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Rick Kunath wrote: "John Plimmer" wrote (in part): I would sell kidney or other spare body part tonight to buy one. However I live less then 4 miles from a littlel 1KW MW on 770. And we a few fairly local power houses at 590 and 630 and 1300. On the 7030+ I could receive the 770+590 fairly strong the , the 770+630 and and the 770+1300 very strong. In a nearby park about twice as far from the 770 station as my home, I get no mix products. The 770 is so strong that it will show up in most receivers even with the antenna disconnected and replaced with a 50 ohm terminator. Is there any possibility that you have the rear-panel pre-amp turned on in the 7030? What happens when you add in 10 dB or so of attenuation? Rick Kunath I tried adding 10 db attenuation and even more, but it didn't help. Steve |
Telamon wrote:
The 7030 has a metal case and so is shielded. This looks like a good case of the BCB station coming in on the power cord through the house wiring. With the 50 ohm resistor on the antenna terminal use a RF choke on the DC power cord to the radio to see if the AM station goes away. Same should work for any other radio that has a metal case. The non-shielded radios may have the RF go through the case as an additional path to consider. -- Telamon Ventura, California -------------------------------------------- I can only wish I had my own 2030+. This was a borrowed unit from a friend who was wrapping up the sale of her family farm after graduation. I did try to place several ferrite RFI "snap on", and while I could reduce the interference, even with over 10 on the power cord I still had a very weak signal on 770 and the 770+590. I was really suprised by the R390 and R392. In these receivers the RF was getting in through the audio line. High level RF is hard to completly supress. At least the 770 station cleaned up their harmonics. A nice letter with the comment that I would hate for them to get fined for improper operation got the problem solved within a week. The 1540, 2310 and 3850 were very strong. No 4rth harmonic at all. A high pass filter ruled out my receivers. I wonder how many people have MW ingress and don't know it. Sometime "real soon" I am going to psot the results of my RF week end and how bad normal single or double brain only coax is. By bad, I mean allows LW/MW and HF if any stations are close or strong enough to leak in even with out an antenna connected. I tested 100' of various good quality (Belden) coax. and one run of 200' (borrowed) run of triax. Terry Terry |
I considered this, but I think the problem is too severe...especially
since the HF-150, with its notiously weak front end, is not as badly affected. Also, tonight I noticed an image not just of a powerhouse broadcast station here in NYC, but of a relatively strong shortwave signal (Radio China International). I think a little bench time is required to correct this problem. Steve |
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Rick Kunath wrote:
Is there any possibility that you have the rear-panel pre-amp turned on in the 7030? What happens when you add in 10 dB or so of attenuation? Rick Kunath ------------------------------------------------------------------------ Preamp was off. Attenuation didn't mater. It was reduced with a 50 Ohm termanator on the antenna port but not eliminated. Wasn't bad enough to be a problem, after all if a R390 and the R392, completly shielded in a tough aluminium case with 4 1/4" bolts per side of the front pannel, that amke good contact witht he front panel and the case, both received the 770KHz signal, I wan't suprised the 7030+ and almost every other receiver I have tried picks it up. I would consider selling a kidney tonight, if legal, to get one. I LOVED the receiver. Sadly the ARM and QRN noise floor is my limiting factor, even my R2000s don't reach their internal noise floor because of the external crap. But the selection of filters, the synch detector, tunning steps, optional PC control make the 7030+ my dream receiver. At my QTH any signal I could receive with the 7030+ I could receive with either of R2000s. But the synch detector is magic. The better filters allow listening to weak signals that will give you a head ach on the R2000s. Signals that are dificult to impossible to understand on the R2000 are hard much easier to understand. I can't explain the difference, reminds me of the tube/valve HiFi debate, but I will never be satisfied unitl I have my own 7030+. Even with similar bandwidths the 7030+ is the clear winner. And it isn't just a pahse noise issue. Comparing it to a R390 and R392 in a friends fairly RFquite country home, the 7030+ beat the R390 and R392 in weak signal "understandability". I don't have a scale to measure it, or even words to really discribe it, but the 7030+ is just "cleaner". The R39X have "no" phase noise. I had always writtensome of the less then perfect weak signal performance of the R2000 to phase noise. I now know that isn't the whole story. Don't get me wrong, for what I have in my R2000 they are great receivers. Kind of like comparing a Toyota Camray to a Lamborghini. The Camray will get you there, but the Lamborghini will really get you there. The only improvement for the AOR 7030+ that I can think of is a 90% price reduction. I would gladly trade my PCs and all of my radios, ham gear included for a 7030+. Terry |
The 7030 has a low-pass image reject filter that cuts off just above 30MHz,
a low-pass filter that cuts off at 1.7MHz, and a high-pass filter that cuts off at 1.7MHz, so MW bleedthrough shouldn't be a problem. If there is enough interest, I will market a 7-band preselector. This will consist of a low-pass filter for the range below 500kHz, with bandpass filters for the ranges above 500kHz. I will use PIN diodes for range changing. Interested parties can e-mail me directly and we can go from there. Pete wrote in message oups.com... I'd be tempted to agree with you if I hadn't compared the 7030+ with my HF-150 this morning. The HF-150 was significantly less prone to overload than the 7030+, and I can't believe it would be if the latter were performing up to specs. I suspect the SD5400 mixer is damaged, since that's known to produce this sort of problem. I'm also sort of hoping it's a damaged SD5400 mixer, since that's a relatively easy thing to fix. Steve |
I'm using a Wellbrook 330S antenna and I don't think it's suffering
from any problems. I use it with my other receivers and they seem to function well with it. Occasionally there's overload on the HF-150, but it's always pretty minor, not like what I'm experiencing with the 7030. This makes me suspect the problem isn't with the antenna. I can even connect my SW77 to this antenna without getting the kind of overload I'm finding on the 7030. Steve |
wrote in message oups.com... I considered this, but I think the problem is too severe...especially since the HF-150, with its notiously weak front end, is not as badly affected. Also, tonight I noticed an image not just of a powerhouse broadcast station here in NYC, but of a relatively strong shortwave signal (Radio China International). I think a little bench time is required to correct this problem. Steve So Steve, does the 7030 feel a lot like the 150 since Mr.Thorpe designed both? Can you see a lot of the 150 in it? Do you think the 7030 is worth that much more then the 150? Would you call the 150 the "poor man 7030?" Lucky |
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