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I have purchased a large magmount with my Sirio 4000 antenna which I hope to set up soon with a CRT SS 9900.
I also have a small PMR magmount antenna fitted to the roof of my car that is probably useless. I'm wondering if the Sirio would work on PMR ? If not, is there an aerial I could buy to screw onto the magmount ? I'm thinking of getting a CRT space U so it would be handy to use the existing twig or if not just swop over on the same mount.
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GaryWilson CT Directors
Call Sign : 26-CT-1836 Ham 2E0GGQ Posts : 3766 Times Thanked : 308 Join date : 2019-06-27 QTH or Location : Braunston Northamptonshire. Equipment Used : Radios & Wires & Stuff! Age : 58
Hello, no unfortunately you need the right antenna for the frequency in use. C.B is a HF frequency 27Mhz and PMR is UHF 446MHZ you need another antenna for PMR there's loads out there on the market.
73's Gary.
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Sharpshooter Major contributor
Call Sign : 163-CT-329 Posts : 391 Times Thanked : 12 Join date : 2022-04-05 QTH or Location : Flintshire Equipment Used : CRT SS 9900, CRT SS3900 and frequency counter, Ranger 2950DX, Manor Kestrel, tti 881n, Sirio 4000 Sirio gainmaster, sirio and firestick dipole antennas, CRT space U, Sirio SU375-480 PL antenna, UV5R's x2,
Thanks Gary, I thought so unfortunately. Is there an antenna I could buy to fit the magmount ?
Razz229 Major contributor
Call Sign : 26 CT 2290 & 26 CI 2290 Posts : 582 Times Thanked : 25 Join date : 2019-07-01 QTH or Location : Kent Equipment Used : On 11m a Anytone 6666, Solarcon A99 vertical antenna or a Sirio 4000. On PMR a TYT TH-9800, a 1/4 wave GPA, homemade mag mount & sometimes a 8 element beam. Age : 55
Subject: Re: CB antenna/ PMR antenna compatibility question. Sat May 28, 2022 8:46 am
Hi Sharpshooter
What mag mount have you got? Is it a SO239 or a 3/8 tread connection?
Will you be using it while driving or parked up?
Because I can't see a problem with buying an adaptor so you could swap antenna's over but use the same mag mount.
73 Ray
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Sharpshooter Major contributor
Call Sign : 163-CT-329 Posts : 391 Times Thanked : 12 Join date : 2022-04-05 QTH or Location : Flintshire Equipment Used : CRT SS 9900, CRT SS3900 and frequency counter, Ranger 2950DX, Manor Kestrel, tti 881n, Sirio 4000 Sirio gainmaster, sirio and firestick dipole antennas, CRT space U, Sirio SU375-480 PL antenna, UV5R's x2,
Subject: Re: CB antenna/ PMR antenna compatibility question. Sat May 28, 2022 4:17 pm
Hi Ray, I've got the Sirio Mag 145 PL. RG58 coax and PL 259 plug to SO239 .
It's the connection for the antenna to the magmount I'm wondering about . (Or is that the same? ) So I could change from the Sirio 4000 whip to a PMR one on the same magmount. Cheers.
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Victor CT Directors
Call Sign : 26-CT-3228 / M7VIC Posts : 4633 Times Thanked : 295 Join date : 2019-11-10 QTH or Location : Bedford Equipment Used : Various
Subject: Re: CB antenna/ PMR antenna compatibility question. Sat May 28, 2022 5:15 pm
Sirio do an adapter for the mag mount as Ray pointed out.
Search Google for "Sirio PL Mag to 3/8" and you'll get a ton of hits.
Then you can unplug the Sirio antenna from the mag mount base and screw in a 3/8ths PMR antenna via the adapter.
