- Reviewed by
- Review date
- Aug 16th 2009, 08:30
- 5 of 5
- Build quality
- 5 of 5
- 5 of 5
- User friendliness
- 5 of 5
- Value for money
- 4 of 5
Icom IC-7700 and IC-775DSP compared
This review was written by Bob WB8B and is placed here by permission.
This review of the Icom IC-7700 is essentially a benchmark comparison to my Icom IC-775DSP, which has served me well as the main rig for the last 10 years. My objective is to point out some of the main characteristics that I have observed on the IC-7700. Please note that there are many other apparent qualities of the IC-7700 in regards to phone and digital modes of operation but which go beyond the scope of this review and commentary.
I’ve been an avid, all band, CW DXer for 22 years with emphasis on 160mtrs while also operating in the CQWW-CW, ARLDX-CW, and other contests. I am not a phone op, and am as rare on phone as P5 North Korea is on all the bands, so my review may not help those who favor operating phone. Previously owned rigs include Icom IC-735, 746, 751, 751A, 765, and 775DSP along with a short term in-shack usage of an IC-781 and Yaesu FT-1000MP.
Sometimes we hams fall victim to a “wow” trap when we first get a new rig, just dying to put a review out instead of waiting a while and then giving a more non-biased observation once the new rig’s been in the shack for a while. Before a rig review, it’s nice to hear that the new owner gave some time and attention in performing real A-B comparisons to old shack benchmarks that have been used to for many years. Since I perform testing, validation, and benchmarking of electrical and mechanical components as a test engineer, and am analytical by nature, I can easily state things like I see them and give a non-biased observation even though it was a lot of ‘my’ hard earned money spent.
The IC-7700 was put to the test against my old IC-775DSP that has the stock cascaded 500 Hz CW filters for the 9 MHz and 455 kHz, and an optional 250 Hz filter by Inrad for the 455 kHz I.F. Please note, there is one CW filter spot empty on the IC-775 which is the place holder for another 250 Hz filter in the 9 MHz I.F. The high pass and low pass receive audio filters were set on the IC-7700 to match the widest settings of those in the IC-775 during my observations.
S9+30dB and greater CW signals were hunted down on all bands with an emphasis on 80/160mtrs. I frequently looked for the perfect recipe for receiver comparisons by searching for those situations where a very weak DX signals fell within 100-200 Hz of those bigger S9+30dB and greater signals. These are the basic metrics (in my opinion) in a receiver that can make or brake getting that weak one in the log while fighting big signal QRM.
What I had found was that both rigs performed almost equally when the filter bandwidth of the IC-7700 was set to the same 250 Hz bandwidth of the IC-775 narrow filter. If the IC-7700 had the shape of the filter set to “soft”, the IC-775 did a better job; but when the IC-7700 had the shape of the filter set to “sharp”, the IC-7700 was slightly more selective. To get the interfering CW signal out the IC-775 pass band, you had to be 200 Hz or greater from the QRM signal, while the IC-7700 could give you an additional 100-125 Hz of playground next to that big signal. The IC-7700 can also go down to a bandwidth of only 50 Hz; this is where the upper hand comes in. I discovered that the IC-7700 is more capable in selectivity verses the IC-775. These observations included repeated deep scrutiny of the weak signals to make sure the classic desense issue was not evident as typically found in older generation DSP only rigs where close in signals became severely desensitized due to poor blocking dynamic range. I found no audible attenuation from filtering of even the weakest signals, even on the higher 10-15mtr bands where the noise floor was very low and quiet with preamp2 engaged. My consensus is that the IC-7700 has more capability in selectivity due to these selectable narrower bandwidths down to 50 Hz, but without noticeable receiver desense. However, the horse race could get tight if I were to opt for one of those 125 Hz, 455 kHz IF, CW 8-pole filters by Inrad to place inside the IC-775DSP.
Many hours were spent comparing the IC-7700 to the IC-775 on the higher 10-20mtr bands in search of the weakest signals. What I had found was that the receiver sensitivity of each rig was practically equally sensitive. This was also the case even on the noisiest of bands including 80/160mtrs in the late evenings while pulling out the weakest signals I could find. The comparisons were done with the receiver preamps in the OFF, preamp1 and preamp2 settings. More emphasis was placed on comparing preamp2 of both rigs on the high bands 10-20mtrs. It was a draw between the two receivers by my ears.
