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 permissible in your locale.

Author Topic: Icom IC R-75 comms receiver performance...  (Read 5915 times)

Offline Looking-Glass

  • DX Legend
  • ******
  • Posts: 1139
  • Condobolin, NSW, Australia
  • "Old fashioned DXer, no offshore computer rxing!"
    • View Profile
Icom IC R-75 comms receiver performance...
« on: July 26, 2018, 0723 UTC »
Finally, in the last few days I have had the opportunity to put the newly purchased Icom IC R-75 communications receiver through its paces and compare it with my long trusted Yaesu FT-2000D transceiver, which also doubles as a comms receiver.  Some of the regulars asked me to post what I think of the radio so here I go:

I was fortunate enough to purchase one of the last two brand new IC R-75 receivers from Icom Australia down in Melbourne, I was told this line ceased production some two years ago.

Primarily, I purchased the radio for LW and MW DXing and it has not let me down and compares well to the Yaesu. 

On MW I noticed that many stations are distorted and this was rectified by switching out the Noise Blanker, beautiful clear reception with the NB switched off. It pulled in ZB Talk Radio in Wellington, New Zealand (around 2,200kms distance) quite well on my evening Grey Line and compared well to the FT-2000D reception of same.

Early this morning the NDB band was performing well and the following were logged:

1534z  FRT  278KHz  Forrest WA for 2,191kms 319-419 report.
1536z  LEO  377KHz  Leonora WA for 2,793kms 319 report, new logging, first time heard.
1541z  WLU  383KHz Wiluna WA for 2,973kms 419 report.
1548z  KA   404KHz  Karratha WA for 3,581kms 419 report.
1624z  WP  377KHz  Weipa QLD for 2,468kms 319-419 report, this beacon not heard for around two years.
1631z  GV  380KHz  Gove NT for 2,783kms 419-519 report.
1905z  TNK 272KHz  Tennant Creek NT for 2,224kms 519 report.

The above loggings attained by NOT using either Pre-Amp-1 or Pre-Amp-2, running 380 feet of wire via the PL-259 plug to the radio SO-239 socket.  I found reception of weak NDB's much clearer without introducing the PreAmp functions.  The PreAmp both 1 & 2 increase the noise threshold too much, so left off.  I did introduce the Twin PBT function and found it clarified some of the weaker NDB's pulling them out of the noise but for the majority of the time this function was left off.

Unfortunately the band was not open to New Zealand but I did log Kaitaia, New Zealand on 238KHz 519 report around 1130z a couple of nights previous for 2,081km on the R-75, its first overseas logging.

Surprisingly the R-75 doesn't seem to attract as much crud and birdies from MW on the NDB band that the FT-2000D does and I didn't really need to use the home brew filter (cut off at 500KHz) that is in line all the time with the FT-2000D.

The digital bar graph signal meter seems to lack with NDB local beacons, about a one and a half to two 'S' points difference compared to the analogue FT-2000D meter.

The small speaker at the face of the radio is a little bit of a let down, but once you get used to it things are fine, however, I find by connecting it to the Yaesu SP-8 external speaker (matches the old FT-1000D transceiver) with High/Low filters the R-75 sounds a lot better also NDB reception audio is enhanced by tweaking the High/Low filter switches on the SP-8 speaker.

Receiver noise level is excessively high until you connect an earth wire to ground, so using the R-75 in the bedroom is out of the question at present, thinking of filling a five gallon drum with good garden soil and run the wire to that and see what happens?

A surprise bonus was to find out that I have in fact the Asian domestic version of the R-75 with continual coverage from 30KHz to 60MHz, the Australian import version does not have this feature and cuts out at 30MHz and comes back in just below 50MHz I am told. So will be utilised well for the summer 50MHz DX season to check on rising MUF and out-of-band indicators.

Have filled up just over half of the 100 Memory Channels with NDB and M89/V07/HM1 frequencies plus some aviation and marine frequencies. 

