ICOM R7000 lack of sensitivity

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ICOM R7000 lack of sensitivity

Postby ebdons » Sat Feb 03, 2018 5:28 pm

Hi All, just joined this forum, so a newbie I am!, I know the R7000 is a bit ancient compared to what is available now, but these do have a following even now?, I bought mine as a base scanner/radio for analysing radio freq etc, lots of info about these online, so I wanted to ask if this unit needs a CAP rebuild, it takes 5 min to warm up to get even Radio 1, as I'm picking up very little in weak signals even with m1000 amp and discone ant, had a look inside and work has been done ie: some new caps etc, should this receive radio 1 without an amp? please forgive my ignorance of terminology etc, is there a test signal I can use to test signal strength etc? all the best Tony
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Re: ICOM R7000 lack of sensitivity

Postby m0lsx » Sat Feb 03, 2018 6:13 pm

I have a R7000 & it's a a very capable receiver. I love mine.
I use mine mainly on satellites, as I can follow the Doppler shift so easily. And occasionally on amateur SSB RX.
As a scanner it is terrible, but as a RX I find it to be very good.
Why are you using a pre amp with it? That could be causing desensitisation & all sorts of problems. And I assume that is a M-100 & not a M-1000.
Pre amps have a place to play in radio, but not if you are putting them the wrong end of the coax. A pre amplifier should go either the antenna end of the coax & have good bandpass filtering, or just before a splitter. They should never go the radio end of the coax.
All of the deterioration in a signal happens in the coax, so amplify the signal while it's at it's best quality, not after it has deteriorated.
Also have you checked the antenna system to make sure that is not at fault for the poor RX?
But having said the above it does sound like it's either the pre amp messing things up, or the Icom not working like it should.
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Re: ICOM R7000 lack of sensitivity

Postby ebdons » Sat Feb 03, 2018 6:48 pm

Hi Thankyou for the quick reply, my amp is the M100 moonraker,i have a discone Hf type antenna with low loss rg213 coax to a lightning protector, length of coax 12 ft max with the amp connected between the last length of coax and the radio, if I turn the amp off I get poor recep even on radio1,so maybe this unit needs re-capping?, . all the best Tony
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Re: ICOM R7000 lack of sensitivity

Postby m0lsx » Sat Feb 03, 2018 6:55 pm

How does the antenna behave on other radios?
Who soldered the connectors onto the coax? And have you made sure you have continuity where it should be & none between outer shield & inner core?
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Re: ICOM R7000 lack of sensitivity

Postby ebdons » Fri Feb 09, 2018 4:23 pm

Hi, sorry for the delay, tried my old cb radio which is only 40 channels but nothing picked up not surprised, transmit power 9 on the meter, but looked at the leads can't find anything wrong with the connections, can only get strong FM stations but only after waiting for 5 mins for unit to warm up, if I turn the amp off on a weak signal as it powers down I get a stronger signal for 1-2 secs then nothing, I'm thinking this needs either a full cap replace kit or just the ac/dc unit? will look into it. all the best Tony
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