[Milsurplus] R-388

[D C *Mac* Macdonald]

I have seen the trick of using the TV balun on  ALL
of the old receivers that use balanced high impedance
input mentioned previously somewhere.

In other words, if you are using Hammarlund, National,
Hallicrafters, etc. receivers from the 60s and earlier,
you stand to gain from using the TV balun.

Mac, K2GKK/5



----Original Message Follows----

From: "gl4d21a at juno.com" <gl4d21a at juno.com>
To: telegrapher at att.net
CC: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] R-388
Date: Tue, 9 Aug 2005 13:33:44 GMT

Larry:

AFIK, the break-in switch mod is one of the ways you can differentiate a 
R-388 from a 51J-3.

I do not recall if I previously mentioned that that series of receivers 
follows the time honored tradition of the Signal Corps and is a high 
impedance input device.  The R-390 vintage stuff were the transition to 
lower impedance (75 and then 50 ohm) system impedance.  Somewhere (Electric 
Radio, perhaps) I read that adding a 75 to 300 ohm TV balun in front 
improves the sensitivity remarkably in a 50 ohm system.  Other than that, it 
is indeed a sensitive receiver.

hth,
George
W5VPQ