[Milsurplus] R-388

[Todd, KA1KAQ]

Someone actually makes a matching transformer for receivers,
unfortunately it's for matching up a 50 ohm receiver input to a long
wire or similar. We need one that works somewhat the opposite. Cable
TV transformers are apparently the closest thing out there.

You can also get an adaptor to fit the smaller barrel on the TV cable
transformer that converts up to SO-239 for easy hook up to any of your
PL-259-wired antennae. Of course, I can't remember the correct number
of the adaptor, but they're out there. The connector dealers have them
at most hamfests.

~ Todd/'Boomer'  KA1KAQ


On 8/9/05, D C *Mac* Macdonald <k2gkk at hotmail.com> wrote:
> 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.