You should test again with a short ground on the connector to simulate a radio and body. These antenna are usually pretty resonant with dips when you do this test.
I kind of agree. People often take "the thing off the top" and declare that they are going to test "the antenna". What they are really testing is half of the antenna, and they omit the other half - the radio case. The capacitive effects of holding the radio should probably be isolated in tests, as it would be hard to repeat and thus render comparisons with other results impossible. For a while now, I have been hoarding old knackered radio chassis. My plan is to strip the guts out, and replace them with a simple coax patch lead. The idea would be that I could attach any "antenna" to any of these radio cases and test the REAL return loss on a REAL radio case.
@@HA7DN All antennas are either dipoles, or modified dipoles. There are two parts to a dipole, the (usually) upper driven pole and the lower pole. It isn't always possible or convenient to implement a dipole - imagine a vehicle roof - how would you mount a conventional dipole? How would you feed it? This is where modified dipoles are useful. On a vehicle, you only have the upper driven element, and then a groundplane which is large enough to "look" like the lower element. It is the same thing with a handset - even at UHF frequencies, say around 430MHz, the wavelength is around 70cm. A halfwave diploe would be 35cm long, with each of the two elements 17.5cm long. That's not very convenient, and most commercial users would refuse to carry that around. Luckily, the radio chassis and a bit of capacitive coupling to your body can be used as a poor groundplane, and some creative arrangement of the upper part of the antenna (coils) can be employed to put an antenna together that is merely "acceptable" in performance. It's a compromise. Taking the upper driven part of a dipole off the radio chassis is actually splitting "the antenna" in half. At this point, the test instument becomes the groundplane. If the test instrument has a different size, shape or mass, or even a different coating (powdercoat vs plastic) then you are testing the upper part of the antenna under different circumstances than those found on the original radio. What is needed, is to test the complete antenna, and that means having a connection to the upper driven part AND the radio chassis. Easy enough to do so long as you have a donor radio. Cut any trace or component leading away from the antenna, and splice in a coax patch lead that can be connected to an external test set. What you have to be careful about is the feedpoint impedence - The RF circuit may be some odd impedence and the PCB may have part to play in matching. Far easier is to simply swap antennas on a perfectly working radio, and observe the difference in signal - is it better or worse?
@@digitalradiohacker I am aware of the general theory behind antennas, dipoles, monopoles, etc. I am looking for practical tips to test antennas. "What you have to be careful about is the feedpoint impedence - The RF circuit may be some odd impedence and the PCB may have part to play in matching." The radios I want to test (Motorola P110) have only a capacitor between the antenna and the external antenna jack (supposadly 50 ohms) iirc. Sadly, using the external jack to test the built-in antenna is mechanically impossible, so I was thinking about soldering a coax into it. Do you have any other tips on feedpoint impedance? "Far easier is to simply swap antennas on a perfectly working radio, and observe the difference in signal - is it better or worse?" Sadly, I don't have any radios that aren't quite old, it seems I can't get around testing each radio one-by-one. I am still not sure the issue is antenna-related, but it seemed to make a difference - the rubber of some of the antennas just disintegrated.
Need more explain about the coils length of antenna. Why do they work with this coil and how does it work. I think this is very interesting. Keep on the good work !
Handheld antennas usually don't test well on a nanovna or antenna analyzer. If you put an inline SWR meter on the radio you might find the results change quite a bit.
@@Janktzoni the usual explanation is that the antenna is using the metal frame of the radio to capacatvely couple to your hand, making it the counterpoise. Using it without that detunes it.
Hard to imagine L’s and C’s like that not having a resonance somewhere. Any chance there was a dip around 300 MHz or anything? You didn’t see anything that could’ve been a resistor, did you? Just the idea of a thin broadband antenna is pretty much smoke and mirrors I think.
This Is Not A real test, He Did Not Put A Load Between Antenna And The test, You Dont use Antenna Itself You Know, you Use It ON THE RADIOA and TThat makes It resonant And Better With Peaks And Valleys, I bet If He tested The ANtenna Teh Correct Way It Would Show 40% Increase Of "" Juicyness ""
For a 20 bucks radio there is more to that antenna than I would have expected !
You should test again with a short ground on the connector to simulate a radio and body. These antenna are usually pretty resonant with dips when you do this test.
I kind of agree.
People often take "the thing off the top" and declare that they are going to test "the antenna".
What they are really testing is half of the antenna, and they omit the other half - the radio case.
The capacitive effects of holding the radio should probably be isolated in tests, as it would be hard to repeat and thus render comparisons with other results impossible.