One feature on the IC-7700 is the choice of 15, 6 and 3 kHz roofing filters in the filter menu. These filters allow for high values in close in blocking dynamic range to fight against very strong close by signals. To actually hear a difference between the 3 selectable filters, the very strong interfering signal or signal(s) must be somewhere between 6 to 20 kHz or so from your receive center frequency to observe any differences between the filter selections. I aggressively toggled between the three bandwidths during a couple of contests that including many loud stateside signals on 20 and 40mtrs. I honestly did not hear much difference between the three roofing filters. This may have been due to the strongest signals on the bands only making it up around S9 +35dB, and far from 50 to 60 over S9 where various test lab characterizations of the receiver have been done which verified the integrity of the roofing filters performance. A run down to the local AM broadcast band here in the Detroit area provided a myriad of 40-60 over S9 signals to experiment with. I noted a small difference in selectivity when attempting to pull in weak AM signal carriers 10 kHz away from 60 over S9 local station signals. These filters do work, but don’t expect them to jump out at you and act like conventional optional SSB or AM filters with deep skirts.
When operating the IC-7700, initially it was not apparent that you can turn off the AGC, something that I had overlooked and only found out literally the next day after submitting my initial review (I apologize on my part). Turning off the AGC is not achievable via the AGC button, nor is it even selectable as a pre-setting in the AGC set up menu, but via the AGC VR button by holding it in for 1 second. For that matter, the feature can easily be missed even after many rounds through the 200 plus page owners manual. I had initially figured that you just can’t turn off the AGC and did not pursue the matter any further since it had a decently fast AGC attack setting anyway selectable down to 100ms. The AGC is fast enough to help copy those weak signals within frequent large signal transients and static crashes. After getting used to the IC-7700 faster AGC response, I never realized how extremely slow the IC-775 AGC circuit really was!
There haven’t been too many instances where my AC line noise has been terrible enough where I really needed to run the NB feature hard on the IC-7700. There was an instance where I had the classic AC line insulator arcing interference at an S4-S7 signal on 10-17mtrs. This line interference was a little more random and rough in sound than usual, and the IC-775 was having an issue getting rid of all of it, which is usually not the case. A-B comparisons between the two rigs at that time revealed the IC-7700 did a lot nicer job at getting rid of that particular AC line noise. Please note however, the IC-7700 noise blanker is not a “smoking gun” by my standards (none of them are). The IC-7700 still suffers from the problem that every rig I have ever operated has, and that is the NB blanker will fall apart even with adjacent, moderately strong signals, even with the front end preamp in the off position. As an example; 10 meters with no signals on the band and a high level of line noise. Enable the noise blanker and it’s gone, even at the lowest NB level setting and depth. However, get one station calling CQ on the band within 50 kHz and an S4 or greater signal and you will hear a splatter sound from that calling station up and down the band. I think this NB anomaly is one symptom we will never see go away in a receiver.
CW SIDE TONE MONI ADJUSTMENT:
I’m not sure why the IC-7700 manual makes a pictorial reference to the front panel “MONI” control adjustment for the CW side tone, because this control does not function in CW mode. There is a CW side tone level adjustment in one of the set menus for adjustment of the side tone output level, but the “MONI” adjustment on the rigs face does not apply. Most other Icoms I have had in the past included an external “MONI” adjustment without going into a menu. This may, or may not be an issue to other CW ops, but I do find myself adjusting the side tone in the SET menu semi-frequently depending on the level of shack ambient noise.
AF GAIN / SPEAKER:
The first impression I had of the IC-7700 receive audio with the built in speaker was not too good. The internal speaker requires a high level of AF gain setting to obtain a decent level of audio out. However, the internal speaker did produce fairly decent fidelity when listening to some AM broadcast stations in 10 kHz bandwidth. It didn’t take long though to hook up my commercial Motorola communications speaker which improved the audio level greatly. The IC-775 suffers similarly with its internal speaker and I recall even my old IC-765 was the same regards to level output. Many of Icom HF transceivers have been plagued with this issue after the IC-751A era. My old IC-751A will throw you out of the room with just its internal speaker and the AF gain at less than 10-11 o’clock! The IC-7700 has half the volume output at the same setting with its internal speaker. The question is; what happened to Icoms audio output level over the years?
DIGITAL MODES / USB KEYBOARD:
The IC-7700 accepts a USB keyboard to function on PSK and RTTY, along with sending of the four CW memory keyer memories via the keyboard F1-F4 keys (with firmware v1.10). With the ability of the IC-7700 to do both RTTY/PSK31 with its internal modem, it baffles me as to why it couldn’t also include provisions to send CW via the keyboard. I seriously doubt this could have added much, if anything, to the cost of the rig! Keyboard CW with the IC-7700 would have been a very nice feature for us CW ops! Hopefully this is something that could be added in the future with a simple firmware upgrade.