73 Victor
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Razz229 Major contributor
Call Sign : 26 CT 2290 & 26 CI 2290 Posts : 582 Times Thanked : 25 Join date : 2019-07-01 QTH or Location : Kent Equipment Used : On 11m a Anytone 6666, Solarcon A99 vertical antenna or a Sirio 4000. On PMR a TYT TH-9800, a 1/4 wave GPA, homemade mag mount & sometimes a 8 element beam. Age : 55
Subject: Re: CB antenna/ PMR antenna compatibility question. Sat May 28, 2022 5:23 pm
. I've been beaten by Victor
I was going to offer this up
Up until I got my £1 mag mount from a radio rally, I was going to get a Sirio SO239 to 3/8" adaptor and then fit a 3/8" whip adaptor with bike wheel spoke cut to about 17cm. I can then use my Sirio mag mount for both CB & PMR.
Yes there will be some coaxial loss but you will see an improvement on TX & RX, on a UV5R (or any hand held) over a rubber duck antenna.
Ray
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Sharpshooter Major contributor
Call Sign : 163-CT-329 Posts : 391 Times Thanked : 12 Join date : 2022-04-05 QTH or Location : Flintshire Equipment Used : CRT SS 9900, CRT SS3900 and frequency counter, Ranger 2950DX, Manor Kestrel, tti 881n, Sirio 4000 Sirio gainmaster, sirio and firestick dipole antennas, CRT space U, Sirio SU375-480 PL antenna, UV5R's x2,
Subject: Re: CB antenna/ PMR antenna compatibility question. Sat May 28, 2022 6:07 pm
Ok thanks all. Sorry, it's not really for the UV5R. I'm thinking of buying a CTR space U from Knights. They do a Sirio PMR antenna for £14 and a Nagoya for £18 with magmount. Also the Nagoya is £15 if bought with the radio.
Call Sign : 26CT526/MR021/M6XXX. Posts : 262 Times Thanked : 10 Join date : 2019-06-27 QTH or Location : wooler north northumberland or some were near it Equipment Used : mobile 4000hp base A99 radio base magnum257hp mobile magnum 257 standed power Age : 66
Subject: Re: CB antenna/ PMR antenna compatibility question. Sun May 29, 2022 1:13 pm
make your self a pmr antenna there not hard to make you need a 3/8 mag and a 3/8 fitting and a steel whip and cut it and measure from the base of 3/8 whip holder 16cm and thats if the whip is to thick drill out the whip holder,and fit it to the 3/8 mag mount check the transmission one they have whip lenths and i got a crt space and it works great 20 miles from my bro he was shouting for me, i was mobile and i heard him so stopped at a little car park at 900 ft asl. and had a great contact such a small antenna, and it works this is what we used to do years ago with the cb, and now we are using pmr, and lots of time we can not hear the cb, but hear the pmr i like my cb but i love the pmr harder contact but a satisfaction with the pmr, am i mad no not never but just feel great getting the great pmr contacts,.
Last edited by stephen Gunrunner on Mon May 30, 2022 12:26 pm; edited 1 time in total
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Sharpshooter Major contributor
Call Sign : 163-CT-329 Posts : 391 Times Thanked : 12 Join date : 2022-04-05 QTH or Location : Flintshire Equipment Used : CRT SS 9900, CRT SS3900 and frequency counter, Ranger 2950DX, Manor Kestrel, tti 881n, Sirio 4000 Sirio gainmaster, sirio and firestick dipole antennas, CRT space U, Sirio SU375-480 PL antenna, UV5R's x2,
Subject: Re: CB antenna/ PMR antenna compatibility question. Sun May 29, 2022 5:18 pm
Thanks very much for all the replies. I see knights do the adaptor for £8.45.
So are most CB antenna connections SO239 and PMR 3/8" ?
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Sharpshooter Major contributor
Call Sign : 163-CT-329 Posts : 391 Times Thanked : 12 Join date : 2022-04-05 QTH or Location : Flintshire Equipment Used : CRT SS 9900, CRT SS3900 and frequency counter, Ranger 2950DX, Manor Kestrel, tti 881n, Sirio 4000 Sirio gainmaster, sirio and firestick dipole antennas, CRT space U, Sirio SU375-480 PL antenna, UV5R's x2,
Subject: Re: CB antenna/ PMR antenna compatibility question. Sun May 29, 2022 5:38 pm
Razz229 wrote:
. I've been beaten by Victor
I was going to offer this up
Up until I got my £1 mag mount from a radio rally, I was going to get a Sirio SO239 to 3/8" adaptor and then fit a 3/8" whip adaptor with bike wheel spoke cut to about 17cm. I can then use my Sirio mag mount for both CB & PMR.
