Posted: 9/26/2007 1:12:44 PM EDT
| I think this has been covered before but I am unable to find it. I need to find a quality compact HT antenna for my VX-170. I currently use a SRH77CA but its rather large and prevents me from putting it in my pocket and keeping it with me. |
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Portable radio antennas are always a compromise. Even a large antenna on a portable radio is a seriously compromised antenna compared to even a modest vertical or dipole you'd mount on your mast. A compact version WILL be an even MORE compromised antenna. The laws of physics can't be ignored or cheated on. Any more compact portable radio antenna will perform more poorly than a larger one, assuming both are engineered well. You're going to sacrifice performance for convenience. If you want a compact antenna, you'd better get used to that fact. I go out of my way to find the BEST performing portable radio antennas. They're always larger than the standard antenna and usually perform notably better. CJ |
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Laws of Physics? Surely you jest, CM_J. Didn't the US GOV let an order for a JTTR's radio that could work from DC to Light? Actually the range was 30 to 512 Mhz, which the broadbanded radio circuits could do, but alas, the antenna was not up to it. Major amounts of cash are being spent to solve the problem. Seems that someone should have stepped up and told the Army officials that, but they probably had a conference before the meeting and decided the contract was more important than the laws of physics. Thales does make a military (green) portable that supposedly can do it to some degree across the 30 to 512 range. There is a trade off between portability and effectiveness especially at 2 meters (144mhz) where the antennas are still coil loaded. Most VHF portable antennas are less than 50 percent efficient. This means 5 watts from the radio turns into less than 2.5 watts signal. Incidently, I have always heard that the low dual band antenna efficiency is the reason Motorola doesn't make VHF/UHF HT's. RS |
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actually the PRC-148 MBITR (the one made by thales ref above) does 30-512, AM and FM.. comes with a "broadband" 108-512 antenna and a 3ft tape antenna for the low bands. as far as performance on say 2m? I put it up against my T-90A and it gets blown out of the water with either antenna. that's with the stock icom antenna. it works well on vhf-low 30-90... it works pretty damn well on UHF... all that in between is just for show I think Look up a PRC-117, that's a radio I'd like to have... oh- just to add, found out our PRR antenna (2.4Ghz) is SMA- that makes for a real nice compact antenna for my T-90.... anyone know what the SWR would be on 70 cm before I try it?  -Roth |
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Probably wouldn't want to try it even though handheld radios are fairly resistant to high impedances, if it presented a real low impedance (rf short), it could damage the output transistors. Very interesting on the comparison of the Thales vs the T90. I was going to ask you to comment on the Icom F43, but since you are using the PRR, that means you are Marine, not the other service. RS |
in my EDC bag i have a VX6R with a Comet/Maldol micro-duck mounted on it (Maldol PN MH-209SMA). in the bag is the OEM antenna. in my BOB i have a AEA HotRod and a roll-up Jpole. for it's size, the Comet MH209 micro-duck works incredibly well. if you are in reasonable operating range to your repeaters, it is a perfect substitute for the OEM antenna. short, very flexible, no stress on the SMA whatsoever. the nice thing about using this antennna on Yaesu HT's is that the base of the antenna mates perfectly with the rubber waterproofing seal -- mantaining the watertight nature of the VX170, VX6R, etc. www.eham.net/reviews/detail/3053 ar-jedi    |
I'll keep the better antenna in my vehicle. I basically want something small to stick on my HT so I can keep tabs on things. If I really need to get out I'll walk out to my vehicle or the mobile in my home or office. |
I was using that one on 70cm, just because it's the highest freqs I could TX in out of the T-90... I'm not going to be TXing with it and I have my SMA to BNC comming out so I can use some of the antennas we have here... I was dumb and left my antenna back in the states somewhere. I carry that radio around the fob if someone needs me they know how to reach me- not encrypted but we don't have enough moto's for everyone to have one... Haven't tried it for range yet though, seems to work well... -Roth |
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Sounds like a plan to me. All the hollering about unecrypted comms in Afganistan and Iraq. Well, if I got shot and needed help, give me any radio that help can be gotten on. Bear hunting season is opening here in upper SC, and I will be trying out comms on MURS4 up there in about 2 weeks. Will be interesting to see what range we get in the hills. I used GMRS years ago and it was okay. RS |