On the Tropical Band section of SW it pulled in the regular stations I hear from the USA, Pacific and Asia on the FT-2000D with ease and nice audio (providing the NB is left off).  The test will come this weekend when I chase African shortwave DX between 3 and 7MHz in my early mornings.

Not into digital bar graph style signal meters but beggars cannot be choosers I guess, signal strengths compared with the analogue meter on the FT-2000D are favourable and acceptable.

Bit disappointed that no internal AC power supply, as with the majority of HF comms receivers of days gone by.  Not real keen on the AC adapter method of providing power, time will tell.  Another irritation is the poor quality Earth connection via a plastic push mount next to Antenna-2 long wire connector.  Should have been a more solid wing nut connector towards the bottom of the radio.

In built speaker is suffice, but could have been better, once you get used to it it's acceptable, external "quality" speaker is the way to go.

Be interesting to see what advantages the optional UT-106 DSP Unit and Automatic Notch Filter features have to offer, perhaps someone reading this has these two options and can comment on their worthiness?

Also it will be most interesting to see how it performs in the 30-50MHz sector when the six metre band summer DX season rolls around as I am a very keen 50MHz DXer with 75 DXCC countries confirmed.

Overall, I am happy with the radio and look forward to many hours of DXing with it... ;)
« Last Edit: July 26, 2018, 0735 UTC by Looking-Glass »
Condobolin, NSW.

Grid Square:  QF37ub

Yaesu FT-1000D, Yaesu FT-2000D, ICOM IC-736 HF/50MHz, ICOM IC R75 & Tecsun S-2000 to 450 feet of wire, 27MHz 1/2 wave CB antenna converted to 21MHz & a multi band vertical of dubious reliability.

Offline pinto vortando

  • Hero Member
  • *****
  • Posts: 924
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #1 on: July 26, 2018, 0904 UTC »
Good to hear you are happy with your new R75.    ;)

A real analog S-meter beats the bar graph any day.

A comfortable headphones is my choice for weak signal listening.  IMHO, the small speakers on most radios are inadequate.

All my stuff runs off a 12 volt battery...  no power supply noise.

Enjoy your new radio.    :)
Das Radiobunker somewhere in Michigan

Offline ThaDood

  • DX Legend
  • ******
  • Posts: 1209
  • Likely, not where you are.
    • View Profile
    • Extreme Part #15!
    • Email
Re: Icom IC R-75 comms receiver performance...
« Reply #2 on: July 26, 2018, 1425 UTC »
       A friend of mine sold his IC-R75 recently, and it beats me why he did that, since I don't know what he replaced it with. He got rid of a TS-870 also. (That was a beautiful rig in every respect as well.) Anyway, In the long run, you'll get lots of enjoyment from this rig. I don't think that the "S" meter is bad in the R75, albeit I'll take that nice 'ol Icom classic analog meter in my IC-745 anytime over any digital bargraph meter. As far as having to power with an external power supply? In the long run, that is actually a better option. Why's that? It's been my experience that internal power supplies generate more than 1/2 the heat in a rig and age the components faster and cause FREQ drift. I experienced that 1st hand with a TS-711A 2M all-mode rig, (Cousin to the famed TS-440 HF rig.). I ran it for years with the internal Kenwood PS in it and it did indeed add to 5/8th more heat to the rig, even on idle receive. Then I read in the 1990's that one of Kenwood owner's biggest gripes were the failure of the Kenwood internal power supplies, and the heat that they pumped into the rigs that they powered. Long story short, I later ran my TS-711A with an EXT PS, and it indeed ran much cooler, but the damage was done, and today that rig is still wayyyyyyyyyyyyyy off FREQ on me. Come to think of it, I ran the internal PS in an old Kenwood R1000, and that 1st 30min, it would drift almost 1kHz, then stabilized. Bet ya that if I ran that with EXT PS the drift would have been less. (Damn, I miss that fun rig.) The point is, an EXT PS, especially if it's a linear power supply, and not switching, could help make that rig last almost twice as long and let you enjoy RX'ing with less noise. Annnnnnnnnnnnnnd, your idea of a GND line to a large-ass bucket of soil? Even better. Try a bucket of brine, i.e. salt water. Way more conductive than soil. Finally, try that R75 on DX'ing MW stations as well. It won't be the best sounding receiver for that, but you'll get some nice catches for sure. As far as audio quality goes on it? Got a bookshelf stereo speaker that you can add to it? And, I understand that there is a MOD to open up the audio in the R75, so that you can appreciate the audio from some of those catches. For that, and other neat MOD's, I believe that there's a Yahoo Group for that to join up.   
I was asked, yet another weird question, of how I would like to be buried, when I finally bite the big one. The answer was actually pretty easy. Face-down, like a certain historical figure in the late 1980's, (I will not mention who, but some of you will get it, and that's enough.) Why??? It would be a burial that will satisfy everyone: (1) My enemies will say that it will show me where to go. (2) On the same point, I can have my enemies kiss my butt. (3) It will temporarily give someone a place to park a bicycle. See??? A WIN / WIN for everyone.

