[600MRG] NDB Antenna Calculator

[Kenneth G. Gordon]

On 27 Sep 2015 at 14:00, Edward R Cole wrote:

> Frank,
> 
> OK.  Never in my nearly 60-years in ham radio have I measured Q.  But 
> this calculator asks for the Q of the loading coil.  So you are 
> saying I have to shell out kilobucks to buy a HP Q-meter.

No. There are prefectly suitable "Q" meters available from various sources 
including e-bay for very little money. Hardly anyone uses the old ones any 
more, so those can be bought cheaply. Heathkit made one which can be 
easily modified for any reasonable frequency. Someone else mentioned both 
HP and Boonton meters which will do the job too. And there are also military 
versions which I have seen on e-bay which did not sell because no one knew 
how to use them. I have manuals or copies for some of those military 
models.

> Sorry, 
> that's not going to happen.
> 
> I never dipped a choke, either.  I do have my old Heath Tunnel dipper 
> but has lain unused for decades - do not even know if it works or if 
> all the coils are still there.

I have at least three GDOs. VERY handy instruments at times. I have two 
military AN/PRM-10s, and a Millen which includes the LF and MF coils in the 
sets.

> I can tell you that my antenna SWR bandwidth is about 5-Hz (F0 2:1 to 
> F1 2:1).  That is pretty high Q.

Yes, but I would ask, "Is that the bandwidth of the antenna SYSTEM, which 
would include any loading and coupling devices between the transmitter 
output and the air, or just the antenna itself?"

>  Guess I have to hit the books to 
> calculate Q (Z/R right?).

Yes...at least for coils...

>  My MFJ is busted so no way to measure Z, either).

Aaargh....

Well, there ARE other ways. ;-)

Ken W7EKB