We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Author Topic: Antenna Tuner  (Read 8717 times)

Offline Dxer92

  • Jr. Member
  • **
  • Posts: 60
  • Karma: +0/-0
    • View Profile
Antenna Tuner
« on: November 01, 2013, 1514 UTC »
Will a Antenna tuner help with SWL reception?? I hear it will help and then others will tell me it will not help reception. What are anyone's thoughts?? I'm thinking about getting a antenna tuner not just for Ham radio alone but for SWL as well.

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 26073
  • Karma: +55/-45
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: Antenna Tuner
« Reply #1 on: November 01, 2013, 1541 UTC »
Yes and no. An antenna tuner primarily matches the impedance of the antenna to the radio, allowing maximum signal transfer. It's very important when transmitting, especially since modern solid state radios often dislike high SWR. For receiving, I am not convinced of the benefits personally, except in some cases.

I have improved reception on longwave with a tuner, I believe this was a case where the impedance mismatch was really horrible. It was a homebrew affair, two variable caps and a tapped inductor.

Another use is to reduce images and overloading from nearby AM transmitters, although I don't have any experience with this.

Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 300 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline moof

  • Full Member
  • ***
  • Posts: 211
  • Karma: +0/-0
    • View Profile
    • Email
Re: Antenna Tuner
« Reply #2 on: November 01, 2013, 2137 UTC »
If I have my matcher (used for transmitting) purposefully set way bad, yes, I can take a hit of several S units and reception is a little worse. I don't think I can really set it to make reception better than running the antenna straight in the radio.
Maybe what you want is a preselector with a preamp.  I can't remember the model I had 15 years ago, but it wasn't MFJ, about $70 back then.  It was an active indoor antenna, had frequency selection knob, and preamp on-off.  It made a good difference with my large portable radio.  Something fried in it after 5-6 years but it was good while it lasted.

Offline skeezix

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 4244
  • Karma: +2/-0
  • Minneapolis, MN
  • What does 'RNO stand for?
    • View Profile
Re: Antenna Tuner
« Reply #3 on: November 01, 2013, 2153 UTC »
Another use is to reduce images and overloading from nearby AM transmitters, although I don't have any experience with this.

Yes, this does work nicely for that. When I have those sorts of problems, the tuner usually clears it right up. Of course, tuning around is now a pain since have to tune the radio and then the tuner.

Minneapolis, MN

Offline RCCI

  • DX Legend
  • ******
  • Posts: 1240
  • Karma: +0/-0
  • Chicagoland
    • View Profile
    • Email
Re: Antenna Tuner
« Reply #4 on: November 01, 2013, 2351 UTC »
I use the MFJ SW/MW/LW tuner, Model MFJ-956, You can usually find them cheap on eBay, for $35-$45. I use it for my Kenwood R-1000 and it does a pretty good job. The antenna I use is only 30 feet, so it has it's limits. There is also a MFJ -1046 Passive Preselector and it's AC powered amplified twin MFJ-1048. Just remember when using anything amplified, it also for the most part, amplify the noise as well. I've used both over the years, different models, etc. I prefer the passive, other's swear by the amplified, it's a personal choice -- your mileage may vary. ;D
+ Equipment: Yaesu FRG 100B, Kenwood R-1000, Yaesu FRG7,
+ Antenna: 75' dipole, height 21', running north and south.  Chicagoland area.
 *** QSLs welcomed at: gangwise1997@yahoo.com   Thanks!   ...Steve

Offline BoomboxDX

  • Hero Member
  • *****
  • Posts: 699
  • Karma: +5/-0
    • View Profile
Re: Antenna Tuner
« Reply #5 on: November 15, 2013, 0735 UTC »
If your radio is prone to images from strong signals, an antenna tuner will help. I had a single conversion solid state comm receiver that was prone to images below the SW broadcast bands. 

I homebuilt an antenna tuner out of a couple AM radio tuner capacitors and a coil of copper wire wrapped around a large plastic spice bottle, put it between the long wire and the radio. It got rid of the images.

An AM radio Boombox DXer.
+ GE SRIII, PR-D5 & TRF on MW.
The usual Realistic culprits on SW (and a Panasonic).

cmradio

  • Guest
Re: Antenna Tuner
« Reply #6 on: November 15, 2013, 1010 UTC »
If your antenna is any type of wire antenna (monopole or dipole), then most likely, yes. I built a SWL tuner for my E5 to listen using the beacon antenna.

If you have any kind of tuned loop antenna, then no. A properly designed loop antenna's pickup coil should be the design impedance (50 or 75R most common) at resonance throughout its tuning range.

Peace!

Offline Pigmeat

  • DX Legend
  • ******
  • Posts: 4578
  • Karma: +77/-34
    • View Profile
Re: Antenna Tuner
« Reply #7 on: November 15, 2013, 2005 UTC »
If your radio is prone to images from strong signals, an antenna tuner will help. I had a single conversion solid state comm receiver that was prone to images below the SW broadcast bands. 

I homebuilt an antenna tuner out of a couple AM radio tuner capacitors and a coil of copper wire wrapped around a large plastic spice bottle, put it between the long wire and the radio. It got rid of the images.



I've used a very similar circuit for listening to random wires for years, Boombox. (And at times with an E5 to boot, CM.) It does well once you figure out how to tune and tweak the thing for the best sig to noise ratio. I use a large pill bottle for the coil form, with about 20 turns of 22 gauge mag wire tapped every 5 turns.

I've got MFJ transmitting ATU for random wires I picked up for 5 bucks at a hamfest. I like it for listening, it will tune up about any hunk of wire. If I can figure out what box of radio junk it's in, I'll post the model number. I know they still make version of it.

Offline OldSeaRock

  • Full Member
  • ***
  • Posts: 121
  • Karma: +0/-0
  • Earth, TX
    • View Profile
Re: Antenna Tuner
« Reply #8 on: November 18, 2013, 1653 UTC »
From what others say here and what I know, the answer is that it depends on the type of antenna you're using (Reception).

For transmitting, I believe the tuner is critical.  And I believe that a good, manual tuner is far superior to most auto tuners in transceivers.

I run a multi-band vertical so the tuner is critical for me, regardless.

There's a good many knowledgeable people who post in these forums and it's much appreciated.  I personally hope for some great osmosis to occur. 
eQsl appreciated:  theoldsearock@yahoo.com
Listening on & off since 1968.  Howdy from Tejas!