Could I utilize a UHF stubby on an 800 portable and vice-versa in reality without damage. Talking about HT1000/XTS2500. The length should be close or not?
Like I said, just curious
Just curious - UHF & 800 portable antenna
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Tom in D.C.
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Re: Just curious - UHF & 800 portable antenna
Unfortunately the thread to which you've been referred contains some possibly misleading information.
Briefly stated, for an antenna to be duaiband without traps or coils installed it must be used at THREE times the frequency of the base antenna. In other words, an antenna cut for 400 mHz should work fine on 1200 mHz, but it will not work well on 800 mHz. If you go back to the stuff you studied for your license you find references mostly to HF antennas, and the common example always used is that a 40 meter antenna (7 mHz or so) works fine on 15 meters (21 mHz or so). If you use an 800 antenna on a UHF radio you may think that it's working okay, but you may also be shortening the life of the radio's final amplifier, but the more basic fact is that you're not following good engineering practice which is the point from which proper care and operation of equipment starts.
Briefly stated, for an antenna to be duaiband without traps or coils installed it must be used at THREE times the frequency of the base antenna. In other words, an antenna cut for 400 mHz should work fine on 1200 mHz, but it will not work well on 800 mHz. If you go back to the stuff you studied for your license you find references mostly to HF antennas, and the common example always used is that a 40 meter antenna (7 mHz or so) works fine on 15 meters (21 mHz or so). If you use an 800 antenna on a UHF radio you may think that it's working okay, but you may also be shortening the life of the radio's final amplifier, but the more basic fact is that you're not following good engineering practice which is the point from which proper care and operation of equipment starts.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
Re: Just curious - UHF & 800 portable antenna
Testing of 800/900 whips for use on 440 was done simply to illustrate they can be used for short term needs, they are not intended to to be a replacement for the proper band antennas.
The testing was done from the low end of the UHF ham band to the upper limit(449.900).
In almost all instances of the testing, both 800/900 antennas exhibited a good match(under 2.5:1), and as expected, there were several points across the entire band where the resonance improved and the match to the antenna lowered to under 1.5:1.
Using the previously mentioned test procedures, it provided useful information about using these antennas without harm on the UHF ham band for a
temporary usage scenario, not for permanent use.
I had an instance where I did lose my UHF antenna, and all I had access to was an 800 whip, so I tried it, and it worked very well, and in actual testing on air, I could not discern any distance issues from using it, so I dug deeper and tested both 800 and 900 antennas with two spectrum analyzers and return loss bridge, as well as a standard SWR bridge.
The results were very acceptable, and well within range as to indicate that temporary use has no ill side effects.
In fact, I determined to life cycle test my MTS using nothing but an 800 whip, and for two years, running high and low power, in various terrain, I have yet to
experience even the slighest problem, and my radio still produces the same RF output during prolonged transmission now, as it did when I started my testing.
From repeaters a few miles away, to several that are over 50 miles away, I have had zero problems hearing or talking.
I live in mountainous areas, and this terrain doesn't play favorites with radio, especially portables.
I tested UHF simplex range from Pinal Peak on 439.650 446.000 and 462.600 to the town of Maricopa, about 60 nautical miles(est.).
Signals were clear, and solid 90% of the time, with slight hysterisis noted also.
I then tested the UHF antenna on the same frequencies and my signal was almopst identical in all respects, but I did have a slight reduction in RSSI from the lower band segment(439.650) when the 800 antenna was used(no surprise here).
While the standard UHF antenna exhibited a flatter signal strength across the bands tested, the 800 antenna only showed a lower recceived signal at 439.650, but that was only by a small margin. My test station in Maricopa does not have test equipment and was relying solely on the radio's meter(IC7000).
I have since returned to using the factory UHF whip, but now I have no reservations using an 800 or 900 whip on UHF. and feel secure knowing I will not
damage the PA by using these on UHF should the need really occur.
I hate stubbies, no matter the band, so I don't use them even though I have several. You can't make these work anywhere outside the intended band range.
Maybe fudging a little, like 1 or 2 mHz. above/below.
Never bothered to test these, so I don't care.
The testing was done from the low end of the UHF ham band to the upper limit(449.900).
In almost all instances of the testing, both 800/900 antennas exhibited a good match(under 2.5:1), and as expected, there were several points across the entire band where the resonance improved and the match to the antenna lowered to under 1.5:1.
Using the previously mentioned test procedures, it provided useful information about using these antennas without harm on the UHF ham band for a
temporary usage scenario, not for permanent use.
I had an instance where I did lose my UHF antenna, and all I had access to was an 800 whip, so I tried it, and it worked very well, and in actual testing on air, I could not discern any distance issues from using it, so I dug deeper and tested both 800 and 900 antennas with two spectrum analyzers and return loss bridge, as well as a standard SWR bridge.
The results were very acceptable, and well within range as to indicate that temporary use has no ill side effects.
In fact, I determined to life cycle test my MTS using nothing but an 800 whip, and for two years, running high and low power, in various terrain, I have yet to
experience even the slighest problem, and my radio still produces the same RF output during prolonged transmission now, as it did when I started my testing.
From repeaters a few miles away, to several that are over 50 miles away, I have had zero problems hearing or talking.
I live in mountainous areas, and this terrain doesn't play favorites with radio, especially portables.
I tested UHF simplex range from Pinal Peak on 439.650 446.000 and 462.600 to the town of Maricopa, about 60 nautical miles(est.).
Signals were clear, and solid 90% of the time, with slight hysterisis noted also.
I then tested the UHF antenna on the same frequencies and my signal was almopst identical in all respects, but I did have a slight reduction in RSSI from the lower band segment(439.650) when the 800 antenna was used(no surprise here).
While the standard UHF antenna exhibited a flatter signal strength across the bands tested, the 800 antenna only showed a lower recceived signal at 439.650, but that was only by a small margin. My test station in Maricopa does not have test equipment and was relying solely on the radio's meter(IC7000).
I have since returned to using the factory UHF whip, but now I have no reservations using an 800 or 900 whip on UHF. and feel secure knowing I will not
damage the PA by using these on UHF should the need really occur.
I hate stubbies, no matter the band, so I don't use them even though I have several. You can't make these work anywhere outside the intended band range.
Maybe fudging a little, like 1 or 2 mHz. above/below.
Never bothered to test these, so I don't care.