Date
1 - 18 of 18
Reception on Grundig G3 NOT Amazingly Improved with new 80 Ft Longwire Antenna
|
jerry_popiel
|
|
|
|
|
|
Michael <michael.setaazul@...>
Not surprising, Jerry : total overload! Take care not to fry the front-end.
toggle quoted message
Show quoted text
You could try a trap circuit between the longwire and the receiver to null out the 680kHz local to some degree. Michael UK ----- Original Message -----------------------------------------------------
From: Jerry Popiel To: ultralightdx@... Sent: 09 July 2011 22:25 Subject: [ultralightdx] Re: Reception on Grundig G3 NOT Amazingly Improved with new 80 Ft Longwire Antenna Well after DXing late last night I am dissappointed. The Antenna seems to be way too strong!! One local 50.000 watt station here was overriding ALL the Shortwave Bands. AM reception wasn't as bad, in fact its better, but even in the AM band that 50000 watt Station at 680 Hz is showing up. The only way to reduce the Shortwave overdriving was to wrap the Antenna Jumper around the Radio instead of clipping it to the Aerial, then it wasn't so bad. Is there a way to fix this? Seems like such a waste after all the work it took to put up the 80 foot Antenna. |
|
|
|
|
|
Ken Kizer
Jerry Popiel writes...
Well after DXing late last night I am dissappointed. The Antenna seems to be way too strong!! One local 50.000 watt station here was overriding ALL the Shortwave Bands. AM reception wasn't as bad, in fact its better, but even in the AM band that 50000 watt Station at 680 Hz is showing up. The only way to reduce the Shortwave overdriving was to wrap the Antenna Jumper around the Radio instead of clipping it to the Aerial, then it wasn't so bad.I had to put two of the adjustable (discontinued) Radio Shack FM attenuators in serial connection between my 150' (AM) antenna and most of my receivers. The only one that doesn't complain about full signal is the Drake R8. Hi-fi component tuners freak completely out (strong station images up and down the dial). Ken |
|
|
|
|
|
Jay Heyl
On Sat, Jul 9, 2011 at 14:25, Jerry Popiel <jerry_popiel@...> wrote:
I would suggest using the antenna input on the radio rather than clipping it to the whip. The whip antenna is typically amplified, which is obviously not what you want here.
It doesn't appear the G3 has any adjustable gain aside from the DX/Local switch. That limits what you can do with the radio to tame that local flamethrower. About the only other option is to get a high-pass filter designed to block out the MW frequencies for when you're trying to listen to SW.
-- Jay |
|
|
|
|
|
Graeme Zimmer <gzimmer@...>
The only way to reduce the Shortwave over-driving was to wrap theAntenna Jumper around the Radio instead of clipping it to the Aerial, then it wasn't so bad. - As Jay said, use the antenna input, that is what it is there for. Connection direct to the whip is far too sensitive. - Use the attenuator switch, or wire up a simple potentiometer as a variable attenuator. - If images and breakthrough are still a problem, hook up a simple antenna tuner. .................... Zim |
|
|
|
|
|
jerry_popiel
--- In ultralightdx@..., Graeme Zimmer <gzimmer@...> wrote:
|
|
|
|
|
|
Graeme Zimmer <gzimmer@...>
I have an Antenna Tuner - an MFJ 16010 which I used years ago but it does nothing to stop that 50,000 watt 680 Hz blowtorch interference on the Shortwave Bands with the 80 Ft Antenna.http://www.mfjenterprises.com/support.php?productid=MFJ-16010 The MFJ-16010 is configured as a low-pass filter, so it is probably not ideal for eliminating BC overload. Do you have a good earth ??? Any ATU can't do much without an earth. .......... Zim |
|
|
|
|
|
Graeme Zimmer <gzimmer@...>
I have an Antenna Tuner - an MFJ 16010 which I used years ago but it does nothing to stop that 50,000 watt 680 Hz blowtorch interference on the Shortwave Bands with the 80 Ft Antenna.http://www.mfjenterprises.com/support.php?productid=MFJ-16010 The MFJ 16010 is configured as a low-pass filter, so it probably won't eliminate BC overload. Do you have a good earth ??? An ATU can't do much without an earth. .......... Zim |
|
|
|
|
|
jerry_popiel
|
|
|
|
|
|
Graeme Zimmer <gzimmer@...>
Hi Jerry,
Yes, judging by the pix at http://www.mods.dk/picture.php?brandid=15&model=mfj-16010 the MFJ-16010 has coax connectors for both in and out. The earth wire should connect to the case. You could put the wire under a screw, or use one of those dual binding posts, plus a PL259 to BNC adaptor... http://en.wikipedia.org/wiki/File:Binding_post_adapter.JPG and http://www.jaycar.com.au/productView.asp?ID=PA3652 But then I'm sure you can figure it out regards ............ Zim |
|
|
|
|
|
jerry_popiel
Thanks for the reply Michael. What type of trap circuit do you mean? I do have a MFJ Antenna Tuner in series with the 80 Ft Balun Antenna and Zim just pointed out it needs to be grounded which it wasn't. Is that the type of Trap Circuit you mean or where can I get info on a Trap cct?