Offline Josh

  • DXing Phenomena
  • *******
  • Posts: 4322
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #3 on: July 26, 2018, 1806 UTC »
I assume there's a way to adjust the levl of the nb? What i do is find a strong but unsteady sig and tune off a kc or so and then adjust the nb for the highest it can go without causing the signal to distort. Then you should be pretty good to go with respect to any strong sigs. You don't want a steady strong sig to adjust with as that sets the agc and keeps it at a specific level, a strong voice ssb sig is pretty much ideal for this.

On the dsp option, I find it excellent for notching, and set to about 4 in noise reduction when noise reduction is desired worked well for me. In the end, the dsp option is worth it for the autonotch alone.
We do not encourage any radio operations contrary to regulations.

Offline Looking-Glass

  • DX Legend
  • ******
  • Posts: 1139
  • Condobolin, NSW, Australia
  • "Old fashioned DXer, no offshore computer rxing!"
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #4 on: July 27, 2018, 0600 UTC »
Pinto Vortando: Thanks for your feedback, yes, cannot agree more about headphones, had a good set of Marconi Marine headphones from my times at sea in the late 1970's but they were lost in between moves about 30 years ago.  Had a pair of Kenwood headphones but too "heavy" on my ears so don't use them, they fell to pieces after 10 years.  Good on the 12 volt battery, bit cumbersome here, by the way, what hours do you get off one full charge of the battery?

ThaDood:  Interesting comments and observations, all taken in.  As for the brine in the earth bucket, well I live around 250kms from the ocean in the mountain area west of Sydney so no brine for me. Good heavy earth kept damp will be probably the way to go and see what happens. I often question the accuracy of the bar graph strength meter from time to time.  Just too used to my two big Yaesu analogue meters on them I guess.

Josh:  Not greatly worried about the Noise Blanker, it's just a push button function on the R-75 unlike the FT-2000D which is adjustable, thanks for your the comment on the DSP option, will ring Icom and see if they are still continued and in stock.
Condobolin, NSW.

Grid Square:  QF37ub

Yaesu FT-1000D, Yaesu FT-2000D, ICOM IC-736 HF/50MHz, ICOM IC R75 & Tecsun S-2000 to 450 feet of wire, 27MHz 1/2 wave CB antenna converted to 21MHz & a multi band vertical of dubious reliability.

Offline Pigmeat

  • Marconi Class DXer
  • ********
  • Posts: 6684
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #5 on: July 27, 2018, 1100 UTC »
Pinto Vortando: Thanks for your feedback, yes, cannot agree more about headphones, had a good set of Marconi Marine headphones from my times at sea in the late 1970's but they were lost in between moves about 30 years ago.  Had a pair of Kenwood headphones but too "heavy" on my ears so don't use them, they fell to pieces after 10 years.  Good on the 12 volt battery, bit cumbersome here, by the way, what hours do you get off one full charge of the battery?

