Antenna question

[WRTB501]

Hello all, so i just got my new Wouxun KG-935G this morning and playing around with it and really love it so far, i have been able to hit the repeater in my area but some areas like my moms house and a few other spots does become a dead zone, i currently also purchased and put the Nagoya NA-771G antenna on it as well because the reviews were really good from what i saw, so my question is would there be something that would possibly give me more range than what im currently using on the Wouxun. Thanks in advance for any opinions or comments!

-Chris/WRTB501

[marcspaz]

Is this while mobile or are you walking around/standing outside?

 

Just my opinion, but I doubt any other antenna is going to help, even if it is advertised as having more gain.  Every 3 dB is one signal unit.  If you are on the very edge of the repeater where you are just barely out of range, you need to increase your effective radiated power to impact the receiver on the repeater 3 signal units to "possibly" be heard and understood.  That is gain of anywhere from 9 to 12 dB gain... equal to about 50 watts of radiated power from your handheld... and that is assuming you are just barely out of range.  It's not gonna happen.

 

If those "dead spots" are due to terrain blocking your signal, being too far below the line of sight horizon, radio frequency interference, heavy woods or several buildings (or any number of other issues)... you won't be able to boost the signal enough.

[WRTB501]

24 minutes ago, marcspaz said:

Is this while mobile or are you walking around/standing outside?

 

Just my opinion, but I doubt any other antenna is going to help, even if it is advertised as having more gain.  Every 3 dB is one signal unit.  If you are on the very edge of the repeater where you are just barely out of range, you need to increase your effective radiated power to impact the receiver on the repeater 3 signal units to "possibly" be heard and understood.  That is gain of anywhere from 9 to 12 dB gain... equal to about 50 watts of radiated power from your handheld... and that is assuming you are just barely out of range.  It's not gonna happen.

 

If those "dead spots" are due to terrain blocking your signal, being too far below the line of sight horizon, radio frequency interference, heavy woods or several buildings (or any number of other issues)... you won't be able to boost the signal enough.

Thanks for the reply, ya it may just be the area im using it in at the time, i am in the cities but for the most part i seem to pick the repeater up pretty decently and im still a good portion of inside the radius of the repeater as well. I appreciate your reply, was just thinking even though its decent is there a possiblity of making it any better but sounds like what i have atm is as good as i can try to get with what im using. I thought of picking up  a longer antenna say something 20inch or more if that would even make a diff? maybe a foldable thats like 42.5inch i was looking at, not sure if thats a reasonable solution or not, im new to GMRS and still learning alot of what  and does work and taking the info i  do get in from the pros and vets to it all lol. 

(Antenna i was looking at if its even worth it assuming it would work on the Wouxun KG-935G: 42.5-Inch Length ABBREE SMA-Female Dual Band 144/430Mhz Foldable CS Tactical Antenna for GMRS Radio)

[OffRoaderX]

That 42.5 inch Abbree is not a GMRS antenna and would likely perform worse than your stock antenna.

If you really need more farz, and assuming you are in/have a vehicle, look at a mobile 20 or 50W unit and put an external mobile antenna on it.. 

[WRTB501]

Just now, OffRoaderX said:

That 42.5 inch Abbree is not a GMRS antenna and would likely perform worse than your stock antenna.

If you really need more farz, and assuming you are in/have a vehicle, look at a mobile 20 or 50W unit and put an external mobile antenna on it.. 

oh ok, thxs for that info. i was confused tbh because they do label it as a GMRS but the MHZ isnt the same as my NA-771G, thats why i figured i would mention it as well so appreciate that feedback

[OffRoaderX]

GMRS is 462Mhz/467Mhz - so unless that antenna is 430Mhz and UP TO 467Mhz, then its not ideal for GMRS..

[WRTB501]

Just now, OffRoaderX said:

GMRS is 462Mhz/467Mhz - so unless that antenna is 430Mhz and UP TO 467Mhz, then its not ideal for GMRS..

ya ok, thats what the thought in my head was, thought i remember someone telling me the same thing so was gonna research it more before buying it but thxs for confirming that for me, sounds like what i have is the best i could hope for atm with a HT, thxs all for the replies! very much appreciated

[marcspaz]

I fell for the advertising for the Abbree antenna too.  I kept it because I am a Ham and can use it on amateur radio frequencies.  On the GMRS 462 MHz frequencies, the SWR is 2.6:1 and on the 467 MHz frequencies, the SWR is 3.1:1.  I definitely would not use it for GMRS.  It will perform terribly and with prolonged use on the repeaters, you may damage your radio.