7” COLOR TFT LCD DISPLAY:
I am quite pleased with the brightness and contrast capability of the IC-7700 LCD display. My shack includes a nearby outside window with a moderate level of incoming outdoor light at a 60-90 degree angle from the radios. The display has contrast and brightness settings on the front with a menu setting “pre-adjustment” for the brightness level. I am the type that doesn’t need or want an enormous level of brightness on any kind of display such as a computer monitor or TV screen, so there really aren’t any issues here on the IC-7700. I’ve been content with leaving both brightness control levels down all the way with just a bit of contrast. There’s been just a few times when direct sunlight is close to the operating that desk I’ve turned the brightness up to 40 to 50% and the contrast up a little to compensate. Nice job on the display!
AUTOMATIC TRACKING RF PRESELECTOR:
For those who first operate an IC-7700, you may ask yourself the same question I did regarding the digital preselector. “Does this thing work, or just make a bunch of clicking noises when you dial around the bands making you think it’s doing something?” This automatic preselector adds selectivity ahead of the 1st mixer. It reduces IMD from strong signals near the received frequency. My first verification of the preselector’s integrity was when I was calling CQ on 30mtrs at 200 watts on the IC-775, while tuning around on 15-20mtrs with the IC-7700 with a yagi on the same tower. I definitely detected the infamous IMD noise quite familiar at any field day site or during a contest station with a multiple transmitters going on different bands. When I first heard the interference, the first thing I thought of was to engage this auto preselector feature and see what happens! Well, it worked! The interference from the 200w transmitter at on an antenna on the same tower disappeared! Please note however that under typical, casual, operating environments, where there are no pile-ups, no super big signals or contests going on, you may not even know this feature works. When you do need it though, it is very impressive!
VFO SPLIT OPERATION with XFC BUTTON.
One small inconvenience while operating split VFO in a pile up on the IC-7700 is the type of button used for the XFC (transmit frequency check). I operate many DX pile-ups, and I use this feature literally 100% of the time when working splits. The IC-7700 XFC button is mostly flat against the surface of the face of the rig and located in the top left area of the main VFO knob. I find myself frequently using the finger on one hand to hold in the button, while using the other to tune the VFO. When using an XFC feature, I found the IC-775 more comfortable to use because the button protrudes out a little, so that just the tip of the finger can easily depress the button, while keeping the thumb and index finger free for turning the VFO knob. This allows for easy checking of the TX frequency AND control of the VFO knob at the same time with only one hand, while keeping the other hand free for things like the cw paddles, keyer controls, antenna rotor controls and etc. This may seem like a very small concern, but if you haven’t worked pile-ups in split mode that sometimes last for hours, you just won’t know. The IC-775 has an XFC button that sticks out about an eighth of an inch making it a bit easier to depress with the finger tip AND spin the VFO knob with the same hand at the same time compared to the IC-7700. A “softer touch” button requiring less depression force and protruding out a little from the face of the rig would have been nice. Again, it’s just a small inconvenience.
This is serious money for a new rig, but referencing a 1996 AES catalogue shows that $5800 today (the deal ‘I’ got, before the increase to $6500+ now) is the about the same dollar amount one could have spent (inflation adjusted) for a new Kenwood TS-950SDX, Yaesu FT-1000D, a bit more than an Icom IC-775DSP, and also 30% less money than a brand new Collins KWM-2 transceiver in 1959! The Icom IC-7700 is a very capable transceiver with a lot of bells and whistles, but at a price that many may not afford. There are other transceivers available that do a decent job for less money, but without some of the refinements contesters and DXers prefer. An analogy I use on HF rigs is that their cost could be like comparing cars to drive on a long distance trip, driving say 1000 miles a day (this is like a “contest”). Most vehicles (radios) will do the job. Most vehicles (radios) will get you there. The question is, how tired, fatigued and frustrated will you be on the way to your destination? If this happens to you, it’s possible you just don’t have a nice enough vehicle for the trip and you got what you paid for.
I agree with Icom’s marketing phrase used for the IC-7700 as “The Contesters Rig”. That’s exactly what it is and it could also be easily marketed as “The DXers Rig”. The IC-7700 has many receiver refinements and features that provide you the necessary tools and comfort required for those very long durations in the operating chair, making contacts and enjoying the bands, while not getting disappointed like you can with other rigs that provide inadequate selectivity, fatigue from a noisy receiver, and poor ergonomics. HF rigs are a hams tool to get the job done, make contacts, and have fun. ‘You’ have to ultimately be the judge and are governed by what your wallet says and what your operating preferences are. The IC-7700 may not be for you, but at least I can speak for the DXing/Contesting arena, we have a big winner in the shack and, yes, it’s a keeper!
I hope you enjoyed my review and commentary on the IC-7700. I have read many reviews by fellow hams over my 20+ years as a DXer and have accumulated a wealth of information and knowledge from them. I thank all of those who have provided such information. I thought I would return the favor and give a little back, especially for those who may be contemplating an IC-7700.
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