Yes there will be some coaxial loss but you will see an improvement on TX & RX, on a UV5R (or any hand held) over a rubber duck antenna.
Ray
Why 17cm Ray ? Is that for swr ? I take it CB swr meters don't work on the PMR frequency ?
Razz229 Major contributor
Call Sign : 26 CT 2290 & 26 CI 2290 Posts : 582 Times Thanked : 25 Join date : 2019-07-01 QTH or Location : Kent Equipment Used : On 11m a Anytone 6666, Solarcon A99 vertical antenna or a Sirio 4000. On PMR a TYT TH-9800, a 1/4 wave GPA, homemade mag mount & sometimes a 8 element beam. Age : 55
Subject: Re: CB antenna/ PMR antenna compatibility question. Sun May 29, 2022 8:22 pm
Sharpshooter wrote:
Razz229 wrote:
. I've been beaten by Victor
I was going to offer this up
Up until I got my £1 mag mount from a radio rally, I was going to get a Sirio SO239 to 3/8" adaptor and then fit a 3/8" whip adaptor with bike wheel spoke cut to about 17cm. I can then use my Sirio mag mount for both CB & PMR.
Yes there will be some coaxial loss but you will see an improvement on TX & RX, on a UV5R (or any hand held) over a rubber duck antenna.
Ray
Why 17cm Ray ? Is that for swr ? I take it CB swr meters don't work on the PMR frequency ?
I use a home made antenna for most of my PMR contacts and the whip is cut to about 16.7cm. This is about the length for a 1/4 wave antenna tuned to channel 8 PMR, which gives me a SWR of 1:1 & a reading of 52 ohms on a Nano VNA Analyzer Yes you would need a UHF/VHF SWR meter.
73 Ray
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Razz229 Major contributor
Call Sign : 26 CT 2290 & 26 CI 2290 Posts : 582 Times Thanked : 25 Join date : 2019-07-01 QTH or Location : Kent Equipment Used : On 11m a Anytone 6666, Solarcon A99 vertical antenna or a Sirio 4000. On PMR a TYT TH-9800, a 1/4 wave GPA, homemade mag mount & sometimes a 8 element beam. Age : 55
I did similar with wire, and also cut a mobile whip for 4m for use with an Ascom SE550, but I did invest in an Antenna Analyser to check the SWR before connecting up a transceiver, good idea, not sure it meets type approval for PMR446, but whose to know? Next would be a 70cms Linear Amplifier...
Update: The 25 Watt Icom IC-F210 here is programmed with 16x PMR446 Channels, obviously TX is inhibited for those worried about type approval...
Last edited by Wireless on Sat Jun 11, 2022 1:59 pm; edited 1 time in total
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Victor CT Directors
Call Sign : 26-CT-3228 / M7VIC Posts : 4633 Times Thanked : 295 Join date : 2019-11-10 QTH or Location : Bedford Equipment Used : Various
Great stuff there Ray and a really good 'show and tell' mate.
Good little 1/4 wave that does the job and often better than the standard 'rubber duck' as well as some dubious Chinese teeny mag mount affairs.
As metal wire type coat hangers are thin on the ground nowadays I suggest everyone looks out for a missing wheel spoke the next time they are out on their bicycle - some PMR nut may have nicked it!!
Worthy of a 'Thanks'.
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Sharpshooter Major contributor
Call Sign : 163-CT-329 Posts : 391 Times Thanked : 12 Join date : 2022-04-05 QTH or Location : Flintshire Equipment Used : CRT SS 9900, CRT SS3900 and frequency counter, Ranger 2950DX, Manor Kestrel, tti 881n, Sirio 4000 Sirio gainmaster, sirio and firestick dipole antennas, CRT space U, Sirio SU375-480 PL antenna, UV5R's x2,
Great stuff there Ray and a really good 'show and tell' mate.
Good little 1/4 wave that does the job and often better than the standard 'rubber duck' as well as some dubious Chinese teeny mag mount affairs.
