMS] 5.7 GHz rainscatter question



On 8/8/2012 12:12 PM, Danny Pease wrote:
> I see I can get a couple of boards and devices from a seller on Ebay 
> for 1 watt out for a very reasonable price, but I was pretty sure that 
> 1 watt and the 18 inch dish I have would be a little on the weak side 
> plus having to split the single output of the transverter into 
> separate TX and RX for the amplifier and preamp, meaning a decent pair of
relays or PIN diode switches.
> I am getting a little antsy to try this stuff out and I am pretty sure 
> the few milliwatts I have available won't get me too many QSO's from 
> around here.
>
> Danny NG9R
> EN40la
>
>
Bigger dishes aren't difficult to acquire. Look for a 30" at a farm that
used to get data from DTN on KU satellite. Or Channel Master dishes are sold
on line at reasonable prices (though any price is infinitely greater than
free).

Can the Tx and Rx lines be separated inside the transverter, and their
combining relay moved outside? The only case of them being inherently
combined thatt I can think of is seeing the mixer directly which means poor
receiver sensitivity and minuscule Tx power.

Sometimes suitable relays can be had at reasonable prices like from Hangar
18 Surplus. The may take 28 volts though.

73, Jerry, K0CQ
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