ThaDood:  Interesting comments and observations, all taken in.  As for the brine in the earth bucket, well I live around 250kms from the ocean in the mountain area west of Sydney so no brine for me. Good heavy earth kept damp will be probably the way to go and see what happens. I often question the accuracy of the bar graph strength meter from time to time.  Just too used to my two big Yaesu analogue meters on them I guess.

Josh:  Not greatly worried about the Noise Blanker, it's just a push button function on the R-75 unlike the FT-2000D which is adjustable, thanks for your the comment on the DSP option, will ring Icom and see if they are still continued and in stock.

You can make your own brine by pouring water over some rock salt in the bottom of the bucket and stirring it well. A lot of CB'er's still use the "brine bucket ground" if their shack is on the second floor as the ground wire from transceiver to the ground outdoors can be resonant in the CB band.

I remember versions of them going back to when I was a kid, and that was a long time ago. Use a plastic bucket if you go that route, the tales of galvanized buckets and washtubs being corroded by the brine were and are legendary.

Offline pinto vortando

  • Hero Member
  • *****
  • Posts: 924
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #6 on: July 27, 2018, 1151 UTC »
Pinto Vortando:   Good on the 12 volt battery, bit cumbersome here, by the way, what hours do you get off one full charge of the battery?


Actually have a couple of 12 volt batteries here in the shack under the bench.  They get charged once or twice a week depending on usage for several hours with my small  1 amp charger.
Once a month they get an equalizing charge with the big charger.  The smaller battery of the two is a garden tractor battery that gets replaced every year or two in the springtime when the tractor batteries go on sale and can be had for less than 20 bucks.  The larger battery is from my car.  My car batteries  get replaced every 3 years.  The car battery goes into the shack and the shack battery gets turned in at the auto parts store.   The key thing is to not let the batteries get discharged too far.  Deep discharge and not recharging promptly is a good way to quickly kill a SLI type battery. 
Das Radiobunker somewhere in Michigan

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 31106
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: Icom IC R-75 comms receiver performance...
« Reply #7 on: July 27, 2018, 1253 UTC »
Sorry... I'm somewhat skeptical of a bucket of dirt in the shack being even remotely useful as a electrical ground. Maybe you can grow a tomato in it, with enough light?  ;D
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 / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline GC

  • Jr. Member
  • **
  • Posts: 92
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #8 on: July 27, 2018, 1440 UTC »
Sorry... I'm somewhat skeptical of a bucket of dirt in the shack being even remotely useful as a electrical ground. Maybe you can grow a tomato in it, with enough light?  ;D


I was thinking the same thing.  To me it sounds more like a short makeshift counterpoise which may help a bit but is no way a RF ground or earth if you prefer.


cheers, G near ottawa Canada

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 31106
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: Icom IC R-75 comms receiver performance...
« Reply #9 on: July 27, 2018, 1456 UTC »
I was thinking the same thing.  To me it sounds more like a short makeshift counterpoise which may help a bit but is no way a RF ground or earth if you prefer.

Yes, this OTOH seems entirely possible. I seem to recall MFJ had a device to do this with a random wire (MFJ makes a lot of devices to do things with random pieces of wire).  IIRC I have also seen plans to make your own, often using a tuned LC circuit, and a meter or even light bulb as an indicator for a proper adjustment (assuming you're using this with a transmitter). 

Speaking of proper grounding (or rather, changing the topic to proper grounding, from improper grounding), I have been on a grounding kick here. My two new recently installed beverages (south and west-southwest) have a run of about 175 ft of coax or so. This run along a fence line most of the way, about a foot above ground. Then underground and above ground another distance to a post where each antenna starts. The coax runs are not one length of coax, but made of several shorter lengths. Yesterday I decided to add grounding rods and connections to each location where two pieces of coax connect. Too soon to observe any obvious improvements, but it makes me feel better.
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 / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline Josh

  • DXing Phenomena
  • *******
  • Posts: 4322
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #10 on: July 27, 2018, 2121 UTC »
Sorry... I'm somewhat skeptical of a bucket of dirt in the shack being even remotely useful as a electrical ground. Maybe you can grow a tomato in it, with enough light?  ;D