For a while now, I have been hoarding old knackered radio chassis. My plan is to strip the guts out, and replace them with a simple coax patch lead. The idea would be that I could attach any "antenna" to any of these radio cases and test the REAL return loss on a REAL radio case.
Can you give a few more tips on this? I have a similar idea to test P110 antennas as @digitalradiohacker, but not totally sure about that either.
@@HA7DN
All antennas are either dipoles, or modified dipoles.
There are two parts to a dipole, the (usually) upper driven pole and the lower pole.
It isn't always possible or convenient to implement a dipole - imagine a vehicle roof - how would you mount a conventional dipole? How would you feed it? This is where modified dipoles are useful. On a vehicle, you only have the upper driven element, and then a groundplane which is large enough to "look" like the lower element.
It is the same thing with a handset - even at UHF frequencies, say around 430MHz, the wavelength is around 70cm. A halfwave diploe would be 35cm long, with each of the two elements 17.5cm long. That's not very convenient, and most commercial users would refuse to carry that around.
Luckily, the radio chassis and a bit of capacitive coupling to your body can be used as a poor groundplane, and some creative arrangement of the upper part of the antenna (coils) can be employed to put an antenna together that is merely "acceptable" in performance.
It's a compromise.
Taking the upper driven part of a dipole off the radio chassis is actually splitting "the antenna" in half. At this point, the test instument becomes the groundplane. If the test instrument has a different size, shape or mass, or even a different coating (powdercoat vs plastic) then you are testing the upper part of the antenna under different circumstances than those found on the original radio.
What is needed, is to test the complete antenna, and that means having a connection to the upper driven part AND the radio chassis.
Easy enough to do so long as you have a donor radio. Cut any trace or component leading away from the antenna, and splice in a coax patch lead that can be connected to an external test set.
What you have to be careful about is the feedpoint impedence - The RF circuit may be some odd impedence and the PCB may have part to play in matching.
Far easier is to simply swap antennas on a perfectly working radio, and observe the difference in signal - is it better or worse?
@@digitalradiohacker I am aware of the general theory behind antennas, dipoles, monopoles, etc.
I am looking for practical tips to test antennas.
"What you have to be careful about is the feedpoint impedence - The RF circuit may be some odd impedence and the PCB may have part to play in matching."
The radios I want to test (Motorola P110) have only a capacitor between the antenna and the external antenna jack (supposadly 50 ohms) iirc. Sadly, using the external jack to test the built-in antenna is mechanically impossible, so I was thinking about soldering a coax into it.
Do you have any other tips on feedpoint impedance?
"Far easier is to simply swap antennas on a perfectly working radio, and observe the difference in signal - is it better or worse?"
Sadly, I don't have any radios that aren't quite old, it seems I can't get around testing each radio one-by-one. I am still not sure the issue is antenna-related, but it seemed to make a difference - the rubber of some of the antennas just disintegrated.
Need more explain about the coils length of antenna.
Why do they work with this coil and how does it work. I think this is very interesting.
Keep on the good work !
Yes, I would like to know that too.
Maybe you can make a video how to calculate coils length and.......
Thanks for all your interesting video's !
Handheld antennas usually don't test well on a nanovna or antenna analyzer. If you put an inline SWR meter on the radio you might find the results change quite a bit.
How come there is such a difference?
@@Janktzoni the usual explanation is that the antenna is using the metal frame of the radio to capacatvely couple to your hand, making it the counterpoise. Using it without that detunes it.
I usually put NanoVNA close to my head as if it was a radio - changes readings quite dramatically.
Love your videos! As a newby, doesn't the 'conductor' coil present inductive properties messing up with the inductor?
no, it is actually like a wire cable, with internal wires, as well as, the wrapped outside ones.
Thanks 👍
Very interesting stuff 😊👍🇮🇪
Never seen that flavor of chinesium before.
Nice!
Ah, an antenna designed for the FM mode!
Yes, What Else? AM? Then That Would Be Not Working Good On Any FM, Better To Make It On FM And Then It Can Get Some AM To.
Hard to imagine L’s and C’s like that not having a resonance somewhere. Any chance there was a dip around 300 MHz or anything? You didn’t see anything that could’ve been a resistor, did you? Just the idea of a thin broadband antenna is pretty much smoke and mirrors I think.
reach moon or jupiter florida is amazing sir
The return loss around 145 MHz is really bad...
This Is Not A real test, He Did Not Put A Load Between Antenna And The test, You Dont use Antenna Itself You Know, you Use It ON THE RADIOA and TThat makes It resonant And Better With Peaks And Valleys, I bet If He tested The ANtenna Teh Correct Way It Would Show 40% Increase Of "" Juicyness ""