As metal wire type coat hangers are thin on the ground nowadays I suggest everyone looks out for a missing wheel spoke the next time they are out on their bicycle - some PMR nut may have nicked it!!
Worthy of a 'Thanks'.
I'll just nip to the local bike shop. I'm sure he'll give me an old spoke Or I could just cut down the existing twig as it seems short anyway
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Razz229 Major contributor
Call Sign : 26 CT 2290 & 26 CI 2290 Posts : 582 Times Thanked : 25 Join date : 2019-07-01 QTH or Location : Kent Equipment Used : On 11m a Anytone 6666, Solarcon A99 vertical antenna or a Sirio 4000. On PMR a TYT TH-9800, a 1/4 wave GPA, homemade mag mount & sometimes a 8 element beam. Age : 55
Great stuff there Ray and a really good 'show and tell' mate.
Good little 1/4 wave that does the job and often better than the standard 'rubber duck' as well as some dubious Chinese teeny mag mount affairs.
As metal wire type coat hangers are thin on the ground nowadays I suggest everyone looks out for a missing wheel spoke the next time they are out on their bicycle - some PMR nut may have nicked it!!
Worthy of a 'Thanks'.
Cheers Victor
The next step I guess, is to 'prove' if there is any improvement in the real world, over the whip antenna on my UV5R. So watch this space for a comparison video.
You can't go wrong with a meatal coat hanger. They have, over the years, proven to be a great receive antenna when bent into a diamond and used to replace a broken car aerial
When you look around, there must be that old rusty bike sitting in the front/back garden of the family where the children have out grown it. Now look at the spokes and think elements for a PMR beam (but that is for another time)
73
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Alan Pilot Major contributor
Call Sign : 163-CT-220...MW7TTA Posts : 2170 Times Thanked : 52 Join date : 2019-11-19 QTH or Location : Anglesey North Wales Equipment Used : Yaesu FT-991A,,Yaesu FTDX-10,,Icom ic-7300,,Anytone AT-D878UV PLUS",,LINCOLN II+. Age : 149
Linda got me wire coat hangers from B&M I think it was 5 for £1 and not long ago.
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Razz229 Major contributor
Call Sign : 26 CT 2290 & 26 CI 2290 Posts : 582 Times Thanked : 25 Join date : 2019-07-01 QTH or Location : Kent Equipment Used : On 11m a Anytone 6666, Solarcon A99 vertical antenna or a Sirio 4000. On PMR a TYT TH-9800, a 1/4 wave GPA, homemade mag mount & sometimes a 8 element beam. Age : 55
I thought I would make a PMR antenna that would work on a CB mag mount.
This is more a proof of concept and before anybody points it out, yes I know the coax is not ideal.
The 1st picture shows what I'm going to be working with. A metal coat hanger, a 3/8" whip adaptor, and a 7" mag mount of dubious quality.
The 2nd picture shows the approximate length of the whip once cut down.
3rd picture shows the mount assembled and on an old biscuit tin
4th picture show the sacrificial radio if it all goes wrong.
And the last picture shows the SWR reading while transmitting
So it seems to work as it's showing no reflective power.
Now I invite those with more knowledge to improve, my proof of concept
Cheers for reading
Ray
Interesting Ray as I was considering this old antenna I have.
A cheaper option but then I don't want two magmounts on the roof. (I see yours has seen better days, do you live by the sea ? )
Question, does the PMR not need a base loading coil like a CB ?
Cheers Nige.
Hi Nige
Glad you liked the "show & tell" and found it interesting.
Does your Sirio mag mount have this style of connection?
Then I would go with the earlier suggestion of a SO259 to a 3/8" adaptor and 3/8" to whip adaptor with the cut down coat hanger, bike spoke, metal rod.
2 antennas and 1 mount
The mag mount I show is over 10 years old and I have had to re-solder the coax to the mount due to corrosion
Short answer, no the antenna I show is a 1/4 wave and doesn't need any loading coil, which keeps it simple and cheap to make.
