[AMRadio] Need some help here

[Evangelistic Faith Missions Honduras]

Dan,
I read with intrest your conversion of the BG-1J.  I coverted on of these to
90 meter shortwave for a Christan broadcast station in Honduras.  The
Freequency is 3250 Khz.  Had the same problem with the rig wanting to
double.  I made some changes.  First I put in a big air-variable in the
plate network.  I also replaced the variable caps in the driver stage with a
Vacume.  It will want to arc on you.  I still yet have it to get up to the
required 100-150 ma grid drive.   I think you will also find the audio
sections lacks enough drive.  The one I converted had beed the audio section
changed over to 4 6B4g's.  If you would like I can give you the coil
settings I use for 3.250 wich will get you near 80 meters.

73's
Don Moore  W5FFK/HR5DRM
----- Original Message -----
From: "Dan Hall" <kj7fx at tdn.com>
To: <amradio at mailman.qth.net>
Sent: Monday, March 04, 2002 1:32 PM
Subject: [AMRadio] Need some help here


> Greetings Gang:
> I have just about gotten my BC1-J up on 3870.  I'm using crystal control
and
> have wound a plug in coil for the oscillator. It's on frequency and dips
> well. The Gates manual says it should make about 2-4 MA of grid drive for
> the 6146 exciter pair. It does. I have re-tapped the exciter coil and get
a
> dip when it is tuned, though no where near as sharp as I would like to
see.
> The manual says it should provide about 140 MA of grid drive to the 833A
PA
> tubes. It does not. I'm getting about 25 MA. I have shorted the low grid
> relay so that I can put plate voltage to the finals and it will tune, with
> 2000 VDC on the plates to about 5-600 Watts. The problem is that the
> frequency is all over the place depending on the variable coil setting. By
> that I mean , when moving toward the dip the frequency will rise from
> 3869.667 (funky crystal, thanks Jan) to around 4050 KC. The frequency
shift
> is not in jumps either but seems relatively smooth. There is no decent dip
> at all until the PA begins to act like a doubler, then she dips good.
When
> tuned and loaded through much trial and error to about 350 Watts, and on
> frequency, the frequency is not stable and can jump to 3900+/- or higher
> when switching between transmit and standby (exciter and PA plates turned
> off). On top of all that, the modulator isn't modulating. I get the 80 MA
> idle current and the current jumps around when speaking into the mic, but
> nothing out on the peak meter.
>
> ????
> Dan
> KJ7FX
>
>
> _______________________________________________
> AMRadio mailing list
> AMRadio at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/amradio