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Ca346
| | Posted on Monday, October 27, 2003 - 12:22 pm: | 
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The BookKeeper approved the purchase of another antenna, so I could put up my extra radio in the workshop/garage. LOTS of discussion..... Had to agree to taking the G5RV down. Here's the question:
I have a 4 element Quad (Lightning4+)on a rotator at 50 ft high. The boom is 18 ft long and it obviously has a 9ft radius. It sits against one end of a 36ft long garage. I am going to put the old 36ft radio shack vertical mast back up at the other end of the garage and put an IMAX2000 or something like it from COPPER at the top. I'm pretty sure I will get the GPK for the IMAX, which means the 9ft? radial will be over the garage at 35ft high.
With 18ft clearance between the two antenna's, (tips) does anybody see any problems? |
Bruce
| | Posted on Monday, October 27, 2003 - 3:03 pm: |
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my astroplane and dypole were about that far and it worked fine it will depend how far apart in frequency you are.....when i was on 20 meters nothing was heard on the cb....... |
Mr_Rf
| | Posted on Monday, October 27, 2003 - 3:51 pm: |
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You will probably never notice and change in antenna/signal performance (if any) from either.
However the real problem is protecting the receiver in one radio while transmitting on the other radio. The transmitter power seen by the other radio at 18ft seperation will certaintly be enough to "saturate" the front end and possibly cause the RF front end transistors to fry. It's a gamble!
One preventive measure would be to simply disconnect the antenna from the other radio when not in use, or add an inline antenna switch to allow you to switch the antenna away from the radio when not in use.
Good Luck |
Bruce
| | Posted on Monday, October 27, 2003 - 7:33 pm: |
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Mr RF
Good point but i found that @ 100 watts and on diffrent bands there was not a problem how ever if soeone is running high power i agree with you be able to switch the antenna out of the radio your not using |
Kc0gxz
| | Posted on Monday, October 27, 2003 - 8:58 pm: |
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Ca346
Or, just simply turn the RF Gain control all the way down on the radio that you are not transmitting on. I kind of doubt that you're going to have two radios tuned to the same frequency.
Also, if the feed-point of your I-Max is at 35 feet, I wouldn't worry about a groundplane kit. You're going to like the I-Max 2000. At 24' long, it's very broadbanded and will easily cover 2.8-3Mhz of usable frequency without the need of a tuner. No other antenna on the market has that kind of bandpass.
I can't say enough good things about the I-Max antenna. And you won't find them anywhere cheaper other than at Copper.
Jeff, kc0gxz. |
Ca346
| | Posted on Monday, October 27, 2003 - 10:04 pm: |
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Sounds like it will not be a problem. When in the shop/garage I will not have the other radio even turned on. That's the whole idea of the project in the first place, to get the noise out of the house for awhile. (That's me) Hi, Hi.
And, Jeff, you're right about the cheaper price at COPPER, but it's the shipping to me in California that's the killer...
Hope to have this all put together by Thanksgiving. Thanks for the info. as usual. |
Kc0gxz
| | Posted on Monday, October 27, 2003 - 11:19 pm: |
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Ca346
Yes, shipping. I forgot all about that. That's something that Copper has no control over. Neither does anyone else for that matter.
Did your wife politely kick your radios out of the house?
Jeff. |
Ca346
| | Posted on Tuesday, October 28, 2003 - 10:55 am: |
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No, she hasn't 'kicked' them out. Just keeps "hinting". She is one of those people that needs quiet. Guess who needs NOISE? I got a HEIL PRO headset with the boom mike to shut out the incoming noise on the ICOM when I use it instead of the HR2510, but she says I'm louder than the incoming? How could that possibly be????
My current dilemma is trying to see if it's worth it ($$$$) to move a radio out to the shop if I also have to duplicate the power supplies, low pass filters, etc. I'm currently running two radios and one amp, two power supplies, a shortwave radio, police scanner, and enough antenna's around the place that it looks like a broadcast radio station... |
Bigbob
| | Posted on Tuesday, October 28, 2003 - 8:49 pm: |
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Is it feasible to make an active rf gain control,like an amc only for incoming signals at a predetermined level with a fast attack time,I've seen clipping diodes that were fried,seems a mosfet would be perfect for dumping excess energy before it got to the first stage,I'm sure yaesu and icom have these.Bigbob |
Kc0gxz
| | Posted on Wednesday, October 29, 2003 - 6:43 pm: |
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Bigbob
You're right. It sure doesn't take much to blow the front end out of a receiver from RF over-load. But it looks like he doesn't have to worry about it now since he's only going to have one radio on at a time.
Jeff. |
Ca346
| | Posted on Wednesday, October 29, 2003 - 7:59 pm: |
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Well, I jumped in today and ordered an IMAX 2000 and a filter to keep the TVI down. I found by testing yesterday and today that I could run my President HR2510 and the GALAXY 350W both on the one Pyramid 46 power supply. Even at stage 4 on the amp, it registers 40 amps on the pyramid. I usually run much less than that. I hold with the ARRL standard of whatever is the minimum needed to transmit.
I did not order the GPK for the IMAX, as the base will be at 35 ft, putting the tip of the IMAX at 59 ft? Without the GPK, it will be about 30ft or so horizontally from my tower with the other antenna.
Thanks for the feedback.
Jim
CA346/CEF197 |
Crafter
| | Posted on Wednesday, October 29, 2003 - 8:59 pm: |
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So what you doing with the G5RV ? What are you doing for a low pass filter? Bencher makes a good one I use 2 myself a Drake and a Johnson basically the same as a bencher YA1. I run legal limit usually and have had no problems with them not holding the power. Have had no problems yet with TVI either except on my wife's cheap cricket phone. |
Ca346
| | Posted on Wednesday, October 29, 2003 - 10:58 pm: |
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Crafter:
The G5RV is coiled up and under my feet again in the radio shack. I think I've had that thing up and down 3 or 4 times since 1999. I have a vectronics low pass filter to run my ICOM through in the house and purchased another low pass filter from COPPER today for the HR2510 to go through in the shop/garage when the IMAX goes up. The filter was pretty cheap, ($23) so I'm hoping it works okay. I don't run too much power, so it should be fine. |
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