[ARC5] BC-230 first run

[AKLDGUY .]

Yes that's easy to try too. I'm out for lunch right now but will try it
this evening. Thanks for the suggestion.

73 DE Neil ZL1ANM
Sent from my Android smartphone
On 28/03/2016 12:42 pm, "J Mcvey" <ac2eu at yahoo.com> wrote:

> All of the aircraft radios were designed for electrically short antennas
> 5-12 ohms plus a boatload of capacitive reactance . They spec 90 to 150 pf .
> Try putting a 100 pf transmit cap in series with the 5 ohm load. It will
> probably load up that way.  The original dummy load has a 100 pf cap in it.
> I made one with a wirewound resistor and  variable cap to tune out the
> inductance of the resistor and provide the series capacitance. Sounds crazy
> but works!
>
>
> On Sunday, March 27, 2016 10:34 AM, Glen Zook via ARC5 <
> arc5 at mailman.qth.net> wrote:
>
>
> I am not really familiar with the transmitter.  However, is it designed to
> work into a 5-ohm load?  That is almost a dead short where r.f. is
> concerned.
>
> You indicated a dummy load of 5-each 1-ohm resistors in series.  I would
> try 5-each 10-ohm resistors to get the load impedance up to 50-ohms.
>
> Glen, K9STH Website: http://k9sth.net
>
>
> ------------------------------
> *From:* AKLDGUY . <neilb0627 at gmail.com>
> *To:* ARC-5 List <arc5 at mailman.qth.net>
> *Sent:* Sunday, March 27, 2016 5:38 AM
> *Subject:* [ARC5] BC-230 first run
>
> Need some suggestions because I may have overlooked something.
>
> BC-AO-230 with 4 x 6AQ5 in adapter sockets with 12.8 VDC on the
> heater line and 320 VDC plate supply. All 4 heaters light up and look
> normal. To protect the modulator and final tubes in case the VFO
> failed to start or bias wasn't developed, I connected 5 x 10V batteries
> in series to the bias line (battery -ve to junction of R100 and R104
> via a diode).
>
> I heard the VFO on a monitor receiver, so disconnected the batteries
> and sure enough, about 70 V bias was present at the same junction
> so the VFO was operating and no tube showed any sign of distress.
> Freq was reasonably stable and the note was good. Freq: 6200 KHz;
> 6200-7700 KHz coil set inserted. All coil windings have continuity.
>
> No matter what I did, I could get no output from the final into a dummy
> load of 5 x 1 ohm carbon resistors in series. No indication on the RF
> ammeter, nothing but a steady 25mA final plate current with a meter
> plugged into the meter jack. No sign of dip when tuning the final tank
> capacitor through its range. The coil wiper contact is good and several
> settings don't work.
>
> Mike (ex-taxi radio) not yet connected but its PTT switch operates a
> 12V relay to switch on the B+ to the set.
>
> Have I overlooked something?
>
>
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