Icom r75 owners

[ridgescan]

I want to share a little SWL tool that I have used for many years that can improve shortwave listening considerably. Some of you know of this, some aren't aware that this can be useful. This is for those folks.
It's called "minimum RF gain" or "RF gain reduction" and many folks in the radio world use it to refine signals. I have owned my Hallicrafters sx-88 for just shy of 24 years and have used its "sensitivity" control the same way.
I was laughed at on another forum for suggesting this tip to a SWListener as a way to bring up weaker signals out of the noise floor. Here are two short videos, one of a weak SSB signal, and one of a 10,000 mile AM SW broadcast, both of which I utilize minimum gain to bring forth better desired signal. The r75 does this trick very well because it retains more of the desired signal as you null unwanted noise minimizing the gain. There is a balance you have to strike between nulling and gain but there is a sweet spot that will yield cleaner SWL.
Icom r75-nulling noise - YouTube

icom r75 nulling noise - YouTube

and here are several HAMS who find this a useful tool as well
Optimum RF gain settings for WSPR | WSPRnet
http://www.qsl.net/ve3mcf/elecraft_reflect/K2_Using_RF_Gain_versus_AF_Gain_versus_NB2.txt
Reducing RF gain helps

I'm not the only one.

 

[k9rzz]

I'm on a super slow WiFi connection so I can't watch the videos, but if I may also add that sometimes turning the AGC - OFF plus backing off on the RF gain might help as well. Sometimes the time it takes it to recover, even in FAST mode, is too long and you can miss crucial audio. AGC is nice, but not always! Thank you.

 

[ridgescan]

yup k9 and other hams within those links have said what you said.

 

[Romak3]

http://home.comcast.net/~phils_radio_designs/Phil_R75_Cookbook.pdf

 

[zl2taw]

yeah thats the way to pull a good signal out of the noise, thanks for sharing & lets hope some of the newer SWLers will try it

 

[pathalogical]

Great vid ridge ! As k9rzz said, I've often used the AGC OFF very often and usually add the preamp 1 along with it, pre 2 is too much.

 

[ridgescan]

Thanks all-I saw that "Phil's hints" a while back-like I said I've been using this trick for years before that with the old boatanchor. I have tried the gain reduction here with AGC off but on the r75, as you see in the clips, it works just as well AGC on, which was my original intent with a SWL in another forum as he just bought an r75 and I wanted to convey to him that with the r75, you can use minimum rf gain with great results. My r71a will NOT do this well on AM like the r75 does. On the 71a, when you back the gain off, you just cut the desired signal down. This may not work on many receivers as well.
When you SWListeners are hearing a distant AM broadcast sometime on your r75, and the carrier is very wavy causing lots of hash to inject into the desired signal, just try this in small increments increasing the volume accordingly as you null.

 

[SCPD]

Yeah but r-e-a-l SWL'ers use SDRs these days!

j/k Ridge...

(I'm just giving Ridge a hard time...)

 

[ridgescan]

Not funny Nick, the way you jumped in that other forum, laughed at this idea and put me in a bad light as if I was an idiot for even bringing it up when I was trying to give that guy a tip for his new r75-well let's just say I know for sure you'd never embarrass Token or Brandon that way. Like I said before I show nothing but respect for everyone here including you and always have. I show respect for the new folks coming into the hobby as well as the veterans. Why you figure you can belittle me like you did when I was trying to help someone Nick? You still won't even acknowledge that many folks use this practice besides me even when I posted links above showing some. Why is that? You don't have to agree that it's a good tip-but at the same time you didn't need to be the way you were either.
I'm out of that forum too.

 

[SCPD]

Nick, the way you jumped in that other forum, laughed at this idea and put me in a bad light as if I was an idiot for even bringing it up when I was trying to give that guy a tip for his new r75-well let's just say I know for sure you'd never do Token or Brandon that way. Like I said before I show nothing but respect for everyone here including you and always have. I show respect for the new folks coming into the hobby as well as the veterans. Why you figure you can belittle me like you did when I was trying to help someone Nick? You still won't even acknowledge that many folks use this practice besides me even when I posted links above showing some. Why is that? You don't have to agree that it's a good tip-but at the same time you didn't need to be the way you were either.
I'm out of that forum too. You embarrassed me Nick and I dont think I had it coming

Ridge, you are taking this hobby way too seriously.

 

[ridgescan]

You'd feel the same as I do if someone slammed you that way. The hobby itself is fun to me-people who berate me the way you did is what I take seriously.

 

[majoco]

Nick said:

Yeah but r-e-a-l SWL'ers use SDRs these days!

