[Hallicrafters] Outline of HT-30 and SWR Meters

[Robert Sauvan]

ORIGINAL QUESTION TO THE REFLECTOR:

Hi all,
I am a bit baffled trying to get swr meters to work with my newly 
restored HT-30 transmitter. I have 4 which I have swapped and tried with 
the unit. The radio works fine when I dont have a meter in line. But, 
anytime I hook one up inline, the transmitter goes into transmit when I 
turn the dial from "warm up" to "standby". All of the meters work fine 
with all of my other transmitters. A Viking Ranger and a Hammarlund 
HX-50. All of the swr meters are the Radio Shack/Micronta style. Anybody 
have any idea what might be going on? Not that I really need one but it 
is nice to see the power output and the swr in case it changes for some 
reason.

Thanks-Bob-W0YBS


RESPONSES:

  -Sounds like its interfering with the keying circuit by completing the ptt line In Some way.

-Have you checked the output frequency with a counter when it magically
goes key down? Wonder if it might be 'flying' or self oscillating which
would certainly bypass the keying circuitry.

-I have not checked anything with a counter, but how would an swr meter 
cause oscillating? If that is the case, would that mean I can never use 
an swr meter? The radio works great without an swr meter. No issues of 
self oscillating. But,I am having some issues with 20 meters losing 
power and them pooping out until I turn the band switch back and forth a 
few times. So Im thinking that is caused by a dirty wafer. Im still 
chasing that problem. Dont know if they are related to the swr meter or 
not. Still baffled.

Bob-W0YBS

-Try changing the length of the cable between the HT-30 and
the SWR meter even if it's only a few feet long.
Ron
K0IDT

-I have tried changing cable lengths but maybe I should try one a bit 
longer?  I had one that was only about 2-2 1/2 ft long and then I put 
one on that was 6 ft. Didnt seem to make much difference. Since we are 
talking about coax, I am using RG-58. Maybe I should change to RG-8 or 
RG-213. Possibly that might be a possible cure?

Bob-W0YBS

-Decided to check the coax swap a bit more thorough.Put the rig on the 
air for a bit and all was good for the time. So, decided to swap swr 
meters to see if they were reading the same as the last one inline. I 
noticed when I was taking off the cable from the meter I saw some 
sparking between the coax fitting and the fitting on the meter as I was 
pulling them apart. The sparking was on the ground side of the PL259 
before the center pin came out of the SO239. This was all done while the 
radio was turned on in warmup mode. I put another meter on and I had my 
warmup to standby transmit problem back. Looks as though it is a bit 
intermittent but that sparking I saw should be a clue as to what may be 
occurring with the meters and the radio. I will admit, I have seen this 
sparking before and wondered but disregarded it at the time. The cable I 
saw it on was the antenna side of the meter. I did not check the 
transmitter to meter input yet. Now I'm thinking it is a very big hint. 
I do have the radio grounded. The saga continues.

Bob-W0YBS


-Does that HT-30 have a 2-wire power cord?  Does it have caps across the 
AC input?

Ron
K0IDT


-Yes it does have a 2 wire power cord and no it does not have caps 
across the terminals. I will add them today.

Bob-W0YBS

-Hi all,
Got up this morning and put a volt meter on the coax connector on the 
back of the radio. It shows 1.4 volt ac across it. I would venture a 
guess that wouldnt be something that should be there. Im assuming this 
is why I am seeing a small spark when I put the coax on and off. I 
noticed this again when checking the fitting. Ron, K0IDT asked if the 
radio was a 2 wire power cord and if I had caps across the ac. It does 
have a 2 wire power cord, and it does not have the caps across the ac 
line. It clearly shows on the schematic that they should be there. So, I 
am going to put a couple on today. Possible cure? We will see.

Bob-W0YBS

-What are you measuring between? Voltage on the coax connector of a two 
wire powered unit is usually caused by the two capacitors across the 
power cord.

Are you sure the capacitors are really not there?

The capacitors need to replaced by the PROPER type. Not just any capacitor.

Bob Macklin
K5MYJ

-And you really oughta put a 3-wire cord on it so you're grounded 
properly for AC.
73,

Al, W8UT

-Does the 2 wire power cord have a polarized plug?

David
KW4DH

-

If it has a two wire cord, try reversing plug in socket.  It is normal for
many old radios to have that little 'leakage' voltage on them.
Oh, capacitors will 'enhance' the voltage too, they -all- leak a little
AC.....

Rod
KØEQH

-

Do NOT just add bypass capacitors!  Replace the 2-wire cord with a 
3-wire cord.  Wire the 3-wire cord so that the black wire goes first to 
the fuse, then through the off/on switch, and finally to the transformer 
primary.  If there is not a fuse, definitely add a fuse.
The white wire goes to the opposite side of the transformer primary and 
the green wire needs to go directly to the chassis.
A 3-wire cord is for safety and getting the chassis properly grounded 
may clear up a LOT of problems!  Also, a 3-wire cord meets NFPA NEC 
(national electrical code).
Glen, K9STH

- I can pretty much come to the conclusion that I should replace the 
power cord
with a 3 wire. I will do that. Would I still want to put the caps on the
ac lines? In answer to another comment as to whether or not the existing
power cord is polarized. I will have to say yes, so I cant really turn
it around in the plug socket so to reverse it, I will have to unsolder
it anyway so I may as well put the proper 3 wire cord on it. I will let
you all know how it turns out.

Bob-W0YBS


-Well,
We will keep our fingers crossed but I think putting the 3 wire cord and 
the line to ground capacitors in the HT-30 took care of my SWR/Power 
meter problem. The radio has been working flawless all day. I have been 
in and out of the shack testing it and all seems to be working fine. The 
swr meters are now working and I do not get a spark when I put the coax 
cable on and off of the coax connector.
I cant thank everyone enough for your suggestions on how to possibly 
remedy my problem and the details to insure I did it right.

Thanks again to all-
Bob-W0YBS :-)