Fw: Re: SB-104A

[Kees & Sandy Talen]

Hi guys, I just have to jump in here ........before rusty
knives are drawn.

The RCA connector is a good 50 ohm connector system at
100 watts (better electrically than the old PL-259 system) but
after many years the ceramic insert starts to chip and deteriorate
through use (compare it to the other RCA connectors). Also,
one of the causes of problems in a SB-104(A) is that the
internal RCA connectors come loose, oxidize, etc .....pointed
out in the Heathkit manual. RCA connectors are not real
good for mechanical retention, especially where the cables
are stressed as they exit the unit.

The BNC connector system is an excellent, low power, 50 ohm
system ....both electrically AND mechanically (and convenient).
See how much equipment, test and otherwise, out there uses
BNCs. The only drawback is power handling capability. I've
never had a problem with around 100 watts but would definitely
go to the outstanding 50 ohm impedance N type connector for
more power than that (but N type connectors are large).

Now for my point .....I also do NOT want to modify equipment
unnecessarily. A  BULKHEAD mount BNC connector does
NOT modify the chassis. If you can't find them at a swapmeet,
Mouser Elec 523-31-221-RFX. You remove the RCA connector
(carefully store it, in case you are selling the rig to Charles later)
and install a bulkhead BNC, which has a small threaded barrel
on the back, with the nut provided. The diameter of the
threaded portion is actually smaller than the RCA connector
and it goes through the hole with plenty of room to spare.

I've done this to a number of Heathkits and yes, a few Collins
rigs with great results (and I keep a small bag with the old
parts in case I want to go back to original).

73s  Kees K5BCQ

Radio Homepage   http://www.qsl.net/k5bcq/
......for SB-104(A) repair, HBR receivers, and other stuff


----- Original Message -----
From: Charles W. Morehouse <w4gbw at BREVARD.NET>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Thursday, April 05, 2001 9:54 PM
Subject: Re: SB-104A


> Hi Dave and Murry,
> The chassis mount RCA jack is an excellent 50 ohm connector. It will
handle 100 watts
> plus with no problem. You can get an adapter to UHF connector at China
Shack. DO NOT
> replace it and butcherize your radio. People who do that should have a
certain pair on
> their anatomy removed with a rusty knife.
>
> David C Thompson wrote:
>
> > Hello Murray
> > Hope you didn't mind me posting to the list rater than to you direct.
> > There is an excellent SB104 site at:
> > http://www.inetport.com/~talen/sb104.html
> >
> > It's part of the K5BCQ homepage.  But here is a quote from the page:
> > 'Some may want to replace the "Ant" phono plug with a round chassis
mount
> > BNC connector. They fit nicely and provide an excellent, solid, 50 ohm
> > antenna connection."
> >
> > Hope this helps
> > 73 de David VK2NH
> >
> > ----- Original Message -----
> > From: Murray Grandy <mgrandy at TELUS.NET>
> > To: <HEATH at LISTSERV.TEMPE.GOV>
> > Sent: Friday, April 06, 2001 2:10 PM
> > Subject: SB-104A
> >
> > > Have just acquired SB-104A, not familiar with it and was surprised to
find
> > > the antenna connection is just an RCA jack. The manual shows it
connected
> > to
> > > SB-230 PA. Is there no way to use this radio without external amp? .
> > > Can anyone help me with this. Thanks in advance.
> > > Murray
> > >
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