Doesn't work with my WinRadio G303e! I have grizzled to them about it but no response. They thoughtfully put in a control called "IF gain" but unfortunately it's just an attenuator. Others (even people on this site!) have said that I don't know what I'm talking about, but, Ridgy, you have reinforced what I mean. The RF gain (aka Sensitivity) control works (on most receivers) by adding a voltage to the agc line - you can see it working 'cos the "S" meter rises up the scale. This will reduce the background noise in your receiver and the background antenna noise - leaving your signal at the same level. It's also used on older receivers when listening to SSB and CW signals so that the noise level doesn't rise in between pauses or in the morse spaces. Also for best SSB reception the inserted BFO level should be about the same level as the signal - AGC can't do that.
Good on yer - Ridgy, keep up the good work. Remember - question everything!

 

[RoninJoliet]

Thanks "ridgescan", it worked great on my R75.....

 

[SCPD]

Not funny Nick, the way you jumped in that other forum, laughed at this idea and put me in a bad light as if I was an idiot for even bringing it up when I was trying to give that guy a tip for his new r75-well let's just say I know for sure you'd never embarrass Token or Brandon that way. Like I said before I show nothing but respect for everyone here including you and always have. I show respect for the new folks coming into the hobby as well as the veterans. Why you figure you can belittle me like you did when I was trying to help someone Nick? You still won't even acknowledge that many folks use this practice besides me even when I posted links above showing some. Why is that? You don't have to agree that it's a good tip-but at the same time you didn't need to be the way you were either. I'm out of that forum too.

Okay my .02 -- and then I'm done commenting on this...

Ridge, you need to grow some thicker skin. This wasn't a forum! #wunclub is a PUBLIC chat room.

1. #wunclub is not Ridge's private teaching how-to clinic. Do that in a PRIVATE chat
2. I asked you twice what you were talking about and you ignored me
3. I did not "be-little" you in any way. I was asking for clarification of what you were talking about. You got all pissy -- because I questioned you -- OMG, what a crime! -- and then you went to make a video to PROVE that YOU were absolutely correct.

NOTE: You do this ALL the time, BTW. Someone questions YOU -- and you freak out. You're taking this stuff WAY too personally.

4. We watched your video and I even ACKNOWLEDGED that it helped remove some of the noise. I simply asked why you're not using the built-in Noise Blanker -- which does the same task. You said "well I don't like it"

5. You stayed in chat for about another hour or so and seemed fine after that...

6. So what's the big deal? We disagreed on a subject? So what... Learn to take critique or you're going to have a heart-attack.

7. It doesn't matter if either of us is correct or wrong. Agree to disagree and act like an adult.

If anyone has any questions about these events, I can provide a transcript of the chat log from #wunclub

I'm done.

 

[ridgescan]

You didn't "question" me-you "lol'd" called me "silly" and basically responded like it was stupid. So go ahead and provide the transcript hotshot-it's NOT the way you just twisted it. I do videos because I am tired of people like you, who, by the way TAKE THIS HOBBY WAY TOO SERIOUSLY in that you act like an arrogant know-it-all and talk down to people you deem to not know what you know. Then when I provided proof in the videos that it actually works, you only said "ya it will reduce noise etc" only AFTER I prompted you to at least acknowledge the video. You STILL have yet to acknowledge the fact that lots of folks use this technique, because you don't want it to be true
You are mad now because as it turns out, I'm not alone in using this technique, which, by the way, has a MUCH better effect of bringing forth the desired voice than that crappy sucky variable noise reducer which, past setting ONE out of FIFTEEN is completely useless. Same with the ANF which only sounds like the speaker has been placed into a tunnel.
Sure, I am probably over reacting to this, but it still aint as bad as you arrogant bigshots in here who like to think you're the last word in all things tech-turns out YOU wound up the minority in this case.
Ya I need to learn to take critisizm better yup.
YOU need to learn to be respectful in turn towards those who show you respect
Like I said before, and this is KEY to why I am upset so pay attention Nick; you would NEVER think to talk down to people like Brandon or Token in that "chatroom" but you decided it was perfectly ok to do it to me. Think about that. Yeah I don't even pretend to know what you and those guys know..matter of fact, it's pretty clear in my asking of questions to you guys that I KNOW I have a bunch to learn right? So as a man I feel I deserve the same respect from you as you would readily give to them..I feel I try to help people with what I DO know which is what the conversation there sort of turned into so I feel I have earned at least not to be embarrassed in a forum.
The fact that I somehow elicit that kind of disrespect from someone like you is why I am upset. I did NOTHING to you to warrant it.
Get the transcript so at least people reading this can get why I would be so upset-AND-when you read the way Nick talked to me there, try to fathom him talking that crap to Token lol or Brandon.
Then I will rest my case.

 

[ridgescan]

By the way-your personal attacks on me say a lot about the kind of person you are Nick-which is what started this.
"YOU need to grow thicker skin"
"YOU do this all the time"
"YOU freak out"
You know what is the funny thing-Token and Brandon happen to show me mutual man-to-man respect both here AND there in that chatroom Nick. Never had one problem with either of those gentlemen. Know why? They BOTH have corrected me and otherwise took issue with something I have posted that was wrong or needed more explanation, BUT they know how to convey without disrepect.

Thanks to Martin and Ron for helping me out. Sorry to the forum.