[axorlov]

57 minutes ago, marcspaz said:

SWR is 2.6:1

Friendly reminder: measuring SWR on HT antenna is meaningless, no matter what youtube expert would say.

[marcspaz]

29 minutes ago, axorlov said:

Friendly reminder: measuring SWR on HT antenna is meaningless, no matter what youtube expert would say.

 

Why would you say this?

[kidphc]

8 hours ago, marcspaz said:

 

Why would you say this?

I think because as you know it can be difficult to get a repeatable reliable number.

Although watching Offroaderx/Notarubicon's videos on the surecom units I might pick one up for ht testing. He show cased one with a ground plate adapter.

 

For the OP.

Get a decent mag mount if using mobile you will get better range. If you are stationary, then a nice slim jim like N9Tax's (if you want pre built) thrown up a tree with a leader line will work. I made a fake blade antenna inside the house by using wiring track, fastening the slim jim (N9Tax's version) inside and stuck it to the wall inside. Connected to an Anytone 779UV i get reliable connections to a friend's repeater on a commercial site (approximately 6 miles, through rolling urban hills) . It wasn't doing it reliably with an HT and the 771g from  indoors.

[marcspaz]

@kidphc I have one of the inexpensive surecom units and it is extremely close in accuracy to my very expensive commercial meters. I would use it with confidence. 

[kidphc]

1 minute ago, marcspaz said:

@kidphc I have one of the inexpensive surecom units and it is extremely close in accuracy to my very expensive commercial meters. I would use it with confidence. 

I just REALLY DON'T need it. The chinese stuff are decent for the price, I just don't expect reliability over the long term, you know you get what you pay for.  Not like I could not take mild steel and make the ground plate myself for the NANO VNA, which might be another project to add to the list.

I have a different rabbit hole I am working on outside of the DXCommander antenna. Which is I was basically gifted by some of the local Gov/Commercial friends 4x CDM1250's. Need to acquire the cables, software and terminology, which looks like it could be a pain. Only because I know nothing about the radio or software. 

Still working on setting up my new to me Landcruiser. Really want to do a fun run to an ORV park with you and your son.

Enough of me derailing the topic.

[SteveShannon]

2 hours ago, marcspaz said:

@kidphc I have one of the inexpensive surecom units and it is extremely close in accuracy to my very expensive commercial meters. I would use it with confidence. 

But within these forums (fora?) we have had accounts of Surecom 102 meters that did not match higher priced instruments which were known to be nearly accurate.   I suspect most are pretty close, close enough for hobbyists like me anyway, and I would trust a Surecom if I had previously compared it to something better, like you have.

[axorlov]

13 hours ago, marcspaz said:

Why would you say this?

You have an off center feed dipole with a MASSIVE capacitive component on one leg, you break it at feed point, you extend one leg by about 1/5th wavelength with SW-33 (it's always Surecom SW-33 with youtube experts, LOL!), and you do a measurement of SWR, which is essentially, a relation between forward and reflected power.

Tell me, how your measurement have any relation to a real forward and reflected power observed at feed point by the HT transmitter. I will wait here, I have the whole day.

[axorlov]

Off tangent: The UV5R and SW-33 are truly a match made in heavens. When both are connected and used for <anything> it is a very good indication of youtube expert having no clue.

And I have SW-33. It is not consistent. Most of the time it shows my grandma's birthday. And other times it shows completely random numbers. I can't trust it for anything.

[marcspaz]

25 minutes ago, axorlov said:

You have an off center feed dipole with a MASSIVE capacitive component on one leg, you break it at feed point, you extend one leg by about 1/5th wavelength with SW-33 (it's always Surecom SW-33 with youtube experts, LOL!), and you do a measurement of SWR, which is essentially, a relation between forward and reflected power.

Tell me, how your measurement have any relation to a real forward and reflected power observed at feed point by the HT transmitter. I will wait here, I have the whole day.

 

 

So, I usually understand what you are saying and typically agree with you on technical issues, but I am seriously missing something here. 

 

Are you implying that there is no way to measure the SWR of an antenna that screws to the top of the handheld radio? Or are you implying there is no way to to measure the SWR while the antenna is on the handheld? Or are you implying some other type of measurement can't be done?