toggle quoted message
Show quoted text
--- In ultralightdx@..., "Michael" <michael.setaazul@...> wrote:
|
|
|
|
|
|
Graeme Zimmer <gzimmer@...>
What type of trap circuit do you mean? II imagine that Michael is referring to a simple parallel tuned circuit which is inserted in the antenna lead. see www.dxing.com/tnotes/tnote06.pdf if you google on "Wave Trap" you'll find lots of reading! later ...... Zim |
|
|
|
|
|
Jay <jaypolicow@...>
The G3 is not well suited to an external antenna...my Wellbrook ALA330S overloads it badly even in teh daytime. My PL-660 handles it much better.
toggle quoted message
Show quoted text
Jay http://radiojayallen.com --- In ultralightdx@..., Jerry Popiel <jerry_popiel@...> wrote:
|
|
|
|
|
|
Graeme Zimmer <gzimmer@...>
see www.dxing.com/tnotes/tnote06.pdfJust a note: The circuit shown in fig 2B is incorrect. I think he meant the parallel circuit to be in series with the antenna lead, not in shunt configuration as shown. Like this http://www.qsl.net/vk3gjz//Misc/zim01.JPG ..........Zim |
|
|
|
|
|
Michael <michael.setaazul@...>
Yes, the qsl jpg below from Graeme is the correct
one,
such as I had in mind. I´m not sure what
effect the low-Z
ouput from the long-wire balun might
have on its tuning sharpness,
however. Fig 2A would probably work best. The L/C would
be tuned
to the unwanted frequency to suppress it. Add a
few turns on top
of the tuned L, one end to earth, the other to the 50ohm cable
centre
conductor from the
balun. If overload is still evident, reduce the number
of turns to one or two. I would also
recommend two reverse-connected diodes
across the tuned circuit to absorb any surge from distant lightening strikes
that gets past the low-Z winding. I would
also suggest protecting the input
and output connections to the balun with self-amalgamating tape or at least
vaseline or grease. This would protect them from
corrosion, which could in time
produce a primitive rectifier between
unlike metals at the connection point.
This can generate spurious mixing products and
inter-modulation - which
we definitely don´t want!
Experiment ! If success is not impressive
enough, you might wish
to consider a loop, which could be above the roof
and remote-tuned
from inside, or a ferrite or FSL.
Keep us posted on your progress!
Michael UK
|
|
|
|
|
|
kevin asato <kc6pob@...>
--- On Sun, 7/10/11, jerry_popiel wrote:
|
|
|
|
|
|
Phil Pasteur
Jerry,
toggle quoted message
Show quoted text
You may want to try a pre-selector rather than an antenna tuner. Years ago when I got my first Sony 2010 I put up a 90 foot trapped sloper hoping to make things much better. Unfortunately I found that the two 10KW AM stations within a mile or two from my house showed up in images all over the shortwave bands. I got a MFJ 956 pre-selector. It knocked out 95% of the images but let me tune it to the BCB when doing MW DX. Pre-selectors work best at their characteritic impedance, so I had a balun at the antenna, coax to the 956 and coax to a mini plug going into the external antenna input on the 2010. At least this keeps things close. This does require more fiddling with knobs everytime you change frequencies, but I found it to be quite worth it. There are much better pre-selectors around than the 956, and even mod instructions for it to make it much better. http://www.bobsamerica.com/mfj-956.html This is what I am using now. If you browse his site, there is a wealth of information about pre-selectors. http://www.bobsamerica.com/preselect-basics.html I use this device for all of the radios in my shack now, it sits in front of my antenna switch. It makes things much better even for radios like my R8B, Modded R-75 and NRD 545, all with stouter front ends than most portables. If you try the pre-selector route, let us know how it goes. Phil --- In ultralightdx@..., "Michael" <michael.setaazul@...> wrote:
|
|
|
|
|
|
jerry_popiel
Great 95 % Reception Improvement with Ground Connection on MFJ 16010:
toggle quoted message
Show quoted text
Thanks very much Zim, late last night I unscrewed the side screw & sanded off the black paint a bit and attached a #14 solid wire connected to my cold water meter and Power Ground Clamp - connected it to the side of the MFJ 16010 Antenna Tuner and boy what a difference! I also connected the Antenna Tuner to the Antenna Jack on the Grundig G3 Radio, which also may have helped. Pulled in Stations at 2200 and 2500 Hz that I never had before, is this the Tropical Band? and many other stations. Also the Antenna Tuner is now working well. Thanks to Graeme Zimmer, Michael and many others for their great TIPS. I wiil also look into the Traps issue as suggested by Michael. Thanks guys, the wonderful advice here sure has helped me, this is a great helpful web group!! --- In ultralightdx@..., Graeme Zimmer <gzimmer@...> wrote:
|
|
|
|