Cheers
Ray
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Sharpshooter Major contributor
Call Sign : 163-CT-329 Posts : 391 Times Thanked : 12 Join date : 2022-04-05 QTH or Location : Flintshire Equipment Used : CRT SS 9900, CRT SS3900 and frequency counter, Ranger 2950DX, Manor Kestrel, tti 881n, Sirio 4000 Sirio gainmaster, sirio and firestick dipole antennas, CRT space U, Sirio SU375-480 PL antenna, UV5R's x2,
I'll get a Sirio SO259 to 3/8th, and a 3/8th to 2.5mm whip, and also the PL259 to SMA female for into a Baofeng
I can test the waters on PMR with the UV5R then first before buying a CRT space U,
Simple and cheap to make ? It'll work out more expensive than buying a PMR antenna with magmount
Thanks for all the advice etc all. Much appreciated.
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Razz229 Major contributor
Call Sign : 26 CT 2290 & 26 CI 2290 Posts : 582 Times Thanked : 25 Join date : 2019-07-01 QTH or Location : Kent Equipment Used : On 11m a Anytone 6666, Solarcon A99 vertical antenna or a Sirio 4000. On PMR a TYT TH-9800, a 1/4 wave GPA, homemade mag mount & sometimes a 8 element beam. Age : 55
Subject: Re: CB antenna/ PMR antenna compatibility question. Sat Jun 11, 2022 1:54 pm
Get a Sirio SU375-480 PL antenna.
Cut it down for PMR, Sirio supply the instructions, then you can use the same mount.
I think this fulfils all of your requirements.
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Sharpshooter Major contributor
Call Sign : 163-CT-329 Posts : 391 Times Thanked : 12 Join date : 2022-04-05 QTH or Location : Flintshire Equipment Used : CRT SS 9900, CRT SS3900 and frequency counter, Ranger 2950DX, Manor Kestrel, tti 881n, Sirio 4000 Sirio gainmaster, sirio and firestick dipole antennas, CRT space U, Sirio SU375-480 PL antenna, UV5R's x2,
Subject: Re: CB antenna/ PMR antenna compatibility question. Sat Jun 11, 2022 9:14 pm
Razz229 wrote:
Get a Sirio SU375-480 PL antenna.
Cut it down for PMR, Sirio supply the instructions, then you can use the same mount.
I think this fulfils all of your requirements.
Thanks Razz. I was just trying to order this from Knights along with a PL to SMA adaptor . But I can't work out how to add a second hand swr/pwr meter so I'm going to ring them Monday to order everything. Cheers
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BigTone Contributor
Call Sign : G8YMW or 26CT4498 Posts : 92 Times Thanked : 17 Join date : 2019-07-16 QTH or Location : Lincoln and Finningley Equipment Used : CRT 9900, Icom 705, Kenwood TS570, Icom 910 Age : 68
Subject: Re: CB antenna/ PMR antenna compatibility question. Sun Jun 19, 2022 5:21 pm
For PMR the magmount will be perfect. You could use a 2m/70cms amateur radio aerial. Or roll your own. A PL259 and a a length of brazing rod. Solder the rod to the centre of the PL259, pack the gap between the rod and the body of the PL259 with epoxy. Trim the rod to best swr (about 6")
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Wireless Major contributor
Posts : 350 Times Thanked : 12 Join date : 2021-11-19 QTH or Location : Shrewsbury Equipment Used : kit
Subject: Re: CB antenna/ PMR antenna compatibility question. Mon Jun 20, 2022 10:15 am
Sharpshooter wrote:
Razz229 wrote:
Get a Sirio SU375-480 PL antenna.
Cut it down for PMR, Sirio supply the instructions, then you can use the same mount.
I think this fulfils all of your requirements.
Thanks Razz. I was just trying to order this from Knights along with a PL to SMA adaptor . But I can't work out how to add a second hand swr/pwr meter so I'm going to ring them Monday to order everything. Cheers
Just Get a Diamond MC-200 or MC-201 Kit, both come complete with a Cutting Chart that cover PMR446.
Today at 7:24 am by SangueG
Subject: CB antenna/ PMR antenna compatibility question. 
and used to replace a broken car aerial 
sitting in the front/back garden of the family where the children have out grown it.