Agreed, I am thinking the exact same thing. Just run a wire out the window to the ground, or ground it to the ground of the ac outlet. So what if the ground wire's a wavelength on 10m, it'll work better and better the lower you go freqwise. I had a 3/4wl 10m antenna up about 1wl, with the ground rod directly below antenna, not only did it work great on 10m it was freaking amazing on vlf. This is reminiscent of a study done by USN on hf rx antenna traits, they determined that a 6ft vertical over a good ground plane (ie a ship) matched to the line was just about all one needed in many cases.
We do not encourage any radio operations contrary to regulations.

Offline Pigmeat

  • Marconi Class DXer
  • ********
  • Posts: 6684
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #11 on: July 28, 2018, 0413 UTC »
I've got a second floor shack, the outdoor spigot is about 12 ft. directly below the window, so I've never had to sweat grounding my radios upstairs or the skyhooks before they go in the house.

When I was still pirating, the studio was in the shack. I didn't want to use the outdoor ground as the wire picked up all sorts of radio traffic from the nearby police and fire station. I got a 500 ft. spool of 16 gauge wire at hamfest for five bucks for that stuff & ran a short length of it to the audio equipment. I broke a couple of toes on it, but it worked.

Offline Looking-Glass

  • DX Legend
  • ******
  • Posts: 1139
  • Condobolin, NSW, Australia
  • "Old fashioned DXer, no offshore computer rxing!"
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #12 on: July 29, 2018, 0119 UTC »
Going to look at the five gallon plastic drum of earth and salts kept damp as a first option to see what happens.

Josh:  Only concrete out side of my bedroom window and a copper water pipe running along the external wall, may try that if the indoor bucket of earth/salt fails... ;)

Little IC R-75 given a run on 2-6MHz last night and was impressed with its results monitoring mixed bag of aviation on USB, M89 on CW and general low band shortwave on AM.

M89 logged on 3.378MHz CW at 1411z running the C4TY/NSF5 round slip around a 419 report impressed me as is was not much better on the big FT-2000D in comparison. ;D
Condobolin, NSW.

Grid Square:  QF37ub

Yaesu FT-1000D, Yaesu FT-2000D, ICOM IC-736 HF/50MHz, ICOM IC R75 & Tecsun S-2000 to 450 feet of wire, 27MHz 1/2 wave CB antenna converted to 21MHz & a multi band vertical of dubious reliability.

Offline Josh

  • DXing Phenomena
  • *******
  • Posts: 4322
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #13 on: July 29, 2018, 1526 UTC »
If the copper pipe's a cold water pipe (ie not directly connected to the water heater) and not a gas pipe you will likely find no better ground.
We do not encourage any radio operations contrary to regulations.

Offline Looking-Glass

  • DX Legend
  • ******
  • Posts: 1139
  • Condobolin, NSW, Australia
  • "Old fashioned DXer, no offshore computer rxing!"
    • View Profile
Re: Icom IC R-75 comms receiver performance...
« Reply #14 on: July 31, 2018, 0154 UTC »
Josh:  Yes, its copper cold water pipe, will find some heavy wire and run the earth to that and see what happens, last resort.

Interesting, yesterday between 1330 and 1420hrs local we had an electricity black out, there was zero noise right across the HF spectrum as a result.

Tuned right across HF with the battery powered Tecsun-2000 and amazed how clear and noise free, just goes to show the HF interference is being generated by the electricity supply lines out front of the house.

Other than the earthing issue, very pleased with the little Icom IC R-75 so far... ;D

Condobolin, NSW.

Grid Square:  QF37ub

Yaesu FT-1000D, Yaesu FT-2000D, ICOM IC-736 HF/50MHz, ICOM IC R75 & Tecsun S-2000 to 450 feet of wire, 27MHz 1/2 wave CB antenna converted to 21MHz & a multi band vertical of dubious reliability.