[ARC5] BC-230 first run

[AKLDGUY .]

Glen Zook 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.

An HF antenna on a plane is very short electrically. Consequently the
impedance is about 5 ohms plus some capacitance. This is the
impedance that the set and the ARC-5 transmitters are designed to
work into. They will not properly work into a 50 ohm antenna unless
some kind of impedance matcher is present.
I appreciate you reading and commenting, though. Thanks.

73 de Neil ZL1ANM


On 3/28/16, AKLDGUY . <neilb0627 at gmail.com> wrote:
> Dave Stinson wrote:
>
>> Inspect the coil connection posts.  Hard to get to
>> the backs of them but not impossible.  Make sure they connect
>> where they should, especailly ground points.
>
> Do you mean the wiring may have been modified by a previous
> owner (no, it hasn't been modified in any way) or that the
> connections are prone to going O/C with old age?
>
>> Are the 6AQ5 screens connected to plate or grid?
>> Must go to plate.
>
> They go to plate.
>
>> Jumper the RF Ammeter. Open thermocouple is
>> another common problem.
>
> That's easily tryable. I'll check that out when I return after lunch.
>
>> If not any of these, I'll get my manuals and
>> start scratching my head.
>
> Thanks. I wondered whether I had overlooked some setting.
>
> 73 de Neil ZL1ANM
>
>
> On 3/28/16, AKLDGUY . <neilb0627 at gmail.com> wrote:
>> Leslie wrote:
>>
>>> If the output tank circuit was "way off" resonance I'd expect more
>>> current in the plate circuit.
>>> My hunch is that there is a discrepancy between the resonant frequency
>>> of the grid and plate tank circuits.
>>> (But the grid cct is untuned.  Only the plate circuit is tuned.)
>>>
>>> I would suspect corrosion in the contacts somewhere - maybe the tank
>>> "C".
>>> I think that's C17.  Check the wiper on the rotor for C-17
>>
>> Yes, my instinct was that the final tank is way off tune, but in that
>> case
>> there should be more plate current and it should be 'dippable' to 25mA
>> at resonance. I'll inspect the rotor wiper, but the capacitor looks
>> pristine, so not hopeful.
>>
>>> If you make a "loop" with a neon on it, does the neon light?
>>> If you make a "sniffer coil" with a 6V or 2V incandescent globe does it
>>> light?
>>
>> The neon loop sounds like a good idea. I may pick up a neon at Jaycar
>> while out for lunch today, if they're open this holiday weekend.
>>
>> 73 de Neil ZL1ANM
>>
>