[ardf] Transmitters and Fox Boxes...

Sam Smith sam.smith at ece.gatech.edu
Thu Aug 14 15:01:34 CDT 2003

Matthew Robbins wrote:
>    1.  Do you use bulkhead connectors for piercing the ammo can, or just 
> RTV the coax in a hole, or something else?
bulkhead connectors for the 2 meter, binding posts for the 80 meter.

>    2.  Do you use different connectors (e.g., BNC, SO-259) for the 2m 
> and 80m antennas?  Where do you have disconnects?  I was thinking 
> soldered coax at the 80m TX, BNC at the HT, and then disconnects at the 
> box bulkhead, inside and out, and then soldered joints the rest of the way.
different connectors. I never disconnect anything inside the box except 
the battery. Everything else is soldered with strain relief except for 
the BNC connection to the HT.

>    3.  For 80m do you use coax or twinlead from the box to the antenna 
> (e.g., SO-259 or binder posts).
 From the binding posts just short lengths of wire straight to the 
antenna and ground radials. It's only a few inches.

>    4.  Do you have a way to measure and adjust SWR in the box, or do you 
> do that at home and assume everything is the same at the transmitter site?
Adjust SWR at home and don't worry in the field. I did adjust radials at 
the US Champs on 80 meters for lowest SWR but not usually.

>    5.  If you use HTs for control of an 80m transmitter, what kind of 
> antenna do you use for the 2m link?  (Probably not a turnstile?)
The same turnstile that I use for the 2 meter transmitter.

>    6.  Do you try to eliminate the ON7YD oscillator noise on 80m?  How?
Yes, I have a little circuit that turns on the oscillator whenever the 
key line is active. It's an RC delay of a few seconds, so it stays 
active during the CW and turns off the oscillator a few seconds after it 

>    7.  Have you had any trouble with RF on feedlines or power cables?  
> Do you use Ferrite or loops of the cable/coax (common-mode chokes)?
No, I don't use anything.

>   8.  Did you try to keep the CG underneath the handle?  It seems like 
> you have to put the battery in the middle of the ammo can to make it 
> balance right.
Batteries are in a back corner, at the bottom, wedged in with foam.

>   9.  How do you select 80m or 2m or both?  Switches?  Solder?  Change 
> plugs at the Controller?  (Can a Pic-Con do both at the same time?)  
> (For PicCon users with remote control: How do you switch off or 
> otherwise disconnect the 80m TX when set up for 2m?)
I have a switch that changes? something, I forget what. I don't want the 
2 meter transmitting at the same time. Actually I can still control the 
80 meter transmitter when it is transmitting, which is sort of cool. 
There is also a command to the piccon that changes the CW control line 
to real CW. (B502? B500?)

>   Today I went to three different stores looking for ammo cans.  (One 
> place advertised 50cal boxes for $2.99.)  They were all out.  *sigh*  
> Well, Tomorrow is another day.
One of my boxes is the smaller ammo can with a 5ah battery. Works just 
as well.


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