View Single Post
  #7   Report Post  
Old March 7th 08, 02:52 AM posted to rec.radio.shortwave
Telamon Telamon is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 4,494
Default RP2100 Antenna Hookup

In article
,
garthpdm wrote:

On Mar 6, 2:19*pm, Telamon
wrote:
In article
,





*garthpdm wrote:
On Mar 5, 1:13 pm, wrote:
Hi,


I have a Redsun RP2100 and have been trying different antenna setups
to try to get reception here in S Korea. *I have had a little success
but it hasn't been great. *I am able to get reception on SW1 but SW2
and SW3 have virtually nothing when I listen at night. *I have a
question about my RP2100. *Recently I attached a longwire antenna to
the radio through the external jack on the back. *There was no
noticeable improvement in reception for SW2 and SW3. *But, when I
changed the switch on the side from external to internal and touched
the whip with my finger suddenly the longwire worked from 10000 -
30000. * If I unplug the longwire from the external jack and continue
touching the whip the reception in gone. *If I connect the longwire
directly to the whip, again the reception is great. *This is all while
the switch is set to internal antenna. *Is the external jack is
broken? *Strangely, I have tried using a small Degen DE31 with the
external jack and the switch set to external and it seems to work(but
not on SW2 & SW3). * My knowledge of antennas is low and perhaps I am
doing something wrong. *I am using 20m of 50 ohm RG-58 coax lead.
Unfortunately I can't get the antenna any closer to my house and
shorten the coax. *I am going to try grounding the antenna next.


On a side note, does anyone know where you can receive service for a
Redsun product? *I have tried writing to many different email
addresses and have had no response.


Thanks for any help
Regards


Garth


Hi again,


I used a multimeter to check the line and it certainly is shorted.
But the short is on the transformer/balun of the longwire. *Is the
outside of the SO239 jack supposed to be connected with the center
hole of the SO239? *ie. when I touch one lead to the center hole and
one to the circumference of the jack, current flows. *This is how the
antenna is shorting I guess. *Is the transformer/balun supposed to
work this way? *The antenna is the World-Listener SWL End-Feed
purchased from Northwest Antennas at this site
http://my.tbaytel.net/mccourts/homepage.html


Thanks for any help,


I'm not quite sure what you have there but chances are the S0239
connector is across a transformer winding and will look like a short
with a multi-meter at DC but it should not be a short at RF frequencies.
Check the coax for shorts or opens. If the coax looks OK then the
antenna UNUN might have a problem. Make sure you are connecting the
antenna to the proper jack on the radio. I looks like two jacks on the
back of the radio are are similar looking.


Thanks Telamon,

One thing I enjoy about this hobby is that there is so much to learn.
I checked and it is connected to the correct jack. Is it possible
that since I have not yet grounded the antenna it is behaving this
way? Thanks


Generally these UNUNs work better with a ground on the right terminal
but from the web site I can't tell if this unit even has a ground
terminal.

Another thing to look at is the Local/DX and INT/EXT switches. The
switches set in the wrong combinations could be causing you problems.

Here you would start with DX and EXT.

--
Telamon
Ventura, California