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Author Topic: QRP  (Read 941 times)

W9KY

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QRP
« on: June 03, 2021, 12:32:52 PM »

A number of years ago I had the FT817 which had so-so results for me. AM broadcast overload and mediocre selectivity. Jumping forward to the IC-703+ a big improvement but both radios have been sold. Now to the IC-705 and would like to know if anyone has done a comparison to either the 817 or the 703+ .  Don't care about the digital modes, just interested in the overall receive side from AM broadcast, shortwave, FM broadcast and the aircraft bands. Plus how easy is the radio to program memory items that would be used on 2 mtrs and the 70cm bands for FM simplex and or repeater use ? Finally I would use the radio for some HF CW or SSB activities. Might also be used as a "go to" radio. 
Tnx in advance, Mike W9KY         
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GRUMPY2021

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Re: QRP
« Reply #1 on: June 03, 2021, 01:43:00 PM »

Thomas Witherspoon has a video.  https://youtu.be/d9StxTizNpI
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K6AER

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Re: QRP
« Reply #2 on: June 03, 2021, 01:50:35 PM »

Any radio can suffer from front end overload if the local interference is strong enough. What you should have purchased is a high pass filter for the antenna feed line with a low frequency cutoff of 1.8 MHz. Another words the filter will only pass RF above 2 MHz.

As for sensitivity, if you connect the antenna to the radio and the noise level goes up then your sensitivity issues is set by the performance of the antenna not the radio.

Two KHz abject channel selectivity is set by the radio design and with SDR engineering, great strides in the last 10 years have been made. Now radios like the IC-7300 will out perform the IC-7800 ($9000) from 13 years ago.
« Last Edit: June 03, 2021, 01:55:38 PM by K6AER »
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KC6RCM

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Re: QRP
« Reply #3 on: June 03, 2021, 02:02:30 PM »

I like the IC-705 so much better than the FT-817.  To me, the audio just sounds better with the front-mounted speaker.  It's easy to program too.  There is absolutely no comparison with the display (and its capabilities) on the 705 to the 817.  I still have both radios and use the 705 primarily on the bands/modes that you mentioned.

I also purchased the Manfrotto mini tripod, a Nifty desk stand and Nifty reference guide; NM-IC705.
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KU3X

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Re: QRP
« Reply #4 on: June 07, 2021, 07:48:23 AM »

LIke K6AER said, you can get a filter to null out the AM broadcast band. Some years ago, my friend had the same issue. He had a Kenwood TS 850SAT and the local AM station some 5 miles away was really creating havoc on 160 and 80 meters. He even could hear them on 40 and 20 meters. At that time ICE made a filter just for that and it cured his problem. I have no idea who makes those types of filters now, but if you still have that problem, give DX Engineering a call. They may be able to help you out.
I had an FT 817 but back then replaced it with the IC703+. I now use a KX3 and a KX2 but I just can't part with my IC 703+, it's that good of a radio.
Barry, KU3X
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N8AUC

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Re: QRP
« Reply #5 on: June 08, 2021, 07:12:34 PM »

I've had good luck, and good results with my FT-817 (pre-ND), so I've stayed with it.

If it ever dies, I'd have to take a very serious look at an Icom 705 to replace it.
That just seems like an extremely cool little radio.

73 de N8AUC
Eric
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WA8NVW

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Re: QRP
« Reply #6 on: June 11, 2021, 02:46:13 PM »

For KU3X:
The inline Hi-Pass filter only helps when the undesired harmonic is generated in your receiver.  No filter works against incoming signals directly on channel or extremely close.  When the local 1300 kHz BC station's 10 kW xmtr 3rd harmonic is legal at 60 dB below carrier, the signal radiated on 3900 kHz is still 10 milliwatts ERP, which is pretty darn strong.  If you live within 20 miles of the antenna your receiver will hear little else on 75 meters. 
One of our former local MARS members (now SK) used to call the Detroit FCC office almost monthly to force the BC station engineer to retune, just so he could copy traffic broadcasts on 4011 kHz from our east coast military command.  He could even tell which days they mowed the grass under the multi-tower antenna array by the S-meter level.
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KX4OM

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Re: QRP
« Reply #7 on: June 11, 2021, 04:32:34 PM »

Rob Sherwood has the results of his receiver testing on the IC-705 and the IC-703+. Tabulated among many others.

http://sherweng.com/table.html

Ted, KX4OM
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