New SDR CommRadio CR-1

[ktulhu]

1872 was released to correct a tuning step bug for broadcast FM.

I can see that the tuner chip employed in this receiver, is quite sensitive on he BC FM band (-107.3 dBm), meaning there is no hardware limitation as far as FM sensitivity is concerned. Meaning - CR-1 might potentially be a good FM-DX machine, too!
At the same time, CR-1 specs list a much worse figure (-88 dBm) for the FM broadcast band. Is that a typo or tuner gain is deliberately limited/set to low for some particular reason?

I clearly realize that UHF/VHF coverage comes (or at least is positioned) as bonus, and may be of limited interest to designers/buyers, however, isnt it worth using the tuner chip potential at its maximum, regardless of received band?

Can you also clarify what's the currently programmed bandwidth setting for the BC FM band? Owner's manual lists 200 kHz,, however, i must have seen a different figure somewhere in this thread (100 kHz).

My question is - are there any plans to develop the WFM functionality of the receiver? What i mean is adding a couple of additional WFM bandwidths like, say, 80 and 50 kHz for FM DX-ers? Or, maybe, RDS/PI decoding? Hopefully, EEPROM chip has sufficient memory for additional coding.

I understand that you have different priorities at the moment, however, can we (FM DX-ers) expect some advancement in the future?

 

[W8RMV]

Hi to the group. I've been playing around with my CR-1 (SN0240 latest updates) for a week now. I think I have all of the menu functions, tuning, scanning, memory etc mastered at least on HF. I don't have any VHF or UHF antennae so will get to that later. I find the unit performs very well in all respects running of my 67.5 foot Eavesdroper SWL Sloper. Don't find the AGC an issue at these frequencies. Haven't done any comparisons to other receivers yet but this unit is convenient and simple to operate once you get the hang of it.

I read this entire thread when I got the radio but now can't seem to find the posts relating to the "Last" button and functions. Also, (probably related) I am looking for the protocol that defines where the frequency is set for each Ham or SWL Band when you land there scrolling through the bands. Can someone please point me to that page?

Cheers,
Rick

Hi Rick,
I am surprised (but happy for you) that you find the AGC is OK. Maybe there are differences in radios or just significant variation to the listener and/or QTH. The AGC remains the biggest detractor to the radio for me. And CommRadio has admitted that it is being worked on. Once the AGC is fixed, I think I'll be a happy camper.

It is very ez to make a simple FM BC band dipole with some simple lengths of wire. Even old rabbit ears work very well. The CR1 is not the most sensitive radio for the FM BC band, but it will pull in strong stations.

And I also can't get the LAST button to work either. Maybe operator error. - 73 Bob SN76

 

[W5RST]

The "Last" button doesn't seem to be implemented yet, as far as I can tell. It's also not mentioned in the PDF version of the manual, which is searchable.


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[NRD-505]

Here's an explanation of "Last" button:

http://forums.radioreference.com/2012790-post749.html

 

[W5RST]

OK, thanks for the information. I'll give it a try tonight when I get home.

73, Mike N5JKY


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[tuihill]

Thanks to all for the info about the "Last" button. Works as explained well by Bob WB2KTG. In answer to Bob's questions: 1. - Yes, I will use this feature often. 2. - Yes, it works how I want it to and I can't think of any way to improve it.

 

[W5RST]

I also tried it, and yep, it works as the previous post describes. It is handy for within band checking of two frequencies.

Mike

 

[WB2KTG]

Thanks for your inputs regarding LAST. I'd welcome additional inputs from others as well...

Bob

 

[W5RST]

Interesting experiment

One of traits of homebrewing radio equipment is that you tend to acquire test gear. I have a little crystal-controlled signal generator that puts out either an S9 or S1 signal on several popular ham qrp frequencies. We're not talking about laboratory grade stuff here, but it does come in handy for testing receivers. So, I did a comparison between my Yaesu FT-817 and the CR-1 on 7040 kHz. Here is what I found:

S9 setting:
FT-817 - S meter read S9
CR-1 - S meter read S9

S1 setting:
FT-817 - S meter went between no signal and S1
CR-1 - S meter read S3(!)

Also, at the S1 setting, the audio was definitely louder on the CR-1. I didn't try to get fancy by taking readings with an audio voltmeter to get accurate S9 to S1 ratios, but by ear, having not adjusted the volume control of either radio from the S9 signal, the CR-1 was louder. These results tend to confirm my subjective impression that for shortwave the CR-1 is at least as sensitive as other commercial gear. It also suggests to me that some of the occasional AGC issues I've heard might be solved if it were possible to reduce the sensitivity when needed.

 

[MrMushroom]

check you dropbox new updates

 

[WB2KTG]

Like MrMushroom said...

There will be a newsletter and software upgrade in the DropBox site shortly. "One small step for man, one giant leap for the AGC" or something like that. I used it for the past few days and am very happy with the improvements!

Bob

 

[W5RST]

Just looking through the newsletter, this update looks to be potentially exciting. Can't wait to get home after work and load it up. Really like the slow-medium-fast AGC option. FM for 10M is nice, too.


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[NRD-505]

Just in time for Labor Day weekend!

 

[disapa]

UPDATE!

The new update seems very good. I have been tuning in radio Greece here on both my CR1 and my radiojet and the signal hovers at between +10 to +15 on the radiojet while the CR1 is at +10 to +30. Even on the fast agc setting, I hear no "pops" at these levels. I am going to test it on 40 meters next. I can also crank the volume on the CR1 much louder without the same "pops" that used to follow the volume settings. I am very happy with this update and eagerly awaiting what others think. This radio is getting better and better. Now it does not desense when tuning the miracle antenna to find the loudest signal point either! Nice job Commradio Crew! Dion

 

[shortwaver]

Very happy to see the AGC update! Is it just me or does it seem like this update changed the volume in some way? My volume seems to increase or decrease in steps...not smoothly.
It may just be because I'm in a quieter area while testing it today.

Yes..Thanks to the Commradio crew and Don.

 

[disapa]

It has always increased in steps. Sometimes I use a headphone amp to make adjusting the volume more precise. There is also a distinct difference between the agc choices. This is like a new receiver to me! Dion

 

[W5RST]

I put the new CR-1 update through it paces tonight: W1AW code bulletins, SKCC CW sprint action, SSB ragchews, SW broadcast stations, FM broadcasts, HF utilities... I have to say this update is a big step up in performance, particularly in AGC function. Also, it seems to me that VHF performance is improved: at least commercial FM reception of my favorite station is now solid without noise. Don and the crew at CommRadio deserve a big tip of the hat for this update.

 

[W3OWL]

I returned my CR-1 today for a refund. After 5 days, I decided this rig really didn't offer anything unique, except for the small size. It's a rather expensive radio for something requiring continuing "upgrades" just to get it to function properly. Bill.

 

[scowl]

Now we're getting somewhere!

At least in the HF band last night, tuning is much more pleasant. In some crowded areas full of strong signals I heard very light tapping sounds but nothing like the horrible popping and grinding and dropouts of previous firmwares. Almost all of the time it was no different from tuning a quiet analog receiver. In fact for the first time I came across a very weak Australian weather station that I was probably missing because it's close to WWV.

I was using the Fast AGC setting. I haven't tried any other settings. I also haven't checked to see if this has made VHF tuning acceptable.

I have a lot more testing to do but the early results puts the CR-1's performance even closer to a classic high end analog receiver.

 

[NRD-505]

It is noticed that the AGC speed is not saved upon shutdown and reverts to "Medium" upon power-up. Is this behavior by design?