[axorlov]

35 minutes ago, marcspaz said:

Are you implying that there is no way to measure the SWR of an antenna that screws to the top of the handheld radio? Or are you implying there is no way to to measure the SWR while the antenna is on the handheld? Or are you implying some other type of measurement can't be done?

All of the above. You would need to modify the HT to put an SWR bridge before feedpoint to measure SWR accurately. And even this measurement will not have much meaning because when you hold HT in the hand and when it is on the belt, or on bicycle handlebars, will produce different measurements. I do not imply any hidden message here, I say that one cannot measure SWR of the HT antenna by plugging SWR meter between the HT body and the thing misleadingly called "HT antenna". The HT antenna is: 1) that thing; 2) body of the HT; 3) body of the operator. All three together.

There was a link on this forum about measuring the field strength of the same HT with different "antennas". This is how you can measure efficiency of the HT+antenna. Let me see if I can find it. 

[marcspaz]

29 minutes ago, axorlov said:

You would need to modify the HT to put an SWR bridge before feedpoint to measure SWR accurately.

 

Agreed.  For the best, most accurate results, an impedance bridge is the correct method.  That is usually only worth it for someone designing a radio or antenna.  For the average user, the labor and risk are to high.

 

29 minutes ago, axorlov said:

I do not imply any hidden message here, I say that one cannot measure SWR of the HT antenna by plugging SWR meter between the HT body and the thing misleadingly called "HT antenna". The HT antenna is: 1) that thing; 2) body of the HT; 3) body of the operator. All three together.

 

I also agree with this.  The human body and the radio are part of a capacitive coupled counterpoise.

 

29 minutes ago, axorlov said:

There was a link on this forum about measuring the field strength of the same HT with different "antennas". This is how you can measure efficiency of the HT+antenna. Let me see if I can find it. 

 

Ehh... that can be handy, but it doesn't tell us if the antenna is balanced with the transmitter.

I actually have an antenna analyzer that emulates having the antenna on an HT.  You can rely on using a capacitive coupled counterpoise (by holding the meter) or you can add a wire to use as a counterpoise.  The meter tells me the resonant frequency and the SWR of the antenna at that frequency.  Most antennas I have tested have a 78 ohm impedance for their advertised center frequency.  Some as low as 73 Ohms.... so a 1.5:1 SWR.  The worst I have seen was 250 ohms about 5:1.

[axorlov]

Found it, the link: https://www.hamradio.me/antennas/ht-antenna-comparisons.html

And the thread where Lscott brings it up, and our resident infulenzer is also quoted:

 

[axorlov]

2 hours ago, marcspaz said:

I actually have an antenna analyzer that emulates having the antenna on an HT

I would guess, that analyzer measures SWR at the feed point of the antenna. Of an actual antenna, not of the "rubber duck" part of it. Actual antenna would consist of the "rubber duck" + body of the analyzer + counterpoise.

And when I say about capacitive component, I do not mean that operator's body is capacitively coupled. It could be very well galvanically coupled with the body of HT. I'm talking about the capacitive part of antenna impedance -j*G, where "G" stands for "ginormous". That's in free space. When operator takes HT in his/her hand it becomes -j*G*1000.
 

[marcspaz]

17 hours ago, axorlov said:

I would guess, that analyzer measures SWR at the feed point of the antenna. Of an actual antenna, not of the "rubber duck" part of it. Actual antenna would consist of the "rubber duck" + body of the analyzer + counterpoise.

 

Correct.

 

17 hours ago, axorlov said:

And when I say about capacitive component, I do not mean that operator's body is capacitively coupled. It could be very well galvanically coupled with the body of HT.

 

Being galvanically coupled to the HT is extremely unlikely.  Galvanism must occur via direct contact with a conductive case or conductor on the case.  Most HT's are made out of non-conductive plastics and other non-conductive materials.  Due to the air-gap between the antenna ground inside the radio and the operator, combined with the resistance of the material of the body of the radio, the only way a human body can become part of the antenna system (which is dependent on the radio design and operating frequency) is via capacitive coupling. 

In a vast majority of VHF and UHF radios, the human body is in obstructive obstacle in the radiation path, rather than a useful part of the antenna system.

 

17 hours ago, axorlov said:

I'm talking about the capacitive part of antenna impedance -j*G, where "G" stands for "ginormous". That's in free space. When operator takes HT in his/her hand it becomes -j*G*1000.
 

 

Yeah, I got nothing on that one.  LOL